In vitro antioxidant,cholinesterase and tyrosinase inhibitory activities of Calophyllum symingtonianum and Calophyllum depressinervosum(Guttiferae)

Objective:To screen the antioxidant,cholinesterase and tyrosinase enzymatic inhibition activities of the leaves and heartwood of Calophyllum symingtonianum(C.symingtonianum),and the bark of Calophyllum depressinervosum(C.depressinervosum).Methods:Samples of leaves and heartwood of C.symingtonianum and bark of C.depressinervosum were tested for their total phenolic content and in vitro antioxidant assay by 2,2-diphenyl-1-picrylhydrazyl radical scavenging and β-carotene bleaching.Cholinesterase inhibition by Ellman’s method and tyrosinase inhibition using L-3,4-dihydroxyphenylalanine as a substrate were also tested.Results:All methanol extracts were found to exhibit strong 2,2-diphenyl-1-picrylhydrazyl radical scavenging effects.Extracts from the heartwood of C.symingtonianum gave a low IC50(5.17±0.04)μg/mL followed by bark of C.depressinervosum[(7.30±0.14)μg/mL]and C.symingtonianum leaves[(15.70±1.43)μg/mL].The methanol extract of C.depressinervosum bark showed 95.08%inhibition ofβ-carotene bleaching.All extracts showed moderate inhibition towards tyrosinase activity with an IC50 of more than 100μg/mL.The methanol extract of C.depressinervosum stem bark showed the highest inhibition(78.46%)against butyrylcholinesterase.Conclusions:These results showed that both Calophyllum species are potential sources of antioxidant and cholinesterase inhibitors.Further study is needed for the isolation and characterization of the active metabolites responsible for both activities.

Antioxidant,antimicrobial and total phenolic contents of Calophyllum symingtonianum

Objective:To determine the total phenolic content,antioxidant and antimicrobial activities of the extracts from Calophyllum symingtonianum.Methods:The extracts were tested for their antioxidant activity by the DPPH radical scavenging assay and the β-carotene bleaching assay,while the antimicrobial activity was determined by disc diffusion method.Results:All the tested extracts showed antioxidant and antimicrobial properties.The extracts showed moderate antimicrobial activity against Staphylococcus aureus with zone of inhibition values of 10,11 and 12 mm for n-hexane,dichloromethane and methanol extracts respectively at 30μg/disc.N-hexane showed low antimicrobial activity against Pseudomonas aeruginosa(5 mm)at 30μg/disc.The total phenolic test showed that methanol has high phenolic content(162.25 mg GAE/g of extract)compared to the other extracts.Conclusions:The ability of the extracts to inhibit microbial growth at a concentration of 30μg/disc indicated the its potent antimicrobial activity.