Setyabudi, C; Tanda, S; Soetaredjo, FE; Irawaty, W
In Indonesia, kaffir lime fruit is commonly discharged as waste. On the other hand, the fruit peel contains phenolics and flavonoids compounds that can be used as one of natural antioxidant souces. In the present work, we investigated the possibility to extract phenolics and flavonoids compounds from kaffir lime peel. Several solvents possesses different polarity were employed. Following the extraction step, the extracts have been tested to be used as antidiabetic agent by retarding the conversion of starch to sugars. Several steps have been performed to achieve the aims. Firstly, kaffir lime peel was prepared by drying, grinding and sieving to obtain certain particle size. Secondly, kaffir lime peel extracts were prepared by soaking the kaffir lime peel with solvents possessing different polarity (water, ethanol, ethyl acetate and hexane). Thirdly, the extracts were subjected to analyses of total phenolic content, total flavonoid content and antidiabetic activity. Fourthly, phenolics and flavonoids compounds in the extracts were detected by using High Performance Liquid Chromatography. The results show extracts of kaffir lime peel, i.e. water, ethanol and ethyl acetate demonstrated antidiabetic activity to different extents. Ethanolic extract exhibited the strongest antidiabetic activity with 34.2% inhibition, whilst the phenolic and flavonoid contents in the extract were detected lower than the water extract. Ethyl acetate and water extract possessed the ability to retard starch conversion by 12.3 and 5.7 %, respectively. Several phenolics and flavonoids were identified in the three extracts. Gallic acid content was found higher in the ethanolic extract which can be up to 22.5 and 10 times higher compared to water and ethyl acetate, respectively. Different amounts of flavonoids of rutin, quercetin, naringin, hesperidin and naringenin have been detected present in the extracts. The ability to kaffir lime peel extracts, particularly the ethanol extract, to inhibit starch conversion promises to be used as nutraceutical supplements especially as antidiabetic agent. © 2006-2018 Asian Research Publishing Network (ARPN).
