Ginseng, the root of the Panax ginseng, has been widely used as a traditional herbal medicine in Korea, China, and Japan for thousands of years. Now ginseng has become popular as functional health food and natural medicine and it is one of the bestselling natural products in the world. Gut microbiota has been found to play an important role in the metabolism and pharmacological action of orally administered ginseng. Recent animal and clinical studies have shown that compound K (20-O -beta-D-glucopyranosyl-20(S)-protopanaxadiol, CK) is the major ginsenoside metabolite deriving from gut microbiota-induced biotransformation and is more efficiently absorbed into the systemic circulation than its parent ginsenosides. Since ginsenoside metabolism varies between individuals depending on the population of gut microbiota, much attention paid to the transformation of major ginsenosides into more pharmacologically active ginsenosides using diverse methods including heating, acid hydrolysis, microbial conversion, and enzymatic treatment. Recently, in food and drug industry and academia, the development of fermented ginseng products using probiotic bacteria is being intensively studied due to the potential health benefits of ginsenoside metabolites and probiotics. This review summarizes recent studies on the metabolism of ginsenoside by gut microbiota and biotransformation of ginsenoside using lactic acid bacteria and their enzymes.

Ginsenosides, ginseng saponin, are the principal components responsible for the pharmacological and biological activities of ginseng. In order to improve absorption and biological activities, the biotransformation of major ginsenoside to minor ginsenoside, as the more active compound, is required. In this study, we isolated Lactobacillus brevis THK-D57, which has high β-glycosidase activity, from Kimchi. The major ginsenoside Rb₁ was converted to the minor ginsenoside ‘compound K’ during the fermentation of L. brevis THK-D57. The results propose that the biotransformation pathway to produce compound K is as follows: ginsenoside Rb₁→ginsenoside Rd→ginsenoside F₂→ginsenoside compound K.

Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl₄-induced hepatotoxicity. The hepatoprotective effect of subfractions has been evaluated by analyzing blood and hepatocyte biochemical analyses and biotransformation enzyme analyses. Treatment of BS-5 subfraction has significantly decreased the activities of alanine aminotransferase and aspartate aminotransferase. In addition, the levels of cholesterol and triglyceride in liver have been decreased as compared with that of CCl₄ treated rats. The hepatoprotective effect of BS-5 subfraction on the CCl₄-induced hepatotocicity would be mediated of the attenuation of the level of cytochrome P450 and the enhancement of the activity of glutathion S-transferase.

We evaluated the anti-allergic effect of black colored rice (Oryza sativa L.) and its main constituents, cyanidin 3 glucoside (C3G) and cyanidin (Cy) on scratching behavior in mice. The black rice extract (BRE) and its constituts inhibited the scratching behavior induced by compound 48/80 and histamin. To understand the role of intestinal microflora in the anti-allergic effect of C3G, which was suspected to play a key role in depressing scratching behavior, C3G was incubated with human fecal bacteria. Protocatechuic acid (PCA) was found within the 30 min and its concetration sharply increased. Vanillic acid (VA) was also detected in the incubated sample mixture. The anti-allergic effect of these compounds, C3G, Cy, PCA and VA, were investigated. PCA and Cy potentely reduced scratching behavior in mice induced by compound 48/80 and histamin. These findings enable us to conclude that intestinal bacterial metabolites, PCA and VA, produced by intestinal micro flora contributed to suppressing the scratching behavior induced by compound 48/80 and histamin.

감초의 에틸아세테이트 분획 중 flavonoid 지표물질인 liquiritin이 들어있는 분획 (GUE6)에 살구 및 복숭아 종자로부터 얻은 조효소액 (PDE, PAE, PPE)을 법제 처리하였다. 각 조효소액에서 β-glucosidase 활성도는 아몬드 (P. dulcis) 259.6 U/g 살구 (P. persica), 복숭아 (P. persica) 조효소액의 β-glucosidase 활성도가 가장 높게 관찰되었다. PDE, PAE, PPE를 이용한 발효 법제 후 liquiritigenin의 함량 비교 결과, 효소중의 β-glucosidase에 의해 liquiritin이 대사되어 항산화, 향군, 세포 독성 억제, 항치매, 항피부암 등 많은 약리효능을 가진 활성 물질인 liquiritigenin이 생산됨이 확인되었으며, 세효수 모두 liquiritin에 1.2배의 효소 처리 시 가장 대사가 활발한 것으로 나타나 변환을 위한 최적 농도로 결정되었다 세효소 중 특히 PPE 처리 시 liquiritin이 모두 liquiritigenin으로 변환됨으로써 liquiritin의 변환에 복숭아 종자 유래 효소가 가장 효율적인 것으로 밝혀졌다.