Extraction of bioactive compounds and antioxidant activities from longan (Dimocarpus longan) seeds

No. O-O-000 Natural Products Research and Development Center (NPRDC), Science and Technology Research Institute (STRI), Chiang Mai University, Chiang Mai, 28-30 Nov. 2012 Extraction of bioactive compounds and antioxidant activities from longan (Dimocarpus longan) seeds Pitikan Wisitsak, Junniphaphorn Nimkamnerd, Natthawut Thitipramote, Nisakorn Saewan, Punyawatt Pintathong and Phanuphong Chaiwut Excellent Center for Cosmetics and Wellness, Mae Fah Luang University, Chiang Rai, 57100, Thailand School of Cosmetic Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand E-mail address: excellent_center@mfu.ac.th Introduction and Objective Antioxidant compounds are found in various fruits, vegetables including longan (Dimocarpus longan). In Chiang Rai province, the yield of cultivated longan was around 62,296 tons in year 2010. The enormous by-products (peel and seed) from the fruit processing industry and human consumption are generated (~15% w/w of whole fruit). The aim of present study was to extract the bioactive compounds and their antioxidant capacities from longan seed. Utilization of fruit processing industry by-products as a material for value-added product preparation would be useful. Methods The dried longan seeds were extracted with five polar solvents (water, methanol, 95% ethanol, acetone and ethyl acetate) at ratio 1:10 (sample: solvent, w/v) with using the shaking extraction at 150 rpm, 55C for 3 hours. The bioactive compounds (total phenolic content and flavonoid content) and their antioxidant activities (DPPH, ABTS and FRAP assays) of extracts were investigated. The main bioactive compounds were determined by using HPLC method. Results The highest extraction yield was found in methanol extract (10.31%, wet basis). The phenolic compounds and their antioxidant activities in all treatments were significantly difference (p water>95% ethanol>acetone>ethyl acetate extracts. The longan seed can be used as alternative source of antioxidant material.