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Background: The aim of this study was to evaluate the antimicrobial activity and the cytotoxicity of the ethanol crude extract, fractions and isolated compounds from the twigs of Eriosema robustum, a plant used for the treatment of coughs and skin diseases., Methods: Column chromatographic and spectroscopic techniques were used to isolate and identify eight compounds, robusflavones A (1) and B (2), orostachyscerebroside A (3), stigmasterol (4), 1-O-heptatriacontanoyl glycerol (5), eicosanoic acid (6), 3-O-β-D-glucopyranoside of sitosterol (7) and 6-prenylpinocembrin (8), from E. robustum. A two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against fungi and bacteria, and the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay was used to evaluate the cytotoxicity., Results: Fraction B had significant antimicrobial activity against Aspergillus fumigatus and Cryptoccocus neoformans (MIC 0.08 mg/ml), whilst the crude extract and fraction A had moderate activity against A. fumigatus and Candida albicans (MIC 0.16 mg/ml). Fraction A however had excellent activity against Staphylococcus aureus (MIC 0.02 mg/ml), Enterococcus faecalis and Escherichia coli (MIC 0.04 mg/ml). The crude extract had significant activity against S. aureus, E. faecalis and E. coli. Fraction B had good activity against E. faecalis and E. coli (MIC 0.08 mg/ml). All the isolated compounds had a relatively weak antimicrobial activity. An MIC of 65 μg/ml was obtained with robusflavones A (1) and B (2) against C. albicans and A. fumigatus, orostachyscerebroside A (3) against A. fumigatus, and robusflavone B (2) against C. neoformans. Compound 8 had the best activity against bacteria (average MIC 55 μg/ml). The 3 fractions and isolated compounds had LC50 values between 13.20 to > 100 μg/ml against Vero cells yielding selectivity indices between 0.01 and 1.58., Conclusion: The isolated compounds generally had a much lower activity than expected based on the activity of the fractions from which they were isolated. This may be the result of synergism between different compounds in the complex extracts or fractions. The results support the traditional use of E. robustum to treat infections. The crude extract had a good activity and low preparation cost, and may be useful in topical applications to combat microbial infections.

The first phytochemical investigation of Solandra grandiflora Sw. leaves using LC/MS resulted in the identification without isolation of eight known and one unknown compounds from the neutral and the alkaloidal fractions. Further chromatographic fractionation and isolation of both fractions using RP-HPLC resulted in the isolation of chlorogenic acid, neochlorogenic acid, protocatechuic acid, scopoletin and isoscopoletin from the neutral fraction. Moreover, a new tropinene glycoside identified as 3-O-β-D-glucosyl 6-tropinene, together with atropine, scopolamine and hyoscyamine were isolated from the alkaloidal fraction. The structures of all isolated compounds were established and confirmed by 1H-, 13C-NMR, COSY, HSQC & HMBC spectroscopy, while the exact masses were confirmed by HRESIMS. The cytotoxic activity of all isolates was evaluated against HepG-2, HCT-116, A-549 and MCF-7, and the obtained results suggested selective antiproliferative and cytotoxic effect. [ABSTRACT FROM AUTHOR]