Antioxidant activity of ethanol extract ofLycium barbarum'sleaf with removal of chlorophyll

Abstract

Purpose: The aim of this study was to estimate the antioxidant activities of 50%, 70%, and 100% ethanol extracts of Lycium barbarum leaf and chlorophyll removal extract. Methods: The antioxidant activities were estimated by measuring total polyphenol content and by assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfate) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). In addition, reactive oxygen species (ROS) production, DNA fragmentation, and antioxidant enzyme (superoxide dismutase and catalase) activities of the extracts were measured in hydrogen peroxide (H2O2)-stressed HepG2 cells. Results: The total polyphenol content, DPPH and ABTS radical scavenging activities, and FRAP value of the extracts increased in an ethanol concentration-dependent manner. The antioxidant activities of the chlorophyll-removal extracts were much higher than those of the chlorophyll-containing extracts. Cytotoxicity was not observed in HepG2 cells with extracts up to 1,000 μg/mL. All extracts inhibited ROS production in a concentration-dependent manner from 31.3 μg/mL and inhibited DNA damage at 250 μg/mL. The SOD and catalase activities of cell lines treated with the extracts and H2O2 were similar to those of normal cells, indicating a strong protective effect. Conclusion: Lycium barbarum leaf extracts had high antioxidant activities and protected H2O2-stressed HepG2 cells. Since the chlorophyll-removal extract exhibited higher antioxidant activities than the chlorophyll-containing ones and the cytoprotective effect was similar, chlorophyll removal extract of Lycium barbarum leaf could be developed as ingredients of functional food and cosmetics. (http://creativecommons. org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 서 론 구기자 (Lycii fructus)는 가지과 (Solanceae)에 속한 구 기자 나무의 성숙한 과실을 건조한 것으로 우리나라를 비롯한 중국, 대만, 일반 등지에서 자생하거나 재배되고 있는 생약재로 한방에서는 인삼 등과 함께 독성이 없는 120종의 상약 (上藥)군으로 취급하고 있다 [1]. 구기자나 무의 종류는 상당히 많으나 그 열매를 식용으로 사용하는 나무 중 잘 알려진 것으로 한국의 청양 등에서 주로 재배 되는 Lycium chinense Miller와 중국, 티벳, 몽고 등에서 재배되는 Lycium barbarum Linne (영하구기자)로 볼 수 있다 [2]. 구기자에는 carotinoid, choline, zeaxanthin, physalin (dipalmity-zeaxanthin), vitamin B1과 meliscic acid 등의 불 포화지방산과 같은 영양성분이 다량 함유되어 있고, 또한 phytochemical로서 β-sitosterol, betaine과 rutin과 같은 기 능성 성분이 함유되어 있다. 이에 따라 구기자의 항암 [3], 면역증진 [4], 간 기능 개선효과 [5], 혈중 지질 저하 [6] 등 의 효능에 대한 연구가 진행되었다. 구기엽의 성분으로는

Protective effect ofLycium barbarumleaf extracts on atopic dermatitis:in vitroandin vivostudies

“…[ 17 ] measured the degree of DNA damage after administration of L. barbarum leaf ethanol extracts or chlorophyll-removed ethanol extract in BALB/c mice with an lipopolysaccharide-induced inflammatory response and found that there was no significant difference between the 2 groups. In another study examining the antioxidant efficacy of L. barbarum leaf ethanol extract in HepG2 cells, it was shown that the antioxidant activity of chlorophyll-removed ethanol extract of L. barbarum leaves was higher than that of the ethanol extract of L. barbarum leaf before the removal of chlorophyll [ 16 ]. In that previous study, the yield, chlorophyll content, and total polyphenol content of the 2 ethanol extracts of L. barbarum leaf (LLE and LLE[Ch-]) were reported.…”

“…In that previous study, the yield, chlorophyll content, and total polyphenol content of the 2 ethanol extracts of L. barbarum leaf (LLE and LLE[Ch-]) were reported. As 99.8% of chlorophyll was removed from LLE(Ch-), the yield decreased from 20.5% to 16.45%, and the total polyphenol content more than doubled (140.5 ± 7.45 mg gallic acid equivalent [GAE]/extract g vs. 312.9 ± 10.2 mg GAE/extract g) [ 16 ]. Also, the content of flavonoid, a type of polyphenol, increased from 34.77 ± 1.29 mg catechin equivalents (CE)/g to 42.75 mg CE/g (data not shown).…”

“…This study is the result of an experiment using the same sample as in the study by Kim et al . [ 16 ]. Concerns about a decrease in antioxidant efficacy were predicted by removing chlorophyll from the ethanol extract of L. barbarum leaf; however, the antioxidant activity increased as the polyphenol content increased.…”

“…In this experiment, L. barbarum leaves with chlorophyll were denoted as LLE, and L. barbarum leaf ethanol extract from which chlorophyll was removed was denoted as LLE(Ch-). The chlorophyll contents of LLE and LLE(Ch-) were analysed as 1,194.6 µg/kg dry weight and 1.7 µg/kg dry weight, respectively [ 16 ].…”

“…However, since chlorophyll is also a component that has antioxidant activity, it was necessary to study whether the antioxidant activity of L. barbarum leaf was maintained even after the removal of chlorophyll. In previous studies of our laboratory, we reported on the antioxidant and anti-inflammatory effects of the ethanol extracts of L. barbarum leaf with or without chlorophyll [ 16 17 ].…”