Phytochemical Screening and In vitro Study of Free Radical Scavenging Activity of Flavonoids of Aloe vera

Aloe is a very popular plant, and present study aimed to correlate the flavonoids and their antimicrobial activity, antioxidant activity and nitric oxide scavenging activity. So, phenolic content and flavonoids were determined and studied in vitro their antimicrobial activity, antioxidant activity and nitric oxide scavenging activity with well diffusion method, minimum inhibitory concentration and scavenging by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical and nitric oxide radicals (NO.) respectively with reference of Ascorbic acid as standard. The phenolic content was analysed by Folin Ciocalteu's phenol reagent and flavonoids with aluminium chloride. Phenolic content and flavonoids contents were 16.971mg tannic acid equivalent/g and flavonoids was 21.84mg Querecetin/g of extract powder respectively of Aloe leaves. The MIC value of extracts ranges between 0.95μg-1.24μg against Gram-positive and Gram-negative bacteria. The flavonoids inhibited significantly DPPH radical with IC50 value of 893μg as compared to standard IC50–714μg. IC50 of nitric oxide is 973μg as compared to standard IC50–500μg. These results represent the contents of phenolic components and flavonoids in Aloe and their correlation with antimicrobial activity, antioxidant activity and nitric oxide scavenging activity.