| dc.description.abstract | Background: Indigenous management of diabetes mellitus is common but not fully explored.
Objective: The study determined and compared the hypoglycemic activities of root bark and leaf extracts of R. vulgaris in high glucose loaded (mimicking Type II DM) Wistar albino rats and their safety profiles (acute toxicity in Wistar albino mice, sub-acute toxicity in wistar albino rats).
Methods: An experimental laboratory-based study was done to determine the hypoglycemic activities of selected parts of R. vulgaris in a parallel design among high glucose loaded (4 g/kg) groups (22 groups of 6 Wistar albino rats) and subjected to different aqueous and total crude R. vulgaris root bark and leaf extracts doses (62.5, 125, 250, 500 and 1000 mg /kg). Blood glucose levels were determined using a glucometer at different time intervals (0, 30, 60, 90,120,180 and 240 minutes). Data was analyzed using SPSS version 23.0 and compared using Students’t-test (p<0.05) with water (negative control) and glibenclamide (0.6mg/kg, positive control). One-way ANOVA was used to compare differences between groups means followed by Bonferroni analysis for binary comparison of the different group treatments.
For safety studies, death following a single dose administration of the most active, total crude bark extract in wistar albino mice was noted during the 24 hour (Lethal dose 50{LD50} determined by the graph pad prism method) for acute toxicity. Sub-acute toxicity of total crude root bark and leaf (as alternative) extracts was then determined by performing liver (AST, ALP, ALT, albumin and total proteins) and renal (serum creatinine and urea) functions at 0, 7, 21 and 28 days. Data was analysed using SPSS version 23.0. Furthermore, one-way ANOVA was used to compare (p<0.05) means differences between the control and the extract treated rats. Histopathological changes in the organs (liver, kidney and heart) were also evaluated.Results: All doses (62.5, 125, 250, 500 and 1000 mg/kg) of root bark and leaves extracts, both aqueous and total crude variably lowered (p<0.05) BGL with overall less reduction than glibenclamide (average mean BGL: -7 vs -17.5% (p<0.05), -30 vs -36.3% (p<0.05), -51.6 vs -56.7% (p<0.05), -61.5 vs -66.7% (p<0.001), at 60, 90, 120 and 240 minutes respectively). Generally aqueous (root bark and leaf) extracts exhibited dose dependent reduction BGL. This was comparable or non-significantly less or less compared to glibenclamide for rats that received aqueous root bark at ≥125 mg/kg and aqueous leaf at > 250 mg/kg. Although aqueous root bark displayed more potent hypoglycemic activity than aqueous leaf, at ≥500 mg/kg comparable activity were observed. Total crude (both root bark and leaf) extracts were more potent than aqueous extracts, but displayed competitive antagonistic effects variably with increasing doses. Maximal reduction in MBGL was observed in groups that received 62. 5 mg/kg total crude rootbark uptill 240 minutes; between 0 to 120 minutes in groups receiving 125 mg/kg but superseded by 250 mg/kg total crude leaf between 120 and 240 minutes.
Observed LD50 was 2268.8 mg/kg. Kidney (creatinine) and liver (ALP and AST) functions were significantly raised (P<0.05) in the rats that were administered total crude root bark and leaf extracts doses of 286.3 mg/kg. Histopathological examination of the liver and kidneys showed abnormalities with no significant lesion in the heart. Conclusion: This study showed that both R.vulgaris plant parts (root bark, leaves) possess comparable hypoglycemic properties. Although crude extracts are more potent, competitive antagonistic effects with increasing dose reduces its applicability, also total crude root bark exhibited more hepatotoxicity than total crude leaf of R. vulgaris. Aqueous root bark and leaf have comparable effects at higher doses (≥500mg/kg). So, in the interest of vegetation conservation and safety practices, leaves are recommendable substitute and can be as efficacious as root bark. | en_US |
