ANTIDIABETIC EFFECT OF METHANOLIC EXTRACTS OF Laguncularia racemosa (White Mangrove) IN ALLOXAN INDUCED DIABETIC RATS

Abstract

Diabetes mellitus is a metabolic disorder affecting carbohydrates, protein and fat metabolism. The treatment of diabetes mellitus has been confined to the use of oral hypoglycemic agents and insulin, which possess serious side effects. This lead to increasing demand for herbal products having little side effects. The aim of this study is to determine the effects of methanolic extracts of Laguncularia racemosa in alloxan induced diabetic rats. Phytochemical screening and antioxidant activity were carried out using standard methods while acute toxicity study was done using up and down method (limit test). Diabetes was induced intraperitoneally in albino rats with 120 mg/kg body weight of alloxan. A total of forty-five rats were treated as follows; Group 1 vehicle (distilled water), Group 2 (induced with no treatment), Group 3 and 4 metformin (standard) at 150 and 300 mg/kg body weight respectively, Group 5 and 6 crude (70 %) methanol extract at 150 and 300 mg/kg body weight, Group 7 and 8 methanol fractions (100 %) 150 and 300 mg/kg body weight, an non-indued group 9 was treated with (70 %) methanol at 300 mg/kg body weight single dose. Dipeptidyl peptidase-4 was assessed using enzyme linked immunoabsorbent assay (ELISA) kits in Euthanized rats. Among the secondary metabolites, Tannis was (8.88 mg/g), flavonoids (1.73 mg/g), phenols (1.68 mg/g), Saponins (1.17 mg/g) and alkaloids (0.23 mg/g). Percentage DPPH scavenging activity at 100 µg/ml was 79.86 % with an IC50 value 19.48 µg/ml while percentage inhibition of lipid peroxidation was 63.79 % and ferric antioxidant reducing power assay was 40.65 %. The acute toxicity studies showed that there was no death or lethal effect observed in toxicity study in the anti-diabetic study. Crude and methanol fraction of Laguncularia racemosa significant (p≤0.05) reduce blood glucose level in a dose dependent manner when compared with the diabetic control, crude extract at 300 mg/kg significantly reduced blood glucose level from 20.82 mmoL/l to 5.78 mmoL/l. Laguncularia racemosa shows a non-dose dependent activity against DPP-4, The level of DPP4 was 1008.24 pg/ml, compared to normal control group 1095 pg/ml, negative (untreated group) 1828.91 pg/ml. In conclusion, the results of this study showed that the methanol extract of Laguncularia racemosa exhibited antidiabetic potential which can be investigated further for the development of oral antihyperglycemic drugs