Antimycobacterial evaluation of Peruvian plants

The Genus Cynometra: A Review of Ethnomedicine, Chemical, and Biological Data

Cynometra L. is a Fabaceae genus that is widely distributed throughout the tropics, consisting of tropical forest trees with ecological and economic importance since they are used as food and herbal medicines by the populations of their natural habitats. Our goal is to provide a review of the research data concerning the potential of this botanical genus as a source of herbal medicines and secondary metabolites that are useful for human health. To that end, scientific databases, including PubMed, Science Direct, ISI Web of Science, Scopus, and Google Scholar, were searched using the following terms: Cynometra, medicine, chemical, biological activity, toxicity, and “AND” as the Boolean connector. Eleven Cynometra species (9.7%) were reported to be used in traditional medicine to treat different ailments. A total of 185 secondary metabolites of various chemical classes, mainly flavonoids and terpenoids, were identified in eight Cynometra species (7.1%). Vitexin was the only flavonoid identified as bioactive in the sequence of bioguided studies on this botanical genus. Ten species (8.8%) were submitted to in vitro and in vivo biological activity assays. The main evaluated activities were in vitro antioxidant, antimicrobial, cytotoxic, and in vivo anti-inflammatory activities, but no human clinical trials or safety data about this genus were found. Cynometra cauliflora and Cynometra ramiflora were the most studied species. The present work confirms the use of Cynometra species as a source of medicinal plants. However, more experimental studies must be conducted to better understand this botanical genus’s usefulness as a source of raw materials for pharmaceutical use.

Margaritaria nobilis L.F. (Phyllanthaceae): Ethnopharmacology and Application of Computational Tools in the Annotation of Bioactive Molecules

Margaritaria nobilis is a shrubby species widely distributed in Brazil from the Amazon to the Atlantic Rainforest. Its bark and fruit are used in the Peruvian Amazon for disinfecting abscesses and as a tonic in pregnancy, respectively, and its leaves are used to treat cancer symptoms. From analyses via UHPLC-MS/MS, we sought to determine the chemical profile of the ethanolic extract of M. nobilis leaves by means of putative analyses supported by computational tools and spectral libraries. Thus, it was possible to annotate 44 compounds, of which 12 are phenolic acid derivatives, 16 are O-glycosylated flavonoids and 16 hydrolysable tannins. Among the flavonoids, although they are known, except for kaempferol, which has already been isolated from this species, the other flavonoids (10, 14, 15, 21, 24–26, 28–30, 33–35, 40 and 41) are being reported for the first time in the genus. Among the hydrolysable tannins, six ellagitannins present the HHDP group (6, 19, 22, 31, 38 and 43), one presents the DHHDP group (5), and four contain oxidatively modified congeners (12, 20, 37 and 39). Through the annotation of these compounds, we hope to contribute to the improved chemosystematics knowledge of the genus. Furthermore, supported by a metric review of the literature, we observed that many of the compounds reported here are congeners of authentically bioactive compounds. Thus, we believe that this work may help in understanding future pharmacological activities.

Genus Triplaris (Polygonaceae): A review on traditional medicinal use, phytochemistry and biological activities

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Triplaris (Polygonaceae) comprises approximately 25 species distributed throughout South and Central America. Some species have been used in folk medicine, mainly, to treat malaria, leishmaniasis, diarrheia, dysenteria, pain and inflammation.

AIM OF THE STUDY

The purpose of this review is to provide information on the traditional uses, phytochemistry and known biological activities of Triplaris, an important genus for South America research groups on medicinal plants, in order to explore its therapeutic potential to direct future research in the search for new bioactive molecules.

MATERIALS AND METHODS

The available information on the genus Triplaris was gathered from scientific databases (LILACS, Pubmed, SciELO, Science Direct, Scopus, CAPES Periodicals Portal and Theses and Dissertations Catalog) before March 2020 using the keyword "Triplaris". Works related to traditional uses, phytochemistry and biological activities of plants were included in this review.

RESULTS

Most of the studies involving Triplaris were conducted by research groups located in Brazil, Peru e Bolivia. Probably, because the genus has been used in folk medicine only by these countries. Regarding the annual evolution of the publications, a larger number of articles published in 2010 were observed. Flavonols represent the main classe of secondary metabolites from Triplaris. In terms of the pharmacological investigations, T. americana and T. gardneriana are considered the most studied species, with extensive promising biological activities. The pharmacological activities can be attributed to bioactive phytochemicals.

CONCLUSIONS

All findings indicate that Triplaris is an important genus of the Polygonaceae family. However, considering its chemical and pharmacological importance, the studies developed with Triplaris species are still limited, representing an opportunity to investigate new bioactive molecules and extracts. The review shows that little pre-clinical or in vivo research is available to prove the ethnopharmacological records in the genre. Therefore, this review encourages further studies on Triplaris in the search for a wide range of therapeutic products.

Major Bioactive Alkaloids and Biological Activities of Tabernaemontana Species (Apocynaceae)

Several species belonging to the genus Tabernaemontana have been well researched and utilized for their wide-ranging biological activities. A few of the most prominent species include Tabernaemontana divaricata, Tabernaemontana catharinensis, Tabernaemontana crassa, and Tabernaemontana elegans. These species and many others within the genus often display pharmacological importance, which is habitually related to their chemical constituents. The secondary metabolites within the genus have demonstrated huge medicinal potential for the treatment of infections, pain, injuries, and various diseases. Regardless of the indispensable reports and properties displayed by Tabernaemontana spp., there remains a wide variety of plants that are yet to be considered or examined. Thus, an additional inclusive study on species within this genus is essential. The current review aimed to extensively analyze, collate, and describe an updated report of the current literature related to the major alkaloidal components and biological activities of species within the genus Tabernaemontana.

Efficacy and Mechanisms of Flavonoids against the Emerging Opportunistic Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are the causative agent of severe chronic pulmonary diseases and is accountable for post-traumatic wound infections, lymphadenitis, endometritis, cutaneous, eye infections and disseminated diseases. These infections are extremely challenging to treat due to multidrug resistance, which encompasses the classical and existing antituberculosis agents. Hence, current studies are aimed to appraise the antimycobacterial activity of flavonoids against NTM, their capacity to synergize with pharmacological agents and their ability to block virulence. Flavonoids have potential antimycobacterial effects at minor quantities by themselves or in synergistic combinations. A cocktail of flavonoids used with existing antimycobacterial agents is a strategy to lessen side effects. The present review focuses on recent studies on naturally occurring flavonoids and their antimycobacterial effects, underlying mechanisms and synergistic effects in a cocktail with traditional agents.

A review of traditional uses, phytochemistry and pharmacology of the genus Indigofera

ETHNOPHARMACOLOGICAL RELEVANCE

Indigofera is the third-largest genus in the family of Fabaceae, with approximately 750 species. It is distributed across all tropical regions. Indigofera species are widely employed in traditional medicine all around the world, against many ailments. Thus, based on these medicinal properties, various investigations have been undertaken in order to appraise the pharmacological activities and the chemical composition of these species. A recent paper provides a summary of the phytochemistry and pharmacology of the genus Indigofera. Consequently, this review is a continuation of this previous study by updating some data and adding information about the phylogeny and traditional uses of the genus.

AIM OF THE STUDY

To provide an overview of the phylogeny, traditional uses, phytochemistry, pharmacology and toxicity of the genus Indigofera, and to identify the remaining gaps and thus supply a basis for further investigations.

MATERIALS AND METHODS

A review of the literature was performed by consulting scientific databases such as 'ScienceDirect', 'PubMed', 'Google Scholar' and 'SpringerLink' and using the keyword Indigofera.

RESULTS

Over 60 Indigofera species are reported in traditional medicine. The uses depend on the country and the species, but similarities have been noticed. Indeed, treatments of gastrointestinal disorders, inflammatory conditions and pain, skin ailments, and respiratory and infectious diseases are recurring. Phytochemical studies have led to the identification of more than 200 compounds, notably flavonoids and terpenoids. Many pharmacological activities have been demonstrated, particularly antimicrobial, cytotoxic and anti-inflammatory activities, and thus allowed to assert most of the traditional uses of the genus. Some active compounds have been isolated and have shown remarkable therapeutic potential, like the alkaloid indirubin, which is currently being clinically trialed.

CONCLUSIONS

The data on the genus Indigofera are extensive, but gaps still remain. Indeed, some promising species have not been assessed for their phytochemistry and/or pharmacology and thus remain unexplored. Moreover, relatively few active compounds have been isolated and tested for their biological activity, and studies to explain their mechanism of action are nearly inexistent. Furthermore, some pharmacological studies have inappropriate methodologies that make the results difficult to interpret. Consequently, further in-depth and relevant research is required to supplement the knowledge on this wide-ranging genus and to confirm its reported therapeutic potential.

Antimycobacterial activity of medicinal plants used by the Mayo people of Sonora, Mexico

ETHNOPHARMACOLOGICAL RELEVANCE

Tuberculosis (TB) is an infectious disease mainly caused by Mycobacterium tuberculosis (Mtb), which generates 9 million new cases worldwide each year. The Mayo ethnicity of southern Sonora, Mexico is more than 2000 years old, and the Mayos possess extensive knowledge of traditional medicine.

AIMS OF THE STUDY

To evaluate the antimycobacterial activity levels of extracts of medicinal plants used by the Mayos against Mtb and Mycobacterium smegmatis (Msm) in the treatment of TB, respiratory diseases and related symptoms.

MATERIALS AND METHODS

A total of 34 plant species were collected, and 191 extracts were created with n-hexane, dichloromethane, ethyl acetate (EtOAc), methanol and water. Their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined against Mtb H37Rv using the microplate alamar blue assay (MABA) and against Msm using the resazurin microplate assay (REMA) at 6 and 2 days of exposure, respectively, and at concentrations of 250-1.9µg/mL (n-hexane extracts) and 1000-7.81µg/mL (extracts obtained with dichloromethane, EtOAc, methanol and water).

RESULTS

Rhynchosia precatoria (Willd.) DC. (n-hexane root extract), Euphorbia albomarginata Torr. and A. Gray. (EtOAc shoot extract) and Helianthus annuus L. (n-hexane stem extract) were the most active plants against Mtb H37Rv, with MICs of 15.6, 250, 250µg/mL and MBCs of 31.25, 250, 250µg/mL, respectively. R. precatoria (root) was the only active plant against Msm, with MIC and MBC values of ≥250µg/mL. None of the aqueous extracts were active.

CONCLUSIONS

This study validates the medicinal use of certain plants used by the Mayo people in the treatment of TB and related symptoms. R. precatoria, E. albomarginata and H. annuus are promising plant sources of active compounds that act against Mtb H37Rv. To our knowledge, this is the first time that their antimycobacterial activity has been reported. Crude extracts obtained with n-hexane, EtOAc and dichloromethane were the most active against Mtb H37Rv.

Anti-tuberculosis neolignans from Piper regnellii

The present study determined the anti-Mycobacterium tuberculosis activities of supercritical CO2 extracts, neolignans eupomatenoid-5 (1), conocarpan (4) and eupomatenoid-3 (7) and their derivatives (2, 3, 5, 6, and 8) from Piper regnellii, as well as their cytotoxicities. The supercritical CO2 extract from leaves was purified by chromatographic methods, yielding compounds (1), (4) and (7), which were identified by (1)H NMR and comparison with literature data. Anti-M. tuberculosis activity (H37Rv and clinical isolates) was evaluated using a resazurin microtiter assay plate (REMA) to determine the MIC. The cytotoxicity assay was carried out in macrophages J774G.8 by sulforhodamine B colorimetric assay. The supercritical CO2 extracts from leaves and stems, and compound (4) showed activity against M. tuberculosis (MIC 15.6 μg/ml). Compound (1) showed the best activity (MIC 1.9 μg/ml), with good SI. Compounds (7) and (8) showed low activity against M. tuberculosis H37Rv. The derivative compounds did not show increased anti-M. tuberculosis activity. This is the first report, to our knowledge, to describe neolignans from P. regnellii with activity against M. tuberculosis, and compound (1) is a potential candidate for future antituberculosis drugs.

A review of the medicinal potentials of plants of the genus Vernonia (Asteraceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The Vernonia genus has about one thousand species and members of the genus are widely used as food and medicine. The aim of this review is to analyze published data on the ethnomedicinal, ethnoveterinary and zoopharmacognostic uses of plants of the Vernonia genus. This will help to identify the state of ethnopharmacological knowledge in regard to this genus and to propose future research priorities.

MATERIALS AND METHODS

The major scientific databases including SciFinder, Sciencedirect, Medline and Google Scholar were queried for information on Vernonia genus using various keyword combinations. The International Plant Name Index was also used to verify the names of species and authors.

RESULTS

A total of 109 Vernonia species were reported in the literature to have medicinal properties. One hundred and five (105) plants were linked to the treatment or management of 44 human diseases or health conditions. Plants of the genus also feature in ethnoveterinary and zoopharmacognostic practices. A total of 12 vernonia species were identified to be used in ethnoveterinary medicine while 2 species are used in self medication practices by chimpanzees and gorillas. In vitro and in vivo research studies reporting the validation of the medicinal properties of some species were also reviewed. One hundred and three bioactive compounds isolated from various Vernonia species were also identified. Vernonia amygdalina was identified as the most frequently used member of the Vernonia genus. The Vernolides, a class of sesquiterpene lactone were identified as the most studied compounds from the genus and show interesting bioactivity in antiplasmodial, antileishmanial, antischistosomial, cytotoxicity, antimicrobial and anti-inflammatory assays.

CONCLUSION

On the basis of results from a combination of in vitro and in vivo efficacy and toxicity studies reported, Vernonia amygdalina holds the most promise for development into a nutraceutical against diabetes and malaria while Vernonia cinerea has potential against cancer and inflammatory conditions. Vernolide A is so far the most promising single agent from a Vernonia species that has potential for development into an anticancer agent. The other Vernonia species and isolated compounds require further studies to ascertain their medicinal potentials.

The World Summit of Harmonization on Traditional, Alternative and Complementary Medicine (TACM) in Lima, Peru

The World Summit of Harmonization on Traditional, Alternative and Complementary Medicine (TACM) was held in Lima, Peru, November 7–11, 2007, with almost 600 worldwide participants. This meeting was organized by Peruvian Medical College, the institution that affiliates and authorizes all physicians to practice medicine in Peru. The meeting included seven sections starting with an overview on the current status of the TACM. The second section included experiences from different countries on regulations and quality control in products and services used in the TACM. The worldwide experience of education and training in TACM was a very important part of the meeting in which speakers from Spain, Germany, Argentina, Italy, Brazil, Cuba and Peru shared their experience. The meeting included topics on homeopathy, acupuncture, mind–body medicine, neural therapy, chiropraxis, among others. Two final sessions were related to the ways of linking Traditional medicine to the national Health Systems in the Latin America countries and also the association between bio-commerce and TACM including intellectual properties and bio-piracy.

Natural product growth inhibitors of Mycobacterium tuberculosis

This review covers natural products (secondary metabolites) with reported growth inhibitory activity towards Mycobacterium tuberculosis or related organisms. Such compounds have been isolated from a variety of sources including terrestrial and marine plants and animals, and microorganisms, with the express intent of identifying novel scaffolds for the development of new antituberculosis agents. The literature from January 2003 to December 2005 (inclusive) is reviewed and 146 references to 353 compounds are cited. The compounds are presented in order of chemical type, namely lipids/fatty acids and simple aromatics, phenolics and quinones, peptides, alkaloids, terpenes (monoterpenoids, diterpenes, sesquiterpenes and triterpenes), steroids and miscellaneous structures.