Next Article in Journal
Chemical and Biological Profiles of Dendrobium in Two Different Species, Their Hybrid, and Gamma-Irradiated Mutant Lines of the Hybrid Based on LC-QToF MS and Cytotoxicity Analysis
Next Article in Special Issue
Influence of the Post-Harvest Storage Time on the Multi-Biological Potential, Phenolic and Pyrrolizidine Alkaloid Content of Comfrey (Symphytum officinale L.) Roots Collected from Different European Regions
Previous Article in Journal
Phytochemical Screening, Antioxidant and Sperm Viability of Nelumbo nucifera Petal Extracts
Previous Article in Special Issue
Chemical Profiling and Biological Evaluation of Nepeta baytopii Extracts and Essential Oil: An Endemic Plant from Turkey
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Plants
Volume 10
Issue 7
10.3390/plants10071373
plants-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Phytochemical Composition, Antioxidant, and Enzyme Inhibition Activities of Methanolic Extracts of Two Endemic Onosma Species

by
Kandasamy Saravanakumar
1,
Cengiz Sarikurkcu
2,*,
Saliha Seyma Sahinler
3,
Rabia Busra Sarikurkcu
4 and
Myeong-Hyeon Wang
1,*
1
Department of Bio Health Convergence, Kangwon National University, Chuncheon 24341, Gangwon, Korea
2
Department of Analytical Chemistry, Faculty of Pharmacy, Afyonkarahisar Health Sciences University, Afyonkarahisar 03100, Turkey
3
Department of Pharmacognosy, Faculty of Pharmacy, Afyonkarahisar Health Sciences University, Afyonkarahisar 03100, Turkey
4
Department of Coaching Education, Faculty of Sport Sciences, Ankara University, Golbasi Campus, Ankara 06830, Turkey
*
Authors to whom correspondence should be addressed.
Plants 2021, 10(7), 1373; https://doi.org/10.3390/plants10071373
Submission received: 15 June 2021 / Revised: 2 July 2021 / Accepted: 3 July 2021 / Published: 5 July 2021
(This article belongs to the Special Issue Polyphenols in Plants)
Browse Figures
Versions Notes

Abstract

:
Onosma species have been used as a dye for hundreds of years due to their dark red pigments. These species have also been used by mankind in the treatment of various diseases since ancient times. This work analyzed the phytochemical composition in methanol extract of two endemic Onosma species (O. lycaonica and O. papillosa). Methanolic extract of these species varied in the content of flavonoids and phenolics. The flavonoids were found higher in O. papillosa [32.9 ± 0.3 mg QEs (quercetin equivalent)/g extracts] while the phenolics were higher in O. lycaonica [43.5 ± 1.5 mg GAEs (gallic acid equivalent)/g extracts]. ESI-MS/MS (electrospray ionization-mass spectrometry) revealed the presence of 25 compounds in O. lycaonica and 24 compounds in O. papillosa. The former was richer than the latter for apigenin, luteolin, eriodictyol, pinoresinol, apigenin 7-glucoside, rosmarinic acid, luteolin 7-glucoside, ferulic acid, vanillin, caffeic acid, 4-hydroxybenzoic acid, (+)-catechin3,4-dihydroxyphenylacetic acid. The O. papillosa exhibited low EC50 (1.90 ± 0.07 mg/mL) which indicated its strong phosphomolybdenum scavenging activity as compared to O. lycaonica. However, the O. lycaonica showed low IC50 or EC50 for 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), cupric reducing antioxidant power (CUPRAC), ferric reducing antioxidant power (FRAP) and ferrous ion chelating activity, as compared to O. papillosa. The results proved the presence of potent antioxidant compounds in O. lycaonica. Further, the plant extracts significantly varied for enzyme inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), but the plant extracts did not significantly differ for inhibition of α-glucosidase, α-amylase, and tyrosinase. Onosma species deserve further research towards developing novel drugs to treat oxidative diseases.

Graphical Abstract

1. Introduction

Onosma genus contains species rich in shikonins. Particularly the red dye of Onosma sp., has been used since ancient times both in fabric dyeing (especially in silk dyeing) and a dyestuff in foods [1]. Also, this pigment offers alternative solutions for cosmetics and medicine due to its bioactivity [2,3]. Hence, researchers have been prompted to analyse the bioactivities of Onosma sp. [4]. Oxidative stress stimulates various diseases. Free radicals and reactive oxygen species are oxidants formed as intermediates during various metabolic functions. Oxidants are simultaneously scavenged by elevated synthesis of suitable enzymes (superoxidase dismutase, hydroperoxides, catalase). Therefore, a balance between oxidants and antioxidants is essential to ensure a healthy metabolic activity defense system. However, if unbalancing of oxidants and antioxidants occurs, will lead to the oxidative stress [5,6], which is known to cause various diseases including atherosclerosis, coronary heart disease and aging diseases (cancer, arthritis, osteoporosis, cataracts, type 2 diabetes, Alzheimer’s disease and hypertension) [7]. Several synthetic antioxidant molecules are consumed to prevent oxidative stress-related diseases but they cause adverse effects [8]. The consumption of antioxidant-rich foods such as green tea, fresh vegetables and fruits successfully prevents oxidative stress. Hence, it is essential to discover novel antioxidants from natural resources to erase the risk of oxidative stress-mediated diseases.
Earlier research findings have revealed that medicinal plants are promising among natural resources for the presence of antioxidants such as polyphenols, tannins, flavonoids, polysaccharides, ascorbic acid, tocopherols and anthocyanins [9]. Therefore, it is essential to understand the composition of these metabolites and their antioxidant properties [10]. Earlier studies have screened medicinal plants using primary antioxidant assays (phosphomolybdenum, DPPH, ABTS, CUPRAC, FRAP, ferrous ion chelating) and enzyme inhibition assays (AChE inhibition, BChE inhibition, α-amylase inhibition, α-glucosidase inhibition, and tyrosinase inhibition) [11,12,13]. These screening assays are used to relate the oxidative stress diseases, Alzheimer’s disease, photocarcinogenesis and diabetes mellitus, [14,15,16].
Onosma species (family Boraginaceae) are globally distributed medicinal plants with a total of 180 species. In Turkey, alone there are 85 species of Onosma, including more than 40 endemic species [17,18], and they are traditionally used in the country as natural remedies to cure fever, bladder pain, kidney infections, blood diseases, burns, abdominal pain and wound healing [19]. The phytochemistry and ethnopharmacology of several Onosma spp., have been documented, but not for two endemic Onosma spp., (O. lycaonica and O. papillosa). Hence, the present work analyzed the phenolic and flavonoid compounds from these Onosma spp. by using LC-ESI-MS/MS, and also tested their bioactivities in terms of antioxidation and enzyme inhibition properties.
Onosma species are important medicinal plants due to their promising pharmacological properties, including antioxidant, anti-inflammatory, cytotoxicity, and enzyme inhibition activities [20], Moreover, these plants are traditionally recognized as folk medicines to cure several aging-related diseases [19]. Generally antioxidant, antimicrobial, enzyme inhibitory, anti-inflammatory, and anti-cardiovascular disease biological activities are related to the phenolics, tannins and flavonoids present in plants [21]. It is essential to study the phytochemistry of plants to establish a basis for the isolation of novel compounds as drug candidates to treat the aforesaid diseases. Therefore, the present study examined the phytochemical composition in the methanol extract of two endemic Onosma species (O. lycaonica and O. papillosa) by spectrophotometric and LC-ESI-MS/MS methods.

2. Results and Discussion

2.1. Yield, Total Phenolics and Flavonoids

The two plant species significantly varied in total flavonoids and total phenolics (p < 0.05; Table 1). The yield was higher for the methanol extract of O. papillosa (4.02%) than O. lycaonica (3.52%). Similarly, the content of flavonoids was higher in O. papillosa (32.9 ± 0.3 mg QEs/g extract) than in O. lycaonica (26.0 ± 0.5 mg QEs/g extract). However, the content of phenolics was found higher in O. lycaonica (43.5 ± 1.5 mg GAEs/g extract) than in O. papillosa (33.9 ± 0.4 mg GAEs/g extract). These results revealed that O. lycaonica was rich in phenolics while O. papillosa was rich in flavonoids (Table 1). Several earlier studies have also reported varied levels of total phenolic and flavonoids in Onosma species (O. stenoloba, O. sericea, O. isaurica, O. bracteosa, O. tauricum, and O. gigantea) [11,12,22,23]. For example, the content of total phenolic is reportedly higher in O.sericea (69.8 ± 1.0 mg GAEs/g extract) than O. stenoloba (32.5 ± 0.6 mg GAEs/g extract) [12].

2.2. Phytochemical Composition

Although ESI-MS/MS is a frequently used method for the quantification the phyto compounds, it is essential to standardize the operating conditions for sensitive target compounds based on their MRM ionization modes. Therefore, the present study standardized the analytical parameters of LC-ESI-MS/MS in response to negative and positive ionization using the standard molecules (Table S1). After the establishment of LC-MS operating conditions, a total of 31 standard flavonoids/phenolic compounds were used at different concentrations to prepare a standard curve. The results of standard compounds were fitted to the calibration curve, and their linear equations and R2 values are presented in the Supplementary Information (Table S2). The LC-MS/MS mediated quantification of phytocompounds in two Onosma species are presented in Table 2, which shows that out of 31 compounds studied, a total of 25 compounds were present in O. lycaonica while 24 compounds were observed in O. papillosa (Figure 1). Five compounds, including pyrocatechol, (−)-epicatechin, verbascoside, taxifolin and 2-hydroxycinnamic acid were absent in both O. lycaonica and O. papillosa. Similarly, compounds including pyrocatechol, (−)-epicatechin, taxifolin and 2-hydroxycinnamic acid are reported to be absent in various Onosma species such as O. sieheana, O. stenoloba, O. isaurica, O. gracilis, O. aucheriana, O. pulchra, O. frutescens, O. sericea, O. ambigens, and O. bracteosa [11,13,20,24,25,26]. Moreover, (+)-catechin and eriodictyol were present in O. lycaonica but absent in O. papillosa. Similarly, the earlier research on the phytochemical analysis of Onosma species has indicated that the compounds such as pyrocatechol, (−)-epicatechin, taxifolin and 2-hydroxycinnamic acid are not observed in Onosma species while (+)-catechin and eriodictyol are not commonly observed in Onosma species [11,13,20,24,25,26]. Levels of a total of 15 compounds (apigenin, luteolin, eriodictyol, pinoresinol, apigenin 7-glucoside, rosmarinic acid, luteolin 7-glucoside, ferulic acid, vanillin, caffeic acid, 4-hydroxybenzoic acid, (+)-catechin3,4-dihydroxyphenylacetic acid) were found to be high by their concentration in the methanolic extract of O. lycaonica compared to O. papillosa. These variations in quantity and occurrence of phytochemicals of Onosma species is probably due to difference in the extraction methods and ecological conditions of the plant species (climate, soil properties and altitude) [24].

2.3. Antioxidant Properties

Most oxidative stress-related human diseases occur due to impairment of the balance between oxidant and antioxidant molecules. The screening of the antioxidant activity of plant extracts provides a basis for discovering novel phytocompounds with bio-health-promoting efficiency. The free radicals such as DPPH, ABTS and phosphomolybdenum are scientifically accepted for the screening of antioxidant molecules from medicinal plants [24,27]. Therefore, the current study screened the free radicals for scavenging activity of two Onosma species in comparison with standard antioxidants such as Trolox, ethylenediaminetetraacetic acid, butylated hydroxyanisole, and butylated hydroxytoluene, and the results are shown in Table 3. Phosphomolybdenum scavenging occurs through reduction of Mo (V) to Mo (V) by the interaction of antioxidant molecules from plant extracts or other antioxidant molecules with phosphomolybdenum [28]. In the present work, the methanol extract of the two plants showed a considerable level of phosphomolybdenum scavenging activity, and the EC50 value was found to be low for O. papillosa (1.90 ± 0.07 mg/mL) as compared to O. lycaonica (2.05 ± 0.07 mg/mL). The 1 g extracts of O. lycaonica and O. papillosa were equivalent to 540.6 ± 19.6 mg and 584.3 ± 20.4 mg of Trolox, respectively. The EC50 and TEs values indicted that O. papillosa was a stronger phosphomolybdenum scavenging agent as compared with O. lycaonica. This is in agreement with earlier reports of phosphomolybdenum scavenging activity of Onosma species which showed EC50 values in a range of 1.18–2.73 [24,25].
DPPH is a stable free radical and its scavenging reaction occurs through replacement of the nitrogen atom a by hydrogen atom of an oxidant molecules [29]. In the current study, O. lycaonica exhibited a stronger DPPH savaging activity than O. papillosa, as indicated by a lower IC50 value of 2.69 ± 0.10 mg/mL and a higher Trolox equivalent value (92.6 ± 3.6 mg TEs/g extract) of O. lycaonica as compared to O. papillosa (IC50 −3.41 ± 0.05 mg/mL, 73.1 ± 1.0 mg TEs/g extracts). A similar trend of IC50 and Trolox equivalent was also observed for ABTS scavenging activity. The IC50 and Trolox equivalents of the ABTS+ scavenging significantly varied between the plants studied, with a low IC50 (2.18 ± 0.01 mg/mL) and high Trolox equivalent value (130.6 ± 0.4 mg TEs/g extract) for O. lycaonica. Thus, O. lycaonica was a stronger ABTS+ scavenger as compared to O. papillosa. The sample that exhibits less IC50, EC50 with high Trolox equivalent is considered to be stronger in antioxidant activity than the sample showing high IC50, EC50 with low Trolox equivalent [11] and this is in accordance with our results on free radical scavenging activity of the Onosma species.
Antioxidant molecules scavenge free radicals such as DPPH and ABTS+ through an electron or hydrogen atom transfer mechanism whereas FRAP reduction occurs through an electron reaction related to pH [30]. The methanol extract of O. lycaonica showed a low EC50 for CUPRAC reduction (1.10 ± 0.01 mg/mL) and FRAP reduction (0.69 ± 0.01 mg/mL) as compared to O. papillosa. The EC50 of CUPRAC and FRAP reduction along with the Trolox equivalents indicated that O. papillosa was potent in reducing the CUPRAC and FRAP. O. lycaonica showed higher ferrous ion chelating activity than O. papillosa, which was evidenced by the low IC50 (2.32 ± 0.16 mg/mL) and high EDTAEs (21.60 ± 1.45 mg EDTAEs/g extract) of O. lycaonica (Table 3). Moreover, both plants exhibited low EC50 or IC50 values compared to standard antioxidants tested such as Trolox, ethylenediaminetetraacetic acid, butylated hydroxyanisole, and butylated hydroxytoluene (Table 3). Overall, the methanol extract of O. lycaonica exhibited better antioxidant activity than the O. papillosa one, but the phosphomolybdenum scavenging activity difference between the plants was not significant (p < 0.05). The higher antioxidant activity of O. lycaonica might be attributed to the presence of high levels of antioxidant molecules as evidenced by LC-ESI-MS/MS. The LC-ESI-MS/MS analysis revealed that the total amounts of 15 compounds were found to be higher in O. lycaonica than O. papillosa (Table 2). Particularly, the antioxidant substances such as apigenin [14], luteolin [31], pinoresinol [32], apigenin 7-glucoside [14], rosmarinic acid [33], ferulic acid [34], vanillin [35], and caffeic acid [36] were found to be higher in the methanol extract of O. lycaonica.

2.4. Enzyme Inhibition Assay

The enzyme inhibitory effect of methanol extract of two Onosma species (O. lycaonica and O. papillosa) was assessed for Alzheimer’s disease (AChE, BChE), diabetes (α-amylase and α-glucosidase) and photocarcinogenesis (tyrosinase)-related enzymes by spectrophotometric assays and the results are shown in Table 4. Moreover, the enzyme inhibitory activity was compared to standard enzyme inhibitors such as galantamine for AChE, and BChE, acarbose for α-amylase and α-glucosidase, kojic acid for tyrosinase.
The AChE and BChE inhibition activities varied significantly between the plants, but did not vary for α-glucosidase, α-amylase, and tyrosinase inhibition activities (p < 0.05). O. lycaonica exhibited high AChE inhibition activity (IC50 −1.32 ± 0.02 mg/mL) while O. papillosa showed high BChE inhibition (IC50 −4.96 ± 0.07 mg/mL). Thus, both plants showed potent inhibition of the targeted enzymes. Although the IC50 and standard galantamine equivalent, acarbose equivalent and kojic acid equivalent did not vary between the two Onosma species analyzed in the present study, an earlier work has reported significant variations between the enzyme inhibitory activity of O. sericea and O. stenoloba [12]. Thus the methanol extract of Onosma species is a promising source for the isolation of enzyme inhibitors, as disclosed in earlier reports [12,22,24].

3. Materials and Methods

3.1. Standard Phytochemicals and Chemicals

2,5-Dihydroxybenzoic acid, pyrocatechol, chlorogenic acid, 4-hydroxybenzoic acid, (−)-epicatechin, caffeic acid, gallic acid, (+)-catechin, vanillin, syringic acid, taxifolin, p-coumaric acid, sinapic acid, ferulic acid, 2-hydroxycinnamic acid, rosmarinic acid, pinoresinol, luteolin, quercetin, apigenin and HPLC grade of methanol and formic acid were obtained from Sigma-Aldrich (St. Louis, MO, USA). 3-Hydroxybenzoic acid, vanillic acid, apigenin 7-glucoside, 3,4-dihydroxyphenylacetic acid, luteolin 7-glucoside, eriodictyol, hesperidin, and kaempferol were obtained from Fluka (St. Louis, MO, USA). The hyperoside protocatechuic acid and verbascoside were purchased from HWI Analytik (Ruelzheim, Germany). Ultra-pure water (18.2 mΩ/cm) was prepared by using a Milli-Q water purification system (Milli-Q Millipore Merck KGaA Darmstadt, Germany). All the chemicals and reagents used in the biological assay were obtained from Sigma-Aldrich.

3.2. Plant Material and Extract Preparation

O. lycaonica Hub. -Mor. and O. papillosa Riedl were collected from Sertavul Pass, Mut, Mersin-Turkey (1660 m., 36°54′18″ N 33°16′14″ E, herbarium number: OC.5057) and the Yesilkent-Tufanbeyli highway, Tufanbeyli-Adana (1540 m., 38°15′58″ N 36°20′54″ E, herbarium number: OC.5058), respectively. These plant species were identified and authenticated by Dr. Olcay Ceylan (Mugla Sitki Kocman University). The aerial parts of the samples were separated, and shadow air-dried for several weeks without direct exposure of sunlight. Afterwards, these samples were cut into small pieces. The plant sample weighed at 5 g was immersed in 100 mL of methanol at ambient room condition for 24 h and filtered using the Whatman No.1. filter paper. The extraction was repeated two times and the extracts were pooled together for each plant species, and concentrated using a rotary evaporator [11] and the extracts were preserved at 4 °C for further experiments.

3.3. Analysis of Total Phenolics and Flavonoids

The content of total phenolics in the plant extracts was determined by spectrophotometric assay using Folin-Ciocalteu reagent according to the methods described earlier [37,38]. In brief, 0.25 mL of plant extract was mixed with Folin-Ciocalteu reagent (1 mL, 1:9) and vigorously vortexed for 3 min followed by 0.75 mL of 1% Na2CO3 were added and incubated for 2 h in room temperature. After incubation, the sample was measured for optical density (OD) at 760 nm, and the content of total phenolics is presented as gallic acid equivalents. The total flavonoids in the extracts were measured according to the methods described earlier [39]. In brief, the 2% of aluminum chloride solution was prepared in methanol. Then the plant extract was mixed with AlCl3 solution at 1:1 ratio. A blank, prepared by mixing methanol with AlCl3 at the same ratio. The plant and blanks were incubated at room temperature for 10 min then the OD was measured at 415 nm, and the content of flavonoids is presented as quercetin equivalents.

3.4. Analysis of Phytochemical Composition by LC–ESI–MS/MS

The selected phytochemical constituents were analysed in the methanolic extracts of Onosma spp., by using LC–ESI–MS/MS (1260 Infinity liquid chromatography system hyphenated to a 6420 Triple Quad mass spectrometer, Agilent Technologies, Santa Clara, CA, USA) equipped with Poroshell 120 EC-C18 (100 mm × 4.6 mm I.D., 2.7 μm) column. In order to analyze the compounds, the mobile phases were prepared using different combinations of formic acid, ammonium acetate, methanol and acetic acid according to target compounds isomeric resolution as described in our earlier study [40]. The LC-ESI-MS/MS analysis was operated according to the methods described earlier [40].

3.5. Antioxidant, and Enzyme Inhibition Assays

The antioxidant activities of methanolic extracts of two Onosma spp., were examined according to the protocols described previously [41,42,43,44,45] by using three scavenging assays by using phosphomolybdenum, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylbenzothiazloine-6-sulphonic acid, ABTS+), and two reducing assays measuring the cupric ion reducing (CUPRAC) and ferric reducing (FRAP) properties, and one chelating assay using ferrous ion chelation. The plant extracts were also examined for inhibition of enzymes such as α-glucosidase, α-amylase, acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase, which are related to diabetes, Alzheimer’s disease and photocarcinogenesis, according to the methods described elsewhere [23]. The results are presented as IC50 values and the EC50 values are calculated using a formula described earlier [41].

3.6. Statistical Analysis

Biological assays and phytochemical composition analysis were performed for three times. The statistical analysis such as descriptive statistics, and one-way ANOVA and post hoc test (Tukey’s) and student t-test were performed to observe the significance (p < 0.05) between extracts (O. lycaonica and O. papillosa) by using statistical software package SPSS v. 22.0 (PSS Inc, Chicago, IL, USA).

4. Conclusions

This work reports the phytochemical composition, antioxidant and enzyme inhibitory activity of two Onosma species endemic to Turkey. The methanol extract of O. lycaonica exhibited high levels of ~15 antioxidant-related compounds and antioxidant activities as compared to O. papillosa. Both plant species showed considerable enzyme inhibitory activity. The present results evidenced that these endemic Onosma species (O. lycaonica and O. papillosa) represent promising sources for the isolation of pharmacologically important drug candidate molecules to treat various oxidative diseases, including diabetes, cancer, Alzheimer’s disease and photocarcinogenesis.

Supplementary Materials

The following are available online at https://www.mdpi.com/article/10.3390/plants10071373/s1, Table S1: ESI–MS/MS Parameters and analytical characteristics for the Analysis of target analytes by MRM Negative and Positive Ionization Mode, Table S2: Calibration curves and sensitivity properties of the method.

Author Contributions

Conceptualization, C.S. and M.-H.W.; methodology, C.S.; K.S.; software, S.S.S.; and R.B.S. validation, C.S.; K.S.; and M.-H.W.; formal analysis, C.S.; and R.B.S.; investigation, C.S.; and S.S.S.; resources, C.S. and M.-H.W.; data curation, K.S. and C.S.; writing—original draft preparation, K.S.; writing—review and editing, C.S.; K.S.; visualization, M.-H.W.; and C.S.; supervision, M.-H.W.; project administration, C.S.; funding acquisition, C.S. and M.-H.W. All authors have read and agreed to the published version of the manuscript.

Funding

This study was partially supported by 2018 Research Grant (PoINT) from Kangwon National University and Korea Research Fellowship Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2017H1D3A1A01052610).

Data Availability Statement

The data presented in this study are available in the article.

Acknowledgments

The authors would like to thank to Olcay Ceylan for her kind help in identifying the plant material used in this study.

Conflicts of Interest

The authors confirm that there are no known conflict of interest.

References

  1. He, J. Complex of shikonin and β-cyclodextrins by using supercritical carbon dioxide. J. Incl. Phenom. Macrocycl. Chem. 2008, 63, 249–255. [Google Scholar] [CrossRef]
  2. Noula, E.; Samanidou, V.F.; Assimopoulou, A.N.; Papageorgiou, V.P.; Papadoyannis, I.N. Solid-phase extraction for purification of alkannin/shikonin samples and isolation of monomeric and dimeric fractions. Anal. Bioanal. Chem. 2010, 397, 2221–2232. [Google Scholar] [CrossRef]
  3. Pal, M.; Chaudhury, A. High frequency direct plant regeneration, micropropagation and Shikonin induction in Arnebia hispidissima. J. Crop. Sci. Biotechnol. 2010, 13, 13–19. [Google Scholar] [CrossRef]
  4. Kumar, A.; Kaur, V.; Pandit, K.; Tuli, H.S.; Sak, K.; Jain, S.K.; Kaur, S. Antioxidant Phytoconstituents From Onosma bracteata Wall. (Boraginaceae) Ameliorate the CCl4 Induced Hepatic Damage: In Vivo Study in Male Wistar Rats. Front. Pharmacol. 2020, 11, 1301. [Google Scholar] [CrossRef] [PubMed]
  5. Ighodaro, O.M.; Akinloye, O.A. First line defence antioxidants-superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX): Their fundamental role in the entire antioxidant defence grid. Alex. J. Med. 2018, 54, 287–293. [Google Scholar] [CrossRef] [Green Version]
  6. Zheng, W.; Wang, S.Y. Antioxidant Activity and Phenolic Compounds in Selected Herbs. J. Agric. Food Chem. 2001, 49, 5165–5170. [Google Scholar] [CrossRef] [PubMed]
  7. Wei, D.; Cheng, W.; Wei, Y.; Zhang, L. Phosphorylated modification and in vitro antioxidant activity of Radix Hedysari polysaccharide. Glycoconj. J. 2012, 29, 167–172. [Google Scholar] [CrossRef] [PubMed]
  8. Qi, H.; Zhang, Q.; Zhao, T.; Chen, R.; Zhang, H.; Niu, X.; Li, Z. Antioxidant activity of different sulfate content derivatives of polysaccharide extracted from Ulva pertusa (Chlorophyta) in vitro. Int. J. Biol. Macromol. 2005, 37, 195–199. [Google Scholar] [CrossRef] [PubMed]
  9. Xu, D.-P.; Li, Y.; Meng, X.; Zhou, T.; Zhou, Y.; Zheng, J.; Zhang, J.-J.; Li, H.-B. Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources. Int. J. Mol. Sci. 2017, 18, 96. [Google Scholar] [CrossRef]
  10. Soong, Y.-Y.; Barlow, P.J. Antioxidant activity and phenolic content of selected fruit seeds. Food Chem. 2004, 88, 411–417. [Google Scholar] [CrossRef]
  11. Saravanakumar, K.; Sarikurkcu, C.; Sarikurkcu, R.T.; Wang, M.-H. A comparative study on the phenolic composition, antioxidant and enzyme inhibition activities of two endemic Onosma species. Ind. Crop. Prod. 2019, 142, 111878. [Google Scholar] [CrossRef]
  12. Stanković, J.S.K.; Ceylan, R.; Zengin, G.; Matić, S.; Jurić, T.; Diuzheva, A.; Jeko, J.; Cziáky, Z.; Aktumsek, A. Multiple biological activities of two Onosma species (O. sericea and O. stenoloba) and HPLC-MS/MS characterization of their phytochemical composition. Ind. Crop. Prod. 2020, 144, 112053. [Google Scholar] [CrossRef]
  13. Baltaci, N.; Aydogdu, N.; Sarikurkcu, C.; Tepe, B. Onosma gracilis (Trautv.) and O. oreodoxa (Boiss. & Heldr.): Phytochemistry, in silico docking, antioxidant and enzyme inhibitory activities. S. Afr. J. Bot. 2021. [Google Scholar] [CrossRef]
  14. Prochazkova, D.; Boušová, I.; Wilhelmová, N. Antioxidant and prooxidant properties of flavonoids. Fitoterapia 2011, 82, 513–523. [Google Scholar] [CrossRef] [PubMed]
  15. Tundis, R.; Loizzo, M.R.; Menichini, F. Natural Products as α-Amylase and α-Glucosidase Inhibitors and their Hypoglycaemic Potential in the Treatment of Diabetes: An Update. Mini-Rev. Med. Chem. 2010, 10, 315–331. [Google Scholar] [CrossRef] [PubMed]
  16. Ullah, S.; Son, S.; Yun, H.Y.; Kim, H.; Chun, P.; Moon, H.R. Tyrosinase inhibitors: A patent review (2011–2015). Expert Opin. Ther. Pat. 2016, 26, 347–362. [Google Scholar] [CrossRef] [PubMed]
  17. Binzet, R.; Eren, Ö. Onosma erzincanica (Boraginaceae: Lithospermeae), a new scree species from Turkey. Phytotaxa 2018, 356, 117–130. [Google Scholar] [CrossRef]
  18. Cecchi, L.; Coppi, A.; Selvi, F. Onosma juliae (Boraginaceae), a new species from southern Turkey, with remarks on the systematics of Onosma in the Irano-Turanian region. Phytotaxa 2016, 288, 201. [Google Scholar] [CrossRef]
  19. Kumar, N.; Kumar, R.; Kishore, K.; Onosma, L. A review of phytochemistry and ethnopharmacology. Pharmacogn. Rev. 2013, 7, 140–151. [Google Scholar] [CrossRef] [Green Version]
  20. Sarikurkcu, C.; Sahinler, S.S.; Ceylan, O.; Tepe, B. Onosma pulchra: Phytochemical composition, antioxidant, skin-whitening and anti-diabetic activity. Ind. Crop. Prod. 2020, 154, 112632. [Google Scholar] [CrossRef]
  21. Shahidi, F.; Ambigaipalan, P. Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects–A review. J. Funct. Foods 2015, 18, 820–897. [Google Scholar] [CrossRef]
  22. Kirkan, B.; Sarikurkcu, C.; Ozer, M.S.; Cengiz, M.; Atılgan, N.; Ceylan, O.; Tepe, B. Phenolic profile, antioxidant and enzyme inhibitory potential of Onosma tauricum var. tauricum. Ind. Crop. Prod. 2018, 125, 549–555. [Google Scholar] [CrossRef]
  23. Sarikurkcu, C.; Kirkan, B.; Ozer, M.S.; Ceylan, O.; Atilgan, N.; Cengiz, M.; Tepe, B. Chemical characterization and biological activity of Onosma gigantea extracts. Ind. Crop. Prod. 2018, 115, 323–329. [Google Scholar] [CrossRef]
  24. Sarikurkcu, C.; Sahinler, S.S.; Husunet, M.T.; Istifli, E.S.; Tepe, B. Two endemic Onosma species (O. sieheana and O. stenoloba): A comparative study including docking data on biological activity and phenolic composition. Ind. Crop. Prod. 2020, 154, 112656. [Google Scholar] [CrossRef]
  25. Sarikurkcu, C.; Sahinler, S.S.; Tepe, B. Onosma aucheriana, O. frutescens, and O. sericea: Phytochemical profiling and biological activity. Ind. Crop. Prod. 2020, 154, 112633. [Google Scholar] [CrossRef]
  26. Sarikurkcu, C.; Sahinler, S.S.; Ceylan, O.; Tepe, B. Onosma ambigens: Phytochemical composition, antioxidant and enzyme inhibitory activity. Ind. Crop. Prod. 2020, 154, 112651. [Google Scholar] [CrossRef]
  27. Rahman, M.M.; Islam, M.B.; Biswas, M.; Alam, A.H.M.K. In vitro antioxidant and free radical scavenging activity of different parts of Tabebuia pallida growing in Bangladesh. BMC Res. Notes 2015, 8, 1–9. [Google Scholar] [CrossRef] [Green Version]
  28. Khan, R.A.; Khan, M.R.; Sahreen, S.; Ahmed, M. Assessment of flavonoids contents and in vitro antioxidant activity of Launaea procumbens. Chem. Cent. J. 2012, 6, 43. [Google Scholar] [CrossRef] [Green Version]
  29. Contreras-Guzmán, E.S.; Strong, F.C., III. Determination of tocopherols (vitamin E) by reduction of cupric ion. J. Assoc. Off. Anal. Chem. 1982, 65, 1215–1221. [Google Scholar] [CrossRef]
  30. Cerretani, L.; Bendini, A. Chapter 67-Rapid Assays to Evaluate the Antioxidant Capacity of Phenols in Virgin Olive Oil. In Olives and Olive Oil in Health and Disease Prevention; Preedy, V.R., Watson, R.R., Eds.; Academic Press: San Diego, CA, USA, 2010; pp. 625–635. [Google Scholar]
  31. Ahmadi, S.M.; Farhoosh, R.; Sharif, A.; Rezaie, M. Structure-Antioxidant Activity Relationships of Luteolin and Catechin. J. Food Sci. 2020, 85, 298–305. [Google Scholar] [CrossRef]
  32. Morales, J.C.; Lucas, R. Chapter 97-Structure–Activity Relationship of Phenolic Antioxidants and Olive Components. In Olives and Olive Oil in Health and Disease Prevention; Preedy, V.R., Watson, R.R., Eds.; Academic Press: San Diego, CA, USA, 2010; pp. 905–914. [Google Scholar]
  33. Alagawany, M.; El-Hack, M.A.; Farag, M.R.; Gopi, M.; Karthik, K.; Malik, Y.S.; Dhama, K. Rosmarinic acid: Modes of action, medicinal values and health benefits. Anim. Health Res. Rev. 2017, 18, 167–176. [Google Scholar] [CrossRef]
  34. Zduńska, K.; Dana, A.; Kolodziejczak, A.; Rotsztejn, H. Antioxidant Properties of Ferulic Acid and Its Possible Application. Ski. Pharmacol. Physiol. 2018, 31, 332–336. [Google Scholar] [CrossRef]
  35. Tai, A.; Sawano, T.; Yazama, F.; Ito, H. Evaluation of antioxidant activity of vanillin by using multiple antioxidant assays. Biochim. Biophys. Acta (BBA) Gen. Subj. 2011, 1810, 170–177. [Google Scholar] [CrossRef] [PubMed]
  36. Gülçin, I. Antioxidant activity of caffeic acid (3,4-dihydroxycinnamic acid). Toxicology 2006, 217, 213–220. [Google Scholar] [CrossRef]
  37. Saravanakumar, K.; Park, S.; Sathiyaseelan, A.; Kim, K.-N.; Cho, S.-H.; Mariadoss, A.V.A.; Wang, M.-H. Metabolite Profiling of Methanolic Extract of Gardenia jaminoides by LC-MS/MS and GC-MS and Its Anti-Diabetic, and Anti-Oxidant Activities. Pharmaceuticals 2021, 14, 102. [Google Scholar] [CrossRef] [PubMed]
  38. Slinkard, L.; Singleton, K.; Enol, V.L. Viticult, 28. Anal. Abstr. 1977, 34, 49. [Google Scholar]
  39. Berk, S.; Tepe, B.; Arslan, S.; Sarikurkcu, C. Screening of the antioxidant, antimicrobial and DNA damage protection potentials of the aqueous extract of Asplenium ceterach DC. Afr. J. Biotechnol. 2011, 10, 8902–8908. [Google Scholar]
  40. Cittan, M.; Çelik, A. Development and Validation of an Analytical Methodology Based on Liquid Chromatography–Electrospray Tandem Mass Spectrometry for the Simultaneous Determination of Phenolic Compounds in Olive Leaf Extract. J. Chromatogr. Sci. 2018, 56, 336–343. [Google Scholar] [CrossRef]
  41. Zengin, G.; Sarikurkcu, C.; Gunes, E.; Uysal, A.; Ceylan, R.; Uysal, S.; Gungor, H.; Aktumsek, A. Two Ganoderma species: Profiling of phenolic compounds by HPLC–DAD, antioxidant, antimicrobial and inhibitory activities on key enzymes linked to diabetes mellitus, Alzheimer’s disease and skin disorders. Food Funct. 2015, 6, 2794–2802. [Google Scholar] [CrossRef]
  42. Tepe, B.; Sarikurkcu, C.; Berk, S.; Alim, A.; Akpulat, H.A. Chemical composition, radical scavenging and antimicrobial activity of the essential oils of Thymus boveii and Thymus hyemalis. Rec. Nat. Prod. 2011, 5, 208–220. [Google Scholar]
  43. Apak, R.; Güçlü, K.; Özyürek, M.; Karademir, S.E.; Erçağ, E. The cupric ion reducing antioxidant capacity and polyphenolic content of some herbal teas. Int. J. Food Sci. Nutr. 2006, 57, 292–304. [Google Scholar] [CrossRef] [PubMed]
  44. Kocak, M.S.; Sarikurkcu, C.; Cengiz, M.; Kocak, S.; Uren, M.C.; Tepe, B. Salvia cadmica: Phenolic composition and biological activity. Ind. Crop. Prod. 2016, 85, 204–212. [Google Scholar] [CrossRef]
  45. Zengin, G.; Sarikurkcu, C.; Uyar, P.; Aktumsek, A.; Uysal, S.; Kocak, M.S.; Ceylan, R. Crepis foetida L. subsp. rhoeadifolia (Bieb.) Celak. as a source of multifunctional agents: Cytotoxic and phytochemical evaluation. J. Funct. Foods 2015, 17, 698–708. [Google Scholar] [CrossRef]
Plants 10 01373 g001 550
Figure 1. Liquid chromatography electrospray ionization tandem mass spectrometry (LC−ESI−MS/MS) chromatograms of the methanol extracts of (A) Onosma lycaonica and (B) O. papillosa.
Figure 1. Liquid chromatography electrospray ionization tandem mass spectrometry (LC−ESI−MS/MS) chromatograms of the methanol extracts of (A) Onosma lycaonica and (B) O. papillosa.
Plants 10 01373 g001
Table
Table 1. Extraction yield, total flavonoid and phenolic contents of O. lycaonica and O. papillosa extracts. QEs and GAEs: Quercetin and gallic acid equivalents, respectively. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Table 1. Extraction yield, total flavonoid and phenolic contents of O. lycaonica and O. papillosa extracts. QEs and GAEs: Quercetin and gallic acid equivalents, respectively. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
AssaysO. lycaonicaO. papillosa
Yield (%)3.524.02
Total flavonoids (mg QEs/g extracts)26.0 ± 0.5 b32.9 ± 0.3 a
Total phenolics (mg GAEs/g extracts)43.5 ± 1.5 a33.9 ± 0.4 b
Table
Table 2. Concentration (µg/g extract) of selected phenolic compounds in O. lycaonica and O. papillosa extracts. nd: Not detected. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Table 2. Concentration (µg/g extract) of selected phenolic compounds in O. lycaonica and O. papillosa extracts. nd: Not detected. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
CompoundO. lycaonicaO. papillosa
Gallic acid12.6 ± 0.4 b15.2 ± 0.1 a
Protocatechuic acid162.2 ± 3.6 b249 ± 1.9 a
3,4-Dihydroxyphenylacetic acid11.1 ± 0.6 a7.4 ± 0.1 b
(+)-Catechin30.4 ± 4.2nd
Pyrocatecholndnd
Chlorogenic acid847.5 ± 19.5 b14088 ± 115 a
2,5-Dihydroxybenzoic acid209.5 ± 4.5 b265.8 ± 11.0 a
4-Hydroxybenzoic acid953.4 ± 7.6 a935.3 ± 2.7 a
(−)-Epicatechinndnd
Caffeic acid863.0 ± 43.2 a222.2 ± 2.8 b
Vanillic acid1260 ± 25 a622.1 ± 12.1 b
Syringic acid30.1 ± 1.6 b74.3 ± 0.4 a
3-Hydroxybenzoic acid21.0 ± 1.2 a17.6 ± 0.1 a
Vanillin80.7 ± 3.9 a70.2 ± 6.8 a
Verbascosidendnd
Taxifolinndnd
Sinapic acid26.8 ± 2.8 b83.1 ± 2.1 a
p-Coumaric acid189.5 ± 1.6 b226.7 ± 0.3 a
Ferulic acid1204 ± 8 a495.6 ± 21.6 b
Luteolin 7-glucoside20,846 ± 522 a789.1 ± 10.4 b
Hesperidin15,417 ± 288 b54,123 ± 239 a
Hyperoside2853 ± 64 b4555 ± 100 a
Rosmarinic acid65,632± 1418 a6312 ± 110 b
Apigenin 7-glucoside21,416 ± 361 a1217 ± 129 b
2-Hydroxycinnamic acidndnd
Pinoresinol3567 ± 8 a2756 ± 49 b
Eriodictyol4.3 ± 0.2nd
Quercetin11.0 ± 0.2 b49.6 ± 0.3 a
Luteolin2559 ± 46 a277.4 ± 20.4 b
Kaempferolnd42.2 ± 2.6
Apigenin1623 ± 34 a319.6 ± 18.9 b
Table
Table 3. Antioxidant activity of O. lycaonica and O. papillosa extracts. TEs and EDTA Es mean trolox and ethylenediaminetetraacetic acid (disodium salt) equivalents, BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene). The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Table 3. Antioxidant activity of O. lycaonica and O. papillosa extracts. TEs and EDTA Es mean trolox and ethylenediaminetetraacetic acid (disodium salt) equivalents, BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene). The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Antioxidant Activity O. lycaonicaO. papillosaTroloxBHABHTEDTA
Phosphomolybdenum (EC50: mg/mL)2.05 ± 0.07 c1.90 ± 0.07 c1.16 ± 0.06 b0.31 ± 0.01 a0.38 ± 0.03 a
DPPH scavenging (IC50: mg/mL)2.69 ± 0.10 c3.41 ± 0.05 d0.26 ± 0.02 a0.22 ± 0.02 a1.00 ± 0.03 b
ABTS scavenging (IC50: mg/mL)2.18 ± 0.01 b2.50 ± 0.16 c0.32 ± 0.03 a0.21 ± 0.01 a0.29 ± 0.02 a
CUPRAC reducing (EC50: mg/mL)1.10 ± 0.01 c1.32 ± 0.02 d0.28 ± 0.02 b0.14 ± 0.01 a0.18 ± 0.02 a
FRAP reducing (EC50: mg/mL)0.69 ± 0.01 c0.88 ± 0.02 d0.10 ± 0.01 a0.09 ± 0.01 a0.18 ± 0.01 b
Ferrous ion chelating (IC50: mg/mL)2.32 ± 0.16 b3.65 ± 0.07 c 0.051 ± 0.003 a
Phosphomolybdenum (mg TEs/g extracts)540.6 ± 19.6 a584.3 ± 20.4 a
DPPH scavenging (mg TEs/g extracts)92.6 ± 3.6 a73.1 ± 1.0 b
ABTS scavenging (mg TEs/g extracts)130.6 ± 0.4 a115.1 ± 7.1 a
CUPRAC reducing (mg TEs/g extracts)249.5 ± 1.4 a207.5 ± 3.9 b
FRAP reducing (mg TEs/g extracts)144.4 ± 0.1 a113.1 ± 0.1 b
Ferrous ion chelating (mg EDTAEs/g extracts)21.6 ± 1.5 a14.0 ± 0.3 b
Table
Table 4. Enzyme inhibition activity of O. lycaonica and O. papillosa extracts. GALAEs, KAEs and ACEs mean galanthamine, kojic acid and acarbose equivalents, respectively. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Table 4. Enzyme inhibition activity of O. lycaonica and O. papillosa extracts. GALAEs, KAEs and ACEs mean galanthamine, kojic acid and acarbose equivalents, respectively. The differ superscript in row indicates the significance between the species post hoc (Tukey’s test; p < 0.05).
Enzyme Inhibitory ActivityO. lycaonicaO. papillosaGalanthamineAcarbose Kojic Acid
AChE inhibition (IC50: mg/mL)1.32 ± 0.02 b1.47 ± 0.06 c0.0035 ± 0.0004 a --
BChE inhibition (IC50: mg/mL)8.94 ± 0.08 c4.96 ± 0.07 b0.0058 ± 0.0003 a --
α-Amylase inhibition (IC50: mg/mL)2.57 ± 0.11 b2.40 ± 0.07 b-0.97 ± 0.03 a-
α-Glucosidase inhibition (IC50: mg/mL)2.60 ± 0.14 b2.61 ± 0.04 b-1.74 ± 0.03 a-
Tyrosinase inhibition (IC50: mg/mL)2.20 ± 0.03 b2.05 ± 0.08 b -- 0.31 ± 0.01 a
AChE inhibition (mg GALAEs/g extracts)2.31 ± 0.04 a2.07 ± 0.08 a
BChE inhibition (mg GALAEs/g extracts)0.63 ± 0.01 b1.13 ± 0.02 a
α-Amylase inhibition (mgACEs/g extracts)402.9 ± 18.1 a430.7 ± 13.5 a
α-Glucosidase inhibition (mgACEs/g extracts)670.4 ± 36.7 a666.7 ± 10.7 a
Tyrosinase inhibition (mg KAEs/g extracts)139.0 ± 1.9 a149.0 ± 5.6 a
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Saravanakumar, K.; Sarikurkcu, C.; Sahinler, S.S.; Sarikurkcu, R.B.; Wang, M.-H. Phytochemical Composition, Antioxidant, and Enzyme Inhibition Activities of Methanolic Extracts of Two Endemic Onosma Species. Plants 2021, 10, 1373. https://doi.org/10.3390/plants10071373

AMA Style

Saravanakumar K, Sarikurkcu C, Sahinler SS, Sarikurkcu RB, Wang M-H. Phytochemical Composition, Antioxidant, and Enzyme Inhibition Activities of Methanolic Extracts of Two Endemic Onosma Species. Plants. 2021; 10(7):1373. https://doi.org/10.3390/plants10071373

Chicago/Turabian Style

Saravanakumar, Kandasamy, Cengiz Sarikurkcu, Saliha Seyma Sahinler, Rabia Busra Sarikurkcu, and Myeong-Hyeon Wang. 2021. "Phytochemical Composition, Antioxidant, and Enzyme Inhibition Activities of Methanolic Extracts of Two Endemic Onosma Species" Plants 10, no. 7: 1373. https://doi.org/10.3390/plants10071373

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop