Bioactive triterpenoids, antimicrobial, antioxidant and cytotoxic activities of Eclipta prostrata Linn.

Bioactive triterpenoids; 3-acetylaleuritolic acid, stigmasterol, a mixture of triterpenoids, fatty esters and aromatic components were isolated from the aerial parts of Eclipta prostrata by column chromatography. The plant extracts were investigated for their antimicrobial activity (agar dilution method) against twenty-eight strains of gram-positive and gram-negative bacteria, including diploid fungus. In addition, antioxidant and cytotoxic activities were also evaluated. The extracts and isolated fractions exhibited antimicrobial activity against Morexella catarrhalis, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with the MIC of 64 g/mL including Saccharomyces cerevisiae ATCC 2601 (MIC 256 g/mL). The ethyl acetate extract and isolated fractions displayed antioxidant effect. In addition, the plant extracts showed cytotoxic activity (ED50 > 100 g/mL) toward HuCCA-1 and KB cells. The results demonstrate beneficial effects of E. prostrata as the antimicrobials and bioactive compounds for medicinal usages.

Antimicrobial and cytotoxic acetogenin from Polyalthia debilis.

The objective of the study was to isolate bioactive acetogenin compound and to investigate antimicrobial, antioxidant as well as cytotoxic activities of the isolate, fractions and extracts of Polyalthia debilis. The P. debilis (roots) extracts and isolated compound were tested for their antimicrobial (agar dilution method) against twentyseven strains of microorganisms (gram positive and gram negative bacteria, and diploid fungus), antioxidant (DPPH assay) and cytotoxic activities. The plant extracts were isolated by column chromatography and structure of compound was confirmed by spectral data. The plant extracts and isolated fractions exhibited antioxidant and cytotoxic activities. The isolated acetogenin 1 (debilisone E) displayed antimicrobial activity against Morexella catarrhalis with the MIC of 64 g/mL, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with partial inhibition (50-75%) at 128 g/mL. The compound 1 exerted cytotoxic activity against 5 cancer cells (HepG2, A549, HCC-S102,HL-60 and P388) with IC50 values 18.4 - 40.3g/mL. The results demonstrate novel bioactivities of P. debilis as antimicrobials and anticancer agents.