Medicinal Plants from North and Central America and the Caribbean Considered Toxic for Humans: The Other Side of the Coin

Nephroprotective plant species used in traditional Mayan Medicine for renal-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of kidney disease has increased rapidly in recent years and has emerged as one of the leading causes of mortality worldwide. Natural products have been suggested as valuable nephroprotective agents due to their multi-target and synergistic effects on modulating important proteins involved in kidney injury. There is a large number of plant species that have been used traditionally for kidney-related conditions in Mesoamerican medicine by different cultural groups that could provide a valuable source of nephroprotective therapeutic candidates and could lead to potential drug discovery.

AIM OF REVIEW

This review aims to provide an overview of the currently known efficacy of plant species used traditionally in Mesoamerica by Mayan groups to treat kidney-related conditions and to analyze the phytochemical, pharmacological, molecular, toxicological, and clinical evidence to contribute to public health efforts and for directing future research.

METHODS

Primary sources of plant use reports for traditional kidney-related disorders in Mesoamerica were searched systematically from library catalogs, theses, and scientific databases (PubMed, Google Scholar; and Science Direct), and were filtered according to usage frequency in Mayan groups and plant endemism. The database of traditional plants was further analyzed based on associations with published reports of the phytochemical, pharmacological, molecular, toxicological, and clinical evidence.

RESULTS

The most reported kidney-related conditions used traditionally in Mayan medicine involve reducing renal damage (a cultural interpretation that considers an inflammatory or infectious condition), cleaning or purifying the blood and kidney, reducing kidney pain, and eliminating kidney stones. A total of 208 plants used for kidney-related problems by 10 Mayan groups were found, representing 143 native species, where only 42 have reported pharmacological activity against kidney damage, mainly approached by in vitro and in vivo models of chemical- or drug-induced nephrotoxicity, diabetes nephropathy, and renal injury produced by hypertension. Nephroprotective effects are mainly mediated by reducing oxidative stress, inflammatory response, fibrosis mechanisms, and apoptosis in the kidney. The most common nephroprotective compounds associated with traditional Mayan medicine were flavonoids, terpenoids, and phenolic acids. The most widely studied traditional plants in terms of pharmacological evidence, bioactive compounds, and mechanisms of action, are Annona muricata L., Carica papaya L., Ipomoea batatas (L.) Lam., Lantana camara L., Sechium edule (Jacq.) Sw., Tagetes erecta L., and Zea mays L. Most of the plant species with reported pharmacological activity against kidney damage were considered safe in toxicological studies.

CONCLUSION

Available pharmacological reports suggest that several herbs used in traditional Mayan medicine for renal-associated diseases may have nephroprotective effects and consistent pharmacological evidence, nephroprotective compounds, and mechanisms of action in different models of kidney injury. However, more research is required to fully understand the potential of traditional Mayan medicine in drug discovery given the limited ethnobotanical studies and data available for most species with regards to identification on bioactive components, pharmacological mechanisms, and the scarce number of clinical studies.

Factors and Practices Associated with Self-Medicating Children among Mexican Parents

Background: Pediatric self-medication is based on the subjective interpretation of symptoms in children by the mother or an adult, the decision to self-medicate is made by a third party. The objective of this work is to provide information on the factors and practices associated with the self-medication of children among parents in Mexico. Methods: A cross-sectional and descriptive study was conducted between June 2020 and December 2021 on Mexican parents with children under 12 years of age. Online questionnaires were completed with sections on sociodemographic characteristics, use of medicines or medicinal plants and their treated symptoms, sources of collection, and their recommendation. Results: A total of 9905 online surveys were completed with representation from the 32 states of Mexico, and the prevalence of self-medication was 49.6% (n = 4908). Associated factors were age, having two or more children, children with chronic illnesses, medium educational level, unemployment or employment unrelated to health, medium and high socioeconomic level, and lack of medical security. Respondents self-medicated their children on the recommendation of a family member or friend (55.8%), and own initiative (28%). The most used medication was VapoRub (61.3%), followed by paracetamol (56.9%) and chamomile (33.1%), and the most prevalent symptoms were flu/flow (47.7%) followed by cough (34.2%). The main reasons were perceiving symptoms as not serious (69.9%) and reusing medications (51.9%). Conclusions: There is a high prevalence of self-medication in children in Mexico, mainly associated with children with chronic diseases and families with three or more children.

Biological Activities of Organic Extracts of the Genus Aristolochia: A Review from 2005 to 2021

Different ethnomedicinal studies have investigated the relationship between various phytochemicals as well as organic extracts and their bioactive aspects. Studies on biological effects are attributed to secondary metabolites such as alkaloids, phenolic compounds, and terpenes. Since there have been no reviews in the literature on the traditional, phytochemical, and ethnomedicinal uses of the genus Aristolochia so far, this article systematically reviews 141 published studies that analyze the associations between secondary metabolites present in organic extracts and their beneficial effects. Most studies found associations between individual secondary metabolites and beneficial effects such as anticancer activity, antibacterial, antioxidant activity, snake anti-venom and anti-inflammatory activity. The aim of this review was to analyze studies carried out in the period 2005-2021 to update the existing knowledge on different species of the genus Aristolochia for ethnomedicinal uses, as well as pharmacological aspects and therapeutic uses.

Sanitary Registries and Popular Medicinal Plants Used in Medicines and Herbal Remedies in Mexico (2001–2020): A Review and Potential Perspectives

Mexico, a megadiverse country, hosts approximately 10–12% of the world’s biodiversity and at least 21,989–23,424 vascular plants, 3350 of which are traditional medicinal flora. The Mexican Regulation categorizes herbal medicinal products into two groups: herbal medicines products and herbal remedies products. To date, there is no available information that describes and includes analyzed data about these two types of herbal medicinal products registered in Mexico. The purpose of the study was to analyze national sanitary registries of herbal products from 2001 to 2020 and identify native Mexican plants that are most used in herbal products. Further, the study aims to highlight the impact and relevance of this large number of medicinal plants, which represent a great source of information, genetic resources, bioactive compounds, and potential use in subsequent therapies based on scientific evidence. The future of medicines and herbal remedies is underestimated; thus, the significance of evaluating the great potential in studying plants for medicinal use must be taken into account.

Toxicity and Repellency of Magnolia grandiflora Seed Essential Oil and Selected Pure Compounds Against the Workers of Hybrid Imported Fire Ants (Hymenoptera: Formicidae)

We tested Magnolia grandiflora L. (Magnoliales: Magnoliaceae) seed essential oil and its pure compounds for their repellency and toxicity against workers of hybrid imported fire ants. Series of dosages were tested starting from 156 µg/g to the dose where the treatment failed. Workers removed significantly less sand from the vials with M. grandiflora seed essential oil and 1-octanol treated sand at serial dosages of 156-4.9 µg/g than the solvent control whereas the amount removed at 2.4-0.6 µg/g was similar to the solvent control. In 1-decanol treatments, workers removed significantly less sand at serial dosages of 156-0.15 µg/g than the solvent control whereas the removal of sand at the dose of 0.08 µg/g was similar to the solvent control. In DEET (N, N-diethyl-meta-toluamide) treatments, workers removed significantly less sand at serial dosages of 156-78 µg/g than the solvent control whereas the quantity of removed sand at 39 µg/g was similar to the solvent control. Based on the mean amount of sand removed, M. grandiflora essential oil, 1-decanol, and 1-octanol showed significantly higher repellency than DEET. 1-Decanol and 1-octanol, present in seed essential oil showed toxicity against fire ant workers. 1-Decanol with LC50 of 140.6 µg/g was the most toxic natural compound followed by 1-octanol (LC50 = 486.8 µg/g). Bifenthrin with LC50 value of 0.018 µg/g showed much higher toxicity than these natural compounds. High repellency and toxicity of 1-decanol makes it a natural compound of interest for further studies under field conditions.

Medicinal plants used in traditional Mayan medicine for the treatment of central nervous system disorders: An overview

ETHNOPHARMACOLOGICAL RELEVANCE

For thousands of years, different cultural groups have used and transformed natural resources for medicinal purposes focused on psychological or neurological conditions. Some of these are recognized as central nervous system (CNS) disorders and diseases, whereas other ethnopsychiatric interpretations are explained in culture-specific terms. In traditional Mayan medicine, several herbs have been part of treatments and rituals focused on cultural and ethnomedical concepts.

AIM OF REVIEW

This study aims to provide a comprehensive overview of the medicinal plants used in Mesoamerica by traditional healers and Mayan groups to CNS disorders and associate the traditional use with demonstrated pharmacological evidence to establish a solid foundation for directing future research.

METHODS

A systematic search for primary sources of plant use reports for traditional CNS-related remedies of Mesoamerica were obtained from library catalogs, thesis and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct), and entered in a database with data analyzed in terms of the usage frequency, use by ethnic groups, plant endemism, and pharmacological investigation.

RESULTS

A total of 155 plants used for ethnopsychiatric conditions in Mesoamerica by Mayan groups were found, encompassing 127 native species. Of these, only 49 native species have reported in vitro or in vivo pharmacological analyses. The most commonly reported ethnopsychiatric conditions are related to anxiety, depression, memory loss, epilepsy, and insomnia. The extent of the scientific evidence available to understand the pharmacological application for their use against CNS disorders varied between different plant species, with the most prominent evidence shown by Annona cherimola, Justicia pectoralis, J. spicigera, Mimosa pudica, Persea americana, Petiveria alliacea, Piper amalago, Psidium guajava, Tagetes erecta and T. lucida.

CONCLUSION

Available pharmacological data suggest that different plant species used in traditional Mayan medicine may target the CNS, mainly related to GABA, serotonin, acetylcholine, or neuroprotective pathways. However, more research is required, given the limited data regarding mechanism of action at the preclinical in vivo level, identification of active compounds, scarce number of clinical studies, and the dearth of peer-reviewed studies.

Chemical Composition and Content of Biologically Active Substances Found in Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha Growing in Various Territories

Medicinal plants (Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha) growing in various territories (Kaliningrad, Moscow, and Minsk regions) were the objects of research. This paper presents a study of the chemical composition of these plants. To analyze the qualitative and quantitative composition of biologically active substances, the method of high-performance liquid chromatography was used. Atomic absorption spectrometry was used to study the content of trace elements. The content of organic acids and vitamins was determined by capillary electrophoresis using the Kapel-105/105M capillary electrophoresis system with high negative polarity. Extracts of medicinal plants were obtained on a Soxhlet apparatus using 70% ethanol as an extractant. It was found that among the biologically active substances in the plants under discussion, hyperoside, rutin (C. coggygria), Ferulic acid and Gallic acid (D. maculata), triene hydrocarbon (3,7-Dimethyl-1,3,6-octatriene), unsaturated alcohol (3,7-Dimethyl-2,6-octadien-1-ol), and benzyl acetate (P. chlorantha) prevailed. Samples of these medicinal plants contained trace elements (phosphorus, potassium, calcium, sodium, magnesium, and sulfur) and many aliphatic organic acids (succinic acid, benzoic acid, fumaric acid, citric acid, oxalic acid, and tartaric acid). The largest amount of biologically active substances and secondary metabolites of the studied plants from the Eastern Baltic is associated with climatic and ecological differences from other regions. The composition of these plants determines the potential of their use in feed additives for livestock and poultry as part of measures to improve the quality of livestock products. The use of medicinal plants for the production of feed additives is relevant in terms of improving regional economies, as well as improving the quality of life and nation’s health by providing ecologically clean livestock products.

In vitro cytotoxic potential of extracts from Aristolochia foetida Kunth against MCF-7 and bMECs cell lines

The aim of this study was to evaluate the cytotoxic potential of Aristolochia foetida Kunth. Stems and leaves of A. foetida Kunth (Aristolochiaceae) have never been investigated pharmacologically. Recent studies of species of the Aristolochiaceae family found significant cytotoxic activities. Hexane, dichloromethane, ethyl acetate and methanol extracts were analyzed by 1H NMR and GC-MS to know the metabolites in each extract. In GC-MS analysis, the main compounds were methyl hexadecanoate (3); hexadecanoic acid (4); 2-butoxyethyl dodecanoate (9); ethyl hexadecanoate (20); methyl octadeca-9,12,15-trienoate (28) and (9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid (40). The results showed a significant reduction in cell viability of the MCF-7 (breast cancer) cell line caused by organic extracts in a dose-dependent manner. The cytotoxicity activity of the dichloromethane extract from the stems (DSE) showed IC50 values of 45.9 μg/mL and the dichloromethane extract of the leaves (DLE) showed IC50 values of 47.3 μg/mL. DSE and DLE had the highest cytotoxic potential in an in vitro study against the MCF-7 cell line and non-tumor cells obtained from the bovine mammary epithelial (bMECs). DSE and DLE induced a loss in mitochondrial membrane potential (ΔΨm) and can cause cell death by apoptosis through the intrinsic pathway in the MCF-7 cell line. DSE and DLE are cytotoxic in cancer cells and cause late apoptosis. Higher concentrations of DSE and DLE are required to induce a cytotoxic effect in healthy mammary epithelial cells. This is the first report of the dichloromethane extract of A. foetida Kunth that induces late apoptosis in MCF-7 cancer cells and may be a candidate for pharmacological study against breast cancer.

Study of the Properties of In Vitro Dactylorhiza maculata (L.) Soó (Family Orchidaceae) Extracts

The medicinal plant Dactylorhiza maculata (L.) Soó (family Orchidaceae) is used to treat gastritis, colic, gastrointestinal tract, and bladder diseases. This study aimed to investigate the properties and characteristics of the in vitro Dactylorhiza maculata extract. The recommended parameters for producing Dactylorhiza maculata extract were determined: temperature 60 °C, process duration 60 min, hydro module 1:10. It is recommended to carry out the extraction using an aqueous ethyl alcohol solution with a mass fraction of the parent substance of 70%. It was found that such biologically active substances as rutin, quercetin, 3,3',4',5,5',7-hexahydroxyflavonone, 3,3',4',5,5',7-hexahydroxyflavonone-3-O-glycoside, gallic acid, and ferulic acid were dominant in Dactylorhiza maculata. A high phosphorus content was noted (2410.8 mg/kg dry matter). The studied Dactylorhizamaculata samples contained a large number of organic acids and water-soluble vitamins. The tested extracts were safe in terms of the content of heavy metals, pesticides, aflatoxin B1, and radionuclides, as well as pathogenic and opportunistic microorganisms; the content was significantly lower than the threshold limit values. The studied complex of biologically active substances from Dactylorhiza maculata extract samples had antimicrobial properties. It was found that the antioxidant activity of the samples was 217.89 ± 10.89 mg AA/g (AA-ascorbic acid). The high content of bioactive substances and the antimicrobial and antioxidant properties of Dactylorhizamaculata extract samples determine the application potential of this plant as a substitute for growth stimulants and feed antibiotics in the production of feed additives, aiming to increase the physiological and immune status of livestock and poultry.

Effect of Essential Oils on the Release of TNF-α and CCL2 by LPS-Stimulated THP‑1 Cells

Plants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory tract or causing gastrointestinal or joint problems, among others. To support the traditional uses of plant extracts, EOs have been assessed for their alleged anti-inflammatory properties. However, the effect of EOs on the release of cytokines and chemokines has been much less reported. Considering their traditional use and commercial relevance in Portugal and Angola, this study evaluated the effect of EOs on the in vitro inhibition of the cytokine tumor necrosis factor-α (TNF-α) and the chemokine (C-C motif) ligand 2 (CCL2) by lipopolysaccharide (LPS)-stimulated human acute monocytic leukemia cells (THP-1 cells). Twenty EOs extracted from eighteen species from seven families, namely from Amaranthaceae (Dysphania ambrosioides), Apiaceae (Foeniculum vulgare), Asteraceae (Brachylaena huillensis, Solidago virgaurea), Euphorbiaceae (Spirostachys africana), Lamiaceae (Lavandula luisieri, Mentha cervina, Origanum majorana, Satureja montana, Thymbra capitata, Thymus mastichina, Thymus vulgaris, Thymus zygis subsp. zygis), Myrtaceae (Eucalyptus globulus subsp. maidenii, Eucalyptus radiata, Eucalyptus viminalis) and Pinaceae (Pinus pinaster) were assayed for the release of CCL2 and TNF-α by LPS-stimulated THP-1 cells. B. huillensis, S. africana, S. montana, Th. mastichina and Th. vulgaris EOs showed toxicity to THP-1 cells, at the lowest concentration tested (10 μg/mL), using the tetrazolium dye assay. The most active EOs in reducing TNF-α release by LPS-stimulated THP-1 cells were those of T. capitata (51% inhibition at 20 μg/mL) and L. luisieri (15-23% inhibition at 30 μg/mL and 78-83% inhibition at 90 μg/mL). L. luisieri EO induced a concentration-dependent inhibition of CCL2 release by LPS‑stimulated THP-1 cells (23%, 54% and 82% inhibition at 10, 30 and 90 μg/mL, respectively). These EOs are potentially useful in the management of inflammatory diseases mediated by CCL2 and TNF‑α, such as atherosclerosis and arthritis.

Traditional Herbal Medicine in Mesoamerica: Toward Its Evidence Base for Improving Universal Health Coverage

The quality of health care in Mesoamerica is influenced by its rich cultural diversity and characterized by social inequalities. Especially indigenous and rural communities confront diverse barriers to accessing formal health services, leading to often conflicting plurimedical systems. Fostering integrative medicine is a fundamental pillar for achieving universal health coverage (UHC) for marginalized populations. Recent developments toward health sovereignty in the region are concerned with assessing the role of traditional medicines, and particularly herbal medicines, to foster accessible and culturally pertinent healthcare provision models. In Mesoamerica, as in most regions of the world, a wealth of information on traditional and complementary medicine has been recorded. Yet these data are often scattered, making it difficult for policy makers to regulate and integrate traditionally used botanical products into primary health care. This critical review is based on a quantitative analysis of 28 survey papers focusing on the traditional use of botanical drugs in Mesoamerica used for the compilation of the "Mesoamerican Medicinal Plant Database" (MAMPDB), which includes a total of 12,537 use-records for 2188 plant taxa. Our approach presents a fundamental step toward UHC by presenting a pharmacological and toxicological review of the cross-culturally salient plant taxa and associated botanical drugs used in traditional medicine in Mesoamerica. Especially for native herbal drugs, data about safety and effectiveness are limited. Commonly used cross-culturally salient botanical drugs, which are considered safe but for which data on effectiveness is lacking constitute ideal candidates for treatment outcome studies.

Central nervous system evaluation of an ethanol extract of Bidens odorata Cav (Asteraceae) leaves, and its antinociceptive interaction with paracetamol and naproxen

INTRODUCTION

Bidens odorata Cav (Asteraceae) is a medicinal plant employed for the treatment of pain, anxiety, and depression. This study aimed to evaluate some neuropharmacological effects of an ethanol extract of B. odorata (BOE) and assess its antinociceptive interaction with naproxen and paracetamol.

MATERIALS AND METHODS

The following neuropharmacological effects were evaluated with the ethanolic extract of B. odorata leaves (BOE) (10-200 mg/kg p.o.): the strychnine-induced-convulsion assay (anticonvulsant effect), rotarod test (locomotor activity), tail suspension test (anti-depressant-like activity), cylinder exploratory test (anxiolytic-like actions), and pentobarbital-induced sleep test (sedative effect). The interaction of the BOE-paracetamol and BOE-naproxen combinations were evaluated with the acetic acid-induced writhing test. The ED₅₀ value of each drug was estimated and the combinations of paracetamol and naproxen with BOE were calculated.

RESULTS

BOE (100-200 mg/kg) showed anti-convulsant activity by increasing the latency to occurrence of strychnine-induced convulsions, antidepressant-like effects by 28% and 33%, respectively, exerted anxiolytic actions (ED₅₀ = 125 mg/kg), but did not affect motor locomotion. The pre-treatment with 2 mg/kg flumazenil or 20 mg/kg pentylenetetrazol partially reverted the anxiolytic activity shown by BOE alone. BOE (200 mg/kg) prolonged the duration of sleep with similar effect in comparison to clonazepam (1.5 mg/kg). The combinations of BOE-paracetamol (1:1) and BOE-naproxen (1:1) showed antinociceptive synergism.

CONCLUSION

BOE induces sedative and anticonvulsant effects. The anxiolytic actions shown by BOE are probably induced by the participation of the GABAergic system. BOE exerts antinociceptive synergistic interaction with paracetamol and naproxen probably by the participation of nitric oxide and ATP-sensitive K⁺ channels, respectively.

Inhibition of Key Enzymes Linked to Obesity and Cytotoxic Activities of Whole Plant Extracts of Vernonia mesplilfolia Less

The whole plant of Vernonia mespilifolia is widely used as a traditional remedy for obesity in South Africa. The aim of this study was to investigate the anti-obesity and cytotoxic effects of Vernonia mespilifolia extracts in vitro. The α-amylase, α-glucosidase, and lipase inhibitory activities of aqueous and ethanol extracts of Vernonia mespilifolia were investigated, while the cytotoxic effects of these extracts were analyzed using Hoechst 33342 and propidium iodide (PI) dual staining on a human cervical HeLa cell line. The results showed that the LC50 (the concentration of a material will kill 50% of test organisms) values of aqueous and ethanol extracts of Vernonia mespilifolia were >200 and 149 µg/mL, respectively, to HeLa cells. Additionally, the ethanol extract exhibited the strongest inhibitory effect on the pancreatic lipase (Half-maximal inhibitory concentration (IC50) = 331.16 µg/mL) and on α-amylase (IC50 = 781.72 µg/mL), while the aqueous extract has the strongest α-glucosidase (IC50 = 450.88 µg/mL). Our results suggest that Vernonia mespilifolia’s acclaimed anti-obesity effects could be ascribed to its ability to inhibit both carbohydrate and fat digesting enzymes.

Asteraceae Plants as Sources of Compounds Against Leishmaniasis and Chagas Disease

Leishmaniasis and Chagas disease cause great impact on social and economic aspects of people living in developing countries. The treatments for these diseases are based on the same regimen for over 40 years, thus, there is an urgent need for the development of new drugs. In this scenario, Asteraceae plants (a family widely used in folk medicine worldwide) are emerging as an interesting source for new trypanocidal and leishmanicidal compounds. Herein, we provide a non-exhaustive review about the activity of plant-derived products from Asteraceae with inhibitory action toward Leishmania spp. and T. cruzi. Special attention was given to those studies aiming the isolation (or identification) of the bioactive compounds. Ferulic acid, rosmarinic acid, and ursolic acid (Baccharis uncinella DC.) were efficient to treat experimental leishmaniasis; while deoxymikanolide (Mikania micrantha) and (+)-15-hydroxy-labd-7-en-17-al (Aristeguietia glutinosa Lam.) showed in vivo anti-T. cruzi action. It is also important to highlight that several plant-derived products (compounds, essential oils) from Artemisia plants have shown high inhibitory potential against Leishmania spp., such as artemisinin and its derivatives. In summary, these compounds may help the development of new effective agents against these neglected diseases.

Toxicological evaluation of a standardized hydroethanolic extract from leaves of Plantago australis and its major compound, verbascoside

ETHNOPHARMACOLOGICAL RELEVANCE

Plantago australis is a perennial plant widely distributed in Latin America, and its seeds and leaves are used in folk medicine to treat many diseases and conditions. Among its various chemical compounds, verbascoside is one of the most present, and has several pharmacological activities described, but there is not much information about its toxicity.

AIMS OF THE STUDY

The aims of this study were to optimize the extraction of verbascoside from P. australis leaves with ultrasound methods, to develop a validated HPLC method to quantify verbascoside, and to evaluate the toxicological safety of the extract and verbascoside using in vitro and in vivo assays.

MATERIALS AND METHODS

Dried leaves of P. australis were submitted to different extraction methods (percolation and ultrasound). The optimization of the ultrasound extraction was carried out by complete factorial design (2²) and response surface methodology (RSM), followed by HPLC analysis for marker compounds. HPLC analysis was performed to verify the presence of the marker compounds aucubin, baicalein, oleanolic acid, ursolic acid and verbascoside. Mutagenicity was assessed by Salmonella/microsome mutagenicity assay. Cytotoxicity and genotoxicity were evaluated in V79 cells by reduction of tetrazolium salt (MTT) and neutral red uptake (NRU) assays, and alkaline comet assay, respectively. Verbascoside phototoxicity was assessed in 3T3 cells by the NRU phototoxicity assay. Wistar rats were used to perform the acute and sub-chronic toxicity tests.

RESULTS

Among the marker compounds, only verbascoside was found in the hydroethanolic extract of P. australis leaves (PAHE); its highest concentration was obtained with the ultrasound-assisted extraction (UAE) method, optimized in 40 min and 25 °C, and the method validation was successfully applied. Neither PAHE nor verbascoside showed mutagenic or genotoxic activities. Cytotoxicity assays demonstrated that both PAHE and verbascoside reduced cell viability only at the highest concentrations, and verbascoside had no phototoxic properties. The in vivo toxicity evaluation of PAHE suggested that the LD50 is higher than 5000 mg/Kg, indicating that this extract is safe for use. In addition, no signs of toxicity were found in subchronic exposure.

CONCLUSION

The HPLC method to quantify verbascoside was validated, and the extraction of verbascoside from P. australis leaves through ultrasound method was optimized, yielding an extract with 6% verbascoside. Our results suggest the toxicological safety of PAHE and verbascoside, corroborating the use of P. australis in folk medicine, and also indicate verbascoside as a potential ingredient in topical formulations.

Chemical characterization, pharmacological effects, and toxicity of an ethanol extract of Celtis pallida Torr. (Cannabaceae) aerial parts

ETHNOPHARMACOLOGICAL RELEVANCE

Celtis pallida Torr (Cannabaceae) is employed as a folk medicine for the treatment of inflammation, pain, skin infections, and diarrhea, among other diseases.

AIM OF THE STUDY

The purpose of this work was to assess the chemical composition, the in vitro and in vivo toxicity, the antimicrobial, anti-inflammatory, antidiarrheal, antinociceptive, locomotor, and sedative effects of an ethanolic extract obtained from Celtis pallida aerial parts (CPE).

MATERIALS AND METHODS

The composition of CPE was carried out by GC-MS. The in vitro and in vivo toxic activity of CPE was estimated with the comet assay (10-1000 µg/ml) for 5 h in peripheral blood mononuclear cells, and the acute toxicity test (500-5000 mg/kg p.o.), for 14 days, respectively. The antimicrobial effect of CPE was evaluated using the minimum inhibitory concentration (MIC) assay, whereas the antidiarrheal activity (10-200 mg/kg p.o.) was calculated using the castor oil test. The antinociceptive effects of CPE (50-200 mg/kg p.o.) were estimated with the acetic acid and formalin tests, as well as the hot plate test. The sedative and locomotor activities of CPE (50-200 mg/kg p.o.) were assessed with the pentobarbital-induced sleeping time test and the rotarod test, respectively.

RESULTS

The main compound found in CPE was the triterpene ursolic acid (22% of the extract). CPE at concentrations of 100 µg/ml or higher induced genotoxicity in vitro and showed low in vivo toxicity (LD₅₀ > 5000 mg/kg p.o.). Additionally, CPE lacked (MIC > 400 µg/ml) antimicrobial activity but exerts antinociceptive (ED₅₀ = 12.5 ± 1.5 mg/kg) and antidiarrheal effects (ED₅₀ = 2.8 mg/kg), without inducing sedative effects or altering the locomotor activity. The antinociceptive activity of CPE suggests the participation of adrenoceptors, as well as the nitric oxide/cyclic guanosine monophosphate (cGMP) pathway.

CONCLUSION

C. pallida exerts its antinociceptive effects probably mediated by the nitric oxide/cyclic guanosine monophosphate (cGMP) pathway.