Moringa Leaf Phytochemical Analysis And In Vitro Biological Activity Study

In 2012,Moringa oleifera leaf was approved as a new resource of food by the Ministry of Health and it is rich in phenolic compounds,with antioxidant,antibacterial,antihypotensive,hypoglycemic and other effects.In this study,to evaluate total phenolics,phytochemicals and biological activities of M.oleifera leaf.The extract（MLE）was prepared,and its antioxidant propertes:ABTS,DPPH free radical scavenging ability and ferric reducing ability were investigated.Meanwhile,the inhibition of MLE to Staphylococcus aureus and Escherichia coli was measured.Finally,anti-inflammatory effect and related gene iNOS expression quantity of MLE with abundant phenolics was analyzed using LPS-induced mouse macrophage cell line RAW264.7.The main findings were concluded as follows:1.This chapter mainly analyzed the total phenolic content and phytochemicals of MLE.The total phenolic content is 20.16 mg GAE/g DW,and a total of 39 compounds were identified by mass spectrometry.It concluded 8 organic acids,2 amino acids,2hydroxybenzoic acids,6 hydroxycinnamic acids,14 flavonols,2 flavonoids and 5glucosinolates.It showed that MLE was rich in phytochemicals and varieties.MLE was rich in citric acid and malic acid,and the contents were 199.71 and658.86μg/g DW,respectively.The contents of linolenic acid and linoleic acid were higher,which were 506.46 and 192.30μg/g DW,respectively.The content of chlorogenic acid in MLE was higher,reaching 2218μg/g DW.MLE was also rich in ferulylquinic acid and coumaric quinic acid at 900.98 and 878.30μg/g DW,respectively.In addition,MLE was rich in isothiocyanates up to 3688.31μg/g DW,of which the highest content of acetyl-benzyl inulin isothiocyanate was 1152.81μg/g DW.2.Three antioxidant systems were used to determine the antioxidant activities of MLE.Meanwhile,Vc was used as a positive control.The results indicated that the IC₅₀values of MLE and Vc in the DPPH free radical scavenging system were 5.18 and 3.31μg/mL,respectively.The DPPH free radical scavenging activity of MLE was slightly lower than that of Vc.It also showed higher ABTS free radical scavenging activity with IC₅₀ value of 2.44μg/mL.In the FRAP system,the IC₅₀ values of MLE and Vc were2.66 and 1.05μg/mL,respectively,and the order of their antioxidant capacity was Vc>MLE.3.The antibacterial activity of different concentrations of MLE solution against S.aureus and E.coli was tested.The results showed that MLE had a good inhibitory effect on S.aureus,and the inhibitory effect was concentration-dependent.When the concentrations were 50 and 500μg/m L,the inhibition activity reached 41.28%and84.82%,respectively.MLE with the concentration of 50-500μg/m L had no inhibitory effect on E.coli.4.Different concentrations of MLE could affect the expression of iNOS mRNA from LPS-induced RAW264.7 cells.When the concentration was 40μg/m L,the inhibitory effect on iNOS mRNA expression was obvious.And with the increase of the concentration,the inhibitory effect was more obvious,indicating that the inhibitory effect of MLE on the expression of iNOS mRNA showed a concentration-dependent trend,which was related to the NO release of MLE on RAW264.7 cells.It could be seen that MLE could inhibit the release of NO by inhibiting the expression of iNOS mRNA,which proved that MLE had anti-inflammatory effect.