Antibacterial, cytotoxic, and schistosomicidal activities of the methanolic extract from Cassia grandis L.f. (Fabaceae) stem bark and its fractions

Cassia grandis L. (Fabaceae), a native tree from Amazon Forest, has been used in folk medicine against worms and intestinal parasites, and to treat stomach and respiratory problems, blood diseases, among others uses. This study aimed to evaluate the antioxidant, cytotoxic, antimicrobial, and schistosomicidal activities of the methanolic extract from C. grandis stem bark (CgME) and to elucidate the chemical profile of its active fractions. The antioxidant activity of C. grandis stem bark methanolic extract (CgME) and its fractions were determined by DPPH radical scavenging assay and by the total phenolics and flavonoid contents. The antimicrobial activity was performed by microdilution. The cytotoxicity against MCF-7 (breast), NCI-H292 (lung), and HL-60 (leukemia) cancer cell lines was evaluated by the MTT method. The schistosomicidal activity was investigated in vitro against adult Schistosoma mansoni couple worms. The phytochemical profile of the active fractions was determined by GC-MS and UPLC-MS. The hexane fraction from the CgME was cytotoxic to NCI-H292 and HL-60 cancer cell lines and both major compounds clionasterol and lupeol acetate, determined by GC-MS, are well known for their cytotoxicity against cancer cells. The ethyl acetate fraction (CgEF) exhibited both antibacterial, against multidrug-resistant S. aureus, and schistosomicidal activities, which could be attributed to the presence of flavonoids, such as catechin derivatives, quercetin, and luteolin in the CgEF. These results agree with the popular uses of C. grandis and should stimulate future research on this species. Key words: Antimicrobial activity, antioxidant, Staphylococcus aureus, clinical isolates, Schistosoma mansoni, cytotoxicity.