• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.13-17
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• 1998

The root of Aralia continentalis Kitagawa (Araliaceae) have been used as an analgesic and fever remedy, and for treatment of rheumatism in Chinese medicine, whereas the young leaves are used for ingredient of salad. Antioxidant activity of the young leaves of A. continentails was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at $37^{\circ}C$, using 2-thiobarbituric acid (TBA) and by evaluation the radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Chromatographic separation of active fraction led to the isolation of six flavonoids, among which quercetin, hyperoside and kaempferol showed strong antioxidant activities, while 6"-O-acetyl astragalin, astragalin and trifolin were inactive. Adenosine, oleanolic acid 28-O-glucosyl ester and salsoloside C methyl ester isolated from the somewhat active BuOH fraction exhibited no antioxidant activities.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.518-528
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• 2005

In the present study, the antioxidative and inhibitory activity of Zingiber officinale Rosc. Rhizomes-derived materials (on mushroom tyrosinase) were evaluated. The bioactive co mponents 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 Fe$^{2+}$-induced lipid peroxidation in rat brain homogenate with an IC$_{50}$ = 6.3${\pm}$0.4 ${\mu}$M. 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.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.38-47
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• 2018

In this study, the antioxidant activities of hot water extracts of Rugosa rose (Rosa rugosa Thunb.) were evaluated. Total phenolic compounds (TPC) and total flavonoid compounds (TFC) were the highest in the leaf extracts at 107.29 mg/g and 24.28 mg/g, respectively. The DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activity was in the following order: flower extract > leaf extract > seed extract > fruit extract. The $IC_{50}$ values for DPPH and ABTS of the flower extract were $0.87mg/m{\ell}$ and $0.27mg/m{\ell}$, respectively. The amount of gallic acid was higher in the flower (4.51 mg/g) and leaf extracts (0.97 mg/g) than in the other extracts. Among the fraction (A-F) of each extract, antioxidant activity was the highest in the C fraction of flower extract. It is due to high TPC (3305.43 mg/g) and TFC (878.42 mg/g). Statistical analysis revealed a strong correlation between TFC (or TPC) and radical scavenging activity at p-value < 0.001. Collectively, these results suggest that the hot water extracts of rugosa rose have potential antioxidant effects, and can be used in food, cosmetics, and the pharmaceutical industries.