Screening of plant extracts from the Brazilian Cerrado for their in vitro trypanocidal activity

Abstract

In this study we report the screening of the in vitro trypanocidal activity of 20 extracts obtained from 10 different plant species growing in the Brazilian Cerrado: Aspidosperma macrocarpum Mart. (Apocynaceae), Aegiphila sellowiana Cham. (Verbenaceae), Byrsonima intermedia Juss. (Malpighiaceae), Cyperus rotundus L. (Cyperaceae), Leandra lacunosa Cogn. (Melastomataceae), Miconia ligustroides (DC.) Naudin. (Melastomataceae), Miconia sellowiana Naudin. (Melastomataceae), Myrcia variabilis Mart. ex DC. (Myrtaceae), Solanum lycocarpum St. Hil. (Solanaceae), and Tibouchina stenocarpa Cogn. (Melastomataceae). The most active extracts were submitted to phytochemical analyses. High-resolution gas chromatography analysis of the n-hexane extract of T. stenocarpa (IC₅₀ = 23.6 μg/mL), the most active extract amongst all the tested samples, allowed the identification of β-amyrin, α-amyrin, lupeol, friedelin, β-friedelanol, campesterol, stigmasterol, and β-sitosterol. Oleanolic and ursolic acids were isolated from the methylene chloride extract of T. stenocarpa (IC₅₀ = 51.5 μg/mL), while ursolic acid was isolated from the methylene chloride extract of M. variabilis (IC₅₀ = 38.4 μg/mL). Solasonine and solamargine were identified as major compounds by mass spectrometry analysis in the hydroalcoholic extract of the fruits of S. lycocarpum (IC₅₀ = 57.1 μg/mL). The results showed that the trypanocidal activity may be related to the major compounds identified in the crude active extracts.

Keywords::

• Aspidosperma
• Miconia
• Myrcia
• Solanum
• Tibouchina
• trypanocidal activity

Acknowledgements

We wish to thank Alba Regina Barbosa and Maria Inês Junqueira Garcia Teixeira for helping with plant collection and Dr. Angela Borges Martins for plant identification.

Declaration of interest: The authors alone are responsible for the content and writing of the paper. The authors are grateful to FAPESP for financial support.