Nephroprotective effects of Piper nigrum extracts against monosodium glutamate-induced renal toxicity in rats

Background: The toxicological effects of monosodium glutamate (MSG), widely used as a food additive, are a major public health challenge. This research aimed to investigate the nephroprotective effects of methanol and n-hexane extracts of Piper nigrum (MEPN and HEPN, respectively) against MSG-induced renal toxicity in rats. Materials and methods: The phytochemicals, vitamins, and in vitro antioxidant activities were determined using standard protocols. Acute toxicity was determined with thirty-two Swiss albino mice, while thirty male Wistar albino rats were used for the nephroprotective study. The rats were randomly distributed into 6 experimental groups (n = 5). Group 1 (baseline) was not induced or treated; groups 2–6 were given 2 g/kg body weight of MSG. Additionally, group 2 received normal saline; groups 3–6 were given 250 and 500 mg/kg body weight of MEPN and HEPN, respectively. MSG was administered alone for 21 days, after which MSG was concomitantly administered with the extracts for additional 28 days. After treatment, biochemical tests were done on the serum, and a histopathological examination was determined with the kidney. Results: Both extracts scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reduced ferric ions to ferrous ions in the Ferric Reducing Antioxidant Power (FRAP) assay, with MEPN having higher efficacy. The extracts also ameliorated lipid peroxidation and increased the activities of superoxide dismutase and catalase, as well as the level of reduced glutathione. In addition, intervention with MEPN and HEPN provided nephroprotective effects by decreasing urea and creatinine levels and also improved the histo-architecture of the kidney. This efficacy could be due to the rich phytochemicals and antioxidant vitamins previously identified in the plant. Conclusions: These findings are critical in focusing attention on abolishing the use of MSG in our food sector and highlights the health benefits of incorporating P. nigrum into our food to avert food and drug toxicity