ABSTRACT
This study was conducted to determine the phytochemical contents and radical scavenging activities of twelve Garcinia schomburgkiana extracts from the leaves, roots, twigs and branches. Among all extracts, the root (RA) and branch (BA) acetone extract revealed high phenolic (427.83±4.84 and 390.15±7.89 mg GAE/g extract), flavonoid (626.32±59.97 and 414.49±15.99 mg QE/g extract) and xanthone (625.80±3.78 and 615.07±9.97 mg AME/g extract) contents and possessed greater antioxidant capacities and radical scavenging activities than the standard vitamin C and Trolox. Our results reveal that G. schomburgkiana were potential natural sources of antioxidant with high amount of phenolics, flavonoids xanthones and beneficial fatty acid derivatives.
ABSTRACT
Streptomyces sp. KB1(TISTR 2304), identified by 16S rDNA gene, was collected from the air sample at Ao-nang, Krabi province, Thailand and deposited in the GeneBank database (accession number KF939581.1). It could produce bioactive compounds and excrete into liquid culture medium within 4 days of incubation period at 30 °C, 200 rounds per minute in shaking incubator. Bioactive compounds in culture broth supernatant were extracted with 3-times of ethyl acetate (EA), evaporated by rotary evaporator at 45 °C under reduced pressure, purified by silica gel column chromatography and eluted by gradient solvent system of ethyl acetate: hexane at ratio of 1:9, 3:7, 4:6, 6:4 and 10:0, v/v. Eight pooled fractions were obtained, name PF1 - PF8, from basis of their TLC profile. Only PF4 displayed as purified active compound which showed anti-methicillin resistant Staphylococcus aureus (MRSA) activity. The PF4 was predicted as 2, 4-Di-tert-butylphenol (C14H22O) with molecular weight 206.2.