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Four new 5 alpha-pregnane-type steroidal alkaloids, hookerianamides L(1), M(2), N(3), and O(4), and a known N-formylchonemorphine (5) have been isolated by acid-base extraction of the dichloromethane extract of Sarcococca hookeriana. The structures of all compounds were determined with spectroscopic techniques and by comparison with literature data. All compounds displayed antileishmanial and antibacterial properties. Compounds 1, 4, and 5 were found to be more potent than standard pentamidine (IC (50) = 9.59 microg/mL) with respect to leishmanicidal activity. The minimum inhibitory concentration of most of the compounds against Bacillus subtilis, Streptococcus minor, and Streptococcus ferus was lower than that of the standard ampicillin.

A new prenylated pyranoxanthone, symphonin (1), 2-(3,3-dimethylallyl)-1,5dihydroxy-6,7-dimethoxy-2",2"-dimethylpyrano (5",6":3,4) xanthone, the known compounds guttiferone A, oleanolic acid and sitosterol were isolated from the methanol extract of the seeds of Symphonia globulifera (Guttiferae). The structural elucidation of the new compound was based mainly on spectroscopic analyses. The new xanthone showed antimicrobial activity against Staphylococcus aureus, Streptococcus feacalis, Klebsiella pneumonia and Escherichia coli.

Two novel Schiff bases, 3-[1-(2-(phthalazin-1-yl)hydrazono)ethyl)-1,3-oxazinane (PHEO) and 2-[(2-(phthalazin-1-yl)hydrazono)methyl]phenol (PHMP), derived from hydralazine hydrochloride, an effective drug against hypertension, were synthesized and characterized by spectroscopic methods, Infrared (IR), Proton Nuclear Magnetic Resonance (1 H NMR) and Carbon-13 Nuclear Magnetic Resonance (13 C NMR). PHEO showed low antimicrobial activity against one bacterial strain with MIC value of 250 µg/ml while PHMP showed interesting activity against 4 bacterial strains with MIC of 31.25-250 µg/ml compared to the standard drug, amoxicillin. PHEO and PHMP showed higher reducing activity on ferric ions compared to Vitamin C. On lipid peroxidation, PHEO showed higher inhibition while PHMP showed lower inhibition compared to Vitamin C. Both compounds presented lower stimulating effect and lower catalase activity compared to the standard Vitamin C. PHEO and PHMP showed less than 80% inhibition in the preliminary antiplasmodial assay and so were not considered for the dose-response studies.

Brevipsidone (1), a new depsidone was isolated from the methanol extract of the stem bark of Garcinia brevipedicellata together with known damnacanthal (2), pilloin (3), scopoletin (4). The structure of the new compound was determined by analysis of spectroscopic data. Compounds 1-4 were evaluated for their α-glucosidase inhibition effect and showed significant inhibitory activity.

Emerging drug-resistant bacteria creates an urgent need to search for antibiotics drugs with novel mechanisms of action. Endophytes have established a reputation as a source of structurally novel secondary metabolites with a wide range of biological activities. In the present study, we explore the antibacterial potential of endophytic fungi isolated from different tissues of Terminalia mantaly, Terminalia catappa, and Cananga odorata. The crude ethyl acetate extracts of 56 different endophytic fungi were screened against seven bacterial strains using the broth microdilution method. The antibacterial modes of action of the most active extracts (04) were evaluated using E. coli ATCC 25922 and H. influenzae ATCC 49247 strains. Both the DPPH and FRAP assays were used to investigate their antioxidant activity, and their cytotoxicity against the Vero cell line was evaluated using the MTT assay. Out of the 56 crude extracts tested, about 13% were considered very active, 66% partially active, and 21% nonactive against all tested bacterial strains with MIC values ranging from 0.32 μg/mL to 25 μg/mL. The four more potent extracts (MIC <5 μg/mL) (from Aspergillus sp. N454, Aspergillus sp. N13, Curvularia sp. N101, and Aspergillus sp. N18) significantly lysed the bacteria cells, increased outer membrane permeability, reduced salt tolerance, and inhibited bacterial catalase activity. They exhibited a DPPH free radical scavenging activity with I C 50 ranging from 150.71 to 936.08 μg/mL. Three of the four potent extracts were noncytotoxic against the Vero cells line ( C C 50 > 100  μg/mL). Results from this investigation demonstrated that endophytes from Cameroonian medicinal plants might content potent antibacterial metabolites. The bioguided fractionation of these potent extracts is ongoing to isolate and characterise potential active ingredients.

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