Antioxidant, anti-cholinesterase and antibacterial activities of the bark extracts of Garcinia hombroniana

This study reports an antioxidant, anti-cholinesterase, antibacterial activities and total flavonoids content of different extracts (water, methanol, ethyl acetate, dichloromethane andn-hexane) of the bark of Garcinia hombroniana. The antioxidant activity was evaluated using radical scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and Folin Ciocalteu assay (FCA). Ethyl acetate extract showed the highest antioxidant activity (DPPH = 8667.7 ±166.6 μmol TE/g (trolox equivalent), ABTS (IC50 = 3.03 μg/ml), FRAP (5579.8 ± 117.7.7 μmol TE/g) and FCA = 3320.4 ± 98.3  μmol GAE/g (gallic acid equivalent)). The flavonoids content of ethyl acetate extract is 2385.7 ± 87.3 RE/g (rutin equivalent) and 3317.6 ± 131.0 QE/g (quercetin equivalent) while the methanol extract is 2234.0 ± 90.0 RE/g and 3090.0 ± 135.1 QE/g). Both extracts are statistically close to each other. In anti-cholinesterase study, ethyl acetate extract showed the highest activity against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes with IC50 of 13.73 ± 1.56 and 32.17 ± 0.36 μg/ml, respectively. Dichloromethane and n-hexane extracts showed good antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. The results of this study showed that the bark extracts of G. hombroniana have valuable pharmacological activities.   Key words: Garcinia hombroniana, bark extracts,  antioxidant,  anticholinesterase, antibacterial.