Antiprotozoal, antimycobacterial, and anti-inflammatory evaluation of Cnidoscolus chayamansa (Mc Vaugh) extract and the isolated compounds

Five centuries of Cirsium ehrenbergii Sch. Bip. (Asteraceae) in Mexico, from Huitzquilitl to Cardo Santo: History, ethnomedicine, pharmacology and chemistry

ETHNOPHARMACOLOGICAL RELEVANCE

Several medicinal plants, including the endemic herb Cirsum ehrenbergii (Asteraceae), have been documented in manuscripts, medical and botanical books written in Mexico since the XVI century until the present. This unique circumstance is a real window in the time that allows to investigate historical and contemporary ethnopharmacological knowledge.

AIM OF THE STUDY

To examine the persistence, disappearance, and transformation of ethnomedicinal knowledge of C. ehrenbergii along time. Also, to investigate the chemistry and pharmacology of this species in relation to its historical and present day main ethnomedical applications related to Central Nervous System and inflammation.

MATERIALS AND METHODS

A thorough review was performed of written sources of medicinal plants from XVI and onwards. For the pharmacological studies, the organic extracts were tested in mice models to assess its antidepressant and anti-inflammatory properties. The active extracts were studied chemically. The isolated compounds were identified by ¹H, ¹³C NMR, or characterized by GC-MS.

RESULTS

Cirsum ehrenbergii was illustrated for the first time (1552) in the Libellus de Medicinalibus Indorum Herbis (Booklet of Medicinal Plants of the Indians) and named in the Nahuatl native language as huitzquilitl (edible thistle). It was there recommended as nigris sanguinis remedium (remedy for black blood), and for the treatment of illnesses with an inflammatory component. Nigris sanguinis was well known in the European medicine of that time and currently it has been interpreted as "depression". At the present time, peasants and native population in Mexico mainly name C. ehrenbergii in Spanish as cardo Santo (holy thistle). Its original Nahuatl name has been almost forgotten. However, these communities use this species, among other maladies, to heal "nervios" (anxiety and/or depression) and for anti-inflammatory purposes. These ailments and treatments resemble those recorded in the Libellus and in several medicinal plant books along centuries. The ethanol extract of C. ehrenbergii roots showed antidepressant-like activity in mice administered at 300 mg/kg, as indicated by the forced swim test (FST). The glycosylated flavonoid linarin was identified as antidepressant principle and was active at the doses of 30 and 60 mg/kg in the FST. Regarding to anti-inflammatory activity, the most active was the methylene chloride extract of the aerial parts, which contains taraxasterol, pseudotaraxasterol, β-sitosterol and stigmasterol.

CONCLUSIONS

Cirsium ehrenbergii extracts possess antidepressant-like (roots, EtOH) and anti-inflammatory (aerial parts, CH₂Cl₂) properties, containing active compounds. Our results sustain historical and present day ethnomedical applications of this species documented along five centuries.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

Recent updates in natural terpenoids as potential anti-mycobacterial agents

Tuberculosis is considered as a leading health issue globally. Even though, the todays first line anti-mycobacterial treatments used in the hospital have low deaths, multidrug-resistance forms of the ailment have now spread globally and become a major issue. The wide-ranging biodiversity of medicinal plants, ocean animals have gained considerable attention for drug discovery in previous spans, and the emergence of TB drug resistance has inspired interest in judging natural products (NPs) to cure this disease. Till now, several compounds have been isolated from natural sources with anti-mycobacterial activity, few of which demonstrate significant activity and have the potential for further development. Worldwide huge natural flora and fauna are existing, this flora and fauna must be investigated for new potent lead against infectious TB. This review systematically surveys various classes of terpenoid molecules obtained from different medicinal plants, fungi, sponges, and sea plumes with anti-TB activity, which could be useful for further optimization and development in this field.

Overcoming the Prokaryote/Eukaryote Barrier in Tuberculosis Treatment: A Prospect for the Repurposing and Use of Antiparasitic Drugs

Antimicrobial resistance, the so-called silent pandemic, is pushing industry and academia to find novel antimicrobial agents with new mechanisms of action in order to be active against susceptible and drug-resistant microorganisms. In the case of tuberculosis, the need of novel anti-tuberculosis drugs is specially challenging because of the intricate biology of its causative agent, Mycobacterium tuberculosis. The repurposing of medicines has arisen in recent years as a fast, low-cost, and efficient strategy to identify novel biomedical applications for already approved drugs. This review is focused on anti-parasitic drugs that have additionally demonstrated certain levels of anti-tuberculosis activity; along with this, natural products with a dual activity against parasites and against M. tuberculosis are discussed. A few clinical trials have tested antiparasitic drugs in tuberculosis patients, and have revealed effective dose and toxicity issues, which is consistent with the natural differences between tuberculosis and parasitic infections. However, through medicinal chemistry approaches, derivatives of drugs with anti-parasitic activity have become successful drugs for use in tuberculosis therapy. In summary, even when the repurposing of anti-parasitic drugs for tuberculosis treatment does not seem to be an easy job, it deserves attention as a potential contributor to fuel the anti-tuberculosis drug pipeline.

Anti-Inflammatory Activity of Cnidoscolus aconitifolius (Mill.) Ethyl Acetate Extract on Croton Oil-Induced Mouse Ear Edema

Nowadays, there is a growing interest in the development of medicinal plant-based therapies to diminish the ravages of the inflammatory process related to diseases and tissue damage. Most therapeutic effects of these traditional medicinal plants are owed to their phenolic and antioxidant properties. C. aconitifolius is a traditional medicinal plant in Mexico. Previous characterization reports have stated its high nutritional and antioxidant components. The present study aimed to better understand the biological activity of C. aconitifolius in inflammation response. We developed an ethyl acetate extract of this plant to evaluate its anti-inflammatory capacity and its flavonoid content. The topical anti-inflammatory effect of the ethyl acetate extract of C. aconitifolius was determined by the croton oil-induced mouse ear edema test, while flavonoid detection and concentration were determined by thin layer chromatography and the aluminum chloride colorimetric assay, respectively. Topical application of the extract showed significant inhibition of the induced-ear edema (23.52 and 49.41% for 25 and 50 mg/kg dose, respectively). The extract also exhibited the presence of flavonoids. The finding of the anti-inflammatory activity exerted by the C. aconitifolius and the identification of its active principles may suggest and support its use for inflammation treatment.

Traditional Medicinal Plants as a Source of Antituberculosis Drugs: A System Review

Medicinal plants are the chief components in the different oriental formulations in different traditional medical systems worldwide. As a thriving source of medicine, the medicinal plants with antituberculosis (TB) properties inspire the pharmacists to develop new drugs based on their active components or semimetabolites. In the present review, the anti-TB medicinal plants were screened from the scientific literatures, based on the botanical classification and the anti-TB activity. The obtained anti-TB medicinal plants were categorized into three different categories, viz., 159 plants critically examined with a total 335 isolated compounds, 131 plants with their crude extracts showing anti-TB activity, and 27 plants in literature with the prescribed formula by the traditional healers. Our systemic analysis on the medicinal plants can assist the discovery of novel and more efficacious anti-TB drugs.

Biotechnological processes to obtain bioactive secondary metabolites from some Mexican medicinal plants

The consumption of medicinal plants has increased in recent decades due to the fact that they biosynthesize compounds with many biological activities; thus, some plant species with biological potential are being utilized as raw material by the industries for preparation of drugs, phytodrugs, or food supplements. This has the consequence of overexploitation and deforestation, which endangers plant species-of-interest. In recent years, alternatives have been sought to eradicate this problem. A solution that was given and is maintained is plant biotechnology, which favors the production of secondary metabolites (SMt) with important biological activity. Plant biotechnology allows us to increase the yield of a compound-of-interest, reduces its production times and costs, and allows constant and controlled production of the raw material, while aiding in the protection of medicinal plants that are found in danger of extinction. In the scientific literature, procuring the SMt by means of biotechnological processes is described, highlighting the study of five species from Mexican traditional medicine (Lopezia racemosa, Galphimia glauca, Cnidoscolus chayamansa, and Buddleja cordata), and the main biological activities are as follows: anti-inflammatory, hepatoprotector, neuroprotector, anxiolytic, antitumoral, antibacterial, and antioxidant, among others. KEY POINTS: • Secondary metabolites produce by biotechnology processes • Active secondary metabolites isolated from Mexican medicinal plants • Recent advances on the production of some bioactive secondary metabolites.

Histopathological evaluation of Senecio rhizomatus Rusby in 7,12-dimethylbenz(α) anthracene-induced breast cancer in female rats

Background and Aim:

Senecio rhizomatus Rusby (SrR) is a medicinal plant of the Asteraceae family and traditionally consumed as infusion in the Andean region from Peru for inflammatory disorders. This study aimed to determine the histopathological changes afforded by SrR in 7, 12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer (BC) in rats.

Materials and Methods:

An ethanolic extract of SrR aerial parts was prepared by maceration with 96% ethanol, and the chemical components were identified by gas chromatography coupled to mass spectrometry; the antioxidant activity was determined by 1,1-diphenyl-2-picril-hidrazil (DPPH) assay; and the acute toxicity was assessed according to the OCED 423 guidelines. In a pharmacological study, 30 female Holztman rats were distributed randomly into five groups, as follows. Group I: Negative control (physiological serum, 2 mL/kg); Group II. DMBA (80 mg/Kg body weight); and Groups III, IV, and V: DMBA + ethanol extract of SrR at doses of 10, 100, and 200 mg/kg, respectively.

Results:

The antioxidant activity of the SrR extract against DPPH was 92.50% at 200 mg/mL. The oral administration of SrR at doses of 50, 300, 2000, and 5000 mg/kg did not show any clinical evidence of toxicity or occurrence of death. The groups that received SrR presented a lower frequency of tumors and acumulative tumor volume compared with the DMBA group (p<0.05); the DMBA group exhibited a higher incidence of necrosis and moderate mitosis, up to 66.67% and 100.00%, respectively. Finally, infiltrating carcinoma with extensive tumor necrosis was evidenced.

Conclusion:

In experimental conditions, the ethanolic extract of SrR had a protective effect in DMBA-induced BC in female rats. Furthermore, the antioxidant activity of its main phytochemicals could be responsible for the effect observed, and SrR seems to be a safe extract in the preclinical phase.

Anti-inflammatory and antinociceptive activity of Siparuna guianensis Aublet, an amazonian plant traditionally used by indigenous communities

ETHNOPHARMACOLOGICAL RELEVANCE

Siparuna guianensis Aublet leaves, known as negramina, are used by indigenous and local communities in Brazil and other countries in the Americas to treat pain and inflammatory diseases.

AIM OF THE STUDY

To characterize the chemical constituents and to evaluate the antioxidant, anti-inflammatory, antinociceptive and locomotor activities of the dichloromethane fraction (DF) of S. guianensis leaves. Also, an acute oral toxicity test was accomplished.

MATERIAL AND METHODS

The chemical characterization of DF was performed by ultra-high pressure liquid chromatography (UHPLC) analyses coupled with a high-resolution mass spectrometer. The antioxidant potential of DF was investigated using nitric oxide (NO) and hydroxyl radical (OH) scavenging test. The evaluation study of the anti-inflammatory activity was carried out in vitro by NO measurement in stimulated macrophages and, in vivo, by croton oil-induced ear edema, LPS-induced peritonitis, and zymosan-induced arthritis in mice. Different mechanisms of central and peripheral nociception were stimulated by acetic acid-induced writhing, formalin, and tail-flick tests. Besides that, the open field assay was performed.

RESULTS

UHPLC analyses of DF showed the presence of a mixture of glycosylated and methoxylated flavonoids. DF was able to scavenge NO and OH radicals in vitro and showed anti-inflammatory activity by inhibiting NO production in LPS-stimulated murine macrophages. Oral administration of DF considerably inhibited the ear edema after croton oil application and reduced the leukocyte infiltrated in LPS-induced peritonitis. In the inflammatory intra-articular zymosan-induced process, DF showed a significant reduction in the inflammatory area and of the cells in the synovial and connective tissues adjacent to the joint. Also, DF was able to reduce the intra-articular edema. In nociception models, the oral administration of DF considerably inhibited the acetic acid-induced writhings. The formalin test showed that DF attenuated the licking time in both phases, which suggested that DF reduce the nociception by central and peripheral mechanisms. In the tail-flick test, DF showed no activity. Besides that, DF did not affect the animal locomotion, and no acute toxicity was observed.

CONCLUSIONS

For the first time, the anti-inflammatory and antinociceptive activities of S. guianensis were reported, supporting its ethnopharmacological uses for some inflammatory diseases and painful conditions.

Renal and Hepatic Disease: Cnidoscolus aconitifolius as Diet Therapy Proposal for Prevention and Treatment

The lack of prevention of noncommunicable diseases (NCDs) has caused an increase in the mortality rate including conditions such as chronic kidney disease (CKD) and liver disease (LD). The high complexity of CKD and LD results in alterations in the metabolism of carbohydrates, proteins, and lipids. One of the changes observed in CKD and LD is the decrease in albumin, elevation of PO₄^-3, K⁺, creatinine, urea, and transaminase enzymes. The pharmacological treatment is expensive. Nowadays, phytotherapy is an option to treat NCDs. Aqueous, ethanolic, methanolic, and ethyl acetate extracts of Cnidoscolus aconitifolius have shown nephroprotective and hepatoprotective potential and can be an alternative to prevent and treat CKD and LD. C. aconitifolius, known as Chaya by Mayas in Yucatán, is a shrub that is consumed in Mexico and in the world, has a low cost, it is very accessible, and can growth in extreme weather. The aim of this review is to show the potential biological effects of C. aconitifolius extracts, and the association of the phytochemicals in the extract. It is known that different solvents result in the uptake of different phytochemicals. These have shown various effects such as hypoglycemic, hypotensive, hypolipidemic, and antioxidant, being a natural alternative to the treatment of NCDs.Key teaching pointsPhytotherapy is a proposal to treat NCDs.Cnidoscolus aconitifolius extracts have a hypotensive effect.Cnidoscolus aconitifolius extracts reduce blood sugar in diabetic rats.Chaya extracts are no toxic for renal and hepatic cells.

Cnidoscolus aconitifolius: usos terapéuticos y propiedades fitoquímicas. Revisión de la literatura

Introducción. El uso tradicional de plantas medicinales para tratar diferentes enfermedades, ya sean infecciosas o no, es ampliamente aceptado debido a su bajo costo y sus bajos índices de toxicidad. Estas plantas son frecuentemente usadas en casos que involucran irritaciones de la piel, heridas superficiales, picaduras de insectos y mordeduras de víboras.Objetivo. Recopilar la información disponible sobre los principales usos terapéuticos y los componentes fitoquímicos de Cnidoscolus aconitifolius, una planta conocida popularmente como chaya y que crece en regiones tropicales de México y Centroamérica.Materiales y métodos. Se realizó una revisión de la literatura sobre C. aconitifolius publicada hasta 2017 en las bases de datos BIREME, PubMed/Medline, Elsevier y SciELO. Para la búsqueda se emplearon los descriptores “Cnidoscolus” y “aconitifoloius”, y no se aplicaron filtros de idioma.Resultados. Se identificaron 82 artículos luego de completar la búsqueda inicial. Después de filtrar los estudios por título (presencia de descriptores de búsqueda en el título) y remover duplicados, se incluyeron 18 artículos en la revisión. De acuerdo a la información encontrada, fue posible confirmar que esta planta ofrece diversos beneficios para la salud.Conclusiones. El uso terapéutico tradicional de la chaya está sustentado por evidencia científica, por lo que se sugiere realizar más investigaciones centradas en la identificación de nuevas propiedades fitoquímicas de esta planta y, así, establecer alternativas terapéuticas para distintas afecciones.

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors

Bisphosphonic acids (or bisphosphonates) have been successfully used in the clinic treatment of bone diseases for over decades. Additionally, the antiinflammatory activity of these compounds has been gaining attention. In our previous work, we synthesized and in vivo evaluated the bisphosphonic esters 1 and 2, finding a moderate edema inhibition upon oral and topical administration on BALB/c mice. Thus, in this work, the bioisosteric replacement of an amide functional group for an ester afforded the new bisphosphonates 3-6, which had a moderate oral edema inhibition (25 mg/kg dose) and a significant topical antiinflammatory activity (2 mg/ear) on BALB/c mice, with 6 being the most active hit (55.9% edema inhibition), comparable to the positive control (55.5% edema inhibition) on a TPA topical model. Next, to assess the acute toxicity of the synthesized derivatives, test animals were administered with 50-100 mg/kg of 3-6, respectively, by an oral route, and after 14 days, neither lethality nor a significative weight loss were observed. Finally, a structure-activity relationship (SAR) and a molecular docking analysis of 3-6 helped us to explain the trend observed in biological tests. Considering all these aspects, we propose the inhibition of MMP-8 and MMP-9 as a possible action mechanism of the synthesized derivatives.

Hopane-type triterpenes from Cnidoscolus spinosus and their bioactivities

Chemical investigation of the aerial parts of Cnidoscolus spinosus resulted in the isolation of relatively infrequent hopane-type triterpenes, 3β-acetoxy-hop-22(29)-ene (1), first reported here as natural product, together with 3-oxo-hop-22(29)-ene (2), and 3β-hydroxy-hop-22(29)-ene (3). β-Amyrin palmitate and three phytosterols were also characterized. The structures of the compounds were established using spectroscopic methods, and those of 1 and 2 were confirmed by crystallographic analysis. Selected biological activities for the isolated hopane-type triterpenes were tested through a series of assays for determining the cytotoxic, anti-inflammatory, α-glucosidase inhibition and antiparasitic activities. Compounds 1-3 did not show cytotoxic activity, compound 1 displayed an important inhibitory effect in the mouse ear induced inflammation assay, and significantly inhibited the yeast α-glucosidase activity in vitro and in silico. Additionally, compounds 2 and 3 showed marginal activities against Trypanosoma cruzi and Leishmania mexicana. Therefore, the bioactivities of hopane-type triterpenes deserve further investigation, particularly their anti-inflammatory properties.

Plants used for the treatment of diarrhoea from Mexican flora with amoebicidal and giadicidal activity, and their phytochemical constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Flora of the Mexican region is represented by approximately 30,000 vascular plant species, many of which are used as traditional medicines based on knowledge compiled and refined since ancient times (e.g. Cruz-Badiano and Florentino Codexes). The traditional use of plants as medicines, including the treatment of infectious diseases such as diarrhoea, is generally practiced in communities that are geographically isolated or in human settlements where health services are scarce.

AIM OF THE STUDY

The aim of this review is to evaluate current research advances in the ethnopharmacology and phytochemistry of Mexican medicinal plants exhibiting antiprotozoal activity, used to treat diarrhoea, and to identify the gaps in this research area for future studies.

METHODS

The literature study and compilation of information relied on books and scientific journals from leading electronic databases including Scopus, Springer, SciFinder, ISI Web of Science, PubMed, and Google Scholar; the topics searched for were antiprotozoal activity, followed by Entamoeba histolytica or Giardia lamblia. Ethnopharmacological data were obtained from books regarding medicinal plants and their uses in Mexico as well as from the government databases of "Comisiòn Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO)" as "NaturaLista" and "EncicloVida".

RESULTS

A total of 80 plant species used in the Mexican traditional medicine for the treatment of diarrhoea have been evaluated as potential sources of antiprotozoal agents against E. histolytica or G. lamblia. From these samples, 150 compounds have been isolated and screened in vitro, including specialized metabolites such as flavonoids and terpenoids as well as semisynthesized derivatives. However, in vivo pharmacological studies on these substances are limited. Additional pharmacological and molecular studies of the most active compounds have also been summarized.

CONCLUSION

Research performed in the past 25 years on specialized metabolites derived from plants with antiprotozoal activity has yielded relevant findings whose results provide evidence-based support for the use of these plants in the traditional medicine of Mexico to treat diarrhoea. Toxicological and clinical trials of standardized extracts and bioactive compounds are proposed as priority future works in this research area. In addition, in vivo assays are required, of more extracts and/or pure compounds. The optimization of the pharmacological properties of the bioactive specialized metabolites through semisynthetic derivatives and computational methods could aid in developing new antiprotozoal phytomedicines and novel drugs for the treatment of these types of infections. Furthermore, elucidation of the mechanism of action of these bioactive compounds through pharmacological and molecular studies are also necessary.

[In vitro antioxidant and anti-inflammatory activity of chaya extracts (Cnidoscolus aconitifolius (Mill.) I.M. Johnst)]

Introduction

Introduction: noncommunicable diseases (NCDs) are the main cause of death worldwide. Secondary metabolites from plant sources such as Cnidoscolus aconitifolius may be used as adjuvants in the prevention of diseases related to oxidative stress and inflammation such as NCDs. Objective: the in vitro antioxidant and anti-inflammatory activities associated with biologically active compounds in C. aconitifolius extracts were evaluated. Method: the contents of phenols, flavonoids, flavonones and hydroflavonoles were determined. The potential antioxidant activity was determined with 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, and angiotensin-converting enzyme (ACE) activity. For anti-inflammatory activity quantitative PCR and enzyme-linked immunosorbent assay (ELISA) tests were used in macrophages derived from THP-1 monocytes and stimulated with LPS. Results: the aqueous extract recorded the highest phenolic content (70.61  0.07 g/100 g of extract), and the ethanolic extract registered the highest content in flavonoids (47.76  4.84 g/100 g of extract), flavonones and dihydroflavonoles (70.10  7.29 g/100 g of extract). The acetone extract obtained the highest DPPH inhibition (49.85 ± 5.30%), while the ethanolic extract showed the highest ABTS inhibition (41.01 ± 3.81%). The etanolic and aqueous extracts had the highest ACE inhibition. The ethanolic extract had the highest anti-inflammatory activity, decreasing gene expression for TNF- by 39.78% and for IL-6 by 97.81%, and their production by 46% and 48.38%, respectively, in macrophages stimulated with LPS. Conclusion: these extracts demonstrated in vitro their antioxidant and anti-inflammatory potential due to their content of bioactive compounds.

Additional compounds and the therapeutic potential of Cnidoscolus chayamansa (McVaugh) against hepatotoxicity induced by antitubercular drugs

Previously non-isolated compounds (scopoletin and β-D-Glucopyranoside, (1R)-O-isopropyl 6-O-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-2,3,4-triacetate) were isolated from an organic extract of the Cnidoscolus chayamansa stem. Also, lupeol acetate (main compound, 49.7 mg/g of dry extract) and scopoletin (0.19 mg/g of dry extract) were quantified by HPLC analysis from this organic extract. The protective activity of the C. chayamansa organic extract against hepatotoxicity induced by antitubercular drugs [Rifampicin (50 mg/kg), Isoniazid (50 mg/kg), and Pyrazinamide (100 mg/kg)] are reported. The extract was tested at 200 and 400 mg/kg in Balb/C mice during 85 days, using silymarin (2.5 mg/kg) as positive control. Liver damage was determined using biochemical parameters (AST, ALT, ALP, CHOL, HDL TG, Urea, and CREA), histological analysis, and evaluation of oxidative stress (SOD, CAT, Gpx, Lpx and POx). The extract at both doses favored body weight gain with respect to the anti-TB group; the dose of 200 mg/kg was better. Also, the extract at both doses decreased the values of transaminases (AST, ALT) enzymes (p < 0.05) vs. anti-TB group. In oxidative stress parameters, the SOD value was decreased, as were the levels of peroxidation of lipids and oxidative protein in the group with C. chayamansa extract at 200 and 400 mg/kg vs. the anti-TB group. Histological analyses from liver showed the absence of steatosis in the extract group at 400 mg/kg, and moderate steatosis in the silymarin and extract (at 200 mg/kg) groups with respect to anti-TB group, which demonstrated a steatosis. It should be noted that during the study period, none of the treated mice died. In conclusion, the CHCl₃: MeOH extract of C. chayamansa has a hepatoprotective effect against hepatotoxicity induced by anti-TB drugs.

Phenolic Compounds as Promising Drug Candidates in Tuberculosis Therapy

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) remains one of the deadliest, infectious diseases worldwide. The detrimental effects caused by the existing anti-TB drugs to TB patients and the emergence of resistance strains of M. tuberculosis has driven efforts from natural products researchers around the globe in discovering novel anti-TB drugs that are more efficacious and with less side effects. There were eleven main review publications that focused on natural products with anti-TB potentials. However, none of them specifically emphasized antimycobacterial phenolic compounds. Thus, the current review’s main objective is to highlight and summarize phenolic compounds found active against mycobacteria from 2000 to 2017. Based on the past studies in the electronic databases, the present review also focuses on several test organisms used in TB researches and their different distinct properties, a few types of in vitro TB bioassay and comparison between their strengths and drawbacks, different methods of extraction, fractionation and isolation, ways of characterizing and identifying isolated compounds and the mechanism of actions of anti-TB phenolic compounds as reported in the literature.

Chemistry and Biology of Selected Mexican Medicinal Plants

Herbal medicines are an integral element of alternative medical care in Mexico, and the best testimony to their efficacy and cultural value is their persistence in contemporary Mexican marketplaces where the highest percentages of medicinal and aromatic plants are sold. This chapter summarizes current trends in research on medicinal plants in Mexico, with emphasis on work carried out at the authors' laboratories. The most relevant phytochemical and pharmacological profiles of a selected group of plants used widely for treating major national health problems are described.From this contribution, it is evident that in the last five decades a significant amount of research on medicinal plants has been performed by Mexican scientists. Such efforts have led to the publication of many research papers in noted peer-reviewed journals and technical books. The isolation and structural characterization of hundreds of bioactive secondary metabolites have been accomplished, and most importantly, these studies have tended to support the ethnomedical uses of many different species. A multidisciplinary approach for investigating these plants has led to an increased emphasis on areas such as phytopharmacology, phytotoxicology, quality control, regulation, and conservation issues for these valuable resources. The medicinal plants analyzed so far have shown a very broad chemical diversity of their constituents, which have a high potential for exhibiting novel mechanistic effects biologically. The chapter shows also that there is need to conduct additional clinical studies on herbal drugs, in particular because the longstanding traditional evidence for their safety is not always sufficient to assure their rational use. There is also need to move to "omics" approaches for investigating the holistic effect and the influence of groups of phytochemicals on the whole organism. Mexican scientists may be expected to have bright prospects in this regard, which will imbue medicinal plant research with a new dynamism in the future.

Ethnobotanic, phytochemical uses and ethnopharmacological profile of genus Cnidoscolus spp. (Euphorbiaceae): A comprehensive overview

The application of medicinal plants are the most important biotechnological alternative in the treatment of numerous diseases, especially in developing countries, such as Brazil. Among them, we specified some specimens of the genus Cnidoscolus used as phytotherapies, with healing properties, analgesic, anti-inflammatory, antibiotic and diuretic, anticancer, among others. Such effects are possibly associated with the presence of terpenoids, alkaloids, coumarins, flavonoids phenolic compounds, among others. Thus, the objective of this work was to evaluate in the literature the studies on the phytochemical, ethnopharmacological and biotechnological applications of this genus, from 1998 to 2017. Among the sixty-one studies reported in this review, ten species are popularly utilized to pharmacological and/or biotechnological applications. Cnidoscolus aconitifolius and Cnidoscolus chayamansa are the most cited species, which were also supported by either animal or cellular investigations indicating some beneficial pharmacological actions like antioxidant, anti-inflammatory and potential cytotoxic activity. The plant parts of this genus under study are important as sources for the isolation and identification of bioactive molecules with biotechnological applications, among the many diseases treated with this phytotherapy. Given these verdicts, ethnopharmacological approaches are significant systematic tools in the determination of plant species that exhibit medicinal and nutritional purposes. The results presented here should further stimulate the development of validation studies to ensure the safe and effective use of these plant species.

Hepatoprotective and Anti-Inflammatory Activities of the Cnidoscolus chayamansa (Mc Vaugh) Leaf Extract in Chronic Models

Previous report described that CHCl₃:MeOH extract of C. chayamansa leaves and pure compounds (moretenol, moretenyl acetate, kaempferol-3,7-dimethyl ether, and 5-hydroxy-7-3',4'-trimethoxyflavanone) showed important topical and systemic anti-inflammatory activity in acute model, as well as in vitro antimycobacterial and antiprotozoal activities. In this paper, we describe the in vivo hepatoprotective and anti-inflammatory effects of the CHCl₃:MeOH extract in chronic model and the isolation of additional compounds (moretenone and lupeol acetate). The hepatoprotective activity was determined at 39 days using Balb/c mice with liver damage induced with an antitubercular drug (RIF/INH/PZA). The anti-inflammatory activity was evaluated in a chronic model induced with CFA and in two acute models (TPA and carrageenan). In addition, moretenone and lupeol acetate were isolated and identified by spectroscopic data. Lupeol acetate is a main compound present in fractions 14-42, and this fraction was the majority fraction from the extract; from this moretenone was obtained. In animals with liver damage, the extract at 200 and 400 mg/kg induced better body weight gain with respect to positive control (Silymarin); in addition, the mice that received the extract at 200 mg/kg and Silymarin exhibited slight steatosis; however, the animals' livers at 400 mg/kg did not show steatosis. The extract and fractions 14-42 showed a good anti-inflammatory activity by TPA model (DE₅₀ = 1.58 and 1.48 mg/ear) and by carrageenan model (DE₅₀ = 351.53 and 50.11 mg/kg). In the chronic inflammatory test, the extract at three doses revealed a similar effect to that of phenylbutazone, although the body weight gain was better in animals that received the extract at 900 mg/kg. Conclusion. The CHCl₃:MeOH extract showed significant anti-inflammatory and good hepatoprotective effect on chronic models. The fraction containing moretenone and lupeol acetate as main compounds was more active than extract in both acute models of inflammation.

Isolation and Structural Characterization of Bioactive Molecules on Prostate Cancer from Mayan Traditional Medicinal Plants

Prostate cancer is the most common cancer in men around the world. It is a complex and heterogeneous disease in which androgens and their receptors play a crucial role in the progression and development. The current treatment for prostate cancer is a combination of surgery, hormone therapy, radiation and chemotherapy. Therapeutic agents commonly used in the clinic include steroidal and non-steroidal anti-androgens, such as cyproterone acetate, bicalutamide and enzalutamide. These few agents have multiple adverse effects and are not 100% effective. Several plant compounds and mixtures, including grape seed polyphenol extracts, lycopene and tomato preparations, soy isoflavones, and green tea extracts, have been shown to be effective against prostate cancer cell growth. In vivo activity of some isolated compounds like capsaicin and curcumin was reported in prostate cancer murine models. We prepared a library of plant extracts from traditional Mayan medicine. These plants were selected for their use in the contemporaneous Mayan communities for the treatment of different diseases. The extracts were assessed in a phenotypic screening using LNCaP prostate cancer androgen sensitive cell line, with a fixed dose of 25 μg/mL. MTT assay identified seven out of ten plants with interesting anti-neoplastic activity. Extracts from these plants were subjected to a bioguided fractionation to study their major components. We identified three compounds with anti-neoplastic effects against LNCaP cells, one of which shows selectivity for neoplastic compared to benign cells.

Anti-Helicobacter pylori Potential of Three Edible Plants Known as Quelites in Mexico

"Quelites" are edible plants that are part of the traditional agro-ecosystems in Mexico. These plants, despite their already known nutritional properties, are now considered neglected and underutilized species. With the objective of promoting their reinsertion in the markets and mainly, in daily diets, efforts have been made to study them from multidisciplinary approaches to demonstrate their beneficial properties. To generate evidence of an added health-promoting value that would encourage quelites consumption, in the present work, the anti-Helicobacter pylori activity of three representative quelite species, Anoda cristata (Alache), Cnidoscolus aconitifolius (Chaya), and Crotalaria pumila (Chepil), was tested. H. pylori is considered the etiological agent of gastritis, ulcer, and gastric cancer, and represents a public health problem in Mexico and worldwide. Aqueous (AQ) and dichloromethane-methanol (DM) extracts were obtained from the three species of quelites to investigate their effect on H. pylori growth and on two of its colonization factors (adherence and urease activity). DM extracts from Chaya, Chepil, and Alache exert the best inhibitory effect on bacterial growth, with minimum inhibitory concentrations of 62.5, 125, and 250 μg/mL, respectively. AQ and DM extracts inhibit bacterial adhesion by 30% to 50%. None of them has an effect on urease activity. The two flavonoids present in A. cristata, acacetin and diosmetin, inhibit H. pylori growth by ∼90% with 3.9 μg/mL. These results provide new information about the anti-H. pylori potential of three edible quelites, and give an added value, since their routine consumption may impact on the prevention and/or control of H. pylori-associated diseases.

Flavonoids as a Natural Treatment Against Entamoeba histolytica

Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance.

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

The consumption of medicinal plants has notably increased over the past two decades. People consider herbal products as safe because of their natural origin, without taking into consideration whether these plants contain a toxic principle. This represents a serious health problem. A bibliographic search was carried out using published scientific material on native plants from Mexico, Central America, and the Caribbean, which describe the ethnobotanical and toxicological information of medicinal plants empirically considered to be toxic. A total of 216 medicinal plants belonging to 77 families have been reported as toxic. Of these plants, 76 had been studied, and 140 plants lacked studies regarding their toxicological effects. The toxicity of 16 plants species has been reported in clinical cases, particularly in children. From these plants, deaths have been reported with the consumption of Chenopodium ambrosioides, Argemone mexicana, and Thevetia peruviana. In most of the cases, the principle of the plant responsible for the toxicity is unknown. There is limited information about the toxicity of medicinal plants used in Mexico, Central America, and the Caribbean. More toxicological studies are necessary to contribute information about the safe use of the medicinal plants cited in this review.