In Vitro and In Silico Studies of the Biological Activities of Some Secondary Metabolites Belonging to Ficus sur Forssk (Moraceae): Towards Optimization of Wighteone Metabolite.

Based on ethnomedicinal and chemotaxonomic records of Ficus plants, Ficussur Forssk was studied in the search for bioactive compounds. Eleven known compounds including mixture α -amyrin acetate and ß -amyrin acetate (1 and 2), lupeol (3), 3ß-acetoxy-olean-12-en-11-one (4), lupenyl acetate (5), taraxastan-3,20-diol (6), 3'- (3-methylbut-2-enyl) biochanin A (7), derrone (8), quercetin (9), stigmasterol (10), and stigmasterol glycoside (11) were isolated from stem barks of Ficus sur Forssk. Their structures were obtained through analysis of spectroscopic data (1D and 2D NMR), mass spectrometry, and by comparison of these data with the literature. Nine isolated compounds (1-7, 10, 11) were tested as the active wighteone metabolite previously isolated from the roots of this plant against the human HepG2 hepatocellular carcinoma cells and a small panel of sensitive microbial strains for structure- activity relationship purpose. The compounds didn't show any activity. With the aim of understanding the impact of the structural difference between wighteone metabolite and its analogs, the former were cross-docked to evaluate their anticancer properties via the apoptosis pathway. Wighteone metabolite proved to be the best ligand confirming its previous bioassay result. Thus, the current study lays the framework for the further optimization of wighteone metabolite regarding its anticancer activity.

Xylatolides A and B, new 10-membered macrolides from the endophytic fungus Xylaria sp.

Chemical investigation of the fungal endophyte Xylaria sp. isolated from leaves of Moringa oleifera, collected in Cameroon, resulted in the previously undescribed 10-membered macrolide, and two known natural products. The structures of the xylatolides A and B were unambiguously identified by their mass spectra and by extensive 1D and 2D NMR spectroscopic analysis, featuring a 10-membered lactone core structure with oxygenated substituents and an unsubstituted 10-alkyl chain presenting seven carbon atoms. Compounds were screened for their cytotoxic potential against the human HepG2 hepatocellular carcinoma cells and HCT-116 cells (human colon carcinoma cell line). Moreover, the isolated compounds were also assayed against a small panel of sensitive strains including the bacterial species Escherichia coli, Staphylococcus aureus, and Mycobacterium tuberculosis as well as against the fungal species Candida albicans. However, no significant activities were found.

Prenylated cyclohexene-type meroterpenoids and sulfur-containing xanthones produced by Pseudopestalotiopsis theae.

Chemical investigation of the fungal endophyte Pseudopestalotiopsis theae isolated from leaves of Caloncoba welwitschii, collected in Cameroon, resulted in two previously undescribed sulfur-containing xanthone derivatives sydoxanthones D and E, in addition to three previously undescribed monomeric diisoprenyl-cyclohexene-type meroterpenoids biscognienynes D-F and five known natural products. The structures of the undescribed compounds were unambiguously identified by their mass spectra and by extensive 1D and 2D NMR spectroscopic analysis. Mosher's reaction was performed to determine the absolute configuration of sydoxanthones D and E while TDDFT-ECD calculations were used to assign the configuration of biscognienyne D. Biscognienynes B and D showed significant cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values of 7.7 and 6.7 µM and against the human leukemic cell lines HL60, and Hal-01 with IC50 values ranging from 4.3 to 12.1 µM.