Isolation of a natural antioxidant, dehydrozingerone from Zingiber officinale and synthesis of its analogues for recognition of effective antioxidant and antityrosinase agents.
In the present study, the antioxidative and inhibitory activity of Zingiber officinale Rosc. rhizomes-derived materials (on mushroom tyrosinase) were evaluated. The bioactive components of Z. officinale rhizomes were characterized by spectroscopic analysis as zingerone and dehydrozingerone, which exhibited potent antioxidant and tyrosinase inhibition activities. A series of substituted dehydrozingerones [(E)-4-phenyl-3-buten-2-ones] were prepared in admirable yields by the reaction of appropriate benzaldehydes with acetone and the products were evaluated in terms of variation in the dehydrozingerone structure. The synthetic analogues were examined for their antioxidant and antityrosinase activities to probe the most potent analogue. Compound 26 inhibited Fe2+-induced lipid peroxidation in rat brain homogenate with an IC50 = 6.3+/-0.4 microM. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical quencher assay, compounds 2, 7, 17, 26, 28, and 29 showed radical scavenging activity equal to or higher than those of the standard antioxidants, like alpha-tocopherol and ascorbic acid. Compound 27 displayed superior inhibition of tyrosinase activity relative to other examined analogues. Compounds 2, 17, and 26 exhibited non-competitive inhibition against oxidation of 3,4-dihydroxyphenylalanine (L-DOPA). From the present study, it was observed that both number and position of hydroxyl groups on aromatic ring and a double bond between C-3 and C-4 played a critical role in exerting the antioxidant and antityrosinase activity.
Department of Biotechnology, National Formosa University, Yunlin 632, Taiwan, ROC.
Ping-Chung
PC
Kuo
Amooru G
AG
Damu
Ching-Yuh
CY
Cherng
Jye-Fu
JF
Jeng
Che-Ming
CM
Teng
E-Jian
EJ
Lee
Tian-Shung
TS
Wu
D000818:Animals; D000975:Antioxidants / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology; D020939:Zingiber officinale / Q000737:chemistry*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D013343:Styrenes / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology
D000975:Antioxidants; D004791:Enzyme Inhibitors; D013343:Styrenes; C052933:methyl-3-methoxy-4-hydroxystyryl ketone; D014442:Monophenol Monooxygenase