Abstract:

The peel extracts of Citrus limon（L.）Burm. F. were obtained via an ultrasonic extraction method but with different solvents（methanol，ethanol，acetone，ethyl acetate，distilled water）. Their antioxidant and anti-fungi（Panicum italicum，Penicillium digitatum，Colletotrichum gloeosporioides）activities were tested. Further on the bioactive compounds of phenols from the extraction were analyzed by High Performance Liquid Chromatography（HPLC）. This study provides evidences for the comprehensive utilization of peels of Citrus limon（L.）Burm. F. Our studies suggested that the varieties and concentrations  of phenolic compounds extracted from peels of Citrus limon（L.）Burm. F. via different solvents were with significant differences（P < 0.05）to antioxidant and anti-fungi activities. The solvents’ contributions to antioxidant and anti-fungi were listed in their descending order，methanol，acetone，distilled water，ethanol，ethyl acetate；methanol，acetone，ethanol，distilled water，ethyl acetate. There were 16 phenolic bioactive compounds can be detected with the extraction method with different solvents，including 4 phenolic acids and 12 flavonoids，their content were closely related to antioxidant and anti-fungi abilities. In terms of the bioactive compounds contributing to antioxidant abilities，narirutin，hesperidin，neohesperidin，galic acid，chlorogenic acid and caffeic acid were considered to play the most important roles；whereas contributing to anti-fungi abilities，narirutin，neohesperidin and caffeic acid were the best candidates. Methanol as the best solvent for peel extraction of Citrus limon（L.）Burm. F. can be used for promoting the antioxidant and anti-fungi activities.

Key words: Citrus limon, extracts, total phenol, total flavonoid, antioxidation bacteriostasis, HPLC