Phenolic Profile: Antimicrobial Activity and Antioxidant Capacity of Colocasia esculenta (L.) Schott.

The aim of the study was to investigate the presence of bioactive compounds in the ethanolic extract of C. esculenta by HPLC and GC methods. The identification of phytochemical compounds is based on the peak area, retention time and pharmacological actions. The HPLC chromatogram of ethanol extract showed the presence of 13 compounds namely, 6,2',4'-trimethoxyflavanone, benzoic acid, gallic acid, luteolin-6,8-C-diglucoside, catechin, chlorogenic acid, astilbin, quercetin, kampferol, and major compounds with high concentration of absorbance are, rutin,, vitexin, ellagic acid and caffeic acid. The GC analysis of petroleum ether of C. esculenta extract showed presence 31 saturated fatty acid,volatile organic hydrocarbons and sesquiterpenes.The major components were determined as follows, saturated fatty acid, Stearic acid, Arachidonicacid, 8-Heptadecene, monounsaturated fatty acid, (S)-citronellic acid and volatile organic hydrocarbons, specifically, sesquiterpenes as D-Germacrene and Isoledene, The antimicrobial activity of ethanol extract showed characteristic zone of inhibition against six clinical pathogens. The highest zone of inhibition was observed at 100mg/ml concentration against, the (Gram Negative Bacteria) Proteus vulgaris (ATCC13315) at 15mm, while Escherichia coli (ATCC25955), at 13 mm and Pseudomonas aeruginosa (ATCC27853) at 12 mm, while the zone of inhibition against (Gram positive Bacteria) Staphylococcus aureus (RCMB010010), at 14 mm, Enterococcus faecalis (ATCC 29212), at 12 mm,and no effect against Bacillus subtitis (RCMB 015 (1) NRRL B-543), when compared with the standard drugs Gentamicin. The antifungal activity against six Fungi, was Cryptococcus neoformans ( RCMB 0049001) at 16mm, Aspergillus fumigatus (RCMB 002008) at 11mm, Syncephalastrum racemosum RCM 016001 (1) at 10 mm, and Candida albicans (RCMB 005003 ATCC 10231) at 9 mm. The zone of inhibition was observed at 100 mg/ml concentration when compared with the standard drugs Ketoconazole with (MIC) 100 mg/ml. The antioxidant activities of the extracts were determined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging. ethanol extract of C. esculenta exhibited with IC50 value (22 mu g/mL), while the standard ascorbic acid with IC50 (11.4 mu g/mL).This result is promising. The above findings may justify the medicinal uses of the plants. The results suggest that the leaves of C. esculenta are a good sources of bioactive compounds with potent antimicrobial and antioxidant substances.