16.

Phytochemicals from the Bark of Garcinia hombroniana and Their Biological Activities

Nargis Jamila, Melati Khairuddean, Sadiq Noor Khan, Naeem Khan and Hasnah Osman

School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

Department of Medical Lab Technology, University of Haripur, 22060 Haripur, Khyber Pakhtunkhwa, Pakistan

Department of Chemistry, Kohat University of Science and Technology, 26000 Kohat, Khyber Pakhtunkhwa, Pakistan

Abstract: The dichloromethane and ethyl acetate extracts from the bark of Garcinia hombroniana yielded lupeol (1), lupeol acetate (2), 3β-acetoxy- lup-12,20(29)-diene (3), β-sitosterol (4), 22-dehydroclerosterol (5), mangiferolic acid (6), ursolic acid (7), betulin (8), betulinic acid (9), 1,3,6-trihydroxy-7-methoxy-2,8-(3-methyl-2-butenyl)xanthone (10), leucodin (11), p-hydroxycinnamate (12), p-hydroxybenzoic acid (13) and stearic acid (14). Compounds 10, 12 and 13 exhibited significant antioxidant activities by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric ion reducing antioxidant power) assays. Antibacterial studies showed strong inhibitory effects for compound 11 while other compounds (1-9 and 14) were either inactive or moderately active for the bacterial strains investigated. This study presents the first report on the isolation and biological activities of the chemical constituents from the bark of G. hombroniana. The compounds 3, 5-12 and 14 are reported for the first time from this source.

Keywords: Garcinia hombroniana ; bark; triterpenoids; antioxidant activities; antibacterial activities . © 2014 ACG Publications. All rights reserved.