STRUCTURAL TRANSFORMATION OF LUPEOL AND EVALUATION THEIR IN-VITRO ANTIOXIDANT ACTIVITYAbstract
Lupeol (I) is a naturally occurring triterpene that has been isolated from the stem bark of Crataeva nurvala in appreciable amount. Due to the presence of a single hydroxyl group and a large, apolar skeleton, lupeol acts as an amphiphile. The two possible sites for chemical modification present in lupeol are ring-A and isopropenyl side chain. We modified it in three naturally occurring analogous derivatives, i.e., 3a, 5a, 5b, 8, 8, 11a-Hexamethyl-1-(2-methyl-oxiranyl)-icosahydro-cyclopenta[a] chrysen-9-ol (II), lupeol acetate (III), and lupenone (IV) by oxidation and acylation process. The structures of the newly synthesized compounds were confirmed by elemental analysis, 1H, 13C NMR, IR, and MS spectroscopy. In-vitro antioxidant activity for all the compounds evaluated where ascorbic acid (vitamin C) treated as standard. All the analysis was made with the use of UV-Visible spectrophotometer. Result of the study suggested that all the compounds showed effective efficacy for antioxidant properties in a concentration-dependant manner, although lupeol acetate was found most significant in comparison to standard.
Tek Chand Sharma, Anil Kumar Sharma * and Jai B. S. Kachhawa
Department of Chemistry, Jagan Nath University, Jaipur, Rajasthan, India.
01 May 2021
13 June 2021
21 June 2021
01 February 2022