Alkenyl cyclohexanone derivatives from Lannea rivae and Lannea schweinfurthii.

Phytochemical investigation of the CH 2 Cl 2 /MeOH (1:1) extract of the roots of Lannea rivae (Chiov) Sacleux (Anacardiaceae) led to the isolation of a new alkenyl cyclohexenone derivative: (4 R ,6 S )-4,6-dihydroxy-6-(( Z )-nonadec-14′-en-1-yl)cyclohex-2-en-1-one ( 1 ), and a new alkenyl cyclohexanol derivative: (2 S* ,4 R* ,5 S* )-2,4,5-trihydroxy-2-(( Z )-nonadec-14′-en-1-yl)cyclohexanone ( 2 ) along with four known compounds, namely epicatechin gallate, taraxerol, taraxerone and β-sitosterol; while the stem bark afforded two known compounds, daucosterol and lupeol. Similar investigation of the roots of Lannea schweinfurthii (Engl.) Engl. led to the isolation of four known compounds: 3-(( E )-nonadec-16′-enyl)phenol, 1-(( E )-heptadec-14′-enyl)cyclohex-4-ene-1,3-diol, catechin, and 1-(( E )-pentadec-12′-enyl)cyclohex-4-ene-1,3-diol. The structures of the isolated compounds were determined by NMR spectroscopy and mass spectrometry. The absolute configuration of compound 1 was established by quantum chemical ECD calculations. In an antibacterial activity assay using the microbroth kinetic method, compound 1 showed moderate activity against Escherichia coli while compound 2 exhibited moderate activity against Staphylococcus aureus . Compound 1 also showed moderate activity against E. coli using the disc diffusion method. The roots extract of L. rivae was notably cytotoxic against both the DU-145 prostate cancer cell line and the Vero mammalian cell line (CC 50 = 5.24 and 5.20 μg/mL, respectively). Compound 1 was also strongly cytotoxic against the DU-145 cell line (CC 50 = 0.55 μg/mL) but showed no observable cytotoxicity (CC 50 > 100 μg/mL) against the Vero cell line. The roots extract of L. rivae and L . s chweinfurthii , epicatechin gallate as well as compound 1 exhibited inhibition of carageenan-induced inflammation. [ABSTRACT FROM AUTHOR]