Amazonian Plants: A Global Bibliometric Approach to Petiveria alliacea L. Pharmacological and Toxicological Properties

Petiveria alliacea L. (Phytolaccaceae) holds significant importance in the Amazon region, where it has been traditionally utilized in folk medicine. In this study, we conducted a comprehensive bibliometric analysis using conventional metrics, combined with a critical content review of its pharmacological and toxicological properties, to identify gaps in the existing literature that require further investigation. Our investigation identified a total of 55 articles that met the inclusion criteria for this study. Remarkably, Brazil emerged as the primary contributor within the scope of this review, indicating a strong presence of research from this country. Furthermore, professional scientific societies have played a pivotal role in facilitating the dissemination of scientific findings through specialist journals, fostering the sharing of research work within the community. Analysis of keyword co-occurrence revealed that “Petiveria alliacea”, “plant extract”, and “guatemala” were the most frequently encountered terms, indicating their significance within the literature. In terms of study designs, in vivo and in vitro were the predominant types observed, highlighting their prevalence in this field of study. Our study also identified a lack in knowledge yet to be investigated.


Introduction
Medicinal plants are renowned for their traditional application in the treatment of diseases due to their therapeutic properties, being present in the most diverse cultures and civilizations throughout the ages [1].Even today, these plant species are widely sought after due to the expectation of lower risks of adverse reactions and toxicity, which is associated with their natural origin, coupled with easy access and low cost.For similar reasons, they have become the main source of new drug development [2].In this context, the Amazon biome, which includes one of the largest tropical forests in the world, represents a rich storehouse of species and biomolecules whose therapeutic applicability has been the target of numerous studies validating or reforming folk medicine [3][4][5].
Petiveria alliacea L. (Phytolaccaceae) is a plant species widely distributed in the Amazon region but also found in various regions of the Americas, including the Caribbean islands and Mexico [6].It is characterized as an herbaceous plant with a height ranging from 5 to 150 cm, featuring an erect, cylindrical stem and branches [7].In traditional medicine, P. alliacea finds application in various therapeutic approaches, among which stand out antispasmodic, diuretic, abortive, hypoglycemic, anti-inflammatory, and anticancer activity, in addition to central nervous system activities, such as anxiolytic effects, and use in the treatment of dementia and nervous disorders [8].Pre-clinical studies on the species, Plants 2023, 12, 3343 2 of 34 aimed at clarifying the safety of its use and verifying the properties attributed to it by popular knowledge, have validated some of its properties, offering initial information that subsidizes its rational use, as well as the development of herbal medicines and medicines based on their derivatives [9][10][11][12].
Given the different models, mechanisms, and applications already investigated, reviewing this content is important to synthesize discoveries, connect conclusions, and identify gaps in knowledge to be filled.Bibliometric analysis, in turn, emerges as a type of study that utilizes quantitative measures to evaluate the influence, visibility and impact of research output [13].Overall, these analyses contribute to assessing the impact and trends within a specific field, supporting evidence-based decision-making in research [14].
This study aimed to conduct comprehensive global research using bibliometric analysis to evaluate the scientific production concerning the pharmacological and toxicological activities of P. alliacea L. The objective was to collect relevant metric data and provide a global perspective on key aspects, such as study designs, notable authors, contributing countries, and more.By employing bibliometric analysis, the study sought to identify trends, patterns, and research gaps within the existing literature on P. alliacea.Additionally, the study aimed to highlight areas within the literature that require further investigation and exploration, thereby facilitating the identification of research opportunities and potential future directions in this field.

Bibliometric Analysis
Through the search query performed in WoS-CC, a total of 174 articles was retrieved, of which 55 were selected (Table 1) after meeting the inclusion criteria (Figure 1).The Supplementary Section presents the excluded papers along with the reasons for exclusion.
The oldest of the selected papers was published in 1991 [15,16].Interestingly, both articles reported the analgesic properties of P. alliacea.Using a murine model, de Lima et al. [16] confirmed the analgesic effect of P. alliacea, which was already used in many Latin American and African countries for pain relief.In addition, Ferraz et al. [15], in a more robust research protocol (randomized clinical trial), also reported the analgesic activity of P. alliacea in patients with osteoarthritis.The most recent paper was published in 2023 and addressed the cytotoxic properties of P. alliacea against tumor cells [17].The most cited article is a pre-clinical (in vitro) study that also investigated the cytotoxic effects of P. alliacea against hepatic cancer cells [18].The self-nanoemulsifying drug delivery system of Petiveria alliacea extract reduced the homeostatic model assessment-insulin resistance value, interleukin-6, and tumor necrosis factor-alpha level in diabetic rat models https://doi.org//10.4014/jmb.1705.05003 10 15 19 Hernandez et al., 2017 [25] A cytotoxic Petiveria alliacea dry extract induces ATP depletion and decreases beta-F1-ATPase expression in breast cancer cells and promotes survival in tumor-bearing mice https://doi.org//10.1016/j.bjp.2016.09.008 11 20 Gutierrez and Vadillo, 2017 [26] Anti-inflammatory Potential of Petiveria alliacea on Activated RAW264.7   A total of 284 authors were identified, organized into 41 clusters, contributing to at least 1 article (Figure 1).Fiorentino, S. and Cáceres, A. were the authors who published the most (n = 6 and n = 5 papers per author, respectively), followed by Hernandez, J.F., Maia   The 55 selected articles were published in 37 different journals (Table 2), and only 7 of them were published in 2 or more.The Journal of Ethnopharmacology (JEP; JCR impact factor: 5.4), established in 1979 as the official journal of the International Society for Ethnopharmacology (ISE), contained 13 of the publications, including 6 of the 10 most-cited articles and 50.99% of the total citations (Table 2).The 55 selected articles were published in 37 different journals (Table 2), and only 7 of them were published in 2 or more.The Journal of Ethnopharmacology (JEP; JCR impact factor: 5.4), established in 1979 as the official journal of the International Society for Ethnopharmacology (ISE), contained 13 of the publications, including 6 of the 10 most-cited articles and 50.99% of the total citations (Table 2).
Keywords represent essential topics or concepts covered in a research article.In this study, a total of 195 keywords were found, grouped into 28 interconnected clusters, as shown in Figure 2A.The top 10 most frequent keywords were: Petiveria alliacea (n = 37), plant extract (n = 6), Guatemala (n = 4), Phytolaccaceae (n = 4), antibacterial activity (n = 3), cytokines (n = 3), memory (n = 3), antimicrobial activity (n = 3), antinociceptive effect (n = 3), and immunomodulatory (n = 3) (Figure 2B).cytokines (n = 3), memory (n = 3), antimicrobial activity (n = 3), antinociceptive effect (n = 3), and immunomodulatory (n = 3) (Figure 2B).The scientific production related to P. alliacea properties is primarily distributed among a few countries (Figure 3).Brazil is the country with the highest number of publications (n = 17), followed by Mexico (n = 7) and Nigeria (n = 6).Colombia reached five publications, while Cuba and Spain presented four and three publications, The scientific production related to P. alliacea properties is primarily distributed among a few countries (Figure 3).Brazil is the country with the highest number of publications (n = 17), followed by Mexico (n = 7) and Nigeria (n = 6).Colombia reached five publications, while Cuba and Spain presented four and three publications, respectively.Argentina, Guatemala, and Jamaica presented two publications each, while Venezuela, the United States, Indonesia, Germany, France, and Austria contributed one article each (Figure 3A,B).In terms of absolute number of citations, Brazil also ranks first (n = 289), followed by Argentina (n = 159) and Germany (n = 92) (Figure 3C).When evaluating the citation density, however, Germany takes first place (d = 92 per paper), followed by Argentina (d = 79.50 per paper) and Austria (d = 42 per paper).
Plants 2023, 12, x FOR PEER REVIEW 8 of 38 respectively.Argentina, Guatemala, and Jamaica presented two publications each, while Venezuela, the United States, Indonesia, Germany, France, and Austria contributed one article each (Figure 3A,B).In terms of absolute number of citations, Brazil also ranks first (n = 289), followed by Argentina (n = 159) and Germany (n = 92) (Figure 3C).When evaluating the citation density, however, Germany takes first place (d = 92 per paper), followed by Argentina (d = 79.50 per paper) and Austria (d = 42 per paper).

Content Analysis
Based on publication frequency, the period ranging from 2011 to 2020 (n = 23) showed the highest number of published articles, which received an average of 1.86 citations per year.However, the highest number of citations occurred from 2001 to 2010 (n = 498), despite having fewer publications (n = 14), also presenting the highest average of annual citations per paper (2.05) (Figure 4).
Regarding the methodological approach, 29 studies used in vitro assays, and in 20, it was the only approach adopted.In vivo assays, in turn, were present in 31 articles, being exclusive in 20.Studies based exclusively on in vitro assays have the highest number of citations (n = 536), also showing the highest citation density (26.85 citations per article) (Figure 4).

Content Analysis
Based on publication frequency, the period ranging from 2011 to 2020 (n = 23) showed the highest number of published articles, which received an average of 1.86 citations per year.However, the highest number of citations occurred from 2001 to 2010 (n = 498), despite having fewer publications (n = 14), also presenting the highest average of annual citations per paper (2.05) (Figure 4).
Regarding the methodological approach, 29 studies used in vitro assays, and in 20, it was the only approach adopted.In vivo assays, in turn, were present in 31 articles, being exclusive in 20.Studies based exclusively on in vitro assays have the highest number of citations (n = 536), also showing the highest citation density (26.85 citations per article) (Figure 4).
For the preparation of the extracts, mainly the leaves and roots of P. alliacea were used, highlighting the techniques of maceration, percolation, and Soxhlet extraction.The most frequently used solvents were ethanol and methanol in extraction and fractionation processes, including ethyl acetate.These and other relevant information are summarized in Table 3.For the preparation of the extracts, mainly the leaves and roots of P. alliacea were used, highlighting the techniques of maceration, percolation, and Soxhlet extraction.The most frequently used solvents were ethanol and methanol in extraction and fractionation processes, including ethyl acetate.These and other relevant information are summarized in Table 3.

Antinociceptive study
In this study, the authors investigated the antinociceptive potential of P. alliacea in 14 patients with osteoarthritis.The authors reported no statistically significant evidence that P. alliacea was superior to placebo in reducing the severity of pain.
However, the authors emphasized the possibility that the small sample of patients compromised the statistical analysis performed.In vivo study de Lima et al., 1991 [16] Pre-clinical in vivo study (male and female mice)

Oral administration (gavage) or parenteral administration (intraperitoneal); Single dose
Antinociceptive study In this study, the authors evaluated the effects of aqueous crude extract of P. alliacea on sedative and analgesic properties in mice and rats.The authors stated that the antinociceptive effect in acetic acid, acetylcholine, and hypertonic saline induced animal constrictions but not in hot-plate and tail flick tests.The authors also reported that P. alliacea did not produce any CNS depressor effect.

Antinociceptive study
In this study, the authors investigated the antinociceptive potential of P. alliacea in 14 patients with osteoarthritis.The authors reported no statistically significant evidence that P. alliacea was superior to placebo in reducing the severity of pain.However, the authors emphasized the possibility that the small sample of patients compromised the statistical analysis performed. In

Anti-inflammatory and analgesic study
In this study, the authors investigated the anti-inflammatory properties of P. alliacea crude extract administered to rats with pleurisy.The authors reported that the oral administration did not reduce the total number of leukocytes at the doses tested.However, the highest dose (43.9 mg/kg) reduced mononuclear cell migration, in addition to having an analgesic effect.The authors emphasized that the results provide a basis for folk medicine use, but further studies are necessary to elucidate the mechanism of anti-inflammatory and analgesic actions.In this study, the authors tested the effects of an aqueous extract of P. alliacea on acute and sub-chronic toxicity in male mice.The authors reported that no mortality nor any toxicity signs could be observed.The authors also stated that no significant differences in intestinal motility or blood glucose levels could be found.In this study, the authors evaluated the behavioral and oxidative stress effects of hydroalcoholic extracts of P. alliacea in rats.The authors reported increased locomotor activity, as well as antidepressant and anxiolytic, in behavioral tests.The oxidative stress assessment showed pro-oxidative effects in vivo and in vitro.
The authors also suggest that the polyphenols found in P. alliacea may have neuronal mechanisms that potentially regulate anxiety as well as oxidative stress.In this study, the authors evaluated the morphologic alterations in the respiratory tract of female rats induced by the inhalation of P. alliacea steams.The authors reported that the main histological and morphological alterations were hyperplasia on the trachea epithelium, signs of elevated secretion from goblet cells, and vascular congestion on the bronchiole.The authors also suggest that the morphologic alterations happened due to coumarins present in the chemical composition of P. alliacea.

Christie and
Levy, 2013 [34] Pre-clinical in vivo study (male rats) Leaves Decoction method; Solvent: water Not investigated 200 and 400 mg/kg Oral administration (gavage); Single dose Antidiabetic study In this study, the authors evaluated the hypoglycemic effect of P. alliacea on a model of diabetes induced with streptozotocin, as well as the effect of P. alliacea in normoglycemic female rats.The authors report that they did not observe a hypoglycemic effect in the model used.The authors state that the results are contrary to the medicinal use of the species, which does not support the use of P. alliacea for hypoglycemic purposes.In this study, the authors investigated the acute and repeated toxicity of a powdered suspension of leaves and stems of P. alliacea.The authors reported that there was no death of the animals and no adverse effects that impacted the weight, general condition, and histopathological characteristics of the animals were observed.

Alves et al., 2019 [13]
Pre-clinical in vivo study (male rats) Whole plant No extraction method was adopted.

Petiveria alliacea powder (vegetable drug) was used
For the phytochemical characterization, the authors used fresh leaves of P. alliacea, in which the following were identified: Dimethylsulfide, Diethylsulfide, α-Pinene, ß-Pinene, Di-n-propylsulfide and Nerolidol 25 or 50 mg of the dried plant were burned to charcoal in a specific inhalation device Inhalation route: Single exposure (each animal remained for 60 s in the inhalation chamber)

Behavioral study (anxiolytic activity) plus toxicological study (evaluation of lung inflammation)
In this study, the authors investigated the composition and exposure of animals to P. alliacea smoke.The objective of the study was to evaluate the potential anxiolytic and toxic effects of this exposure.The authors reported that there was no anxiolytic effect in the animals, but after histological analysis, there was possible pulmonary inflammation.

Anti-inflammatory study
In this study, the authors investigated the extract of P. alliacea using a self-nanoemulsifying drug release model in an animal model with insulin resistance.The study evaluates the levels of interleukin (IL)-6 and TNF-α with the aim of evaluating the effects of P. alliacea on inflammation associated with diabetes.The authors reported that the proposed model enabled the reduction in insulin resistance, as well as suppressed the levels of (IL)-6 and TNF-α.
In vitro study In this study, the authors conducted a phytochemical investigation on the extract of P. alliacea roots, isolating five substances known as polysulfides.The authors also tested different fractions for antifungal activity.The authors reported that the fractionation led to the isolation of dipropyl disulfide, dibenzyl disulfide, dibenzyl trisulfide, benzylhydroxymethyl sulfide, and di(benzyltrithio) methane, the last three substances being new compounds.

Not applicable Hematological study
In this study, the authors evaluated the anticycling activities of aqueous fractions of P.
alliacea on hematological cells.The authors reported that three fractions showed significant anticycling activity.The phytochemical screening revealed the presence of saponins, tannins, and alkaloids.The authors also emphasize that the popular use of P. alliacea for sickle cell disease is justified.

Not applicable
Immunomodulatory study In this study, the authors evaluated the immunomodulatory activity of aqueous and organic plant fractions from P. alliacea using human monocyte-derived dendritic cells.The authors found that the aqueous fraction induced morphological changes in dendritic cells and pro-inflammatory cytokines secretion.The fraction also increased NF-kB gene expression while down-regulating TGF β gene expression.
The authors also emphasize that the organic fraction by itself showed no immunomodulatory activity.In this study, the authors investigated the potential antimicrobial activity of P. alliacea from different regions of Martinique.The authors reported that the essential oil extracted from one of the selected sites inhibited the growth of several microorganisms, including some multiresistant strains.The authors also commented on the importance of studies with fractionated oil to identify the antimicrobial molecules involved in the observed activity.

Whole plant
Three types of extract were prepared: aqueous (whole plant, roots), 65% ethanolic (whole plant, leaves and trunk, roots), and 96.5% ethanolic (roots only).A tincture was also prepared using rum as solvent (alc/vol = 63%).In total, seven extracts were prepared; Aqueous type extracts were prepared by the infusion method; the ethanolic ones, by maceration

Not investigated
In this paper, the adopted concentrations were not clearly presented

Not applicable
Pharmacokinetic study In this study, the authors carried out an analysis of the effects of dibenzyl trisulfide (DTS) on the activities of the cytochrome P450 enzyme, an important enzyme for the process of drug metabolism.The authors demonstrate in their study that DTS acts as a cyp450 inhibitor and consider P. alliacea a valuable species for many studies that seek to investigate the impact of high DTS content on drug interactions important for clinical therapy.In this study, the authors evaluated the ability of P. alliacea to control nematodes.The authors reported that in their study, they observed a strong effect of preventing the hatching of eggs when treated with P. alliacea, which is a response to the hypothesis proposed in the study, the use of plants as an alternative for anthelmintic treatment.In this study, the authors investigated the synthesis of silver nanoparticles using P. alliacea.
The authors report that the described model showed 100% inhibition against Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus, as well as antifungal activity and prevented human blood clotting, which confirms the antimicrobial and anticoagulant activities of P. alliacea.

Immunomodulatory study
In this study, the authors aimed to isolate and characterize the molecules responsible for the immunomodulatory properties of P. alliacea.The authors assayed in vitro phagocytosis, in vivo organ assessment, and isolation of dibenzyltrisulfide.The authors stated that P. alliacea extract and its isolated compound caused an alteration in blood cell count and an increase in the weight of the thymus and Peyer's patches, suggesting an increase in the cellular and endocrine process responsible for T-cell differentiation.The authors emphasized that further studies were necessary to elucidate the appropriate mechanisms.

Antiprotozoal study
In this study, the authors investigated the antiprotozoal activity of extracts from five different plants against Trypanosoma cruzi in vitro.
Regarding P. alliacea, the authors state that the hexane and ethanol extracts of P. alliacea leaves and hexane and methanol extracts of the root showed activity against trypomastigotes.However, both plant parts were not effective against epimastigotes.The authors also reported that leaf extracts showed no toxicity in vitro, whereas hexane and methanol extracts were toxic.
The authors conclude that the chloroform fraction was very active against trypomastigotes and showed little activity against epimastigotes but showed in vitro toxicity.

Antimicrobial study
In this study, the authors screened 13 different native plants used in Guatemala for the treatment of protozoal infections, assessing antibacterial and antifungal activities.Regarding P. alliacea, the authors state that the extract showed antitrypanosomal activity in vitro but not in vivo.In the toxicity assay, no toxic effects were present in the studied dose (500 mg/kg).

Quadros et al.,
1999 [53] Pre-clinical in vitro study (microorganisms) and in vivo study (male mice) Roots Maceration method; Solvents: ethanol and water

Not investigated 1000 mg/kg
Oral administration (gavage); Daily for 5 days, once a day

Immunomodulatory study
In this study, the authors investigated the effects of Petiveria alliacea on the hematopoietic response of mice infected with Listeria monocytogenes.The authors state that there was a protective effect of the crude extract of P. alliacea since the survival of the treated infected was higher than that in the infected group.The authors also suggest an immunomodulation effect of Petiveria alliacea extract on hematopoiesis, which may be responsible for the increased resistance of mice to Listeria monocytogenes infection.

Not applicable Cytotoxicity study
In this study, the authors evaluated the potential biological activity of a P. alliacea fraction and its effects in a model of metastatic breast adenocarcinoma (4T1).The authors report that in the study, the fraction of P. alliacea in vitro induced apoptosis of 4T1 cells, as well as reporting that there was regression of primary breast tumors.The authors suggest that the glycolytic pathway contributes to elucidating the action of the fraction in antitumor and antiproliferative activity.

Anticancer study
In this study, the authors evaluated the antitumor capacity of P. alliacea.To evaluate one of its traditional uses, a murine model of breast cancer was used.The authors reported that P. alliacea promoted a decrease in breast cancer cells in the in vitro and in vivo model; mice that were transplanted with tumor and were treated with P. alliacea demonstrated a reduction in primary tumor growth.

Antimalarial study
In this study, the authors investigated the potency of P. alliacea against mosquitoes of the genus Anopheles gambiae in different stages of life.The authors also reported that the use of P. alliaceae was highly effective, which strengthens the idea of replacing chemical insecticides and reducing the harmful effects related to the use of these substances.

Anti-inflammatory study
In this study, the authors carried out an investigation of the topical anti-inflammatory activity of P. alliacea using the paw edema model.The authors state that there was strong topical anti-inflammatory activity and comment that in the evaluation of the molecular docking of some of the most abundant compounds present in the composition of the constituents, some of them proved to be potential topical anti-inflammatory agents.The study also further recommended in vivo studies with isolated compounds to confirm such activities.

Antinociceptive study
In this study, the authors evaluated the effects of some P. alliacea extracts on the antinociceptive activity through the formalin test and on the toxicity of the extracts through the acute oral toxicity test.The authors related the phytochemical composition of the extracts with positive results in the antinociceptive evaluation, where there was a reduction in pain.They also stated that the extracts proved to be safe, with no risk to health.In this study, the authors performed a review with the aim of compiling information on the use of medicinal plants in Mesoamerica as a traditional use for the treatment of CNS disorders.
The authors provide information about the traditional use of P. alliacea as a treatment for dementia, epilepsy, and some nervous treatments.
The study reports some information from pharmacological tests performed on animals, pointing out anticonvulsant and anxiolytic activities and effects on memory.

Discussion
In plants lies the main source of inputs for health care, whether in the industrialtechnological development of medicines or in the popular use of their teas, ointments, and baths, among others.In this perspective, scientific research is essential for the discovery and characterization of new species with therapeutic and economic potential, as well as for subsidizing the safe and rational use of these species as a complementary healthcare strategy [59].Understanding the beneficial and harmful effects of plant species, as well as the dose range and use profile associated with these effects, is valuable information, providing safer and/or more effective alternatives for the treatment of diseases.
It is noticed, however, that the study of medicinal plants often presents a slow and fragmented advance, rarely resulting in robust clinical studies or innovative products.Along with this, it is noted that its application as a complementary strategy for health care lacks foundation and standardization [59].P. alliacea, in turn, is a species widely known by the population of the Americas and regions of Africa, having a diverse range of popular indications, some of which have already been the subject of investigation.To the best of our knowledge, this is the first scientific report with a bibliometric approach plus critical content analysis addressed to an Amazonian medicinal plant.Here, we focused on analyzing the scientific production of this medicinal herb, aiming to highlight its breadth, scope, impact, and stage of development, providing opportunities to identify the main active research groups and any gaps in the existing scientific literature.
Bibliometric studies offer a valuable approach to visualizing scientific production and analyzing metrics and trends within a specific field [60].Conducting a bibliometric review requires a well-defined strategy to rescue studies related to the previously determined object of study.This strategy must be formulated considering Zipf's law, a fundamental concept of bibliometrics, which associates the frequency of specific words (keywords) with terms that determine the essence of a scientific article [60][61][62].In our study, using this approach, we found that the top 10 most frequent keywords aligned with our search strategy, which emphasizes the importance of thorough research and rigorous keyword choice.
Another analysis that this type of study allows us, through Lotka's law, is to observe which are the most prolific authors on the subject analyzed and with which researchers they communicate [60,63].In another way, Lotka's law seeks to understand the trends on the subject and the vision of the connections between research networks [64].This observation is important to know the worldwide contribution of researchers on a theme.We identified 285 researchers involved in the study of P. alliacea, dedicated to elucidating its toxicological and pharmacological properties.Despite the interest of several research groups of different nationalities, the connection between them is scarce, one of the factors that can contribute to the overlapping of trials and difficulty in advancing to new levels of research.The formation of collaboration networks, despite the contiguity of articles and harmony of results, is practically non-existent.
The third law of bibliometric study is Bradford's law, which turns to the evaluation of the journals where the selected studies were published [60,[65][66][67].In this analysis, we used quantitative parameters, such as the Journal Citation Reports (JCR), the number of articles published, the number of citations received, or even the density of citations, to measure the participation and impact of journals in the dissemination of the knowledge investigated [65].In our prospection, the journals had an average impact factor of 2.14 ± 2.15 (0-7.9), with 59% of the journals having JCR ≥ 2.0 and 31.5% > 5.0.JEP, which in 2023 presents JCR = 5.4, stood out for the number of articles on the biological effects of P. alliacea, having published 13 studies, while other journals did not exceed 2 articles.Further, considering that the articles published in JEP had 509 citations, equivalent to 51.16% of the total number of citations obtained by the selected articles, we can point to the journal of the International Society for Ethnopharmacology as the most influential journal in disseminating knowledge about P. alliacea bioactive properties.
Because it is a widely distributed species in the Americas, especially in the Amazon region, but also in Mexico and the Caribbean, its popular use is widespread in traditional communities of the region countries [27].In relation to scientific research on its bioactive properties, we found that it is concentrated in the Americas (n = 41), mainly South America (n = 25), with emphasis on Brazil, the country that hosted 17 of the published studies.Central and North America hosted eight published studies each, with emphasis on Mexico, home to seven studies.Interestingly, however, studies originating in Africa (n = 6), Europe (n = 6), and Asia (n = 1) were also located, showing that the interest in its potential goes beyond the borders of its cultural insertion.Brazil's leadership in the subject is confirmed by the impact of published studies, which have up to 289 citations.Moreover, four of these studies are among the ten most cited.This position may be related to the strong presence of groups dedicated to the study of medicinal plants in the country, greatly stimulated by the local biodiversity [68].Despite this, we noticed that the studies were developed independently by specific institutions, evidencing the lack of interaction between research groups and the formation of networks, as previously discussed.
After the metric design of the dissemination and scientific impact of the P. alliacea knowledge, we turn to the paper's content to expose the main interests in relation to the bioactive properties of the plant, the derivatives and formulations explored, the methodological strategies applied, and conclusions achieved, which are summarized in Table 2.This approach allows us to map the state-of-the-art study and expose its limitations, gaps, and perspectives.
Our research identified the first published studies related to the subject, the article "The effectiveness of tipi in the treatment of hip and knee osteoarthritis-A preliminary report" by Ferraz et al. [15] and "Evaluation of antinociceptive effect of Petiveria alliacea (guiné) in animals" by de Lima et al. [16], both published in Supplementary Volume 2 of the 86th edition of the Brazilian journal 'Memórias do Instituto Oswaldo Cruz', in 1991.Interestingly, the first study tracked on the species was a randomized clinical trial that explored a P. alliacea infusion as a therapeutic alternative for osteoarthritis treatment, which promoted superior pain relief compared to placebo despite having a reduced sample.Even more impressive is that, after 32 years, no further clinical trials related to the species have been identified.This occurrence could be initially related to the scarcity of studies that could subsidize clinical studies, a very present reality when it comes to the evaluation of medicinal plants.As previously mentioned, the lack of continuity and fragmentation of studies constitute a significant barrier to the advancement of herbal medicine research and development [69].
It is also interesting to note the progression in the number of publications over the years, which was 0.9 articles/year in the first decade, increasing in the following decades to 1.4 and 2.3 articles/year.Between 2021 and 2022, eight articles were published [2,4,[6][7][8][9]12,19].This, however, points to the continuity of the progression, reaching four articles/year.In this last period, we also observed the inclusion of computational tools (in silico methods) to investigate the properties and mechanisms of P. alliacea [8].
Toxicity studies investigated the cytotoxicity [6], genotoxicity and acute [58], and sub-chronic [46] toxicity of P. alliacea.In general, the tried extracts and fractions showed low toxicity, except for the described toxicity against cancer cells [48], based on their potential anticancer property.In addition to the most investigated actions, its behavioral effects have also been demonstrated, reducing depressive and anxious-like behaviors, antiparasitic, antifungal, anticoagulant, anticholinesterase, and insecticide activity, among others.These findings point to a multi-target pattern of action, with the potential to treat diseases and comorbidities simultaneously, which, when used rationally, can promote significant gains in terms of therapy and quality of life for patients [3].
Interestingly, despite the pre-clinical and clinical approaches that confirm its properties, no medicine, not even an herbal medicine, has been developed from this species or its metabolites.Unfortunately, this is an overview of studies involving medicinal plants, especially in South American countries, which, in the case of P. alliacea, concentrates most of the studies on their biological activities.
We observed that none of the studies carried out with the plant were continued, in the sense of starting, for example, the toxicity study and carrying out all the steps for the characterization of its toxicological safety.In many cases, a research group performs only the acute oral toxicity, but not the subchronic or chronic, or even only evaluates the basic parameters.A similar occurrence happens in pharmacological evaluation.For example, Gomes et al. [47] performed the antinociceptive evaluation of fractions of P. alliacea extracts.However, they did not report the toxicity data for the fractions.Thus, they discuss the effects on nociception observed based on phytocompounds described in the literature from other derivatives of the species.
It is known that metabolite plant content can be altered by numerous factors, such as the part used, seasonality, extraction type, comminution degree of the particles submitted to extraction, etc.Therefore, it is essential that the assessment of pharmacological properties is always accompanied by the phytochemical profile of the natural product being studied.A chemical content investigation would not only help to validate the results but could also direct research on possible compounds involved, especially in the current scenario, in which in silico studies for the characterization of the structure and activity of compounds or their improvement may be realized.On the other hand, the effect of the medicinal species is not always mediated by a single compound, but by a set of them, called a phytocomplex [70].Such characteristics do not exclude its therapeutic potential; however, it demands a rigorous toxicological characterization, as well as the standardization of the preparation to be tested.This lack of dialogue between chemical and biological analyses is largely due to the fragmentation of studies by different research groups and the lack of an effective network for investigating the biological activity of plants with the aim of generating a product, following all the necessary steps, especially in countries in South America.Such a scenario is in contrast with reality, where one of the largest and richest biomes in the world is located on this continent, whose pharmacological potential still needs to be investigated [71].Thus, this work can contribute to reinforcing the necessity of continuity of research carried out with P. alliacea, pointing out study trends through the presented metrics and reinforcing the gaps in the existing knowledge.

Materials and Methods
We performed a bibliometric-type analysis, as previously reported by our research group [72].

Data Source and Collection
The Web of Science Core Collection (WoS-CC) database was used to perform a global search on P. alliacea.The data collection was performed on 3 August 2023; the applied search strategy is described in Figure 5.This lack of dialogue between chemical and biological analyses is largely due to the fragmentation of studies by different research groups and the lack of an effective network for investigating the biological activity of plants with the aim of generating a product, following all the necessary steps, especially in countries in South America.Such a scenario is in contrast with reality, where one of the largest and richest biomes in the world is located on this continent, whose pharmacological potential still needs to be investigated [71].Thus, this work can contribute to reinforcing the necessity of continuity of research carried out with P. alliacea, pointing out study trends through the presented metrics and reinforcing the gaps in the existing knowledge.

Materials and Methods
We performed a bibliometric-type analysis, as previously reported by our research group [72].

Data Source and Collection
The Web of Science Core Collection (WoS-CC) database was used to perform a global search on P. alliacea.The data collection was performed on 3 August 2023; the applied search strategy is described in Figure 5.

Establishment of Inclusion Criteria
Selected documents were original articles or review articles that explored the pharmacological and toxicological properties of P. alliacea, and no language restrictions were applied.Conference papers, editorials, letters to authors, proceedings papers, articles not freely available, studies focused on ethnopharmacology, and publications that did not assess the pharmacological properties of P. alliacea for therapeutic purposes were excluded.

Establishment of Inclusion Criteria
Selected documents were original articles or review articles that explored the pharmacological and toxicological properties of P. alliacea, and no language restrictions were applied.Conference papers, editorials, letters to authors, proceedings papers, articles not freely available, studies focused on ethnopharmacology, and publications that did not assess the pharmacological properties of P. alliacea for therapeutic purposes were excluded.

Articles Selection
After defining the inclusion criteria, two independent researchers searched for articles through the WoS-CC platform.In cases of divergence about the inclusion of articles, a third experienced researcher was consulted.Subsequently, a survey of citations of selected articles was performed in other databases (Scopus and Scholar Google).

Bibliometric Analysis
Based on the data obtained from WoS-CC, bibliometric analyses were performed.Here, we collected information about articles' titles, author's name, number of citations, Plants 2023, 12, 3343 30 of 34 citation density by country, journal's name, journal's impact factor (considering JCR 2022, ©2023 Clarivate), author's keywords, countries, and institutions.The VOSviewer software (version 1.6.16)was used to visualize the metrics listed [72].The generated networks are represented by nodes (clusters) and lines (connections); the cluster size is directly proportional to the number of publications/citations of authors, frequency of occurrence of keywords, and institutions; the lines between each cluster represent the co-authorship network, the connection between keywords, or inter-institutional connection.Based on this, we also performed the total link strength between authors and keywords.To illustrate the global distribution of selected publications, the MapChart tool (https://mapchart.net/,accessed on 3 August 2023) was used.

Content Analysis
Considering the scarce scientific production on medicinal plants, mainly P. alliacea, it was decided to critically analyze the study designs, phytochemical approaches, protocol used, pharmacological activity, and study summary of the selected articles.With this information gathered, this review provides robust research on the use of P. alliacea for pharmacological purposes.Figure 6 demonstrates the methodological strategy applied to perform the critical analysis.
a third experienced researcher was consulted.Subsequently, a survey of citations of selected articles was performed in other databases (Scopus and Scholar Google).

Bibliometric Analysis
Based on the data obtained from WoS-CC, bibliometric analyses were performed.Here, we collected information about articles' titles, author's name, number of citations, citation density by country, journal's name, journal's impact factor (considering JCR 2022, © 2023 Clarivate), author's keywords, countries, and institutions.The VOSviewer software (version 1.6.16)was used to visualize the metrics listed [72].The generated networks are represented by nodes (clusters) and lines (connections); the cluster size is directly proportional to the number of publications/citations of authors, frequency of occurrence of keywords, and institutions; the lines between each cluster represent the co-authorship network, the connection between keywords, or inter-institutional connection.Based on this, we also performed the total link strength between authors and keywords.To illustrate the global distribution of selected publications, the MapChart tool (https://mapchart.net/accessed on 3 August 2023) was used.

Content Analysis
Considering the scarce scientific production on medicinal plants, mainly P. alliacea, it was decided to critically analyze the study designs, phytochemical approaches, protocol used, pharmacological activity, and study summary of the selected articles.With this information gathered, this review provides robust research on the use of P. alliacea for pharmacological purposes.Figure 6 demonstrates the methodological strategy applied to perform the critical analysis.Figure 6.Methodological strategy applied to perform the critical analysis.

Conclusions
In this bibliometric analysis, we evidenced the paradox between the growing interest in investigating plants with therapeutic potential and the limitations and gaps in scientific research on the subject.Studies on this species, widely disseminated in the medicinal culture of American populations, especially the Amazon, demonstrated an important analgesic -Including through clinical trial -immunomodulatory, anti-inflammatory and

Conclusions
In this bibliometric analysis, we evidenced the paradox between the growing interest in investigating plants with therapeutic potential and the limitations and gaps in scientific research on the subject.Studies on this species, widely disseminated in the medicinal culture of American populations, especially the Amazon, demonstrated an important analgesic -Including through clinical trial -immunomodulatory, anti-inflammatory and antioxidant potential, among others.It is therefore necessary to deepen and advance scientific research, which can be enhanced by greater interaction between research groups.In this sense, this review presents a comprehensive overview of the research already carried out on the toxicity and pharmacological properties of P. alliaceae, its ecosystem of publications and researchers dedicated to the topic, in an intuitive and pragmatic way, providing insights for this subject advancement.

Figure 1 .
Figure 1.Network visualization of authors with the number of publications (A), citations (B), and leading network of authors (C).There is a direct proportionality of the cluster size and the number of publications or citations.

Figure 1 .
Figure 1.Network visualization of authors with the number of publications (A), citations (B), and leading network of authors (C).There is a direct proportionality of the cluster size and the number of publications or citations.

Figure 2 .
Figure 2. Network visualization of the co-occurrence of the keywords used by the authors of the selected studies using the VOS viewer software.Clusters are highlighted by different colors.The node size represents the frequency of the keyword, and the lines reveal the connections between the keywords (A).The top 10 most frequent words are represented in panel (B), associated with their total link strength.

Figure 2 .
Figure 2. Network visualization of the co-occurrence of the keywords used by the authors of the selected studies using the VOS viewer software.Clusters are highlighted by different colors.The node size represents the frequency of the keyword, and the lines reveal the connections between the keywords (A).The top 10 most frequent words are represented in panel (B), associated with their total link strength.

Figure 3 .
Figure 3. Worldwide distribution of selected articles (A) with the representation of countries from published articles (B), total number of citations (C), and citation density (D).

Figure 3 .
Figure 3. Worldwide distribution of selected articles (A) with the representation of countries from published articles (B), total number of citations (C), and citation density (D).

Figure 4 .
Figure 4. Historical series of publications by decade (A) and study types by year (B).

Figure 4 .
Figure 4. Historical series of publications by decade (A) and study types by year (B).

Figure 5 .
Figure 5. Schematic representation of the search strategy applied to retrieve selected articles.

Figure 5 .
Figure 5. Schematic representation of the search strategy applied to retrieve selected articles.

Figure 6 .
Figure 6.Methodological strategy applied to perform the critical analysis.

Accessed on 3 August 2023) Number of Citations
Medicinal plants used in traditional Mayan medicine for the treatment of central nervous system disorders: An overview https://doi.org//10.1016/j.

Table 3 .
Synthesis of selected articles on Petiveria alliacea L. in WoS-CC, highlighting phytochemical and pharmacological aspects and main findings.

Table 3 .
Synthesis of selected articles on Petiveria alliacea L. in WoS-CC, highlighting phytochemical and pharmacological aspects and main findings.
Irwin test method.Regarding P. alliacea, the authors stated that the extract from roots only lightly decreased spontaneous motor activity, and the leaf extract showed hyperexcitability.The authors emphasize that P. alliacea has little effect on behavioral, neurologic, and autonomic signs compared to other plants studied.
In this study, the authors evaluated the effects of aqueous crude extract of P. alliacea on sedative and analgesic properties in mice and rats.The authors stated that the antinociceptive effect in acetic acid, acetylcholine, and hypertonic saline induced animal constrictions but not in hot-plate and tail flick tests.The authors also reported that P. alliacea did not produce any CNS depressor effect.In this study, the authors investigated the effects of P. alliacea extract on the production of Th1-type and Th2-type cytokines and on NK cell activity in normal and infected mice.The authors suggest that P. alliacea administration up-regulates antibacterial immune response by enhancing both Th1 function and the activity of NK cells.

Table 3 .
Cont.Based on tests, the authors demonstrated that P. alliacea has the activities they set out to investigate.

Table 3 .
Cont. the authors stated that the extract did not show any inhibitory effect on Hep G2 in the range of doses assayed (15.5-1000 µg/mL).In this study, the authors assayed five different medicinal plants used in Argentina to detect the inhibition of viral growth.Regarding P. alliacea, the authors stated that the extract inhibited bovine viral diarrhea virus replication but showed no activity against herpes simplex virus type 1, poliovirus type 1, adenovirus serotype 7, and vesicular stomatitis virus type 1.The authors conclude that, among the five different plants studied, P. alliacea was worth studying in the future.