• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1105-1111
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• 2018

The flavin-dependent monooxygenase Sam5 was previously reported to be a bifunctional hydroxylase with coumarate 3-hydroxylase and resveratrol 3'-hydroxylase activities. In this article, we showed the Sam5 enzyme has 3'-hydroxylation activities for methylated resveratrols (pinostilbene and pterostilbene), hydroxylated resveratrol (oxyresveratrol), and glycosylated resveratrol (piceid) as substrates. However, piceid, a glycone-type stilbene used as a substrate for bioconversion experiments with the Sam5 enzyme expressed in Escherichia coli, did not convert to the hydroxylated compound astringin, but it was converted by in vitro enzyme reactions. Finally, we report a novel catalytic activity of Sam5 monooxygenase for the synthesis of piceatannol derivatives, 3'-hydroxylated stilbene compounds. Development of this bioproduction method for the hydroxylation of stilbenes is challenging because of the difficulty in expressing P450-type hydroxylase in E. coli and regiospecific chemical synthesis.

• Natural Product Sciences
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• 제17권3호
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• pp.198-201
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• 2011

Tyrosinase is one of the important enzymes in the mammalian melanin synthesis. In the process of melanin synthesis, tyrosine is oxidized to DOPA (3,4-dihydroxyphenylalanine), and DOPA is further oxidized to dopaquinone. Tyrosinase is an enzyme catalyzing this oxidation of tyrosine, so chemicals that inhibit the activity of tyrosinase can be used as skin whitening agents. In this study, we isolated five constituents from the 80% MeOH extract of Morus bombycis cortex by bioactivity-guided fractionation. We performed mushroom tyrosinase inhibition assay. As a result, 7,2',4'-trihydroxyflavanone (1), 2',4',2,4,-tetrahydroxychalcone (2), and oxyresveratrol (3) showed the more potent inhibitory effect compared to kojic acid, a well-known skin whitening agent with antityrosinase effect. Moracinoside M (4) and moracin M-3'-O-${\beta}$-D-glucopyranoside (5) also showed the moderate tyrosinase inhibitory activities.

• Proceedings of the SCSK Conference
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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• pp.201-212
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• 2003

The heartwood extract of Artocarpus lakoocha Roxb., which contains a potent tyrosinase inhibitor oxyresveratrol, was evaluated for its melanin-reducing efficacy in both guinea pigs and human volunteers. After 4 week-daily application of the extract dissolved in propylene glycol to the back of guinea pigs, significant reduction in melanin content was detected, with the effect greater than 3% kojic acid and solvent propylene glycol (P < 0.05). The extract was subsequently tested in female volunteers (3 groups of 20 subjects) using a parallel clinical trial with self-control. The first group received the A. lakoocha solution in propylene glycol whereas the second and the third group respectively received 0.25% licorice extract and 3% kojic acid in the same solvent. The subject in each group twice daily applied the test solution on one arm whereas the remaining arm was applied with only propylene glycol (self-control) for 12 weeks. The A. lakoocha extract was found to be the most effective agent, giving the shortest onset of significant whitening after only 4 weeks of application (P < 0.05), followed by 3% kojic acid (8 weeks) and 0.25% licorice extract (10 weeks). The whitening effect also increased with time, with the highest extent observed with A. lakoocha at week 12. The in vitro antityrosinase activity of A. lakoocha extract decreased with time upon storage at room temperature but could be stabilized by a combination of several antioxidants. In conclusion, the heartwood extract of A. lakoocha appeared to have promising potential for use as an effective and economical skin-whitening agent.

• Archives of Pharmacal Research
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• 제27권2호
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• pp.199-205
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• 2004

Cytochrome P450 (P450) 1 enzymes such as P450 1A1, 1A2, and 181 are known to be involved in the oxidative metabolism of various procarcinogens and are regarded as important target enzymes for cancer chemoprevention. Previously, several hydroxystilbene compounds were reported to inhibit P450 1 enzymes and were rated as candidate chemopreventive agents. In this study, we investigated the inhibitory effect of 2-[2-(3,5-dimethoxyphenyl)vinyl]-thiophene (DMPVT), produced from the chemical modification of oxyresveratrol, on the activities of P450 1 enzymes. The inhibitory potential by DMPVT on the P450 1 enzyme activity was evaluated with the Escherichia coli membranes of the recombinant human cytochrome P450 1A1, 1A2, or 1B1 coexpressed with human NADPH-P450 reductase. DMPVT significantly inhibited ethoxyresorufin O-deethylation (EROD) activities with $IC_{50}$ values of 61, 11, and 2 nM for 1A1, 1A2, and 1B1, respectively. The EROO activity in OMBA-treated rat lung microsomes was also significantly inhibited by OMPVT in a dose-dependent manner. The modes of inhibition by DMPVT were non-competitive for all three P450 enzymes. The inhibition of P450 1B1-mediated EROD activity by OMPVT did not show the irreversible mechanism-based effect. The loss of EROD activity in P450 1B1 with OMPVT incubation was not blocked by treatment with the trapping agents such as glutathione, N-acetylcysteine, or dithiothreitol. Taken together, the results suggested DMPVT to be a strong noncompetitive inhibitor of human P450 1 enzymes that should be considered as a good candidate for a cancer chemopreventive agent in humans.

• Proceedings of the Plant Resources Society of Korea Conference
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.99-99
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• 2019

꾸지뽕나무(Cudrania tricuspidata)는 뽕나무과(Moraceae)에 속하는 낙엽활엽 소교목이다. 우리나라와 중국, 일본과 같은 동아시아에 주로 분포하며 척박한 땅에서도 잘자라고 병충해에 강하다고 알려져 있다. 예로부터 꾸지뽕나무는 항암, 간보호, 눈을 밝게하는 작용이 있다고 동의보감과 신농본초경에 기록되어 있다. 우리나라는 오랫동안 된장 등 발효식품을 자주 접하고 섭취하여 왔다는 점을 고려하여 본 연구를 수행하였다. 발효균을 접종하면 항암활성, 면역체계 개선 등 다양한 생리활성 물질이 증가한다고 알려져 있다. 본 연구는 가시가 없고 잎이 커 작업성이 용이한 대품 품종을 2018년 9월에 전남 신안군에서 채취하여 분석 시료로 사용하였다. 항산화활성 측정은 프리라디칼(DPPH, ABTS) 소거능을 측정하여 농도(EC50)별 측정결과 $100{\mu}g/mL$ ext. 이하로 항산화 활성이 열매보다 잎이 높다는 것을 확인하였다. 황국균(Aspergillus oryae)을 꾸지뽕나무 잎과 열매에 접종시켜 페놀성화합물을 스크리닝 한 결과 기존에 발견되지 않은 Salicylic acid, Naringenin, Vanilic acid, Oxyresveratrol 등 기능성 물질이 발견되었고, 잎의 경우 36시간 발효물(355mg/g)은 무처리군(179mg/g)에 비해 2배정도 상승하였다. 열매의 경우 48시간 발효시켰을 경우(472mg/g)으로 무처리군(156mg/g)보다 3배정도 상승하였다. 발효를 통해 꾸지뽕나무 잎과 열매의 최적의 추출조건을 확립하고 생리활성 물질 분석을 이용한 효능탐색 등을 진행하였다. 향후 꾸지뽕나무를 활용한 식품 소재개발 등 사업화에 기초적인 자료를 제공하여 임업인의 새로운 소득품목 육성에 기어코자 한다.

• Journal of Nutrition and Health
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• 제49권1호
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• pp.18-27
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• 2016

Purpose: Our previous study demonstrated the hypoglycemic effects of mulberry (Morus alba L.) leaf and the underlying mechanisms. Here we explored the potency of mulberry twigs (TW) and root barks (RB) in postprandial hypoglycemic effects in vitro and in vivo. Methods: The major components of TW and RB were determined by high performance liquid chromatography (HPLC). Alpha-glucosidase inhibition and glucose/fructose uptake inhibition in Caco-2 cells were determined for TW, RB, and their major components, followed by an oral sugar tolerance test (OSTT) in streptozotocin-induced diabetic rats. Male Wistar rats were fed a high-fat diet for 2 weeks and then a single dose of streptozotocin (35 mg/kg B.W) was administered by intraperitoneal injection. Rats with fasting blood glucose levels above 126 mg/dL were randomly divided into 5 groups (n = 8/group) for the following treatments by gavage for 4 weeks: vehicle (normal control and diabetic control), 200 mg/kg B.W of TW or RB or 100 mg/kg B.W of oxyresveratrol (OXY). Results: OXY and mulberroside A were identified as the major components of TW and OXY, mongolicin, and kuwanon H for RB. A significant inhibitory activity on ${\alpha}-glucosidase$ was found for TW, RB, and OXY (p = 0.0099). There was a dose-dependent inhibition of TW and RB on the intestinal sugar uptakes in Caco-2 cells, showing a greater impact on fructose compared to glucose. The OSTT showed that TW and RB significantly delayed time to maximal concentration (p = 0.0088) and decreased maximal concentration (p = 0.0043) compared to the control group. Conclusion: These results suggest that TW and RB may have a postprandial hypoglycemic effect, particularly in the case of high fructose or sucrose intake. OXY was suggested as a contributor to the hypoglycemic effect of TW and RB. Further studies are needed for the systemic effect of TW and RB in circulation.