Study On Antioxidant Activties Of Jackfruit Peel

Jackfruit (Artocarpus heterophyllus Lam),"The queen of the tropical fruit", which is a family of Moraceae, have very remarkable biologic activities and pharmacological functions. During processing, the surface peel of jackfruit was abandoned so as to lead to the great waste of resource. In this paper, the extraction, isolation, purification and identification of jackfruit peel were studied by modern isolation technology and detection methods, The results were as follows:(1)The study aimed to discuss the antioxidant activities in jackfruit which is specially grown in tropical of china. The peel, pulp, testa and seed were separate and exacted by ethanol extract. The antioxidant activity was confirmed through measuring the scavenging capacity of each component in the peel, pulp, testa and seed of jackfruit to DPPH-ABTS.+、and·OH. The extracts in both the peel, pulp, testa and seed of jackfruit had stronger scavenging capacity, showing some activities of antioxidant. The antioxidant activity in peel was highest in four parts, testa was higher than that in pulp, and seed was lowest in four parts. The peel, pulp, testa and seed of jackfruit had some antioxidant activities, which could taken as a kind of good natural antioxidant activity material source.(2)The factors affecting extraction of antioxidant compositions from jackfruit peel were studied and the results showed the ethanol concentration, extraction temperature and the liquid-solid ratio played the main roles in the extracting processing. Then the response surface methodology (RSM) was applied to optimize the process with the three above-mentioned factors as the independent variables. It was demonstrated that all the linear and quadratic and interaction terms had significant effect on yield of DPPH radical scavenging ratio at5%level of significance (p<0.05). Meanwhile, a mathematical model describing the relation between the three variables and the response value was constructed. Y=-3599.1175+66.0335X1+29.6705X2+37.065X3+0.019X1X2-0.18X1X3-0.29X2X3-0.4181X12-0.2441X22-6.6275X32And the analysis of variance showed it was suitable for predicting the experimental results. Finally the optimal extraction conditions obtained from the model was described as follows:ethanol concentration80%, extraction temperature65℃and liquid-solid ratio3:1. Under this condition, the experimental yield of DPPH radical scavenging ratio was5.69%, which agreed with the predicted value5.61%from the fitting model.(3)The antioxidant activities of three fractions partitioned by petroleum ether, ethyl acetate and water from ethanol extract of jackfruit peel were estimated using DPPH, ABTS and ferric reducing/antioxidant power (FRAP) methods. And the content of total polyphenols and flavonoids in each fraction were determined. The results showed that the content of flavonoids and polyphenols from ethyl acetate fraction were the highest and the value was1.346mg/g and1.102mg/g, respectively. However, the water fraction had the poor level of polyphenol and flavonoid content, which was0.593mg/g and0.029mg/g, respectively. Furthermore, the ethyl acetate part showed an excellent antioxidant activity, inhibition ratio of which was94%for DPPH radical and99.1%for ABTS radical. And its ferric reducing/antioxidant power reached952.6μmol/L. The inhibition ratio of petroleum ether was90%for DPPH radical,97.9%for ABTS radical and its FRAP reached733.2μmol/L. The inhibition ratio of water was90%for DPPH radical,89%for ABTS radical and its FRAP reached620μmol/L. The antioxidant activity of crude part followed that of ethyl acetate, petroleum ether and the water fraction presented poor antioxidant activity.(4)By using modern isolation techniques such as silica gel, thin-Layer chromatography and sephadex LH-20, the fraction of petroleum ether and ethyl acetate was obtained ten compounds, and two of them had been elucidated from1H-NMR and13C-NMR spectral data. These were as follows:Cycloartenone and Cycloeucalenol. The structures of another eight compounds have not yet been elucidated, but their purity and molecular weight had been confirmed by MS. This research will be useful for the further study of effective material basic of jackfruit, especically the characteristic composition of terpenoids.