ABSTRACT
The aim of the study was to investigate the phytochemical constitution, antioxidant activity, hypoglycemic potential and safety of Aloe lateritia and Aloe secundiflora. Phytochemical screening was determined using standard procedures and Gas chromatography-mass spectrometry (GC-MS) analysis. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was determined spectro-photometrically. Hypoglycemic studies involved daily administration of 200 mg/kg of metformin and 300 mg/kg of methanol and aqueous leaves extracts of A. lateritia and A. secundiflora to alloxan-induced diabetic mice for 21 days. The safety of the extracts was experimented using OECD protocol on Acute Oral Toxicity-Acute Toxic Class Method Test no. 423. The results showed the presence of hypoglycemic phytochemicals: - phenols, saponins, alkaloids, flavonoids, tannins, anthraquinones, steroids and carbohydrates in both plants. Analysis by GC-MS determined the presence of phytochemicals in A. lateritia and A. secundiflora already established in other Aloe species. Aloe secundiflora extracts were decided to have higher free radical scavenging activity than A. lateritia extracts. Both A. lateritia and A. secundiflora aqueous and methanol extracts showed significant decreases in FBG levels when compared to the diabetic control group while there was no significant difference between A. secundiflora extracts and metformin-treated group at the end of the experiment (P<0.05). Aloe secundiflora methanol extracts achieved the highest percentage glycemic change among the extracts. All the extracts were not toxic at the tested levels. The hypoglycemic and antioxidant activities established in A. lateritia and A. secundiflora can be linked to the phytochemicals present.
ABSTRACT
@#The research of triterpenoids on hypoglycemic and anti-diabetic activities have made great progress. Findings indicated that triterpenoids could reduce blood glucose via different mechanisms, including increasing insulin secretion, enhancing insulin sensitivity, promoting glucose uptake by activation of AMP-activated protein kinase(AMPK), decreasing glycogenolysis and gluconeogenesis, and inhibiting protein tyrosine phosphates 1B(PTP1B), α-glycosidase, aldose reductase(AR)and dipeptidyl peptidase-4(DPP-4). This article reviews the hypoglycemic effects and mechanisms of triterpenoids, providing the reference for further research and development of triterpenoids.
ABSTRACT
Objective: To evaluate the hypoglycemic effect of aqueous extract from Taraxaci Herba (AETH) on postprandial blood glucose (PBG) in diabetic rats induced by Streptozotocin (STZ) and to explore the mechanism. Methods: The PBG within 120 min was measured after 7 d ig administration of AETH (400, 200, and 100 mg/kg) in normal rats and diabetic model rats induced by STZ, and ELISA was performed to detect the serum insulin of rats in each group. The euglycemic clamp assay was performed to investigate the effect of AETH (400 mg/kg) on the insulin sensitivity in normal rats, and the glucose infusion rate (GIR) was detected. The 50% inhibiting concentration (IC50) against α-glucosidase was measured in vitro, using pNPG as substrate. Caco-2 cells were preincubated for 72 h with AETH (200 and 100 mg/L), and then the capacities of Caco-2 monolayer on maltose hydrolysis and glucose absorption were measured. Results: The 7 d ig administration of AETH decreased the PBG significantly in diabetic rats induced by STZ, but had no effect on serum insulin level and GIR. AETH inhibited α-glucosidase in vitro, and the IC50 was higher than that of acarbose. AETH (200 mg/L) inhibited the capacities of Caco-2 monolayer on both maltose hydrolysis and glucose absorption. Conclusion: AETH has the hypoglycemic effect on PBG in diabetic rats, and the mechanism is related to the inhibition of maltose hydrolysis and glucose absorption in small bowel.
ABSTRACT
We extracted, determined preliminary chemical compounds and antioxidant activity of mulberry leaf exttact powder in a our previous research. This continous research is on evaluation of hypoglycemic effect of mulberry leaf extract powder in experimental animals. Objectives: (1) Evaluation of hypoglycemic effect of mulberry leaf extract powder in mice after drinking starch; (2) Evaluation of hypoglycemic effect of mulberry leaf extract powder in diabetic experimental mice. Methods: evaluation of hypoglycemic effect of mulberry leaf extract powder at doses 600mg/kg and 300mg/kg in two mice experimental models: mice after drinking starch and diabetic experimental mice. Results: mulberry leaf extract powder at doses 600 mg/kg and 300 mg/kg have a hypoglycemic effect in starch drunk mice. It is best at second hour with reduces of glucocemia of 18.6 % and 9.2 % after drinking starch, respectively. Mulberry leaf extract powder at both doses of 600 mg/kg and 300 mg/kg have hypoglycemic effects at levels of 29.6 %; 18.5 % in diabetic mice injected STZ of 150 mg/kg. But mulberry leaf extract powder at both doses of 600 mg/kg and 300 mg/kg have not hypoglycemic effect in diabetic mice injected STZ of 300 mg/kg. Conclusion: Mulberry leaf extract powder at doses of 600 mg/kg, 300 mg/kg have hypoglycemic effects in starch drunk mice and diabetic mice injected STZ of 150 mg/kg.