We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O₂⁻) and hydrogen peroxide (H₂O₂) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.

Strychnos henningsii Gilg is recommended among other remedies for the treatment of diabetes in traditional medicine of Southern Africa. The antidiabetic effect of oral administration of aqueous bark extract of the plant at 125, 250 and 500 mg/Kg body weight was investigated in diabetic rats induced with streptozotocin-nicotinamide for 15 days. The extract decreased the blood glucose level, feed and water intake as well as triacylglycerol at the three doses investigated while the best result was obtained at 250 mg/Kg. Similarly, the extract was able to lower the cholesterol level appreciably at 500 mg/Kg while the remaining doses did not have any significant effect as compared with diabetic untreated groups. In addition, the weight loss of diabetic-treated rats was markedly normalized at all doses. The glucose tolerance level of diabetic animals was effectively reduced to near normal level after 90 min of extract administration especially at the dose of 250 and 500 mg/Kg. The phytochemical screening of S. henningsii revealed the presence of flavonoids, tannins and saponins which have been reported to increase the insulin secretion. The results obtained from this study demonstrated that the aqueous extract of S. henningsii possess antihyperglycemic and antilipidemic properties and thus could prevent various complications of diabetes. Generally, this study has validated the traditional use of this plant for the treatment of diabetes mellitus.

Protein bioavailability and digestibility are critical for animal growth and health and are influenced by source and processing methods. This study investigated the effects of diets incorporating processed Clupea harengus (herring) fillets and by-products (heads, bones, viscera) prepared by charcoal, wood, or poaching on growth performance, protein quality, hematology, and blood biochemistry in Wistar rats. Forty rats were randomly allocated to eight dietary groups: charcoal-smoked fillet (CSFBD), wood-smoked fillet (WSFBD), poached fillet (PFD), charcoal-smoked by-products (CSHB), wood-smoked by-products (WSHB), poached by-products (PSF), soybean-based positive control, and basal negative control. Diets were fed for 28 days. Smoked by-product diets (CSHB and WSHB) produced significantly higher final body weights (120.86 ± 0.68 g and 105.52 ± 19.94 g) and weight gains (9.14 ± 1.39 g, p ≤ 0.05) than the basal diet (59.55 ± 1.37 g and 5.35 ± 0.25 g). Smoked diets improved feed intake, feed conversion ratio, apparent protein digestibility, and biological value. Hematological parameters remained within physiological ranges across groups; the soybean diet showed the highest RBC (7.8 × 10¹²/L) and hemoglobin (16.3 g/dL), whereas smoked fish diets recorded slightly lower but normal values (RBC 7.0-7.5 × 10¹²/L; hemoglobin 14-15 g/dL). Biochemical profiles revealed that smoked diets reduced serum triglycerides and creatinine, suggesting enhanced lipid metabolism and renal function. Smoking significantly improves the nutritional quality of Clupea harengus fillets and by-products, making them practical, safe, and growth-promoting protein sources for animal nutrition. Inclusion of smoked fish by-products offers a sustainable alternative to conventional plant proteins while supporting metabolic and systemic health