Study On The Lemonin Biological Activity In Lemon Peel

Limonoids is one of the important bioactive compound in lemons.Limonoids has a variety of biological activities,such as antioxidant,antibacterial,analgesic,anti-inflammatory and anti-tumor.This paper studied the antibacterial properties and antibacterial mechanism of limonoids in lemon peel against Rhizopus,Penicillium and Aspergillus Niger.The antioxidation and antitumor properties of limonoids were studied.Limonoid purification process were investigated.The research results will provide the useful information on how to develop lemon nutrition and health protection,on how to increase the efficient use of lemon.(1)The bacteriostatic effect of citrine extract on Aspergillus Niger,Rhizopus and Penicillium Niger was studied by Oxford Cup method and determination of strain OD.The MIC of citrate extract from lemon peel on Aspergillus Niger and Penicillium Niger was 625mg/kg;The MIC for Rhizopus was 1250 mg/m L.Ningmengkusu's MFC against Aspergillus Niger and Penicillium Niger was 5000 mg/m L.The MFC of Rhizopus was2500?g/m L.Ningmengkusu had strong inhibitory effect on all three kinds of mould.The effect of different temperature,UV,p H,gelatin,Fe³⁺and Fe²⁺on the bacteriostasis of Ningmengkusu extract was studied.The results showed that the three kinds of mould were stable under different temperature and gelatin complex.The bacteriostatic stability was significantly affected by different concentration of UV and metal ions.The bacteriostatic stability was most affected by p H and the bacteriostatic effect was best under acid condition.The antibacterial mechanism of limonin against Aspergillus niger,Penicillium and Rhizopus was studied using spore germination rate,mycelial inhibition rate,electrical conductivity,protein and scanning electron microscopy.Low concentrations of limonin can inhibit the growth of three molds(Aspergillus niger,Penicillium:625?g/m L,Rhizopus:312.5?g/m L),and antibacterial effects of limonoid on Aspergillus niger,Penicillium and Rhizopus It is suppression rather than killing.The inhibition of limonin against Aspergillus niger,Penicillium,and Rhizopus by conductivity,protein and electron microscopy confirmed that the mechanism of action of limonin was to destroy the integrity of the cell wall,increase the permeability of the cell membrane,and change the normal metabolism of the three molds.Inhibit the growth of bacteria.DPPH radical scavenging method(DPPH method)and iron reduction color method(FRAP method)were used to study the effects of temperature,light,and p H on the antioxidation of limonin.Temperature,light,and p H all had significant effects on the antioxidation of limonin(p<0.05).However,only at different p H conditions,there was a significant correlation between limonin content and its DPPH free radical scavenging capacity(p<0.01),the correlation was not significant under other conditions(p<0.05).The anti-tumor effect of limonin in lemon peel was investigated by using the limonisin standard as a control and the growth survival curves of SMMC-7721,A549 and Hep C2tumor cells within 24h and 48h.Limonitin in lemon peel had the best inhibitory effect on A549 tumor cells,followed by Hep C2,and had the weakest inhibitory effect on SMMC-7721.Limontin standard had the effect of incubating SMMC-7721 tumor cells on A549 and Hep C2 tumor cells.There is a certain inhibitory effect.The anti-tumor effect of limonin in lemon peel is significantly better than that of limonin;the anti-tumor effect of limonin in lemon peel is specific,the higher the concentration of limonin extract,the longer the action time,and the proliferation of cells.The stronger the inhibitory effect.The macroporous resin XAD-16 suitable for purifying limonin was selected among six macroporous resins by using the adsorption rate and the resolution as indicators to study the effects of different column concentrations,loading rates,eluent concentrations,and elution rates.XAD-16 macroporous resin dynamic adsorption curve effect.The optimum column concentration was obtained with a sample flow rate of 0.5 m L/min,an optimum column concentration of 2.135 mg/m L,an optimal eluent of 80%ethanol solution,and an optimum elution flow rate of 0.5 m L/min.The structure of limonin extract in lemon peel was resolved from the secondary mass spectrum and two limonoid analogues obaunone glucoside and nomilin glucoside were found.