LCMS Analysis, Antioxidant, Anti-Proliferative and Antimicrobial Activities of Combined Papaya, Honeydew and Mango Fruit Peel Extract

Fruit peels have traditionally been viewed as waste by restaurants, markets and the food and beverage industry, leading to their routine disposal. However, there has been a recent recognition of the valuable phytochemicals present in fruit peels which has increased interest in exploring their biological activity. In this study, a fruit peel extract was produced by macerating a combination of dried mango, papaya and honeydew peels with 95% ethanol at 50°C. The study aimed to identify the flavonoids in the fruit peel extract and to evaluate its pharmacological activities. The flavonoids were identified using the LC/MS-QTOF system and its antioxidant activity was measured using the DPPH and nitric oxide (NO) scavenging assays. The anti-proliferative and antibacterial activity of the extract were investigated using the MTT assay and disc diffusion method. The phytochemical analysis tentatively identified six flavonoid compounds in the ethanolic crude extract based on the database screening. The results showed that the peel extract was more effective at scavenging DPPH than NO. Additionally, the extract was found to be rich in phenolic compounds, containing 416 mg of gallic acid equivalents per gram of dry weight. Although the hexane fraction showed the lowest activity, the ethyl acetate fraction showed better antimicrobial activity towards all tested bacteria compared to the crude extract. Despite the high concentration of phenolic compounds, no significant anti-proliferative activity was observed in the extract. The study recommends exploring the possibility of using selected fruit peel extracts as natural resources of preservative and antioxidant agents in the future.