제주산 재래감귤 과피와 종자 추출물의 항산화 활성 및 주요 플라보노이드 분포

Abstract

Water, 30, 50, 70, and 95% as well as enzymatic extracts from peel and seeds of different citrus varieties such as Citrus sunki, Citrus sulcata, Citrus grandis and Citrus junos were evaluated for their radical scavenging potential by DPPH, superoxide and hydroxyl radical scavenging assays as well as flavonoid content by HPLC. Water extracts, 30 and 50% ethanol extracts of peel from all the citrus samples showed more than 50 % activities in DPPH radical scavenging while 70% ethanol extracts of peel from Citrus sunki, Citrus sulcata and Citrus grandis showed more than 50% scavenging activities in DPPH radical scavenging. Only 95% ethanol extract of peel from Citrus junos showed more than 50% DPPH radical scavenging activity. Among all, 50% ethanol extracts of peel from Citrus sunki showed the highest DPPH radical scavenging activity, and all the extracts of seed from Citrus grandis and Citrus junos showed the lowest activities in DPPH radical scavenging. Among carbohydrase enzymes, the AMG extract of the peel from Citrus sunki showed the highest DPPH radical scavenging activity (60.5%) while all the extracts of seed of all citrus varies showed lower activities (less than 50%). Among proteases enzymes, Nutrase extract of peel from Citrus sunki and Citrus grandis showed strong activities in DPPH radical scavenging (86.2 and 77.1% in Citrus sunki and Citrus grandis, respectively), while Kojizyme extract of peel from Citrus junos showed the third highest activities (70%). However, all the extracts of seed from all the citrus varieties showed the activities less than 50%. All ethanolic and water extracts of peel and seed from Citrus sunki, Citrus sulcata, Citrus grandis and Citrus junos showed mild activities, and it was less than 15%. 95% ethanolic extracts of seed from all the citrus verities showed very low activities in superoxide anion radical scavenging. Among carbohydrase enzymatic extracts of peel, Citrus sunki, Citrus sulcata, Citrus grandis and Citrus junos) showed the activities between 70.5-79, 65.9-83.7, 65.8-82.9 and 70.5-73.8%, respectively in superoxide radical scavenging. All the carbohydrase extracts of peel showed more than 60% activities while AMG and Ultraflo extracts of peel showed more than 70% activities. All the carbohydrase extracts of seed showed moderate activities but AMG and Ultraflo extracts of seeds showed more than 70% activities. Among proteases enzymatic extracts of peel, Citrus sunki, Citrus sulcata, Citrus grandis, and Citrus junos showed the activities between 72.1-79.3, 77-81.9, 79.5-88.8 and 49.2-80.6.%, respectively in superoxide radical scavenging. All the proteases extracts of seed showed moderate activities, but Protamex and Alcalase extracts of seeds showed more than 70% activities. Both peel a and seed water extracts from all the citrus varieties showed the activities less than 30% but 30,50,70 and 95% ethanolic extracts from peel and seed from all the citrus varieties showed moderate activities (around 50%) in hydroxyl radical scavenging. Except water extracts of peel and seed, other extracts showed strong hydroxyl radical scavenging activities compared with the commercial antioxidant, Trolox. All extracts of peel and seed from Citrus sunki, Citrus sulcata, Citrus grandis and Citrus junos were analyzed for their flavonoid content by HPLC, and found that Hesperidin, Hesperitin, Naringin and Rutin are available in considerable amounts. The extracts of peel from Citrus sunki showed 0.730 and 0.255 mg/g of hesperidin and hesperitin, respectively, while the extract of peel from Citrus sulcata showed 0.678 mg/g hesperidin. Further, the extract of peel from Citrus grandis showed 0.206 , 0.865, 0.085 mg/g of hesperidin, naringin and rutin respectively while the extracts of peel from Citrus junos showed 0.234, 0.182, 0.015 mg/g of hesperidin, naringin and rutin respectively. The extract of peel from Citrus sunki showed 0.017 mg/g quercetin, while the extracts of seed from Citrus sunki, Citrus sulcata, Citrus grandis and Citrus junos showed trace amount of caffeic acid.