Schistosomicidal evaluation of flavonoids from two species of Styrax against Schistosoma mansoni adult worms

Abstract

Context: Schistosomiasis is a major health problem worldwide. Thus, the search for new schistosomicidal agents from natural sources can provide prototypes for drug discovery.

Objective: The present study investigated the chemical composition of the EtOAc fractions of Styrax pohlii Pohl (Styracaceae) (EF-SP) aerial parts and S. camporum A. DC. leaves (EF-SC), as well as schistosomicidal activities against Schistosoma mansoni adult worms, which have not yet been studied.

Materials and methods: The crude ethanol extracts of S. camporum leaves and S. pohlii aerial parts (EE-SC and EE-SP) were partitioned with n-hexane, EtOAc, and n-BuOH. The EtOAc fractions were purified by preparative HPLC. The crude extracts, EtOAc fractions and pure compounds were tested against S. mansoni adult worms in vitro.

Results: The purification procedure resulted in the isolation of kaempferol-3-O-(2′′,4′′-di-O-(E)-p-coumaroyl)-β-d-glucopyranoside (1), kaempferol-3-O-(2′′,6′′-di-O-(E)-p-coumaroyl)-β-d-glucopyranoside (2), quercetin (3), and kaempferol (4). The bioassay results indicated that EE-SC, EF-SC, EF-SP, and compounds 2 and 4 are able to separate coupled S. mansoni adult worms. Additionally, EE-SC, EF-SP, and compound 4 killed the adult schistosomes in vitro at 100 µg/mL and 100 µM.

Discussion and conclusion: This is the first time that the presence of compounds 1–2 in S. pohlii and 3–4 in S. camporum has been reported. Additionally, biological results indicated that S. pohlii and S. camporum have great potential as a source of active compounds.

Keywords::

• Flavonol
• schistosomicidal activity
• Styrax camporum
• Styrax pohlii

Acknowledgements

The authors are grateful to Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenadoria de Aperfeiçoamento de Pessoal do Ensino Superior (CAPES), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for fellowships. FAPESP is also acknowledged for financial support (Grant # 2008/10.283-1).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.