Comment on Pyrrolizidine Alkaloids and Terpenes from Senecio (Asteraceae): Chemistry and Research Gaps in Africa
Department of Botany and Plant Biotechnology, University of Johannesburg (Auckland Park Campus), P.O. Box 524, Auckland Park, Johannesburg 2006, South Africa
Molecules 2022, 27(24), 8868; https://doi.org/10.3390/molecules27248868
Submission received: 11 November 2022
/
Revised: 9 December 2022
/
Accepted: 12 December 2022
/
Published: 13 December 2022
(This article belongs to the Collection Bioactive Compounds)
Abstract
The genus Senecio is one of the largest in Asteraceae. There are thousands of species across the globe, either confirmed or awaiting taxonomic delimitation. While the species are best known for the toxic pyrrolizidine alkaloids that contaminate honeys (as bees select pollen from the species) and teas via lateral transfer and accumulation from adjacent roots of Senecio in the rhizosphere, they are also associated with more serious cases leading to fatality of grazing ruminants or people by contamination or accidental harvesting for medicine. Surprisingly, there are significantly more sesquiterpenoid than pyrrolizidine alkaloid-containing species. The main chemical classes, aside from alkaloids, are flavonoids, cacalols, eremophilanes, and bisabolols, often in the form of furan derivatives or free acids. The chemistry of the species across the globe generally overlaps with the 469 confirmed species of Africa. A small number of species express multiple classes of compounds, meaning the presence of sesquiterpenes does not exclude alkaloids. It is possible that there are many species that express the pyrrolizidine alkaloids, in addition to the cacalols, eremophilanes, and bisabolols. The aim of the current communication is, thus, to identify the research gaps related to the chemistry of African species of Senecio and reveal the possible chemical groups in unexplored taxa by way of example, thereby creating a summary of references that could be used to guide chemical assignment in future studies.
Keywords:
pyrrolizidine; alkaloid; cacalol; eremophilane; contamination; adulteration; toxin; poison1. Introduction
According to ‘Plants of the World Online’ (https://powo.science.kew.org/, accessed on 15 October 2022) (POWO), there are 1477 accepted species of Senecio in the world, with a further 3490 tentative species or synonyms, making it one of the largest genera in Asteraceae. According to POWO, 477 of the accepted species are native to Africa, but if the recognized synonyms are excluded [1,2,3], the total number of recognized African Senecio is reduced to 469, many of which are reported as a traditional medicine or a dangerous contaminant of foods and medicines [4,5,6].
It is the pyrrolizidine alkaloids in several species of Senecio that underly the poisonings occurring in ruminants [7] and people, leading to hepatomegaly (enlarged liver), ascites (abdominal fluid), and cirrhosis [4]. The toxicosis of people has been noted in cases of accidental contamination of a medicinal species [8], contamination of honey by bees [9], or by lateral transfer of toxic alkaloids in tea plantations [6], and water contamination [10,11,12].
In South Africa, Senecio angustifolius (Thunb.) Willd., contaminates Rooibos tea (Aspalathus linearis (Burm.f.) R.Dahlgren). Unfortunately, S. angustifolius has a similar growth habit and flower color as A. linearis, making it difficult to eliminate from Rooibos plantations. As the invading species grows among the Rooibos plants, it secretes pyrrolizidine alkaloids into the rhizosphere, where they are enter the root system of A. linearis and accumulate in the tea leaves [6].
Another example from South Africa is related to therapeutic use of Senecio coronatus (Thunb.) Harv. The roots of the species are used in traditional medicine. A suppository of the aqueous extract is given to infants as a means to confer strength to the child during weaning. Unfortunately, several infants have succumbed to hepatic sinusoidal obstruction syndrome, which is known to have been occurring since the 1980s [13], and possibly much longer. Due to superstition around the declaration of materials to forensics, it was not until 2017, following a new wave of deaths, that an examination of the biota could be made, revealing that the material associated with poisoning contained biota that was morphologically different, possibly representative of another species as a contaminant [8] or a toxic genotype currently incorrectly circumscribed as S. coronatus [14].
There are several species of Senecio that are associated with the toxication of honey. The presences of pyrrolizidine alkaloids in honeys has been reported in Europe [15], Brazil [9], China [16], North America [17], and via the South African species S. inaequidens DC [18], which is now naturalized in Italy (and Europe). The honey is toxified by the pollen from species of Senecio, harvested by bees, and carried back to the hive. The issue in Europe has prompted the European Food and Safety Authority to elaborate on the health risks associated with the consumption of honeys or plant products known to express or be contaminated by pyrrolizidine alkaloids [19]. The risks are also evident in Australia, since Echium plantagineum L., known by the vernacular ‘Patterson’s Curse’, expresses pyrrolizidine alkaloids that also find their way into honey. While the local honey, known as ‘Patterson’s Curse Honey’ is popular, it is contaminated with pyrrolizidine alkaloids [20].
Although the chemistry of Senecio is well-known to include pyrrolizidine alkaloids, and the genus is chemically varied. Surprisingly, there are many more terpenoid taxa than toxic species in Senecio. Furthermore, there are several chemical studies of species that were previously circumscribed as Senecio, but they are now revised to such genera as Caputia or Othonna [1] (among others). While the taxonomy has changed, the chemical similarities to species in Senecio are evident, which can be ascertained by reading the previous papers by Bohlmann [21,22]. In another example, the macrolide platyphylline and the pyrrolizidine alkaloid seneciphylline were first discovered after isolation from Senecio platyphyllus D.C. [1]. The etymology of the vernacular names given to these alkaloids is related to the botanical name of the species. However, S. platyphyllus was renamed to Caucasalia macrophylla (M.Bieb.) B.Nord. There are many examples of species revisions that complicate the interpretation of the etymology of the compound names.
The current communication is a summary of the chemistry and toxicity of African species of Senecio. This work is intended to serve as a reference in guiding the further chemical prospection of the species in southern Africa. The correct names of all taxa were determined using the POWO database to remain up to date with the taxonomic status of all species listed. A literature search was conducted on each species individually to ascertain if the chemical characterization was retrievable, to identify what is known, the chemotaxonomic implications thus far, and to reveal research gaps. The literature search was also extended to species synonyms whenever old or outdated names were realized in the course of compiling data.
2. Phytochemistry of African Senecio
A search of the 469 species of Senecio from Africa was conducted on Google Scholar [23] to ascertain if phytochemical studies exist, individually searching the genus and species against the words ‘chemistry’, ‘phytochemistry’, ‘sesquiterpene’, or ‘pyrrolizidine alkaloid’. The species (or subspecies) searched are listed in Table 1, and the tentative number of species associated with phytochemical studies amounted to 83 (Table 2).
The species with phytochemical records, listed in Table 1, have been elaborated upon in Table 2, with details related to the chemical classes identified.
The most common classes of compound identified and published from African Senecio include pyrrolizidine alkaloids, eremophilanes, biasabolols, cacalols, and flavonoids (Figure 1). Derivatives of these include furans, oxides, O-linked moieties, and mere stereoisomers. Other groups of compounds that are less frequently reported include phenylpropanes, essential oils, triterpenes, sterols, oxyeuryopsins, diterpenes, dimers of sesquiterpenes, fatty acid derivatives, and polyunsaturated alkynes and alkenes (Table 2).
The vast majority of the chemical work performed on the world’s species of Senecio was conducted in Germany by Bohlmann and collaborators [21,22,33,41,43,45,55,58,59,61,72,75,79,81,82,84,85,90,94,98]. This group covered a number of the African species, sometimes focused exclusively on those from South Africa (südafrikanischen) [21,22,90]. The majority of the work by Bolmann and his group characterized a significant number of new and existing sesquiterpenes, particularly the cacalols and their derivatives. The cacalols were named from the species Cacalia delphiniifolia Siebold and Zucc. [105], and although the species was revised to Japonicalia delphiniifolia (Siebold and Zucc.) C. Ren and Q.E. Yang, the cacalols are now widely characterized in the genus Senecio (Table 2).
The contents of Table 2 are not representative of exhaustive chemical studies of the respective species. For example, where essential oils have been tentatively characterized, the fixed components of the material have not been studied. Furthermore, in a minority of cases, multiple types of chemical classes are identified, sometimes within a single study. For example, S. vira vira was exhaustively studied, and flavonoids, sterols, triterpenes, and pyrrolizidine alkaloids were identified in that single biota. This underscores the possibility of other classes of metabolite in the other species in Table 2. When chemists study pyrrolizidine alkaloids, they focus on an ‘alkaloids’ extract produced via acid-base partitioning [106]. By following such an approach, non-basic metabolites are excluded from the extracts. Thus, the species listed in Table 2 may be more complex than is realized.
A chemotaxonomic review of Senecio divides the genus into sections, corresponding to the different types of sesquiterpenes, i.e., section bisabolene, sect. cacalol, sect. eremophilane, sect. furanoeremophilane, sect. eremophilanolide, and sect. germacrane [29]. The approach to recognize taxa, according to a specific group of metabolites (the sesquiterpenes), to the exclusion of other metabolites that may be present in the biota, reduces the complexity of the analysis. This approach may have been informed by the impractical division of alkaloids verses terpenes, due to the technical difficulty mentioned above. However, to know if the clustering tree of sesquiterpenes in Senecio is of true value, it may be necessary to test for agreement of a molecular phylogeny [107].
3. Conclusions
The genus Senecio is one of the largest in the family Asteraceae. Species in the genus are chemically varied, and previous scholars have attempted to understand this from a chemotaxonomic perspective. Several of the species have been associated with poisonings of both ruminants and humans, ranging from mild toxicosis to fatality. The pyrrolizidine alkaloids are the toxic principle of the poisonous species, and while there are many species that are not reported to contain this class of compound, studies do not always focus on this class, nor do they confirm that they searched for them in extracts or qualify that they are not present. Thus, the chemical information that has been gathered in this communication is not a robust guide to the exhaustive chemistry of the respective species, but rather a preliminary finding that can be elaborated upon with further study. Thus, it is of essence to re-examine the species that reportedly contain sesquiterpenes to know if pyrrolizidine alkaloids are absent generally, or if the co-occurrence of the two classes of compound is common.
Funding
This research received no external funding.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Acknowledgments
The author would like to acknowledge Ben-Erik van Wyk, who motivated this communication.
Conflicts of Interest
The author declares no conflict of interest.
Sample Availability
Samples of the compounds are not available from the author.
References
- Manning, J.C.; Goldblatt, P. New synonyms and a new name in Asteraceae: Senecioneae from the southern African winter rainfall region. Bothalia 2010, 40, 10. [Google Scholar] [CrossRef]
- Joel, C.; Carlos, A. A Taxonomic Revision of the Eurasian/Northwestern African Senecio doria Group (Compositae). Syst. Bot. 2015, 40, 900–913. [Google Scholar] [CrossRef]
- Beentje, H. Three new species and some nomenclatural changes in Senecio (Compositae/Asteraceae: Senecioneae) in the Flora Zambesiaca area. Kew Bull. 2019, 74, 67. [Google Scholar] [CrossRef]
- Steenkamp, V.; Stewart, M.J.; Zuckerman, M. Clinical and Analytical Aspects of Pyrrolizidine Poisoning Caused by South African Traditional Medicines. Ther. Drug Monit. 2000, 22, 302–306. [Google Scholar] [CrossRef] [PubMed]
- Wiedenfeld, H.; Edgar, J. Toxicity of pyrrolizidine alkaloids to humans and ruminants. Phytochem. Rev. 2011, 10, 137–151. [Google Scholar] [CrossRef]
- Van Wyk, B.E.; Stander, M.A.; Long, H.S. Senecio angustifolius as the major source of pyrrolizidine alkaloid contamination of rooibos tea (Aspalathus linearis). S. Afr. J. Bot. 2017, 110, 124–131. [Google Scholar] [CrossRef]
- Cortinovis, C.; Caloni, F. Alkaloid-Containing Plants Poisonous to Cattle and Horses in Europe. Toxins 2015, 7, 5301–5307. [Google Scholar] [CrossRef]
- Van Schalkwyk, F.J.; Stander, M.A.; Nsizwane, M.; Mathee, A.; Van Wyk, B.E. Fatal pyrrolizidine alkaloid poisoning of infants caused by adulterated Senecio coronatus. Forensic Sci. Int. 2021, 320, 110680. [Google Scholar] [CrossRef]
- Valese, A.C.; Daguer, H.; Muller, C.M.O.; Molognoni, L.; da Luz, C.F.P.; de Barcellos Falkenberg, D.; Gonzaga, L.V.; Brugnerotto, P.; Gorniak, S.L.; Barreto, F.; et al. Quantification of pyrrolizidine alkaloids in Senecio brasiliensis, beehive pollen, and honey by LC-MS/MS. J. Environ. Sci. Health Part B 2021, 56, 685–694. [Google Scholar] [CrossRef]
- Kisielius, V.; Hama, J.R.; Skrbic, N.; Hansen, H.C.B.; Strobel, B.W.; Rasmussen, L.H. The invasive butterbur contaminates stream and seepage water in groundwater wells with toxic pyrrolizidine alkaloids. Sci. Rep. 2020, 10, 19784. [Google Scholar] [CrossRef]
- Hama, J.R.; Strobel, B.W. Occurrence of pyrrolizidine alkaloids in ragwort plants, soils and surface waters at the field scale in grassland. Sci. Total Environ. 2021, 755, 142822. [Google Scholar] [CrossRef]
- Günthardt, B.F.; Wettstein, F.E.; Hollender, J.; Singer, H.; Härri, J.; Scheringer, M.; Hungerbühler, K.; Bucheli, T.D. Retrospective HRMS Screening and Dedicated Target Analysis Reveal a Wide Exposure to Pyrrolizidine Alkaloids in Small Streams. Environ. Sci. Technol. 2021, 55, 1036–1044. [Google Scholar] [CrossRef]
- Savage, A.; Hutchings, A. Poisoned by herbs. Br. Med. J. 1987, 295, 1650–1651. [Google Scholar] [CrossRef][Green Version]
- Sadgrove, N.J. Honest nutraceuticals, cosmetics, therapies, and foods (NCTFs): Standardization and safety of natural products. Crit. Rev. Food Sci. Nutr. 2021, 62, 4326–4341. [Google Scholar] [CrossRef]
- Helge, N. Tansy ragwort (Senecio jacobaea): A source of pyrrolizidine alkaloids in summer honey? J. Verbrauch. Lebensm. 2016, 11, 105–115. [Google Scholar] [CrossRef]
- Zhu, L.; Wang, Z.; Wong, L.; He, Y.; Zhao, Z.; Ye, Y.; Fu, P.P.; Lin, G. Contamination of hepatotoxic pyrrolizidine alkaloids in retail honey in China. Food Control 2018, 85, 484–494. [Google Scholar] [CrossRef]
- Deinzer, M.L.; Thomson, P.A.; Burgett, D.M.; Isaacson, D.L. Pyrrolizidine Alkaloids: Their Occurrence in Honey from Tansy Ragwort (Senecio jacobaea L.). Science 1977, 195, 497–499. [Google Scholar] [CrossRef]
- Bassignana, M.; Mainetti, A.; Madormo, F. Invasion of Senecio inaequidens and risks for honey and bee pollen in Aosta Valley. In Proceedings of the SER Europe Conference 2018: Restoration in the Era of Climate Change, Reykjavik, Iceland, 9–13 September 2018; p. 113. [Google Scholar]
- EFSA Panel on Contaminants in the Food Chain; Knutsen, H.K.; Alexander, J.; Barregård, L.; Bignami, M.; Brüschweiler, B.; Ceccatelli, S.; Cottrill, B.; Dinovi, M.; Edler, L.; et al. Risks for human health related to the presence of pyrrolizidine alkaloids in honey, tea, herbal infusions and food supplements. EFSA J. 2017, 15, e04908. [Google Scholar] [CrossRef]
- Culvenor, C.C.J.; Edgar, J.A.; Smith, L.W. Pyrrolizidine alkaloids in honey from Echium plantagineum L. J. Agric. Food Chem. 1981, 29, 958–960. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. Neue eremophilene aus südafrikanischen Senecio-arten. Phytochemistry 1978, 17, 1337–1341. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C.; Bergert, D.; Suwita, A.; Mahanta, P.; Jeffrey, C. Neue furanoeremophilane und weitere inhaltsstoffe aus südafrikanischen Senecio-arten. Phytochemistry 1979, 18, 79–93. [Google Scholar] [CrossRef]
- Gusenbauer, M.; Haddaway, N.R. Which academic search systems are suitable for systematic reviews or meta-analyses? Evaluating retrieval qualities of Google Scholar, PubMed, and 26 other resources. Res. Synth. Methods 2020, 11, 181–217. [Google Scholar] [CrossRef] [PubMed]
- De Waal, H.; Tiedt, J. The Senecio alkaloids. Part IV. Platyphilline, the active principle of Senecio adnatus, DC. Onderstepoort J. Vet. Sci. Anim. Ind. 1940, 15, 251–259. [Google Scholar]
- Habib, A.-A.M. Alkaloids from Senecio aegyptius and S. desfontainei. Planta Med. 1981, 43, 290–292. [Google Scholar] [CrossRef] [PubMed]
- El-Shazly; DoraI, G.; Wink, M. Chemical Composition and Biological Activity of the Essential Oils of Senecio aegyptius var. discoideus Boiss. Z. Nat. C 2002, 57, 434–439. [Google Scholar] [CrossRef]
- Hassan, W.; Gendy, A.; Al-youssef, H.; El-Shazely, A. Chemical Constituents and Biological Activities of Senecio aegyptius var. discoideus Boiss. Z. Nat. C 2012, 67, 144–150. [Google Scholar] [CrossRef]
- Mohamed, A.E.-H.H.; Ahmed. Eremophilane-Type Sesquiterpene Derivatives from Senecio aegyptius var. discoideus. J. Nat. Prod. 2005, 68, 439–442. [Google Scholar] [CrossRef]
- Zhao, G.; Cao, Z.; Zhang, W.; Zhao, H. The sesquiterpenoids and their chemotaxonomic implications in Senecio L. (Asteraceae). Biochem. Syst. Ecol. 2015, 59, 340–347. [Google Scholar] [CrossRef]
- Porter, L.A.; Geissman, T.A. Angularine, a New Pyrrolizidine Alkaloid from Senecio angulatus L. J. Org. Chem. 1962, 27, 4132–4134. [Google Scholar] [CrossRef]
- Bousetla, A.; Keskinkaya, H.B.; Bensouici, C.; Lefahal, M.; Atalar, M.N.; Akkal, S. LC-ESI/MS-phytochemical profiling with antioxidant and antiacetylcholinesterase activities of Algerian Senecio angulatus L.f. extracts. Nat. Prod. Res. 2021, 1–7. [Google Scholar] [CrossRef]
- Andreani, S.; Desjobert, J.; Paolini, J.; Costa, J.; Muselli, A. Chemical composition and chemical variability of Senecio angulatus essential oils from Corsica. Dim 2013, 1, 57–92. [Google Scholar]
- Zdero, C.; Bohlmann, F.; Liddell, J.R. Seco-eremophilanes and other constituents from South African Senecio species. Phytochemistry 1989, 28, 3532–3534. [Google Scholar] [CrossRef]
- Mattocks, A.R.; Jukes, R. Improved Field Tests for Toxic Pyrrolizidine Alkaloids. J. Nat. Prod. 1987, 50, 161–166. [Google Scholar] [CrossRef]
- Domínguez, D.M.; Reina, M.; Santos-Guerra, A.; Santana, O.; Agulló, T.; López-Balboa, C.; Gonzalez-Coloma, A. Pyrrolizidine alkaloids from Canarian endemic plants and their biological effects. Biochem. Syst. Ecol. 2008, 36, 153–166. [Google Scholar] [CrossRef]
- Richardson, M.F.; Warren, F.L. 121. The Senecio akaloids. Part I. Rosmarinine. J. Chem. Soc. Resumed 1943, 452–454. [Google Scholar] [CrossRef]
- Sapiro, M. The alkaloids of Senecio bupleuroides DC. Onderstepoort J. Vet. Sci. Anim. Ind. 1949, 22, 291–295. [Google Scholar]
- Ndom, J.C.; Mbafor, J.T.; Azebaze, A.G.B.; Vardamides, J.C.; Kakam, Z.; Kamdem, A.F.W.; Deville, A.; Ngando, T.M.; Fomum, Z.T. Secondary metabolites from Senecio burtonii (Compositae). Phytochemistry 2006, 67, 838–842. [Google Scholar] [CrossRef]
- Grue, M.R.; Liddell, J.R. Pyrrolizidine alkaloids from Senecio chrysocoma. Phytochemistry 1993, 33, 1517–1519. [Google Scholar] [CrossRef][Green Version]
- Liddell, J.R.; Logie, C.G. 7-Angelyl-1-methylenepyrrolizidines from Senecio chrysocoma. Phytochemistry 1993, 34, 1198–1199. [Google Scholar] [CrossRef]
- Bohlmann, F.; Ates, N.; King, R.M.; Robinson, H. Two sesquiterpenes from Senecio species. Phytochemistry 1983, 22, 1675–1677. [Google Scholar] [CrossRef]
- Dimande, A.F.P.; Botha, C.J.; Prozesky, L.; Bekker, L.; Rosemann, G.M.; Labuschagne, L.; Retief, E. The toxicity of Senecio inaequidens DC. J. S. Afr. Vet. Assoc. 2007, 78, 121–129. [Google Scholar] [CrossRef] [PubMed]
- Bohlmann, F.; Ziesche, J. Sesquiterpenes from three Senecio species. Phytochemistry 1981, 20, 469–472. [Google Scholar] [CrossRef]
- Zhan, Z.-J.; Ying, Y.-M.; Ma, L.-F.; Shan, W.-G. Natural disesquiterpenoids. Nat. Prod. Rep. 2011, 28, 594–629. [Google Scholar] [CrossRef]
- Bohlmann, F.; Abraham, W.-R. Neue sesquiterpene und acetylenverbindungen aus Cineraria-arten. Phytochemistry 1978, 17, 1629–1635. [Google Scholar] [CrossRef]
- de Wet, H.; Ngubane, S.C. Traditional herbal remedies used by women in a rural community in northern Maputaland (South Africa) for the treatment of gynaecology and obstetric complaints. S. Afr. J. Bot. 2014, 94, 129–139. [Google Scholar] [CrossRef]
- Torres, P.; Ayala, J.; Grande, C.; Anaya, J.; Grande, M. Furanoeremophilane derivatives from Senecio flavus. Phytochemistry 1999, 52, 1507–1513. [Google Scholar] [CrossRef]
- Urones, J.G.; Barcala, P.B.; Marcos, I.S.; Moro, R.F.; Esteban, M.L.; Rodriguez, A.F. Pyrrolizidine alkaloids from Senecio gallicus and S. adonidifolius. Phytochemistry 1988, 27, 1507–1510. [Google Scholar] [CrossRef]
- Mohammadhosseini, M.; Pazoki, A.; Zamani, H.A.; Akhlaghi, H.; Nekoei, M. Chemical Composition of the Essential Oil from Aerial Parts of Senicio gallicus Chaix Growing Wild in Iran. J. Essent. Oil Bear. Plants 2010, 13, 704–709. [Google Scholar] [CrossRef]
- Elsharkawy, E.R. GC-MS analysis of chemical composition, cytotoxicity and antioxidant activities of essential oils of Senecio glaucus under drastic conditions. Main Group Chem. 2022, 21, 233–241. [Google Scholar] [CrossRef]
- Ramadan, T.; Zaher, A.; Amro, A.; Sultan, R. Chemical Composition and Biological Activity of Capetula and Shoots Essential Oils of Senecio glaucus L. J. Essent. Oil Bear. Plants 2020, 23, 168–183. [Google Scholar] [CrossRef]
- Alqahtani, A.S.; Herqash, R.N.; Noman, O.M.; Nasr, F.A.; Alyhya, N.; Anazi, S.H.; Farooq, M.; Ullah, R. In Vitro Antioxidant, Cytotoxic Activities, and Phenolic Profile of Senecio glaucus from Saudi Arabia. Evid.-Based Complement. Altern. Med. 2020, 2020, 8875430. [Google Scholar] [CrossRef] [PubMed]
- Zaher, A.M.; Sultan, R.; Ramadan, T.; Amro, A. New antimicrobial and cytotoxic benzofuran glucoside from Senecio glaucus L. Nat. Prod. Res. 2022, 36, 136–141. [Google Scholar] [CrossRef] [PubMed]
- Randriamampionona, H.R.; Rasolohery, C.A.; Rasamison, V.E.; Bodo, B.; Rafanomezantsoa, R.M.; Rakotovao, M. Flavonoid and triterpenes from the leaves of Senecio gossypinus Baker from Madagascar. J. Pharmacogn. Phytochem. 2020, 9, 1279–1282. [Google Scholar]
- Bohlmann, F.; Suwita, A.; Mahanta, P. Natürlich vorkommende Terpen-Derivate, 73 Weitere Inhaltsstoffe aus Senecio-Arten. Chem. Ber. 1976, 109, 3570–3573. [Google Scholar] [CrossRef]
- Were, O.; Benn, M.; Munavu, R.M. Pyrrolizidine Alkaloids from Senecio hadiensis. J. Nat. Prod. 1991, 54, 491–499. [Google Scholar] [CrossRef]
- Ahmed, S.; Ahmad, M.S.; Yousaf, M.; Nur-e-Alam, M.; Al-Rehaily, A.J. Two New Sesquiterpene Alcohols Isolated from Senecio hadiensis Forssk. Grown in Saudi Arabia. Chem. Biodivers. 2017, 14, e1700144. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. New furanoeremophilanes from South African Senecio species. Phytochemistry 1978, 17, 1161–1164. [Google Scholar] [CrossRef]
- Bohlmann, F.; Jakupovic, J.; Mohammadi, D. Shikimic Acid Derivative from Senecio hieracioides. J. Nat. Prod. 1984, 47, 718–720. [Google Scholar] [CrossRef]
- Arab, Y.; Sahin, B.; Ceylan, O.; Zellagui, A.; Olmez, O.T.; Kucukaydin, S.; Tamfu, A.N.; Ozturk, M.; Gherraf, N. Assessment of in vitro activities and chemical profiling of Senecio hoggariensis growing in Algerian Sahara. Biodiversitas J. Biol. Divers. 2022, 23, 3498–3506. [Google Scholar] [CrossRef]
- Bohlmann, F.; Ehlers, D.; Zdero, C. Einige neue furanoeremophilane aus Senecio-Arten. Phytochemistry 1978, 17, 467–470. [Google Scholar] [CrossRef]
- De Waal, H. Senecio alkaloids. Part III. Chemical investigations upon the Senecio species responsible for “bread-poisoning”. The isolation of senecionine from Senecio ilicifolius Thunb. and a new alkaloid” rosmarinine” from Senecio rosmarinifolius Linn. Onderstepoort J. Vet. Sci. Anim. Ind. 1940, 15, 241–249. [Google Scholar]
- Bicchi, C.; D’Amato, A.; Cappelletti, E. Determination of pyrrolizidine alkaloids in Senecio inaequidens D.C. by capillary gas chromatography. J. Chromatogr. A 1985, 349, 23–29. [Google Scholar] [CrossRef]
- Wiedenfeld, H.; Roeder, E.; Luck, W. O7-Angeloylretronecine, a Pyrrolizidine Alkaloid from Senecio inornatus. Planta Med. 1996, 62, 483. [Google Scholar] [CrossRef]
- Boland, W.; Jaenicke, L. Vinyl-Olefines and Sesquiterpenes in the Root-Oil of Senecio isatideus. Z. Für Nat. C 1982, 37, 5–9. [Google Scholar] [CrossRef]
- Bredenkamp, M.W. The Isolation, Structure and Chemistry of the Major Pyrrolizidine Alkaloids of Senecio Latifolius DC; University of Pretoria: Pretoria, South Africa, 1988. [Google Scholar]
- Roeder, E.; Bourauel, T. Pyrrolizidine alkaloids from Senecio leucanthemifolius and Senecio rodriguezii. Nat. Toxins 1993, 1, 241–245. [Google Scholar] [CrossRef]
- Idrissi, F.E.J.; Ouchbani, T.; Ouchbani, S.; Hourch, A.E.; Maltouf, A.F.; Essassi, E.M. Comparative Chemical Composition and Antimicrobial Activity of Essential Oil and Organic Extracts of Senecio leucanthemifolius Poiret. J. Essent. Oil Bear. Plants 2015, 18, 29–35. [Google Scholar] [CrossRef]
- Torres, P.; Mancheño, B.; Chinchilla, R.; Asensi, M.C.; Grande, M. New Furanoeremophilanes, Cacalohastin Derivatives, from Senecio linifolius. Planta Med. 1988, 54, 257–258. [Google Scholar] [CrossRef]
- Andreani, S.; Paolini, J.; Desjobert, J.M.; Costa, J.; Muselli, A. Study of chemical variablity of Corsican Senecio lividus essential oils. In Proceedings of the 7ème Colloque International sur les Plantes Aromatiques et Médicinales; CIPAM-APLAMEDON 2012, Saint-Denis de La Reunion, France, 6 November 2012. [Google Scholar]
- Herimanana, R.; Nomentsoa, R.Z.; Judicael, R.L.; Ranjana, R.H.; Doll, R.D.A.; Louis, J.V. Chemical composition, antimicrobial and antioxidant activities of the essential oils from Senecio longiscapus Bojer leaves (Asteraceae). World J. Biol. Pharm. Health Sci. 2021, 7, 009–018. [Google Scholar] [CrossRef]
- Bohlmann, F.; Bapuji, M. Cacalol derivatives from Senecio lydenburgensis. Phytochemistry 1982, 21, 681–683. [Google Scholar] [CrossRef]
- Ndiritu, P.N. Phytochemical and Biological Studies of the Compounds of Aerial Parts of Senecio Lyratus (Asteraceae); Jomo Kenyatta University of Agriculture and Technology: Nairobi, Kenya, 2014. [Google Scholar]
- Grue, M.R. A Study of the Alkaloid Content of the Senecio Speciosus/Macrocephalus Complex; Rhodes University: Grahamstown, South Africa, 1991. [Google Scholar]
- Bohlmann, F.; Zdero, C. Natürlich vorkommende Terpen-Derivate, 144: Über ein dimeres Furanoeremophilan und neue Cacalohastin-Derivate aus Senecio crispus Thumb. und Senecio macrospermus DC. Chem. Ber. 1978, 111, 3140–3145. [Google Scholar] [CrossRef]
- Gardner, D.R.; Thorne, M.S.; Molyneux, R.J.; Pfister, J.A.; Seawright, A.A. Pyrrolizidine alkaloids in Senecio madagascariensis from Australia and Hawaii and assessment of possible livestock poisoning. Biochem. Syst. Ecol. 2006, 34, 736–744. [Google Scholar] [CrossRef]
- Yang, Y.; Zhao, L.; Wang, Y.-F.; Chang, M.-L.; Huo, C.-H.; Gu, Y.-C.; Shi, Q.-W.; Kiyota, H. Chemical and Pharmacological Research on Plants from the Genus Senecio. Chem. Biodivers. 2011, 8, 13–72. [Google Scholar] [CrossRef] [PubMed]
- Ndjoko, K.; Wolfender, J.-L.; Röder, E.; Hostettmann, K. Determination of Pyrrolizidine Alkaloids in Senecio Species by Liquid Chromatography/Thermospray-Mass Spectrometry and Liquid Chromatography/Nuclear Magnetic Resonance Spectroscopy. Planta Med. 1999, 65, 562–566. [Google Scholar] [CrossRef] [PubMed]
- Bohlmann, F.; Knoll, K.-H.; Zdero, C.; Mahanta, P.K.; Grenz, M.; Suwita, A.; Ehlers, D.; Le Van, N.; Abraham, W.-R.; Natu, A.A. Terpen-derivate aus Senecio-arten. Phytochemistry 1977, 16, 965–985. [Google Scholar] [CrossRef]
- Kebbi, S.; Noman, L.; Demirtas, I.; Bensouici, C.; Adem, S.; Benayache, S.; Benayache, F.; Seghiri, R.; Gok, M. In vitro Antioxidant and Anticholinesterase Activities of Senecio massaicus Essential Oil and Its Molecular Docking Studies as a Potential Inhibitor of Covid-19 and Alzheimer’s Diseases. J. Biol. Act. Prod. Nat. 2021, 11, 380–394. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. Hilliardinolester und andere furanoeremophilane aus Senecio mauricei. Phytochemistry 1978, 17, 1333–1335. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. New sesquiterpenes from Senecio oxyodontus. Phytochemistry 1978, 17, 1591–1593. [Google Scholar] [CrossRef]
- Paquette, L.A.; Galemmo, R.A., Jr.; Springer, J.P. Synthesis of the alleged structure of senoxydene, the triquinane sesquiterpene derived from Senecio oxyodontus. J. Am. Chem. Soc. 1983, 105, 6975–6976. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. Über einen neuen sesquiterpentyp aus Senecio oxyriifolius. Phytochemistry 1978, 17, 1669–1671. [Google Scholar] [CrossRef]
- Bohlmann, F.; Jakupovic, J.; Zdero, C. Neue norsesquiterpene aus Rudbeckia laciniata und Senecio paludaffinis. Phytochemistry 1978, 17, 2034–2036. [Google Scholar] [CrossRef]
- Logie, C.G. The Pyrrolizidine Alkaloids of Senecio chrysocoma and Senecio paniculatus. Ph.D. Thesis, Rhodes University, Grahamstown, South Africa, 1995. [Google Scholar]
- Pretorius, T. The alkaloids of Senecio paucicalyculatus Platt. Onderstepoort J. Vet. Sci. Anim. Ind. 1949, 22, 297–300. [Google Scholar]
- Oladipupo, L.A.; Adebola, O.O. Chemical Composition of the Essential Oils of the Flowers, Leaves and Stems of Two Senecio polyanthemoides Sch. Bip. Samples from South Africa. Molecules 2009, 14, 2077–2086. [Google Scholar] [CrossRef]
- Castells, E.; Mulder, P.P.J.; Pérez-Trujillo, M. Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity. Phytochemistry 2014, 108, 137–146. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C.; Natu, A.A. Weitere bisabolen-derivate und andere inhaltsstoffe aus südafrikanischen Senecio-arten. Phytochemistry 1978, 17, 1757–1761. [Google Scholar] [CrossRef]
- De Waal, H.L. South African Senecio Alkaloids. Nature 1940, 146, 777–778. [Google Scholar] [CrossRef]
- Kerubo, L.O.; Midiwo, J.O.; Derese, S.; Langat, M.K.; Akala, H.M.; Waters, N.C.; Peter, M.; Heydenreich, M. Antiplasmodial Activity of Compounds from the Surface Exudates of Senecio roseiflorus. Nat. Prod. Commun. 2013, 8, 1934578X1300800210. [Google Scholar] [CrossRef]
- Benn, M.; Were, O. Ruwenine and ruzorine: Pyrrolizidine alkaloids of Senecio ruwenzoriensis. Phytochemistry 1992, 31, 3295–3296. [Google Scholar] [CrossRef]
- Bohlmann, F.; Ziesche, J. Neue germacren-derivate aus Senecio-arten. Phytochemistry 1979, 18, 1489–1493. [Google Scholar] [CrossRef]
- Benn, M.H.; Mathenge, S.; Munavu, R.M.; Were, S.O. The principal alkaloid of Senecio schweinfurthii. Phytochemistry 1995, 40, 1327–1329. [Google Scholar] [CrossRef]
- Tata, C.M.; Ndinteh, D.; Nkeh-Chungag, B.N.; Oyedeji, O.O.; Sewani-Rusike, C.R. Fractionation and bioassay-guided isolation of antihypertensive components of Senecio serratuloides. Cogent Med. 2020, 7, 1716447. [Google Scholar] [CrossRef]
- Chalchat, J.-C.; Maksimovic, Z.A.; Petrovic, S.D.; Gorunovic, M.S. Essential Oil of Senecio squalidus L., Asteraceae. J. Essent. Oil Res. 2004, 16, 227–228. [Google Scholar] [CrossRef]
- Bohlmann, F.; Zdero, C. Sandaracopimarene derivatives from Senecio subrubriflorus. Phytochemistry 1982, 21, 1697–1700. [Google Scholar] [CrossRef]
- Were, O.; Benn, M.; Munavu, R.M. The pyrrolizidine alkaloids of Senecio syringifolius and S. hadiensis from Kenya. Phytochemistry 1993, 32, 1595–1602. [Google Scholar] [CrossRef]
- Glennie, C.W.; Harborne, J.B.; Rowley, G.D.; Marchant, C.J. Correlations between flavonoid chemistry and plant geography in the Senecio radicans complex. Phytochemistry 1971, 10, 2413–2417. [Google Scholar] [CrossRef]
- Villarroel, L.; Torres, R.; Gavin, J.; Reina, M.; de la Fuente, G. 9-Oxo-10αH-furanoeremophilanes from Senecio chilensis and Senecio patagonicus. J. Nat. Prod. 1991, 54, 588–590. [Google Scholar] [CrossRef]
- Jares, E.; Pomilio, A.B. Pyrrolizidine Alkaloids and Other Components of Senecio vira-vira. J. Nat. Prod. 1987, 50, 514. [Google Scholar] [CrossRef]
- Cheng, D.; Nguyen, V.-T.; Ndihokubwayo, N.; Ge, J.; Mulder, P.P.J. Pyrrolizidine alkaloid variation in Senecio vulgaris populations from native and invasive ranges. PeerJ 2017, 5, e3686. [Google Scholar] [CrossRef]
- Andreani, S.; Paolini, J.; Costa, J.; Muselli, A. Essential-Oil Composition and Chemical Variability of Senecio vulgaris L. from Corsica. Chem. Biodivers. 2015, 12, 752–766. [Google Scholar] [CrossRef]
- Liu, W.; Furuta, E.; Shindo, K.; Watabe, M.; Xing, F.; Pandey, P.R.; Okuda, H.; Pai, S.K.; Murphy, L.L.; Cao, D.; et al. Cacalol, a natural sesquiterpene, induces apoptosis in breast cancer cells by modulating Akt-SREBP-FAS signaling pathway. Breast Cancer Res. Treat. 2011, 128, 57–68. [Google Scholar] [CrossRef]
- Heinrich, M.; Barnes, J.; Gibbons, S.; Williamson, E.M. Fundamentals of Pharmacognosy and Phytotherapy; Churchill Livingstone (Elsevier): Budapest, Hungary, 2004. [Google Scholar]
- Rønsted, N.; Symonds, M.R.E.; Birkholm, T.; Christensen, S.B.; Meerow, A.W.; Molander, M.; Mølgaard, P.; Petersen, G.; Rasmussen, N.; van Staden, J.; et al. Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of amaryllidaceae. BMC Evol. Biol. 2012, 12, 182. [Google Scholar] [CrossRef]
Figure 1.
Common classes of compound in African species of Senecio.
Table 1.
A list of all of the currently accepted species of Senecio that are native to Africa, according to POWO (477 species, 469 after synonyms are subtracted), conveying those with phytochemical information and those with no records listed here, as they were not identified in the literature search. Y = phytochemical study found, N = no phytochemical study found.
Table 1.
A list of all of the currently accepted species of Senecio that are native to Africa, according to POWO (477 species, 469 after synonyms are subtracted), conveying those with phytochemical information and those with no records listed here, as they were not identified in the literature search. Y = phytochemical study found, N = no phytochemical study found.
| Species and Author | Y/N | Species and Author | Y/N | Species and Author | Y/N |
|---|---|---|---|---|---|
| S. abbreviatus S.Moore | N | S. glutinosus Thunb. | Y | S. paniculatus P.J. Bergius | Y |
| S. abruptus Thunb. | N | S. gossweileri Torre | N | S. parascitus Hilliard | N |
| S. acetosifolius Baker | N | S. gossypinus Baker | Y | S. parentalis Hilliard and B.L. Burtt | N |
| S. achilleifolius DC. | N | S. gramineticola C. Jeffrey | N | S. parvifolius DC. (Synonym of S. carroensis) | N |
| S. actinoleucus F.Muell. | N | S. gramineus Harv. | N | S. paucicalyculatus Klatt | Y |
| S. acutifolius DC. | N | S. grandiflorus P.J. Bergius | Y | S. pauciflorus Baker | N |
| S. adenostylifolius Humbert | N | S. gregatus Hilliard | N | S. pauciflosculosus C. Jeffrey | N |
| S. adnatus DC. | Y | S. hadiensis Forssk. | Y | S. pearsonii Hutch. (Synonym of S. asperulus) | N |
| S. adscendens (syn. andinus) Bojer | N | S. halimifolius L. | Y | S. pellucidus DC. | N |
| S. aegyptius L. | Y | S. harveyanus MacOwan | N | S. peltophorus Brenan | N |
| S. aequinoctialis R.E.Fr. | N | S. hastatus L. (Synonym of S. erosus and S. robertiifolius) | N | S. penninervius DC. | N |
| S. aetfatensis B.Nord. | N | S. hastifolius (L.f.) Less. | N | S. pentactinus Klatt | N |
| S. affinis DC. | Y | S. haygarthii M.Taylor ex Hilliard | N | S. pentecostus Hiern | N |
| S. agapetes C.Jeffrey | N | S. hebdingii (Rauh and Buchloh) G.D. Rowley | N | S. perralderianus Coss. | N |
| S. albanensis DC. | N | S. hedbergii C. Jeffrey | N | S. perrieri Humbert | N |
| S. albanopsis Hilliard | N | S. hederiformis Cron | N | S. perrottetii DC. | N |
| S. albifolius DC. | N | S. heliopsis Hilliard and B.L. Burtt | Y | S. persicifolius L. | N |
| S. albopunctatus Bolus | N | S. helminthioides (Sch.Bip.) Hilliard | Y | S. petiolaris DC. | N |
| S. aloides DC. | N | S. hermannii B. Nord. | N | S. petraeus Boiss. and Reut. | N |
| S. altissimus Mill. | N | S. hesperidum Jahand, Maire, and Weiller | N | S. phalacrolaenus DC. | N |
| S. ambositrensis Humbert | N | S. hieracioides DC. | Y | S. pillansii Levyns | N |
| S. amplificatus C.Jeffrey | N | S. hildebrandtii Baker | N | S. pinifolius (L.) Spreng. | N |
| S. anapetes C.Jeffrey | N | S. hirsutilobus Hilliard | N | S. pinnatifidus Less. | N |
| S. andapensis Humbert | N | S. hirtifolius DC | N | S. pinnatipartitus Sch.Bip. ex Oliv. | N |
| S. andohahelensis Humbert | N | S. hirto-crassus Humbert | N | S. pinnulatus Thunb. | N |
| S. angulatus L.f. | Y | S. hochstetteri Sch.Bip. Ex A.Rich. | N | S. piptocoma O.Hoffm. | N |
| S. angustifolius (Thunb.) Willd. | Y | S. hoggariensis Batt. and Trab. | Y | S. pirottae Chiov. | N |
| S. anomalochrous Hilliard | N | S. hollandii Compton | N | S. plantagineoides C. Jeffrey | N |
| S. antaisaka Humbert | N | S. holubii Hutch. and Burtt Davy | N | S. pleistophyllus C. Jeffrey | N |
| S. antambolorum Humbert | N | S. humidanus C. Jeffrey | N | S. poggeanus Mattf. | N |
| S. antandroi Scott Elliot | N | S. hypochoerideus DC. | Y | S. polelensis Hilliard | N |
| S. anthemifolius Harv. | N | S. ilicifolius Thunb. | Y | S. polyadenus Hedberg | N |
| S. antitensis Baker | N | S. ilsae A.Santos and ReY-Bet | N | S. polyanthemoides Sch.Bip. | Y |
| S. aquifoliaceus DC. | N | S. immixtus C. Jeffrey | N | S. polyodon DC. | N |
| S. arabidifolius O.Hoffm | N | S. inaequidens DC. | Y | S. poseideonis Hilliard and B.L. Burtt | N |
| S. arenarius Thunb. | N | S. incomptus DC. | N | S. praeteritus Killick | N |
| S. arniciflorus DC | N | S. incrassatus Lowe | N | S. propior S. Moore | N |
| S. asperulus DC | Y | S. infirmus C. Jeffrey | N | S. prostratus Klatt | N |
| S. auriculatissimus Britton | N | S. ingeliensis Hilliard | N | S. pseudolongifolius Sch.Bip ex J. Calvo | N |
| S. austromontanus Hilliard | N | S. inornatus DC. | Y | S. pseudosubsessilis C. Jeffrey | N |
| S. balensis S.Oritz and Vivero | N | S. intricatus S.Moore | N | S. ptarmicifolius Bory | N |
| S. bampsianus Lisowski | N | S. isatideus DC. | Y | S. pterophorus DC. | Y |
| S. barbatus DC. | N | S. isatidoides E. Phillips and C.A.Sm. | N | S. puberulus DC. | N |
| S. baronii Humbert | N | S. jacksonii S. Moore | N | S. pubigerus L. | Y |
| S. barorum Humbert | N | S. junceus (Less.) Harv. | N | S. purpureus L. | Y |
| S. basalticus Hilliard | N | S. juniperinus L.f. | N | S. purtschelleri Engl. | N |
| S. baurii Oliv. | N | S. junodii Hutch. and Burtt Davy | N | S. qathlambanus Hilliard | N |
| S. belbeysius Delile | N | S. kacondensis S. Moore | N | S. quartziticola Humbert | N |
| S. bellis Harv. | N | S. kalambatitrensis Humbert | N | S. quinquelobus (Thunb.) DC. | N |
| S. bipinnatus Less. | N | S. kalingenwae Hilliard and B.L. Burtt | N | S. quinquenervius Sond. | N |
| S. Bollei Sunding and C.Kunkel | Y | S. karaguensis O. Hoffm. | N | S. ragazzii Chiov. | N |
| S. boutonii Baker | N | S. katangensis O. Hoffm. | N | S. randii S.Moore | N |
| S. brachyantherus (Hiern) S.Moore | N | S. kayomborum Beentje | N | S. rehmannii Bolus | N |
| S. brachypodus DC | Y | S. keniophytum R.E.Fr. | N | S. repandus Thunb. | N |
| S. brevidentatus M.D. Hend | N | S. kerdousianus Gomiz and Llamas | N | S. reptans Turcz. | N |
| S. brevilorus Hilliard | N | S. kuluensis S.Moore | N | S. resectus Bojer ex DC. | N |
| S. brittenianus Hiern | N | S. kundelungensis Lisowski | N | S. retortus Benth. | N |
| S. bryoniifolius Harv. | N | S. kuntzeanus Dinter | N | S. retrorsus DC. | Y |
| S. bulbinefolius DC. | N | S. laevigatus Thunb. | N | S. rhammatophyllus Matt.f. | N |
| S. bupleuroides DC. | Y | S. laevis Humbert | N | S. rhomboideus Harv. | Y |
| S. burchellii DC. | Y | S. lamarckianus Bullock | N | S. rhyncholaenus DC. | N |
| S. burtonii Hook.f. | Y | S. lanceus Aiton | N | S. rigidus L. | N |
| S. byrnensis Hilliard | N | S. latecorymbosus Gilli | N | S. robertiifolius DC. | N |
| S. cakilefolius DC. (Synonym of S. arenarius) | N | S. latibracteatus Humbert | N | S. roseiflorus R.E.Fr. | Y |
| S. caloneotes Hilliard | N | S. laticipes Bruyns | N | S. rosmarinifolius L.f. | Y |
| S. canabyi Humbert | N | S. latifolius DC. | Y | S. rugegensis Muschl. | N |
| S. canaliculatus Bojer ex DC. | N | S. latissimifolius S. Moore | N | S. ruwenzoriensis S. Moore | Y |
| S. canalipes DC. | N | S. lawalreeanus Lisowski | N | S. sabinjoensis Muschl. | N |
| S. capuronii Humbert | N | S. laxus DC. | N | S. saboureaui Humbert | N |
| S. cardaminifolius DC. | N | S. leandrii Humbert | N | S. sakalavorum Humbert | N |
| S. carnosus Thunb. | N | S. lejolyanus Lisowski | N | S. sakamaliensis (Humbert) Humbert | N |
| S. carroensis DC. | N | S. lelyi Hutch. | N | S. sandersonii Harv. | Y |
| S. cathcartensis O. Hoffm. | Y | S. leptopterus Mesfin | N | S. saniensis Hilliard and B.L. Burtt | N |
| S. caudatus DC. | N | S. lessingii Harv. | N | S. schimperi Sch.Bip. ex Hochst. | N |
| S. cedrorum Raynal | N | S. letouzeyanus Lisowski | N | S. schultzii Hochst. ex A. Rich. | N |
| S. chalureaui Humbert | N | S. leucadendron (G. Forst.) Hems.L. | N | S. schweinfurthii O.Hoffm. | Y |
| S. chrysocoma Meerb. | Y | S. leucanthemifolius Poir. | Y | S. scitus Hutch. and Burtt Davy | N |
| S. cinerascens Aiton | N | S. lewallei Lisowski | N | S. scoparius Harv. | N |
| S. citriceps Hilliard and B.L.Burtt | N | S. lineatus DC. | N | S. semiamplexifolius De Wild. | N |
| S. cochlearifolius Bojer ex DC. | N | S. linifolius L. | Y | S. seminiveus J.M. Wood and M.S. Evans | N |
| S. coleophyllus Turcz. | N | S. Lisowskii Long Wang and Beentje | N | S. serratuloides DC. | Y |
| S. comptonii J.C.Manning and Goldblatt | N | S. litorosus Fourc. | N | S. serrulatus DC. | N |
| S. confertus Sch.Bip. Ex A.Rich. | N | S. littoreus Thunb. | N | S. serrurioides Turcz. | N |
| S. conrathii N.E.Br. | Y | S. lividus L. | Y | S. shabensis Lisowski | N |
| S. consanguineus DC. | Y | S. lobelioides DC. (Synonym of S. flavus) | N | S. simplicissimus Bojer ex DC. | N |
| S. cordifolius L.f. | N | S. longiscapus Bojer ex DC. | Y | S. sisymbriifolius DC. | N |
| S. cornu-cervi MacOwan | N | S. luembensis De Wild. and Muschl. | N | S. skirrhodon DC. | N |
| S. coronatus (Thunb.) Harv. | Y | S. lycopodioides Schltr. | N | S. snowdenii Hutch. | N |
| S. cotyledonis DC. | N | S. lydenburgensis Hutch. and Burtt Davy | Y | S. sociorum Bolus | N |
| S. crassissimus Humbert | Y | S. lygodes Hiern | N | S. sophioides DC. | N |
| S. crassiusculus DC. | N | S. lyratus Forssk. | Y | S. sororius C. Jeffrey | N |
| S. crassorhizus De | N | S. mabberleyi C.Jeffrey | N | S. sotikensis S. Moore | N |
| S. crenatus Thunb. | N | S. MacOwanii Hilliard | N | S. spartareus S. Moore | N |
| S. crenulatus DC. | N | S. macrocephalus DC. | Y | S. speciosissimus J.C.Manning and Goldblatt | N |
| S. crispatipilosus C.Jeffrey | N | S. macroglossoides Hilliard | N | S. speciosus Willd. | Y |
| S. crispus Thunb. | Y | S. macroglossus DC. | N | S. spiraeifolius Thunb. | N |
| S. cristimontanus Hilliard | N | S. macrospermus DC. | Y | S. squalidus L. | Y |
| S. cryphiactis O.Hoffm. | N | S. madagascariensis Poir. | Y | S. stella-purpurea V.R.Clark, J.D.Vidal, and N.P.Barker | N |
| S. cryptolanatus Killick | N | S. malacitanus Huter | Y | S. steudelii Sch.Bip. ex A. Rich. | N |
| S. cyaneus O.Hoffm. | N | S. malaissei Lisowski | N | S. striatifolius DC. | N |
| S. cymbalariifolius (L.) Less. | N | S. mandrarensis Humbert | N | S. strictifolius Hiern | N |
| S. decaryi Humbert | N | S. maranguensis O.Hoffm. | N | S. subcanescens (DC.) Compton | N |
| S. decurrens DC. | N | S. margaritae C.Jeffrey | N | S. subcoriaceus Schltr. | N |
| S. deltoideus Less. | Y | S. marginalis Hilliard | N | S. subfractiflexus C. Jeffrey | N |
| S. denisii Humbert | N | S. mariettae Muschl. | Y | S. submontanus Hilliard and B.L. Burtt | N |
| S. dentatoalatus Mildbr. Ex C.Jeffrey | N | S. maritimus L.f. | Y | S. subrubriflorus O.Hoffm. | Y |
| S. depauperatus Mattf. | N | S. marnieri Humbert | N | S. subsessilis Oliv. and Hiern | N |
| S. diffusus L.f. | N | S. marojejyensis Humbert | N | S. subsinuatus DC. | N |
| S. digitalifolius DC. | N | S. massaicus (Maire) Maire | Y | S. sylvaticus L. | Y |
| S. dilungensis Lisowski | N | S. matricariifolius DC. | N | S. syringifolius O.Hoffm. | Y |
| S. diodon DC. | N | S. mattirolii Chiov. | N | S. tabulicola Baker | N |
| S. diphyllus De Wild. and Muschl. | N | S. mauricei Hilliard and B.L. Burtt | Y | S. tamoides DC. | Y |
| S. discodregeanus Hilliard and B.L.Burtt | N | S. maydae Merxm. (Synonym of S. albopunctatus) | N | S. tanacetopsis Hilliard | N |
| S. discokaraguensis C.Jeffrey | N | S. mbuluzensis Compton | N | S. teixeirae Torre | N |
| S. dissidens Fourc. | N | S. melastomifolius Baker | N | S. telekii O.Hoffm. | N |
| S. dissimulans Hilliard and B.L.Burtt | N | S. mesembryanthemoides Bojer ex DC. | N | S. telmateius Hilliard | N |
| S. doryphoroides C.Jeffrey | N | S. mesogrammoides O.Hoffm. | N | S. tenellus DC. | N |
| S. doryphorus Mattf. | N | S. meuselii Rauh | N | S. teneriffae Sch.Bip. ex Bolle | N |
| S. dracunculoides DC. | N | S. meyeri-johannis EngL. | N | S. thamathuensis Hilliard | N |
| S. dregeanus DC. | N | S. microalatus C. Jeffrey | N | S. thunbergii Harv. | N |
| S. dumeticola S.Moore | N | S. microglossus DC. | Y | S. torticaulis Merxm. | N |
| S. dumosus Fourc. | N | S. microspermus DC. | N | S. tortuosus DC. | N |
| S. eenii (S.Moore) Merxm. | N | S. mimetes Hutch. and R.A. Dyer | N | S. trachylaenus Harv. | N |
| S. elegans L. | N | S. mitophyllus C. Jeffrey | N | S. trachyphyllus Schltr. | N |
| S. ellenbeckii O.Hoffm. | N | S. mlilwanensis Compton | N | S. transmarinus S. Moore | N |
| S. eminens Compton | N | S. monticola DC. | N | S. triactinus S. Moore | N |
| S. emirnensis DC. | N | S. mooreanus Hutch. and Burtt Davy | N | S. trilobus L. | N |
| S. englerianus O.Hoffm. | N | S. moorei R.E.Fr. | N | S. triodontiphyllus C. Jeffrey | N |
| S. eriobasis DC. (Synonym of S. erosus) | N | S. mooreioides C. Jeffrey | N | S. triplinervius DC. | N |
| S. eriopus Willk. | N | S. morotonensis C. Jeffrey | N | S. triqueter Less. | N |
| S. erlangeri O.Hoffm. | N | S. muCronatus Willd. | N | S. tsaratananensis Humbert | N |
| S. erosus L.f. | N | S. multibracteatus Harv. | N | S. tugelensis J.M. Wood and M.S. Evans | N |
| S. erubescens Aiton | Y | S. multicaulis DC. | N | S. tysonii MacOwan | N |
| S. erysimoides DC. | N | S. multidenticulatus Humbert | N | S. ulopterus Thell. | N |
| S. esterhuyseniae J.C.Manning and Goldblatt | N | S. muricatus Thunb. | N | S. umbellatus L. | Y |
| S. euriopoides DC. | N | S. myriocephalus Sch.Bip. ex A.Rich. | N | S. umbricola Cron and B. Nord. | N |
| S. evelynae Muschl. | N | S. nanus Sch.Bip. ex A. Rich. | N | S. umgeniensis Thell. | N |
| S. exarachnoideus C.Jeffrey | N | S. napifolius MacOwan | N | S. unionis Sch.Bip. ex A. Rich. | N |
| S. exuberans R.A.Dyer | N | S. natalicola Hilliard | N | S. urophyllus Conrath | N |
| S. fanshawei Beentje | N | S. navicularis Humbert | N | S. urundensis S.Moore | N |
| S. farinaceus Sch.Bip. Ex A.Rich. | N | S. navugabensis C. Jeffrey | N | S. vaingaindrani Scott Elliot | N |
| S. flavus (Decne.) Sch.Bip. | Y | S. neo Bakeri Humbert | N | S. variabilis Sch.Bip. | N |
| S. foeniculoides Harv. | N | S. neoviscidulus Soldano | N | S. venosus Harv. | N |
| S. forbesii Oliv. and Hiern | N | S. ngandae Beentje | N | S. verbascifolius Burm.f. | N |
| S. francoisii Humbert | N | S. ngoyanus Hilliard | N | S. vernalis Walds. and Kit. | Y |
| S. fresenii Sch.Bip. | N | S. nyangani Beentje | N | S. vestitus P.J.Bergius | N |
| S. gallicus Vill. Ex Chaix | Y | S. nyungwensis P. Maquet | N | S. vicinus S.Moore | N |
| S. gariepiensis Cron | N | S. ochrocarpus Oliv. and Hiern | N | S. villifructus Hilliard | N |
| S. garnieri Klatt | N | S. odontopterus DC. | N | S. vimineus DC. | N |
| S. gazensis S.Moore | N | S. oederifolius DC. | N | S. vira-vira Hieron. | Y |
| S. geniorum Humbert | N | S. ornatus S.Moore | N | S. vitellinoides Merxm. | N |
| S. gerrardii Harv. | Y | S. othonniflorus DC. | N | S. vittarifolius Bojer ex DC. | N |
| S. giessii Merxm. | N | S. oxyodontus DC. | Y | S. voigtii van Jaarzv. | N |
| S. glaberrimus DC. | N | S. oxyriifolius DC. | Y | S. volcanicola C. Jeffrey | N |
| S. glanduloso-lanosus Thell. | N | S. paarlensis DC. | N | S. vulgaris L. | Y |
| S. glandulo-pilosus Volkens and Muschl. | N | S. pachyrhizus O. Hoffm. | N | S. waterbergensis S. Moore | N |
| S. glastifolius L.f. | N | S. paludaffinis Hilliard | Y | S. windhoekensis Merxm. | N |
| S. glaucus L. | Y | S. panduratus Less. (Synonym of S. erosus) | N | S. wittebergensis Compton | N |
| S. glutinarius DC. | N | S. panduriformis Hilliard | N | S. xenostylus O. Hoffm. | N |
Table 2.
Details of phytochemical studies of the 83 species (or subspecies) of Senecio in Africa, for which records could be found.
Table 2.
Details of phytochemical studies of the 83 species (or subspecies) of Senecio in Africa, for which records could be found.
| Species | Details |
|---|---|
| S. adnatus DC. | Toxic alkaloid (macrolide): Platyphylline [24]. |
| S. aegyptius L. | Toxic alkaloids: Senecionine (pyrrolizidine) and otosenine (macrolide) [25]. |
| S. aegyptius L. var. discoideus Boiss. | Sesquiterpenes: 1,10-epoxyfuranoeremophilane (in essential oil), with traces of monoterpenes [26]. Non-volatiles include 1-β-hydroxy-8-oxoeremophila-7,9-dien-12-oic acid, rutin, and quercetin-3-O-glucoside-7-O-rutinoside [27]. Novel eremophilane lactones also described [28]. |
| S. affinis DC. | Sesquiterpenes: Cacalols and bisabolols [29]. |
| S. angulatus L.f. | Toxic alkaloid: Angularine (pyrrolizidine) [30]. Phenols: Cynarin, chlorogenic acid and trans-ferulic acid [31]. Essential oils: α-Pinene, β-pinene, limonene, camphene, germacrene D, viridifloral, β-caryophyllene [32]. |
| S. angustifolius (Thunb.) Willd. | Toxic alkaloids (pyrrolizidines): Senecionine N-oxide, retrorsine N-oxide, retrorsine, seneciphyline, senecionine, senkirkine [6]. |
| S. asperulus DC. | Possible chemotypes. Terpenes: furoeremophilanes, α -humulene, ent-kaurenic acid, ent-kaurenol [33]. Toxic alkaloids: Pyrrolizidine alkaloid N-oxides (exact identity not known) [34]. |
| S. bollei Sunding and C.Kunkel | Toxic alkaloid (pyrrolizidine): Senecivernine [35]. |
| S. brachypodus DC. | Toxic alkaloid (pyrrolizidine): Rosmarinine [36]. |
| S. bupleuroides DC. | Toxic alkaloid (pyrrolizidine): Retrorsine [37]. |
| S. burchellii DC. | Toxic alkaloids (pyrrolizidine): Senecionine N-oxide and senkirkine [6]. |
| S. burtonii Hook.F. | Sesquiterpene: Cacalolide derivative, 4α-[2′-hydroxymethylacryloxy]-1β-hydroxy-14-(5 → 6) abe oeremophilan-12,8-olide. Shikimic acid derivative, (3′E)-(1α)-3-hydroxymethyl-4β,5α-dimethoxycyclohex-2-enyloctadec-3′-enoate. Fatty acid derivatives, octacosan-1-ol, 3β-hydroxyolean-12-en-28-oic acid, and 3β-acetoxyolean-12-en-28-oic acid [38]. |
| S. cathcartensis O.Hoffm. | Sesquiterpenes: Eremophilene derivatives [21]. |
| S. chrysocoma Meerb. | Toxic alkaloids: 7-angelylplatynecine, 9-angelylplatynecine, sarracine, neosarracine [39], and other 7-Angelyl-1-methylenepyrrolizidines (pyrrolizidines) [40]. |
| S. conrathii N.E.Br. | Sesquiterpenes: β-Farnesene, furoeremophilane derivatives, and germacrene D-4-ol [41]. Additionally, a nickel hyperaccumulator. |
| S. consanguineous DC. | Toxic alkaloid: Retrorsine (pyrrolizidine), very low concentration [42]. |
| S. coronatus (Thunb.) Harv. | Species did not contain toxic alkaloids [8], or mere traces, but further work necessary to know of the chemistry. |
| S. crassissimus Humbert | Sesquiterpenes: Germacrene D, bicyclogermacrene, Z-caryophyllene epoxide and other epoxides. Triterpenes: Lupeol, its acetate, lupeone, β-amyrin acetate, β-amyrenone, glutin-5(6)-en-3β-ol, 28-oxo-β-amyrenone, and the angelate [43]. |
| S. crispus Thunb. | Sesquiterpene dimers: Disesquiterpenoid derivative [44]. |
| S. deltoideus Less. | Unusual sesquiterpenes, linear diterpenes, and polyunsaturated alkenes and -kynes [45]. Used as a medicine to treat gynaecological and obstetric disorders [46]. |
| S. erubescens Aiton | Sesquiterpenes: Bisabolanes and eremophilanes [29]. |
| S. flavus (Decne.) Sch.Bip. | Sesquiterpenes (Oxyeuryopsin derivatives): 3β-Methylbutyryloxyeuryopsin, 3β-angeloyloxyeuryopsin, 3β-senecioyloxyeuryopsin, 3β-hydroxyeuryopsin, euryopsin-3-one, furanoligularenone, and others [47]. |
| S. gallicus Vill. Ex Chaix | Toxic alkaloids (pyrrolizidine): Ligularizine, senkirkine and senecionine N-oxide [48]. Essential oil: β-Phellandrene, apinene, germacrene-D, myrcene, α-copaene, sabinene, (Z)-β-ocimene, β-caryophyllene, p-cymene, β-pinene, α phellandrene, α-terpinolene, (E)-β-ocimene, α-humulene, azingiberene, and caryophyllene oxide [49]. |
| S. gerrardii Harv. | Sesquiterpenes: Eremophilene derivatives [21]. |
| S. glaucus L. | Essential oils: Isolongifolen-9-one, longiverbenone, 4-carene, p-cymene, thujone [50], m-mentha-1(7),8-diene, cis-m-mentha-2,8-diene, dehydrofukinone, α-terpinolene, 2,5-cyclohexadiene-1,4-dione,2-(1,1-dimethylethyl)-5-(2-methyl-2-propen-1-yl), sabinene, α-Fenchene and 1,3,8-p-menthatriene [51]. Phenols: Vanillic acid and gallic acid [52]. Flavonoids: Isorhamentin 3-O-β-D-glucoside, and isorhamentin 3-O-β-D-rutinoside. Benzofuran glucosides: 2,3-Dihydro-3β-hydroxyeuparin 3-O-glucopyranoside, isorhamentin 3-O-β-D-glucoside, and isorhamentin 3-O-β-D-rutinoside [53]. |
| S. glaucus L. subsp. coronopifolius (syn. S. desfontainei). | Toxic alkaloids (pyrrolyzidine): Seneciphylline [25]. |
| S. glutinosus Thunb. | Sesquiterpenes (seco-eremophilanes): Senglutinosin, 3α-hydroxy-10β-H-eremophil-11(13)-en-9-one, and nor-seco- glutinosone [33]. |
| S. gossypinus Baker | Flavonoid: Kaempferol-3-O-α-L-arabinopyranoside. Triterpenes: α-Amyrin and β-amyrin [54]. |
| S. grandiflorus P.J.Bergius | Sesquiterpenes (furano): Cacalol derivatives [55]. |
| S. hadiensis Forssk. | Toxic alkaloids (macrolides): Rosmarinine, 12-O-acetylrosmarinine, neorosmarinine, hadiensine (1α-hydroxyplacyphylline), 12-O-acetylhadiewine, 12-O-acetylneohadiewine, and petitianine (2α-hydroxy-1,2-dihydroretronine) [56]. Sesquiterpenes (tricyclic): presilphiperfolan-2α,5α,8α-triol and presilphiperfolan-2α,5α,8α,10α-tetraol [57]. |
| S. halimifolius L. | Sesquiterpenes (furano): Furanoeremophilanes [58]. |
| S. heliopsis Hilliard and B.L.Burtt | Sesquiterpenes: Furanoeremophilanes and cacalols [29]. |
| S. helminthioides (Sch.Bip.) Hilliard | Phenylpropenes: Trimethoxy-phenylpropenes [22]. |
| S. hieracioides DC. | Sesquiterpenes (furo): 9,10-Dehydrofuranoeremophilane, ligularenolide, eremophil-7(11)-en-8,12-olide, 8,8′-epimeric dimers. Shikimic acid derivatives [59]. |
| S. hoggariensis Batt. and Trab. | Phenols: 3,4-Dihydroxybenzoic acid, 4-hydroxybenzoic acid, 6,7-dihydroxycoumarin, vanillic acid, caffeic acid, p-coumaric acid, and ferulic acid [60]. |
| S. hypochoerideus DC. | Sesquiterpenes (furano): Furanoeremophilanes [61]. |
| S. ilicifolius Thunb. | Toxic alkaloid: Senecionine ‘responsible for bread-poisoning’ [62]. |
| S. inaequidens DC | Toxic alkaloids (pyrrolizidine): Retrorsine, senecionine [42], senecivernine, integerrimine, and an analogue of retrorsine [63]. Possibly another chemotype with furanosesquiterpenes [58]. |
| S. inornatus DC. | Toxic alkaloid (pyrrolizidine): O7-Angeloylretronecine [64]. Sesquiterpenes (furano): Furanoeremophilanes [58]. |
| S. isatideus DC. | Vinyl-olefins: Polyunsaturated alkenes [65]. |
| S. latifolius DC. | Toxic alkaloids: Retrorsine, isatidine, sceleratine, chlorodeoxysceleratine (merenskine), and the N-oxides of sceleratine and merenskine [66]. |
| S. leucanthemifolius Poir. | Toxic alkaloids (pyrrolizidine): Integerrimine and senecionine [67]. Essential oils: α-hydroxy-p-cymene, carvacrol, nerol, carveol, and cis-α-bisabolene [68]. |
| S. linifolius L. | Sesquiterpenes: furanoeremophilanes, i.e., maturinone and seven cacalohastin derivatives [69]. |
| S. lividus L. | Sesquiterpenes: Eremophilanes [29]. Possibly essential oils: [70]. |
| S. longiscapus Bojer ex DC. | Essential oils: Sabinene, elemicin, β-pinene, methyleugenol, α-pinene, and myrcene [71]. |
| S. lydenburgensis Hutch. and Burtt Davy | Sesquiterpenes: Multiple cacalol derivatives [72]. |
| S. lyratus Forssk. | Sterols: Sitosterol and stigmasterol. Triterpene: β-Amyrin [73]. |
| S. macrocephalus DC. | Toxic alkaloids (pyrrolizidine): Traces of 7-senecioyl-9-sarracinylheliotridine and 7-angelyl-9-sarracinyl-heliotridine [74]. |
| S. macrospermus DC. | Sesquiterpenes: Cacalohastin derivatives [75]. |
| S. madagascariensis Poir. | Toxic alkaloids (pyrrolizidine): Senecivernine, senecionine, integerrimine, senkirkine, mucronatinine, retrorsine, usaramine, otosenine, acetylsenkirkine, desacetyldoronine, florosenine, and doronine [76]. |
| S. malacitanus Huter | Toxic alkaloids (pyrrolizidine): Unnamed derivatives [77]. |
| S. mariettae Muschl. | Toxic alkaloid (pyrrolizidine): Retrorsine [78]. |
| S. maritimus L.f. | Alkanes: Polyunsaturated aklenes and -ynes. Furanosesquiterpene derivatives [79]. |
| S. massaicus (Maire) Maire | Essential oil: p-Cymene, n-hexadecanoic acid, and docosane-11-decyl [80]. |
| S. mauricei Hilliard and B.L.Burtt | Sesquiterpenes: Senmauricinol-(2-methyacrylat), hilliardinolisobutyrat, hilliardinol-(2-methylacrylat), 10β-hydroxy-1-oxo-6β-isobutyryloxy-2,3-dehydro-furanoeremophil-9-on, 2,3-desoxyhilliardinol-isobutyrat, 2,3-desoxohilliardinol-(2-methylacrylat), and 8,12-dioxo-7,11,9,10-tetradehydroeremophilan [81]. |
| S. microglossus DC. | Sterols: Stigmasterol, sitosterol, dammaradienol, its 3-epimer, and the angelate. Sesquiterpenes: Germacrene D, y- and δ-cadinene, bisabolol, the angelate [41]. |
| S. oxyodontus DC. | Sesquiterpene: Pentaynene sesquiterpene, bisabolene derivatives [82], and triquinane sesquiterpenes [83] p-Hydroxyacetophenone [82]. |
| S. oxyriifolius DC. | Sesquiterpenes: Tricyclic bisabolol derivatives (epoxides) [84]. |
| S. paludaffinis Hilliard | Sesquiterpenes: Cacalol and bisabolol derivatives [85]. |
| S. paniculatus P.J.Bergius | Toxic alkaloids (pyrrolizidine): 7β-Angelyl-1-methylene-8α-pyrrolizidine, 7β-angelyl-1-methylene-8α-pyrrolizidine, 7β-angelyl-1-methylene8α-pyrrolizidine-4-oxide, 7-angelylhastanecine, 9-angelylhastanecine, 7-angelylplatynecine, 9-angelylplatynecine, 9-angelylplatynecine-4-oxide, sarracine, neosarracine, and retrorsine [86]. |
| S. paucicalyculatus Klatt | Toxic alkaloids (pyrrolizidine): Retrorsine and isatidine [87]. |
| S. polyanthemoides Sch.Bip. | Sesquiterpenes (furano): Cacalol derivatives [55]. Essential oils: Limonene, p-cymene, β-selinene, α-pinene, β-pinene, 1,8-cineole, caryophyllene oxide, and humulene epoxide II [88]. |
| S. pterophorus DC. | Toxic alkaloids (pyrrolizidine): Retronecine, otonecine, platynecine, and rosmarinecine derivatives [89]. |
| S. pubigerus L. | Sesquiterpenes: Germacrene D, bicyclogermacrene, beta-farnesene, and bisabolol derivatives. Toxic alkaloid (pyrrolizidine): acylpyrrole [90]. |
| S. purpureus L. | Sesquiterpenes (eremophilenes): Diesters of seneremophilondiol, senescaposone and isosenescaposone, esterified with 4-methyl-5-acetoxy-pent-2-enoic acid [21]. |
| S. retrorsus DC. | Toxic alkaloids (pyrrolizidine): Retrorsine, isatidine, and isatinecic acid [91]. |
| S. rhomboideus Harv. | Sesquiterpenes: Eremophilene derivatives [21]. |
| S. roseiflorus R.E.Fr. | Flavonoids: O-methylated, i.e., 5,4′-dihydroxy-7-dimethoxyflavanone [92]. |
| S. rosmarinifolius L.f. | Toxic alkaloid (macrolide): Rosmarinine [62]. |
| S. ruwenzoriensis S.Moore | Toxic alkaloids (pyrrolizidine): Isoline and bisline [93]. |
| S. sandersonii Harv. | Sesquiterpenes: Diester and germacrene derivatives [94]. |
| S. schweinfurthii O.Hoffm. | Toxic alkaloid (pyrrolizidine): 7β-Hydroxy-1-methylene-8α-pyrrolizidine N-oxide [95]. |
| S. serratuloides DC. | Sterols: Phytosteroids and estran-3-one, 17-(acetyloxy)-2-methyl-, (2à,5à,17á) [96]. Used as a medicine to treat gynaecological and obstetric disorders [46]. |
| S. speciosus Willd. | Toxic alkaloids (pyrrolizidine): 7-Senecioyl-9-sarracinylheliotridine and 7-angelyl-9-sarracinyl-heliotridine [74]. |
| S. squalidus L. | Essential oils: p-Cymene and α-phellandrene [97]. |
| S. subrubriflorus O.Hoffm. | Diterpenes: Sandaracopimarene derivatives. Sesquiterpene: Bisabolene derivative (4,7-oxide) [98]. |
| S. sylvaticus L. | Sesquiterpenes: Alkenes, bicyclic derivatives, and furanosesquiterpenes [79]. |
| S. syringifolius O.Hoffm. | Toxic alkaloids (pyrrolizidine): Angularine, rosmarinine, and 12-O-acetylrosmarine, together with their N-oxides [99]. |
| S. tamoides DC. | Flavonoids: di-C-rhamnosylapigenin, mangiferin, and isomangiferin [100]. |
| S. umbellatus L. | Sesquiterpenes: Furanoeremophilane derivatives [101]. |
| S. vernalis Walds. and Kit. | Sesquiterpenes (furano): Cacalol derivatives [55]. |
| S. vira-vira Hieron. | Toxic alkaloids (pyrrolizidine): Anacrotine, neoplatyphylline, uspallatine. Flavonoids: Quercitrin, rutin, isorhamnetin 3-O-β-robinobioside. Sterols: Sitosterol, campesterol, stimasterol, stimasta-3,5-dien-7-one, and stimasta-4,6-dien-3-one. Triterpenes: α-/β-amyrins [102]. |
| S. vulgaris L. | Toxic alkaloids (pyrrolizidine): Senecionine, senecionine N-oxide, integerrimine N-oxide, seneciphylline N-oxide, retrorsine N-oxide, and spartioidine N-oxide [103]. Essential oils: α-Humulene, (E)-β-caryophyllene, terpinolene, ar-curcumene, and geranyl linalool [104]. |
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
MDPI and ACS Style
Sadgrove, N.J. Comment on Pyrrolizidine Alkaloids and Terpenes from Senecio (Asteraceae): Chemistry and Research Gaps in Africa. Molecules 2022, 27, 8868. https://doi.org/10.3390/molecules27248868
AMA Style
Sadgrove NJ. Comment on Pyrrolizidine Alkaloids and Terpenes from Senecio (Asteraceae): Chemistry and Research Gaps in Africa. Molecules. 2022; 27(24):8868. https://doi.org/10.3390/molecules27248868
Chicago/Turabian StyleSadgrove, Nicholas John. 2022. "Comment on Pyrrolizidine Alkaloids and Terpenes from Senecio (Asteraceae): Chemistry and Research Gaps in Africa" Molecules 27, no. 24: 8868. https://doi.org/10.3390/molecules27248868
APA StyleSadgrove, N. J. (2022). Comment on Pyrrolizidine Alkaloids and Terpenes from Senecio (Asteraceae): Chemistry and Research Gaps in Africa. Molecules, 27(24), 8868. https://doi.org/10.3390/molecules27248868
