ABSTRACT
@#Introduction: Vitamin D deficiency has been implicated as one of the factors involved in endothelial dysfunction associated with diabetes. This study aimed to evaluate the effects of active vitamin D (alphacalcidol) supplementation on aortic endothelial function in diabetic rats receiving vitamin D-deficient diet. Methods: Streptozotocin-induced diabetic rats were fed with standard diet (D) or vitamin D-deficient diet (DD and DDS) for 10 weeks. Group DDS was then supplemented with 0.2 μg/kg alphacalcidol at the last four weeks of the study duration. Non-diabetic rats were fed with standard diet (N) or vitamin-D deficient diet (ND). At the end of the experiment, the rats were sacrificed, and their aortic rings were harvested for endothelial functional study. Results: Acetylcholine-induced relaxation in aorta of diabetic rats (D and DD) were significantly lower compared to non-diabetic rats (N). In the presence of endothelial nitric oxide synthase blocker (L-NAME), maximal relaxation induced by acetylcholine in aorta of D and DD groups were significantly higher compared to N, ND and DDS groups, indicating involvement of non-nitric oxide (NO) relaxation pathways in diabetes. Four weeks supplementation with alphacalcidol in DDS group significantly improved acetylcholine-induced relaxation and reduced the reliance on non-NO relaxation pathways. Conclusion: The present study suggests that impairment of acetylcholine-induced relaxation in aorta of diabetes and diabetes with vitamin D-deficient diet was largely due to a decrease in NO related pathways, and this was compensated by non-NO pathways. Supplementation with alphacalcidol alleviated endothelial impairment in aorta of diabetic rats with vitamin D-deficient diet.
ABSTRACT
OBJECTIVE@#To evaluate vasorelaxant and vasoconstriction effects of Zingiber officinale var. rubrum (ZOVR) on live rats and isolated aortic rings of spontaneously hypertensive rats (SHRs).@*METHODS@#Extracts of ZOVR were subjected to in-vivo antihypertensive screening using noninvasive blood pressures in SHRs. The most potent extract, ZOVR petroleum ether extract (ZOP) was then fractionated using n-hexane, chloroform and water. Isolated thoracic aortic rings were harvested and subjected to vascular relaxation studies of n-hexane fraction of ZOP (HFZOP) with incubation of different antagonists such as N-nitro-l-arginine methyl ester (L-NAME, 10 µmol/L), indomethacin (10 µmol/L), methylene blue (10 µmol/L), atropine (1 µmol/L), glibenclamide (10 µmol/L), prazosin (0.01 µmol/L), and propranolol (1 µmol/L).@*RESULTS@#During the screening of various ZOVR extracts, ZOP produced the most reduction in blood pressures of SHRs and so did HFZOP. HFZOP significantly decreased phenylephrine-induced contraction and enhanced acetylcholine-induced relaxation. L-NAME, indomethacin, methylene blue, atropine, and glibenclamide significantly potentiated the vasorelaxant effects of HFZOP. Propranolol and prazosin did not alter the vasorelaxant effects of HFZOP. HFZOP significantly suppressed the Ca-dependent contraction and influenced the ratio of the responses to phenylephrine in Ca-free medium.@*CONCLUSION@#This study demonstrates that ZOP may exert an antihypertensive effect in the SHR model. Its possible vascular relaxation mechanisms involve nitric oxide and prostacyclin release, activation of cGMP-K channels, stimulation of muscarinic receptors, and transmembrane calcium channel or Ca release from intracellular stores. Possible active compounds that contribute to the vasorelaxant effects are 6-gingerol, 8-gingerol and 6-shogaol.
ABSTRACT
Objective: To elucidate the in vivo hypoglycemic capability, antihyperglycemic and antihyperlipidemic activities of Pereskia bleo (Kunth) leaves extracts and bioactive fraction. Methods: The various solvent extracts of Pereskia bleo were investigated for the hypoglycemic and antihyperglycemic activities using a relevant in vivo normal rat model and streptozotocin-induced diabetic rat model with glibenclamide and metformin utilized as positive controls. The effects of the most potent extract and its bioactive fraction on the insulin level, lipid profile and body weight of the diabetic rats were also analyzed. Results: All the extracts showed no hypoglycemic effect while petroleum ether, chloroform and aqueous extracts demonstrated significant (P<0.05) reduction in blood sugar level in the intraperitoneal glucose tolerance test. Aqueous extract and aqueous fraction significantly (P<0.05) reduced the blood glucose level in streptozotocin-induced diabetic rats as early as day 6 compared to the diabetic control as well as significantly restored the serum insulin of diabetic rats. Moreover, the aqueous extract and aqueous fraction disclosed a significant (P<0.05) reduction in total cholesterol, triglycerides, and low-density lipoprotein levels. An elevation in high-density lipoprotein as well as improved body weight loss of the diabetic rats were also observed. Conclusions: In summary, Pereskia bleo appears effective in the management of diabetes and correlated impairments arising from high blood sugar level. Further studies will possibly bring about the discovery of effective and secure plant derived antidiabetic drugs.
ABSTRACT
Plants have provided sources to find novel compounds. These plants are being used as therapeutic purposes since the birth of mankind. The traditional healers normally utilize medicinal plants as crude drugs while scientists using the folk claim as guides to explore medicinal plants. Moringa oleifera is a famous edible plant having therapeutic and nutritive values. The present study was designed to cumulate the research data regarding to what extent, phytochemical, nutritional and glycemic control studies has been explored using its different extracts. The articles indicated that the powder, aqueous, methanol and ethanol extracts of Moringa oleifera (leaves, pods, seeds, stem and root bark) have significant therapeutic herbal potential to treat diabetes mellitus. Collectively, the mechanism behind is intestinal glucose inhibition, insulin release as well as decrease in insulin resistance probably regeneration of β-cells of pancreas, increase in glutathione and reduction in malondialdehyde. Conclusively, this article give descriptive information about antidiabetic effect, claimed marker compounds and proposed antihyperglycemic mechanism of a single plant. It can be suggested a potential herbal source to treat diabetes mellitus as being widely accepted by major population as nutrition and therapeutic agent.
ABSTRACT
Objective To investigate the antidiabetic activity of Ocimum tenuiflorum L. (O. tenuiflorum) leaves used in the traditional medicine management of diabetes in Malaysia. Methods O. tenuiflorum leaves were extracted sequentially with hexane, chloroform, ethyl acetate, methanol, and water. The extracts were evaluated in terms of antidiabetic activity by using acute, subcutaneous glucose tolerance, and sub-chronic tests in streptozotocin-induced diabetic rats. The extracts were also subjected to phytochemical analyses. Results With an acute dose (1 g/kg), the methanol extracts showed significant reduction (31%) in fasting blood glucose (FBG) of the streptozotocin-induced diabetic rats. The FBG-decreasing effect of ethyl acetate extract was more rapid than that of the other extracts; the decreasing rates were 20% after 2 h, 21% after 3 h, and 8% after 5 and 7 h. After 7 h (31%), the effect of methanol extract on FBG was significantly lower than that of metformin. In the subcutaneous glucose tolerance test, only methanol and hexane extracts showed the similarity of metformin in diabetic rats. After 14 days, the effects of these extracts were similar to those of metformin (63.33%). The total flavonoid and phenolic contents of extracts decreased as the polarity of the extraction solvent increased. Conclusions The results obtained provide support for a possible use of O. tenuiflorum leaves in managing hyperglycemia and preventing the complications associated with it in type 2 diabetic.
ABSTRACT
OBJECTIVES@#To study the antidiabetic and antioxidant activities of nipa palm vinegar (NPV) used in traditional Malay medicine for treating diabetes.@*METHODS@#NPV was extracted using liquid-liquid extraction method and the obtained samples were subjected to antidiabetic studies using normal and streptozotocin-induced diabetic rat models whereas antidoxidant activities were investigated via in vitro antioxidant tests namely 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radicals scavenging activities and the reducing power assay.@*RESULTS@#Single administration of NPV and its extracts were not effective in both normal and diabetic rats. In intraperitoneal glucose tolerance test, NPV and its aqueous extract showed significant blood glucose lowering effect. In the sub-acute study, compared with the diabetic control, aqueous extract of NPV showed the most notable blood glucose lowering effect (56.6%) and a significant improvement in serum insulin levels (79.8%, P < 0.05). To assess NPV's antioxidant activity, three in vitro antioxidant tests were employed: 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radical-scavenging assays, and the reducing power assay. Ethyl acetate extract had the greatest antioxidant potential and content of phenolic and flavonoid compounds. A linear positive correlation between the antioxidant parameters was observed. Chemical profiling analysis of aqueous extract of NPV revealed the presence of acetic acid (35.25%), the main active constituent which significantly contributed to the observed antidiabetic activity.@*CONCLUSIONS@#Aqueous extract of NPV possesses antihyperglycaemic activities comparable to the metformin, while the ethyl acetate extract precipitated significant antioxidant effects attributable to its high phenolic content. These findings suggest that antioxidant compounds of NPV do not contribute much towards the overall observed antidiabetic effect.
ABSTRACT
Objectives: To study the antidiabetic and antioxidant activities of nipa palm vinegar (NPV) used in traditional Malay medicine for treating diabetes. Methods: NPV was extracted using liquid-liquid extraction method and the obtained samples were subjected to antidiabetic studies using normal and streptozotocin-induced diabetic rat models whereas antidoxidant activities were investigated via in vitro antioxidant tests namely 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radicals scavenging activities and the reducing power assay. Results: Single administration of NPV and its extracts were not effective in both normal and diabetic rats. In intraperitoneal glucose tolerance test, NPV and its aqueous extract showed significant blood glucose lowering effect. In the sub-acute study, compared with the diabetic control, aqueous extract of NPV showed the most notable blood glucose lowering effect (56.6%) and a significant improvement in serum insulin levels (79.8%, P < 0.05). To assess NPV's antioxidant activity, three in vitro antioxidant tests were employed: 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid free radical-scavenging assays, and the reducing power assay. Ethyl acetate extract had the greatest antioxidant potential and content of phenolic and flavonoid compounds. A linear positive correlation between the antioxidant parameters was observed. Chemical profiling analysis of aqueous extract of NPV revealed the presence of acetic acid (35.25%), the main active constituent which significantly contributed to the observed antidiabetic activity. Conclusions: Aqueous extract of NPV possesses antihyperglycaemic activities comparable to the metformin, while the ethyl acetate extract precipitated significant antioxidant effects attributable to its high phenolic content. These findings suggest that antioxidant compounds of NPV do not contribute much towards the overall observed antidiabetic effect.
ABSTRACT
Acanthaster planci, the crown-of-thorns starfish, naturally endowed with the numerous toxic spines around the dorsal area of its body. Scientific investigations demonstrated several toxico-pharmacological efficacies of A. planci such as, myonecrotic activity, hemorrhagic activity, hemolytic activity, mouse lethality, phospholipase A2 [PLA2] activity, capillary permeability-increasing activity, edema-forming activity, anticoagulant activity and histaminereleasing activity from mast cells. The present study was performed to evaluate the cytotoxic activity of A. planci extracts obtained by different methods of extraction on MCF-7 and HCT-116, human breast and colon cancer cell lines, respectively. Results of the cell proliferation assay showed that PBS extract exhibited very potent cytotoxic activity against both MCF-7 and HCT-116 cell lines with IC[50] of 13.48 microg/mL and 28.78 microg/mL, respectively, while the extracts prepared by Bligh and Dyer method showed moderate cytotoxicity effect against MCF-7 and HCT-116 cell lines, for chloroform extract, IC[50] = 121.37 microg/mL [MCF-7] and 77.65 microg/mL [HCT-116], and for methanol extract, IC[50] = 46.11 microg/ml [MCF-7] and 59.29 microg/ml [HCT-116]. However, the extracts prepared by sequential extraction procedure from dried starfish found to be ineffective. This study paves the way for further investigation on the peptide composition in the PBS extract of the starfish to discover potential chemotherapeutic agents