This study evaluated the biological activity and cytoprotective effect of guava (Psidium guajava L.) branch against oxidative stress. The contents of vitamin C, beta-carotene, total carotenoids, quercetin and catechin determined were 26.783, 43.676, 65.083, 58.245, and 8.309 mg/100 g, respectively. To measure antioxidant activity, the guava branch was extracted using various concentrations of ethanol (60, 80, or 100%) and water. The highest content of polyphenols (0.245 mg gallic acid equivalent/mg residue) and flavonoids (0.128 mg cathechin equivalent/mg residue) was found in the 100% ethanol extract of the branch (E100). Moreover, E100 also possessed the highest radical scavenging activities and showed the highest inhibition rate of α-glucosidase (77.692%). E100 was the most effective extract to impart cytoprotectant activity against oxidative stress in HepG2 cells. Taken together, our results determine the promising antioxidant activity of guava branch, and indicate the potential to be applied as a natural antioxidant.

Antioxidant activity of dropwort fermented extract (DFE) was measured according to fermentation period, and liverprotective effects were examined using Sprague-Dawley rats. Total polyphenol and flavonoid contents as well as DPPH andABTS radical scavenging activities increased up to 60~80 days and then decreased slightly. Proper fermentation time forDFE was more than 60 days and less than 80 days. Administration of alcohol to rats for 10 days at 10mL/kg/day raisedserum AST, ALT, total cholesterol, and triglyceride (TG) levels, which were then lowered by DFE and sugar liquid with thesame soluble solids. While sugar liquid increased the blood lipid profile, especially TG levels, DFE had no effect due to itsantioxidant activity. When TBARS content of the DFE group in liver tissue significantly decreased in a concentration-dependent manner compared to that of the ALH group (p<0.05). Liver damage was recovered by DFE treatment and wasconfirmed by hamatoxylin-eosin staining. These results suggest that DFE has a protective effect against alcohol-inducedhepatotoxicity in SD rats.

국내 전통식품 인증을 획득한 된장을 대상으로 간 섬유화 억제를 위한 기능 소재로서의 활용가능성을 알아보고자하였다. 국내 농산물로만 제조되어진 전통식품인증 된장총 24개 제품을 전국에서 수집하여 70% 메탄올로 추출한다음, MEF 세포주에 처리하여 간섬유화의 지표인 α-SMA의 발현 억제활성을 측정하였다. 공장식 생산과정을 거치는 일반 시판된장과 대조군 대비, 경북지역에서 수집된No. 13 전통인증된장 추출물이 약 74%의 α-SMA 발현억제활성을 나타내어 뛰어난 간 섬유화 억제활성을 나타내었다. 이는 의약품으로 사용되는 silymarin 84%과 비교시10% 정도밖에 차이나지 않았으며, 2년 이상의 발효시간을거친 제품임을 감안할 때 향후 발효시기에 따른 기능성의향상에 대한 기대도 가능할 것으로 예상된다.