ASSESSMENT OF PHENOLIC COMPOUNDS, ANTIMICROBIAL ACTIVITY AND FREE RADICAL SCAVENGING POTENCY OF THREE SELECTED VEGETABLES

Abstract

Phytochemicals are compounds derived from plants that are assumed to have defensive role against certain disease. They have antioxidants, anticancer, antimicrobial, antifungal, antiviral, antithrombic and anti-inflammatory properties. They have a high specificity to boost the immune system and play important role in the metabolism of hormones. The current study is based on qualitative and quantitative evaluation of total phenolics contents, phenolic compounds, antioxidant potential, free and bound phenolic acids in selected vegetables available at the local market of Hyderabad, Sindh, Pakistan. Two different extraction procedures ultrasonic-assisted base hydrolysis extraction and sonication extraction were used. Total 13 phenolic compounds were found and quantified by high-performance liquid chromatography (HPLC), in which Ferulic acid was quantified in a higher amount of 16.71 mg/g in bitter gourd. Total phenolic contents were determined by using Perklin-Elmer lambda UV/Visible spectrophotometer and higher concentration was found in Bitter gourd 92.56 mg 100/g as compared to Luffa and Brinjal with 79.03 and 66.56 mg 100/g, respectively. The antioxidant activity (DPPH assay) was measured at ?max of 517 nm, results revealed that Bitter gourd possessed the higher antioxidant activity with 182.61 µMol/g followed by Luffa and Brinjal with 112.94 and 82.96 µMol/g. The total Flavonoid contents were higher in Brinjal with 44.32 mg g-1 whereas Luffa and Bitter gourd possess the Flavonoid concentration in the range 38.02 and 34.64mg g-1 respectively, the total tannin contents also higher in Brinjal 31.40 mg/g follwed by in Luffa and Bitter gourd with 25.17 and 21.19 mg/g respectively. Antimicrobial activity showed that, all the extracts are the highly effective against S. aureus as compared to E. coli. Finally, it is concluded that all the selected vegetables are very good sources of Phenolic compounds as well as phytochemicals and should be included in the daily human diet for good health. On the basis of obtained results, it is also suggested that these samples will be further investigated for the determination of fatty acids by GC-MS and liquid chromatography-mass spectrum (LC-MS).

Keywords

• antimicrobial activity
• free radical scavenging (DPPH)
• HPLC-DAD
• phytochemical