Bioassay-guided Fractionation of Carica papaya Seed Extracts against Potassium Bromate-induced Nephrotoxicity Detected Fatty Acid-rich Compounds and Prevents Oxidative Stress in Rat’s Kidney

Aim: To evaluate the effect and identify the bioactive constituents of Carica papaya seed with potency against potassium bromate –induced nephrotoxicity and oxidative stress in renal tissue of rat.

Study Design: For each state of polarity, twenty male Wistar rats were divided into four groups, five rats per group; normal control, KBrO3 control, papaya fraction control and KBrO3 group administered with required concentration of extract of C. papaya seed for 48 hours.

Place and Duration of Study: Department of Biochemistry Laboratory, Faculty of Basic Medical Sciences, Bayero University Kano, Nigeria.

Methodology: A bioassay-guided screening of powdered C. papaya seed and its fractions was carried out against KBrO3 –induced nephrotoxicity and oxidative stress. The tests carried out include serum urea, creatinine, uric acid and electrolytes. Also the following markers of oxidative stress were assayed in renal homogenates; superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and malondialdehyde (MDA). Spectroscopic analysis of the most active fraction was also carried out.

Results: Fractionation of C. papaya seed yielded fractions and sub-fractions that prevent KBrO3 –induced increases in serum urea, creatinine, uric acid and electrolytes as well as the level of MDA. Furthermore there were increases in activities of SOD, CAT, GPx and level of GSH. F1 was the most active fraction. Spectroscopic analysis of F1 identified six functional groups and ten compounds. Seven of the compounds have been previously reported to possess antioxidant activities: 9-octadecenoic acid (z)- 2- hydroxyl-1- (hydroxymethyl) ethyl ester, 17-octadecynoic acid, Hexadecanoic acid methyl ester, 1,2-benzenedicarboxylic acid butyl 2-ethylhexyl ester, 9,12-octadecadienoic acid (z,z) methyl ester, 10-octadecenoic acid methyl ester and 9,17-octadecadienal (z).

Conclusion: Fractions of C. papaya seed contain bioactive compounds that could prevent KBrO3 –induced nephrotoxicity and oxidative stress in rats however isolation and administration of each compound was recommended for a more convincing result.