ABSTRACT
ABSTRACT This paper reports the first study of the variation of the chemical composition and abundance of the essential oil of Croton heliotropiifolius, in four seasons, and the evaluation of its antibacterial activity. Essential oil obtained from leaves of C. heliotropiifolius were analyzed by GC/MS and evaluated against eight bacteria strains by broth microdilution method. The chemical constituents identified were the same in all samples, but with different proportions. The total percentages identified were 96.58% in summer, 92.08% in autumn, 98.44% in winter and 90.78% in spring. The majors constituents are β-caryophyllene, bicyclogermacrene, germacrene-D, limonene and 1,8-cineole. β-Caryophyllene was the major compound in all samples. The results of the antibacterial evaluations showed weak to moderate activity against the analyzed strains. In all analyzes was observed that essential oil sample collected in summer stands out from the others, displaying stronger activity against Gram-positive as Gram-negative bacteria.
ABSTRACT
Aerial parts of Microlicia hatschbachii were extracted with hexane, and the extract was evaluated for antimicrobial activity by a broth dilution method. After phytochemical procedures: GC-MS identified aliphatic alkanes, carboxylic acids and methyl esters of long-chain fatty acids; and two diterpenoids [labd-8(17)-en-15-oic acid and labd-8(17),13-dien-15-oic acid] were identified by (1)H and (13)C NMR. The antimicrobial activity of the hexane extract could be attributed to the presence of labdanes. This identification is the first reported occurrence of labdane diterpenes in the Melastomataceae family.
