Phytochemical Composition and in vitro Antioxidant Activity of Golden Melon (Cucumis melo L.) Seeds for Functional Food Application

ABSTRACT

Aim:Golden melon (Cucumis melo)is an annual herbaceous plant belonging to the family of Cucurbitaceae (Cucurbit). This study was carried out to evaluate the phytochemical composition and in vitroantioxidant activity of golden melon seed extract.Place and Duration of StudyThe study was carried out between a period of July and August 2017 at Baking Milling Division, Federal Institute of Industrial Research Oshodi Nigeria. Methodology:The crude methanolic extracts of the seed were tested for phytochemical and antioxidant activities according to standard analytical procedure. The antioxidant potential of the seed extracts was examined using different assays by determining total phenolic content,total flavonoid content, total antioxidant capacity. The free radicalscavenging activities of the extract such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, in vitrolipid peroxidation, and nitric oxide (NO) scavenging assay weredetermined spectrophotometrically. Results:The phytochemical screening of the seed extracts revealed the presence of some secondary metabolites such as alkaloids, phenolic, steroids, flavonoids, terpenoids and cardiac glycosides. The total phenolic content of extract was found to be 29.39mg/100g while the amount of total flavonoid content was 20.67mg/100g. Scavenging ability was observed to increase in proportion to concentration for all the scavenging assays and at the highest concentrationof100μg/ml.Total antioxidant capacity assay showed 19.44mg per 100 g. This high scavenging ability in the seed extracts may be attributed to the presence of phenolic and flavonoids compounds in the extract. The DPPH free radical scavenging activity of 100μg/ml Cucumis meloextract was 75.20% ± 0.72 while the reference standard (Ascorbic acid) was 83.24% ±0.31. Lipid peroxidation inhibition ability of 100μg/ml Cucumis meloextract was 87.18% ± 0.16 while the standard (ascorbic acid) was 94.96%± 0.16 at the same concentration. Results obtained from this study showed that the nitric oxide scavenging ability of the extract was 80.50%±0.63 while the standard antioxidant was 85.94% ± 0.54. Conclusion:In all the assays, Cucumis meloextract showed maximum percentage of antioxidant potentials at 100μg/ml. Additionally, golden melon seed possess appreciable amount of phenols and high antioxidant properties which could be explored and incorporated in functional food applications particularly in baked products