Bioactivity, phytochemistry studies and subacute in vivo toxicity of ethanolic leaf extract of white mulberry (Morus alba linn.) in female mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional uses of Morus alba L. leaf extracts (MLE) have been reported for treating hyperglycaemia and diabetes. Phytochemical compounds in the leaves demonstrated the ability to enhance insulin sensitivity and ß-cell secretory function, suggesting their potential value in reducing blood glucose and treating diabetes. However, the phytochemical constituents and safety of the herbal medicines need to be verified in each experimental field from different growing areas. Studies on the phytochemistry and toxicity of Morus alba leaves in Southeast Asia, especially in Brunei, have never been investigated. AIM OF THE STUDY: This study aimed to investigate the bioactivity and phytochemistry of Morus alba ethanolic leaf extract from Brunei Darussalam and its subacute toxic effects in the Institute of Cancer Research (ICR) female mice. MATERIALS AND METHODS: The phenolic yield and antioxidant of the extract were analysed. Meanwhile, liquid chromatography-mass spectrometry and high-performance liquid chromatography were utilised to determine the phenolic compound of the MLE. In the subacute toxicity study, twenty-five female mice were randomly divided into five groups: the control group, which received oral gavage of 5% dimethyl sulfoxide solvent (DMSO), and the MLE treatment group, which received the extract at a dose of 125, 250, 500 and 1000 mg/kg. Physiology, haematology, biochemistry, and histology were evaluated during the study. RESULTS: Morus alba leaf depicted total phenolic 10.93 mg gallic acid equivalents (GAE)/g dry weight (DW), flavonoid 256.67 mg quercetin equivalents (QE)/g DW, and antioxidant bioactivity content of 602.03 IC50 µg/mL and 13.21 mg Fe2+/g DW. Twenty compounds in the Morus alba ethanolic leaf extract were identified, with chlorogenic acid (305.60 mg/100 g DW) as the primary compound. As for subacute toxicity in this study, neither mortality nor haematological changes were observed. On the other hand, administration of 500 and 1000 mg/kg MLE resulted in mild hepatocellular injury, as indicated by a significant (p < 0.05) increase in liver enzyme activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The histopathological score showed mild hepatocellular necrosis in administering 250, 500, and 1000 mg/kg of MLE. The parameters of renal injury were within normal limits, with the increase in eosinophilic cytoplasm observed in the histological scoring at 1000 mg/kg of MLE. CONCLUSIONS: Morus alba leaf extract showed abundant polyphenols. In a study on subacute toxicity, MLE caused mild hepatotoxicity in mice. The toxic effect of the extract may be due to kaempferol and chlorogenic acid compounds. The 125 mg/kg MLE dose was safe with no adverse effects.

Protective potential of fish oil supplementation against insulin resistance and pancreatic islet damage in STZ-induced Wistar rats.

Background: Fish oil, which is regarded as the primary source of omega-3 fatty acids, has been long studied for its potential as an antidiabetic therapy. However, its protective ability against insulin resistance and pancreatic islet alteration remains unclear and controversial. Aim: To investigate the beneficial effects of fish oil consumption on the progression of insulin resistance and pancreatic islet dysfunction in a rat model of diabetes. Methods: Diabetic rats model (n = 30) were divided into five groups and received; 1) NS injection + NS oral (normal control); 2) NS injection + 3 g/kg fish oil (fish oil control); 3) streptozotocin (STZ) injection + NS oral [diabetes control (DC)]; 4) STZ injection + 1 g/kg fish oil (DFO1); and 5) STZ injection + 3 g/kg fish oil (DFO3). Fasting blood insulin was analyzed by commercial rat insulin enzyme-linked immunosorbent assay; meanwhile, the determination of insulin sensitivity was calculated by homeostatic model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of beta-cell function. A histological study was conducted on pancreas tissue using H and E staining. Results: Fish oil supplementation reduced hyperglycemia and ameliorated HOMA-IR in STZ-induced animal models indicating that fish oil supplementation improved insulin sensitivity. Furthermore, animals treated with fish oil at a dose of 3 g/kg (DFO3) showed an enhancement in pancreatic islets, which was displayed by less abnormal structures than DC animals. This could imply that the administration of fish oil, especially rich in bioactive omega-3 fatty acids effectively inhibits insulin resistance and restore islet of Langerhans alteration in rats injected with STZ. Conclusion: Thus, the current study suggested that fish oil supplementation could support the treatment of diabetes but should not be considered as an alternative therapy.