Phytochemical and antimicrobial screening of extracts of Aquilaria agallocha Roxb.

Aquilaria agallocha Roxb. is an endangered economic plant used for production of agar wood worldwide. The aqueous and methanol extracts along with dry powder of leaf and bark of the plant was screened for the presence of phytochemicals. Also they were tested for antibacterial activity against pathogenic bacteria such as Shigella flexneri, Bacillus brevis, Pseudomonas aeruginosa and Bacillus subtilis. The result indicates the presence of alkaloids, anthroquinones, triterpenoids, tannins, fixed oils and fats and glycosides in methanol extracts whereas saponins, fixed oils and fats, alkaloids and triterpenoids were found in the aqueous extracts. The highest alkaloid content was in the aqueous extract of the bark (0.06%). The saponin content was found to be high in the leaf powder (0.169%). The bark powder contained 0.067% glycosides while the leaf powder had 0.036%. The leaf powder had the highest amount of carbohydrates (19.42 mg/g dry weight), protein (24.37 mg/g DW) and amino acids (12.1 mg/g DW). The methanol extract of the leaf gave the highest zone of inhibition against B. subtilis (19 mm). All other extracts showed moderate zones of inhibition (14-18 mm) against all the bacteria tested. The present study has proved the usefulness of agarwood tree for medicinal purposes. The presence of phytochemicals indicates its potential as a source of useful drugs.