Isolation of Bioactive Principles and Studies of Antimicrobial, Cytotoxic and Antioxidant Activities of the stem bark of Baccaurea ramiflora (Euphorbiaceae)

Abstract

Phytochemicals are extensively found at different levels in many medicinal plants. Stem bark of Baccaurea ramiflora (common name Latkan) belonging to the family of Euphorbiaceae, has been studied for isolation of its secondary metabolites and evaluation of its bio-activities of the crude extract and fractions with especial emphasis on the antimicrobial, cytotoxic and antioxidant activities. The concentrated chloroform extract was partitioned with petroleum ether, ethyl acetate and methanol and the remaining chloroform crude extract was kept for assessing antimicrobial, cytotoxic and antioxidant activities. After successful separation and purification of the different VLC fractions of the chloroform extract of stem bark B. ramiflora, two secondary metabolites namely BR-F5-B1 and BR-F5-B2 were isolated. The structure of this two compounds were elucidated as phytol (1) and betulinic acid (2) by comparing with their 1H NMR spectral data with published values. The disc diffusion method was used to evaluate the antimicrobial activities. The methanol soluble fraction of B. ramiflora stem bark did not show any activity against the testing bacteria. The petroleum soluble fraction (PESF) and crude extract showed mild to moderate antibacterial activities against both gram positive and gram negative bacteria as compared to control antibiotic disc.The ethyl acetate soluble fraction (EASF) revealed mild activity. Staphylococcus aureus, Shigella boydii and Vibrio mimicus showed the maximum sensitivity to the crude extract of B. ramiflora when compared to control (Ciprofloxacin 30μg/disc). The crude extract showed mild activity against certain fungi. In the DPPH assay, different fractions of chloroform extract of B. ramiflora demonstrated significant antioxidant activity.In the brine shrimp lethality bioassay the LC50 value of crude extract of B. ramiflora was 11.09 μg/ml, which demonstrated moderate cytotoxic principles present in the crude extract.