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TITLE PHYTOCHEMISTRY AND ANTI-TYROSINASE ACTIVITY OF ANAXAGOREA LUZONENSIS A GRAY
AUTHOR WIYADA NOORING
DEGREE MASTER OF SCIENCE PROGRAM IN PHARMACEUTICAL CHEMISTRY AND PHYTOCHEMISTRY(INTERNATIONAL PROGRAM)
FACULTY FACULTY OF PHARMACY
ADVISOR AIMON SOMANABANDHU
CO-ADVISOR WEENA JIRATCHARIYAKUL
 
ABSTRACT
Phytochemical and anti-tyrosinase studies were performed on the stems of Anaxagorea luzonensis A. Gray, collected from a forest area in Petchaburee Province, Thailand. The hexane, dichloromethane and ethyl acetate extracts were found to be active against mushroom tyrosinase with percent inhibition at 0.909 mg/ml of 28.56 %, 58.27 % and 86.76 %, respectively. Results also confirmed the antioxidant activities of these extracts as shown by the IC50 values of 162.7, 10.60 and 3.33 ug/ml, respectively. Bioassay-guided fractionation of these extracts was carried out by chromatographic methods. Phytochemical investigation of these extracts resulted in the isolation and identification of five compounds; the three xanthones were found to be 1,6-dihydroxy-5-methoxy-4',5'-dihydro-4',4',5'- trimethyl-furano-(2',3':3,4)-xanthone (A), 2-deprenyl-rheediaxanthone B (B) and 1,3,6-trihydroxy-5-methoxyxanthone(C) and the two flavonols were identified as kaempferol (D) and quercetin (E). Their structures were established by spectroscopic methods (UV, IR, MS, 1H-NMR and 13C-NMR). This is the first report on the anti-tyrosinase activity of the A. luzonensis, compounds A (IC50 1.18 mM) and B (IC50 1.35 mM), while compound D (kaempferol) and E (quercetin), are known anti-tyrosinase agents. These compounds exhibited scavenging activity toward DPPH radical with IC50 values of 5.56 (A), 7.62 (B), 6.94 (D) and 5.30 (E) uM. However, compound C was found to be inactive against mushroom tyrosinase and to have little free radical scavenging activity. The results of this study demonstrated the potential of A.luzonensis as tyrosinase inhibitory and antioxidant agents for applications in the pharmaceutical and cosmeceutical fields.
KEYWORD ANAXAGOREA LUZONENSIS A. GRAY, XANTHONES, FLAVONOIDS, ANTITYROSINASE, FREE RADICAL SCAVENGING ACTIVITY
 
FACULTY OF GRADUATE STUDIES. MAHIDOL UNIVERSITY. THAILAND
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