ANTIOXIDANT ACTIVITIES AND NEUROPROTECTIVE CAPACITY OF TOMATO (Lycopersicumesculentum) FRUIT AND PASTE AFTER IN VITRO DIGESTION

Abstract

Tomato (Lycopersicumesculentum) is a horticultural crop of great interest, being widely consumed either fresh or processed in products such as tomato juice, soup, paste, puree, ketchup, sauce and salsa. This present investigation was aimed at examining the antioxidant indices (total phenolic content, falvonoid content, ferric reducing antioxudant power, DPPH, ABTS, NO radical scavenging activity,OH radical scavenging activity, and lipid peroxidation) and neuroprotective capacity (Acetylcholinesterase and Butylrylcholinesterase) of tomato fruit (ripe and unripe)and commercially processed paste (pomo and gino) after simulated in vitro digestion. The results of the phytochemical screening of the ethanolic extracts of tomato fruit and paste revealed presence of saponins, flavonoids, steroid, phlobatanin and salkonski with terpenoids absent only in unripe tomatoes and alkaloid absent in gino tomato.In vitro digested tomato fruit and paste showed significantly higher total phenolic content (ripe tomato;61.08mg/g, processed “pomo” tomato; 60.36mg/g, processed“gino” tomato;56.02mg/g, unripe tomato; 38.97mg/g) than the ethanolic extracts (ripe tomato;35.59mg/g, pomo’ tomato; 30.28mg/g, ‘gino’ tomato;29.99mg/g, unripe tomato; 14.91mg/g), with digested ripe tomato having the highest phenolic content. Similar results were obtained for total flavonoidcontent(TFC), ferric reducing antioxidant power (FRAP),DPPH˙, ABTS˙+, nitric oxide (NO˙)andhydroxyl (˙OH) radical scavenging activity assay, with the in vitro digested samples having higher values than their corresponding ethanolic extracts. The ability of the ethanolic extracts and enzyme digested tomato fruit and paste to inhibit Fe2+and sodium nitroprusside (SNP) induced lipid peroxidation in rat’s liver and brain homogenate increased as the concentration of the extracts and digest increased. Similarly, the in vitro digested samples have a higher inhibitory action against lipid peroxidation and also revealed a higher acetylcholinesterase (AChE) and butyrylcholinesterase(BChE) inhibitory action. The in vitro digested samples also have enhanced activities of antioxidant enzymes (GPx, GSH, SOD and CAT) than the ethanolic extracts. The result of this study implies that the selected tomato fruit and pastes possess moderate antioxidant capacity which are better released after digestion and can be considered as health supplements. Therefore, these plants could be harnessed in preventive health care as nutraceutical foods.