METHODS: Two reviewers searched MEDLINE for studies of ≥12 weeks duration in adults with type 2 diabetes. The key search word was "gliclazide", filtered with "randomized controlled trial", "human" and "19+ years". Differences were explored in mean change in glycated hemoglobin (HbA(1c)) from baseline (primary outcome) and risk of hypoglycemia (secondary outcome) between gliclazide and other oral insulinotropic agents; and other sulfonylureas.
RESULTS: Nine out of 181 references reported primary outcomes, of which 7 reported secondary outcomes. Gliclazide lowered HbA1c more than other oral insulinotropic agents, with a weighted mean difference of -0.11% (95%, CI -0.19 to -0.03%, P=0.008, I(2)=60%), though not more than other sulfonylureas (-0.12%; 95%, CI -0.25 to 0.01%, P=0.07, I(2)=77%). Risk of hypoglycemia with gliclazide was not different to other insulinotropic agents (RR 0.85; 95%, CI 0.66 to 1.09, P=0.20, I(2)=61%) but significantly lower than other sulfonylureas (RR 0.47; 95%, CI 0.27 to 0.79, P=0.004, I(2)=0%).
CONCLUSION: Compared with other oral insulinotropic agents, gliclazide significantly reduced HbA1c with no difference regarding hypoglycemia risk. Compared with other sulfonylureas, HbA1c reduction with gliclazide was not significantly different, but hypoglycemia risk was significantly lower.
Methods: Successive extractions of V. pubescens leaf were carried out to produce petroleum ether (VPPE), chloroform (VPCE), methanol (VPME), and water (VPWE) extracts. Spontaneously hypertensive rats (SHRs) received a daily oral administration of the extracts (500 mg/kg/day; n = 6) or verapamil (15 mg/kg/day; n = 6) for 2 weeks, while the systolic and diastolic blood pressures were measured using non-invasive tail-cuff method. Vasorelaxation assays of the extracts were later conducted using phenylephrine (PE, 1 μM) pre-contracted aortic ring preparation. Mechanisms of vasorelaxation by the most potent fraction were studied using vasorelaxation assays with selected blockers/inhibitors. GC-MS was conducted to determine the active compounds.
Results: VPPE elicited the most significant diminution in systolic and diastolic blood pressure of treated SHRs and produced the most significant vasorelaxation in the aortic rings. Vasorelaxant effects of F2-VPPE were significantly reduced in endothelium-denuded aortic rings by glibenclamide (1 μM), whereas calcium chloride and PE-induced contractions were significantly suppressed. Endothelium removal of the aortic rings or incubation with indomethacin (10 μM), atropine (1 μM), methylene blue (10 μM), propranolol (1μM) and L-NAME (10 μM) did not significantly alter F2-VPPE-induced vasorelaxation. Seven compounds were identified using GC-MS, including spathulenol.
Conclusion: F2-VPPE exerted its endothelium-independent vasorelaxation by inhibition of vascular smooth muscle contraction induced by extracellular Ca+2 influx through trans-membrane Ca+2 channels and/or Ca+2 release from intracellular stores, and by activation of KATP channels. The vasorelaxation effects of V. pubescens could be mediated by the compound, spathulenol.