PHYSICOCHEMICAL CHARACTERIZATION ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF PUMPKIN (Cucurbita pepo sp.) SEED AND FRUIT PULP OILS

Abstract

The consumption of pumpkin seeds in oil form or roasted pumpkin seeds has been is proved to exhibit several positive health effects. The aim of the present study was to examine the physicochemical properties, antioxidant and antimicrobial activities of pumpkin (Cucurbit sp.) Seed and pulp oils. The oil extraction was done in Soxhlet apparatus using hexane as a solvent. Then, physicochemical properties of the oil extracts were determined based on determination of oil content, specific gravity, acid value, percent free fatty acid and peroxide values. The antioxidant activity was investigated based on ascorbic acid content, DPPH radical scavenging activity and hydrogen peroxide scavenging activities. The results of physicochemical properties of pumpkin (Cucurbita pepo.) seed and pulp oils indicated significant differences between seed and pulp oils in terms of oil content, specific gravity, acid value (ACV), and free fatty acid. The antioxidant activities of oil extracted from pumpkins (Cucurbit sp.) seed and pulp evaluated based on ascorbic acid content, DPPHradical scavenging and hydrogen peroxide they also demonstrated scavenging activities demonstrated significantly higher antioxidant activities with respect to ascorbic acid content (38.94±2.68), DPPHradical scavenging(32.30±1.27) and hydrogen peroxidescavenging (11.85±0.64. for pumpkin seed oil than for pulp oil. The antimicrobial activity based on the diameter of zone inhibition fruit pulp oils had thestrongest antibacterial activity with maximum zone of inhibition (15.50mm) at highest concentration (3µl/ml) of the oil against Staphylococcus aureus. On the other hand, the stronger antifungal activity with the maximum zone of inhibition (15.00mm) was recorded for seed oil against Aspergillus niger. The oil extracts from pumpkin fruit pulp has exhibited strongest anti bactericidal activity with minimum inhibitory concentration of 0.19µl/ml) and minimum bactericidal concentration of, 0.25 µl/ml) against S. aureus. The pumpkin seed oil extract had demonstrated the strongest antifungal activity with MIC of (0.125µl/ml, the least value) and minimum fungicidal concentration , 0.19µl/ml) against A. niger suggesting that the seed oil had more effective antifungal potential than the fruit pulp oil in pumpkin.