Aim: To investigate the effect of Carica papaya seed extract on KBrO3 - induced nephrotoxicity in rats. Renal toxicity was induced by a single oral dose of 100 mg/kg body weight of KBrO3. Study Design: Thirty (30) male albino rats were divided into six groups, five rats per group; normal control, KBrO3 control, papaya control and KBrO3 group administered with methanol seed extract of 200 mg/kg, 400 mg/kg and 600 mg/kg body weight for 48 hours. Place and Duration of Study: Department of Biochemistry Laboratory, Faculty of Basic Medical Sciences, Bayero University Kano, Nigeria, from April 2018 to August 2018. Methodology: Serum urea, creatinine, uric acid and electrolytes were determined using kits from randox laboratories. Furthermore, activities of renal brush border membrane marker enzymes namely γ-glutamyltransferase (GGT), alkaline phosphatase (ALP), maltase (Mal) and leucine aminopeptidase (LAP) and some parameters of oxidative stress including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH) and malondialdehyde (MDA) were determined in homogenates prepared from renal cortex and medulla of the kidney of rats using colorimetric methods. Results: Administration of KBrO3 significantly (P<0.05) increases the serum levels of urea, creatinine, uric acid and all electrolytes studied in a dose-dependent fashion from 200mg/kg to 400mg/kg and 600mg/kg in that order. Furthermore, the activities of GGT, ALP, Mal and LAP decrease in renal homogenates with KBrO3 administration. Also the activities of CAT, SOD, GPx and level of GSH decreases while the level of MDA significantly (P<0.05) increases however concurrent administration of Carica papaya seed extract prevented all the KBrO3- induced changes in the biochemical parameters studied . Conclusion: It was suggested that methanol seed extract of Carica papaya possess nephroprotective effect against KBrO3 –induced renal toxicity and oxidative stress, and the most effective dose was 600 mg/kg body weight.

Aim: To investigate the effect of the chromatographic fractions of Carica papaya seed on KBrO3 –induced reduction in the activities of renal brush border membrane (BBM) marker enzymes and the changes in activities of some enzymes of carbohydrate metabolism in the kidney of rats. Study Design: 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 126mg/kg body weight of the most active fraction of partially purified methanol extract of C. papaya for 48 hours. Place and Duration of Study: Department of Biochemistry Laboratory, Faculty of Basic Medical Sciences, Bayero University Kano, Nigeria. Methodology: The activities of renal BBM marker enzymes: γ-glutamyl transferase, alkaline phosphatase, maltase and leucine aminopeptidase were assayed in homogenates of renal cortex and medulla, and in brush border membrane vesicle (BBMV) isolated from cortex using standard methods. Furthermore, activities of the following enzymes representing different pathways of carbohydrate metabolism were determined in renal homogenates: hexokinase (HK), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), glucose 6-phosphatase (G6P), fructose 1,6-bisphosphatase (FBP), glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME). Results: KBrO3 administration significantly (P<0.05) decreases the activities of all the BBM marker enzymes in renal homogenates and BBMV. It also decreases the activities of MDH, G6P, FBP and G6PD, and significantly increases (P<0.05) that of HK, LDH and ME in renal homogenates however co-administration of most active fraction of C. papaya  seed prevented all the KBrO3 -induced changes in these biochemical parameters. Conclusion: Chromatographic fractions of C. papaya seed extract possesses potent phytochemicals that could prevent KBrO3 –induced reduction in activities of renal BBM marker enzymes and the changes in enzymes of carbohydrate metabolism studied and therefore could be analyzed further to isolate the bioactive compounds.

Aim: To investigate the proximate composition and phytochemical constituents of matured Carica papaya seed. Study Design: Proximate composition was determined on Carica papaya seed powder while extracts for phytochemical analysis were obtained, in turn using five different solvents of varying polarity, namely n-hexane, chloroform, ethyl acetate, methanol and water. Place and Duration of Study: Department of Biochemistry, Faculty of Basic Medical sciences, Bayero University Kano, Nigeria. The study was carried out between March- April, 2019. Results: The proximate composition of matured Carica papaya seed showed it contained crude fat (27.72%), carbohydrate (23.34%), crude fibre (21.25%), ash (10.25%), crude protein (9.65%) and moisture (7.34%). Qualitative phytochemical screening of Carica papaya seed extracts detected major phytochemicals except anthraquinones and quantitative analyses of these phytochemicals in all the five extracts showed that flavonoids was the most abundant phytochemical with 38.68%, 35.85%, 36.76%, 34.04% and 23.50% for methanol, aqueous, chloroform, n-hexane and ethyl acetate fractions respectively while tannins was the least abundant phytochemical with 0.03% for methanol extract, 0.04% for n-hexane extract, 0.09% for aqueous and ethyl acetate extracts, and 0.14% for the chloroform extract. Conclusion: Seeds of matured Carica papaya contain major nutrients that may be useful in nutrition. The presence of phytochemicals such as flavonoids, alkaloids and saponins in considerable quantities explained the medicinal activity of the plant material as encountered in its therapeutic uses.