Antimicrobial and Antioxidant Properties of Fruits of Capsicum annuum var. cerasiforme (Mill.) Irish and Heracleum nepalense D. Don

Abstract

The fruit of Capsicum annuum var. cerasiforme belonging to the Family Solanaceae is a widely used spice in Sikkim, a North Eastern state of India. The fruit of Capsicum annuum var. cerasiforme locally called ‘Dalle Khorsani’ is a valuable cash crop of Sikkim and also possess medicinal properties. Heracleum nepalense D. Don locally called ‘Chimphing’ belongsto the Family Umbillifereae and is extensively used in folk medicine. The present study evaluated the antimicrobial property of fruits of Capsicum annuum var. cerasiforme (Mill.) Irish and Heracleum nepalense D. Don using agar well diffusion method against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis. The antioxidant property of methanol extracts of fruits of these test plants was also investigated. The antioxidant property was evaluated by 2, 2-diphenyl-1-picryl hydrazyl (DPPH) free radical scavenging activity assay and Ferric reducing power assay. The total phenolic content was determined by using Gallic acid as a standard. The methanol extract of both the plants inhibited the growth of mostly Gram positive bacteria and Escherichia coli among Gram negative bacteria. However the acetone extract of the selected plants did not exhibit antimicrobial activity. The methanol extracts of these plants exhibited significant (p>0.05) concentration dependent increase in DPPH free radical scavenging activity. The extract of Capsicum annuum var. cerasiforme (Mill.) Irish also exhibited significantly higher (p>0.05) ferric reducing ability thereby showing higher antioxidant activity. The phytochemical analyses of the plant extracts revealed the presence of phenol, tannin, flavonoid, alkaloid, steroid and saponin. The results of the present study indicate that Capsicum annuum var. cerasiforme (Mill.) Irish and Heracleum nepalense D. Don can be a potential source of antimicrobial and antioxidant agents and can be explored further for its therapeutic use.