Phytochemical Screening, Antioxidant & Antimicrobial Investigations of Petroleum Ether Extract of Garcinia Cowa Leaves

This thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Pharmacy (B.Pharm) in East West University, Dhaka, Bangladesh.Garcinia cowa has risen the interest of scientists and researchers since some of the active constituents and phytochemicals found on this plant are known to exert many beneficial effects. Garcinia is a rich source of secondary metabolites. Phytochemical investigations of the plant parts indicated that leaves are the best source of secondary metabolites, providing glycosides, alkaloids and xanthones respectively. Many of the isolated compounds have a wide range of pharmacological activities including anticancer, antiinflammatory, antibacterial, anti-fungal, antidepressant and antioxidant. The aim of the present study was to evaluate the antioxidant and antimicrobial activity of petroleum ether ( pet ether ) extract of Garcinia cowa. The antioxidant activity was measured by DPPH and total Phenol test. The IC50 values of DPPH test was 242.188μg/ml for pet ether extract of Garcinia cowa leaves. The Total Phenol content was 107.47±30.62 mg/g equivalent to Gallic Acid for pet ether extract of Garcinia cowa leaves. The antimicrobial activities of pet ether extract of Garcinia cowa leaves were tested against ten microorganisms by observing the zone of inhibition. The antimicrobial test was performed by disc diffusion method.In case of 300 g/disc, the highest antimicrobial activity was shown against Pseudomonas aureus. The diameter of the zone of inhibition was 12mm compared to the 30 mm of diameter of the zone of inhibition of the standard zentamycin. It showed the moderate activity against Bacillus subtilis, Salmonella paratyphi, Salmonella typhi, Shigella dysenteriae, Vibrio parahemolyticus, Staphylococcus aureus and Escherichia coli. In case of 600 g/disc, the highest antimicrobial activity was shown against Bacillus megaterium and Sarcina lutea. The diameter of the zone of inhibition was 12mm compared to the 30 mm of diameter of the zone of inhibition of the standard Gentamycin. In conclusion, further investigations are needed to identify the active constituents and the exact mechanism(s) of action responsible for the reported antimicrobial and antioxidant properties of Garcinia cowa