ISOLATION AND CHARACTERIZATION OF ANTIOXIDANT AND ANTIMICROBIAL COMPOUNDS FROM GARUGA PINNATA

Abstract

Phytochemical analysis was carried out in this study to isolate and characterize antibacterial and antioxidant chemicals found in the stem and bark of Garuga pinnata Roxburgh. Garuga pinnata belongs to the Burseraceae family has been investigated for evaluation of their biological activities. The powder of dried stem and bark of Garuga pinnata was extracted with Hexane, dichloromethane, ethyl acetate, and methanol. Different chromatographic techniques have attempted to isolate secondary metabolites from dichloromethane and ethylacetate extract of the stem and bark. It has been possible to isolate four compounds from the dichloromethane extracts of the stem and bark of Garuga pinnata. Different spectroscopic techniques have established the structures of the compounds. The isolated compounds were Stigmasterol, ß-sitosterol, Isofouequrone, and Lupeol. The isolated compounds were identified by extensive analyses of their high-resolution 1 H-NMR (400 MHz) and 13 C-NMR(100MHz). The extracts of stem and bark of Garuga pinnata, i.e., Methanol Soluble Fraction (MSF), Hexane Soluble Fraction (HSF), Dichloromethane Soluble Fraction (DCMSF), were subjected to assay for various biological screening such as Antioxidant activity screening and Antimicrobial screening. The crude plant extract and its different soluble fractions were investigated to evaluate biological activities in vitro. In the analysis of free radical scavenging, the EASF of bark and stem of Garuga pinnata with an IC value of 21.588 µg/mL had excellent free radical scavenging activity. 50 Test antimicrobial activity against a number of Gram-positive and Gram-negative bacteria and fungi were done for ethyl acetate extract, methanol extract, Dichloromethane extract, and a mixture of compound-1 and Compound-2 (mixture of Stigmasterol and β-sitosterol). The ethyl acetate and dichloromethane extracts exhibited antimicrobial activity against all of the test micro-organisms and fungi. The methanol extract does not show good antimicrobial activity against the Grampositive micro-organisms. The mixture of compound-1 and compound-2(GPE-1 &

2, as a

mixture of Stigmasterol and β-sitosterol) showed almost similar activity as ethyl acetate crude extract (9-12 mm inhibition zone) against nearly all the microorganisms and fungi.

In Brine shrimp lethality bioassay, among all extractives of leaves of Garuga pinnata, the highest brine shrimp lethality was given by HSF (110.15 µg/mL) followed by EASF (55.48 µg/mL), and MSF (80.99 µg/mL).