Cytotoxic and antimicrobial activities of new phytosteroids from the leaves of Anonidium mannii (Oliv.) Engl. & Diels (Annonaceae)

Phytochemical studies of the dichloromethane-methanol (1:1) extract of the leaves of Anonidium mannii (Oliv.) Engl. & Diels led to the isolation of two new phytosteroids named anonimadiol A (AM1C) and B (AM2C) together with the known stigmasterol (AM3C). The structures of compounds were established by means of spectroscopic methods covering NMR analysis (¹H and ¹³C NMR, DEPT135, ¹H–¹H–COSY, HSQC and HMBC), FTIR and high-resolution mass spectrometry (HR-ESI-MS), and by comparison with data previously reported in the literature. Biological activities of the crude extract and the metabolites (AM1C, AM2C and AM3C) were evaluated, namely: cytotoxicity on adenocarcinoma of the cervix (Henrietta Lacks, HeLa) cells; antimalarial test using parasite lactate dehydrogenase (pLDH) from Plasmodium falciparum (3D7) strain; antibacterial test on Escherichia coli (8739), Salmonella typhi (1403), Staphylococcus aureus (25923) and Enterococcus faecalis (6230434); antifungal test using Candida albicans (10231) and anti-mycobacterial test using Mycobacterium tuberculosis (H3DTB). AM1C and AM2C at 20 µg/mL showed considerable cytotoxicity potential with percentage viability of 20.2 and 30.4, respectively, against HeLa cells. Furthermore, the crude extract and AM1C had 50% inhibition concentrations (IC50s) of 50 and 11.21 μg/mL, respectively, against Plasmodium falciparum. Regarding the antituberculosis effects, a notable 90% minimum inhibition concentration (MIC₉₀) value of 39.4 µg/mL was obtained with AM1C. Moreover, AM1C and AM2C had notable activity against Salmonella typhi and Candida albicans delivering MICs of 60 and 250 μg/mL respectively compared to the positive control ciprofloxacin with MICs values of 39 and 1250 μg/mL. However, the crude extract and the three metabolites showed no activity against HIV protease and HIV integrase. These results suggest the possible potential effect of these isolates from Annonidium mannii against cancer of the cervix and many microbial infections.