Ethanolic Extract of Solanum melongena Linn Fruit Mitigated Monosodium Glutamate-Induced Oxidative Stress

Background/Aim: Monosodium glutamate (MSG), a flavour enhancing food additive generally regarded as safe by food regulatory bodies at low concentration can induce oxidative stress at high concentration. The heightened search for underutilized plant-sourced food necessitated this study aimed at determining some phytochemicals and vitamins in Solanum melongena Linn fruit and the influence of the ethanol extract of the sample on MSG–induced oxidative stress.

Study Design/Methodology: Standard protocols were employed in the determination of the studied phytochemicals and vitamins of the sample. In the animal study, twenty four Wistar rats with average weight of 105.00 ± 7.00 g were assigned into six groups and fed thus: Group 1 (control, feed and distilled water only), Group 2 (8000_mg/kg body weight MSG), Group 3 (300_mg/kg body weight the sample extract), Group 4(8000_mg/kg body weight MSG+ 100_mg/kg body weight the sample extract), Group 5(8000_mg/kg body weight MSG+ 300_mg/kg body weight the sample extract) and Group 6(8000_mg/kg body weight MSG+ 500_mg/kg body weight the sample extract). Exposure was oral and daily for 14 days.

Results: The determined vitamins in the sample were vitamin A (0.36 ± 0.02IU), vitamin B3 (9.03 ± 0.07 mg/100 g) and vitamin C (369.67± 7.54 mg/100 g) while the phytochemicals were alkaloids (1.13 ± 0.10 mg/100 g), saponins (5.54 ± 0.37 mg/100 g), tannins (11.87 ± 1.87 mg/100 g), cyanogenic glycogenic (6.21 ± 0.22 mg/100 g) and phytates (30.62 ± 1.54 mg/100 g). The MSG only fed group significantly (P =.05) increased malondialdehyde (MDA) concentration but decreased (P =.05) glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) activity compared to the control, suggesting induction and enhanced generation of reactive oxygen species (ROS) which compromised the antioxidant defense of the MSG-fed rats. Co-administration of MSG with ethanol extract of Solanum melongena Linn fruit significantly (P=.05) reduced the MDA concentration to a value non-significant (P=.05) compared to that of the control rats, and conversely, significantly (P=.05) increased GSH, CAT and SOD activities compared to the group 2 rats.

Conclusion: The Solanum melongena Linn fruit contains the studied phytochemicals and vitamins while the ethanol extract of the fruit could significantly mitigate MSG-induced oxidative stress in the rats.