Abstract

• Citrus medica var. acida Brandis (Shauk thakwa), belonging to the Rutaceae family, has been chosen to investigate phytochemical constituents and some bioactivities. Firstly, preliminary phytochemical tests on C. medica leaves revealed the presence of alkaloids, carbohydrates, flavonoids, glycosides, phenolic compounds, reducing sugars, saponins, starch, steroids, tannins, and terpenes. The EDXRF elemental analysis showed that the leaves contained Ca, Al, K, and S as major elements. In the GC-MS analysis of the essential oil extracted by steam distillation method, the thirteen organic compounds detected (2.30 %) were 4-hydroxy-4-methyl-2-pentanone,-3 acetoxy-4-(1-hydroxy-1-methyl ethyl)-1-methyl-cyclohexene, (R)-(+)-citronellic acid, 2-(2 hydroxy-2-propyl)-5-methyl cyclohexan-1-ol, (E)-3-octadecence, octacosanol, methyl eugenol, benzyl benzoate, cis-9, 12-methyl linoleate, methyl (9E)-9-octadecenoate,di-isobutyl phthalate, heptadecan-1-ol and methyl stearate. The antimicrobial activity of leaves extracts in various solvents (pet-ether, ethyl acetate, 95 % ethanol, and water) was tested against six species of microorganisms: Bacillus subtilis, Bacillus pumilus, Salmonella typhi, Pseudomonas aureginosa, Escherichia coli, and Candida albicans, by the agar well diffusion method. It was found that the ethyl acetate extract (Inhibition zone diameter, 10 -14 mm) and watery extract (10 – 13 mm) exhibited antimicrobial activity against four tested microorganisms except C. albicans and E. coli. The 95 % ethanol extract exhibited the more potent antimicrobial activity (10 - 18 mm) against all tested microorganisms. In the screening of antioxidant activity, the watery extract (IC50 = 148.58 µg/mL) showed more antioxidant activity than 95 % ethanol extract (IC50 = 636.27 g/mL).