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.

Total content of kaurene diterpenes in Annona vepretorum stems via 1 H qNMR: A method for speeding the identification of bioactive extracts

INTRODUCTION

Kaurene diterpenes (KDs) constitute a chemical class often found in the genus Annona with interesting biological activities. To date, chromatographic tools have been mostly used to determine KDs. Quantitative nuclear magnetic resonance (qNMR) has distinguished itself in quantitative estimation of natural products and is an interesting choice to assess total KD contents.

OBJECTIVE

To establish a ¹ H qNMR method for determining the total KD contents in extracts and fractions obtained from Annona vepretorum stems.

METHODOLOGY

Stems were extracted with hexane and methanol, resulting in the hexane extract (HEX-E) and the methanol extract (MeOH-E). The former was partitioned with the acid-base method to obtain the total alkaloid fraction (TA-F) and the neutral dichloromethane fraction (NDM-F). ¹ H qNMR measurements were performed on 400 MHz with samples solubilized in deuterated dimethyl sulfoxide. Quantification was carried out using the signals at 4.71 and 4.78 ppm related to hydrogens of the exocyclic double bond of the basic skeleton of KDs and gallic acid as the standard reference. The selectivity, intra- and inter-day precision, reproducibility, limit of detection, limit of quantification, and robustness of the methodology were evaluated.

RESULTS

Using the newly developed method, the total KD contents (in μg/mg) were 653.80 ± 12.15 (HEX-E), 458.90 ± 25.94 (NDM-F), 375.60 ± 27.52 (TA-F), and 315.10 ± 19.20 (MeOH-E). For determining the most promising bioactive sample, the KD contents and the sample discriminations obtained by principal component analysis were correlated to the antibacterial activity. Such approach pointed out HEX-E as a potential source of KDs.

CONCLUSION

The developed method offers a fast and simple way of determining total KD contents.