GC-MS Analysis and Preliminary Antimicrobial Activity of Albizia adianthifolia (Schumach) and Pterocarpus angolensis (DC)

The non-polar components of two leguminoceae species Albizia adianthifolia (Schumach), and Pterocarpus angolensis (DC) were investigated. GC-MS analysis of the crude n-hexane and chloroform extracts together with several chromatographic separation techniques led to the identification and characterization (using NMR) of sixteen known compounds from the heartwood and stem bark of Albizia adianthifolia and Pterocarpus angolensis respectively. These constituents include, n-hexadecanoic acid (palmitic acid) 1, oleic acid 2, chondrillasterol 3, stigmasterol 4, 24S 5α-stigmast-7-en-3β-ol 5, 9,12-octadecadienoic acid (Z,Z)-, methyl ester 6, trans-13-octadecanoic acid, methyl ester 7, tetradecanoic acid 8, hexadecanoic acid, methyl ester 9, octadecanoic acid 10, tetratriacontane 11, 7-dehydrodiosgenin 12, lupeol 13, stigmasta-3,5-diene-7-one 14, friedelan-3-one (friedelin) 15, and 1-octacosanol 16. Using agar over lay method, the preliminary antimicrobial assay for the extracts was carried out against bacterial (E. coli, P. aeruginosa, B. subtilis, S. aueus) and a fungus/yeast (C. albicans) strains. The n-hexane and chloroform extracts of A. adianthifolia showed the best activity against E. coli with minimum inhibition quantity (MIQ) of 1 µg each while the remaining exhibited moderate-to-weak activity against the test microorganisms.