Antihyperglycemic and antioxidant activities of Rhododendron schlippenbachii maxim. bark and its various fractions

In this research, we evaluated the antidiabetic and antioxidant potential of 80% aqueous methanolic extract of the bark of Rhododendron schlippenbachii Maxim. along with its various fractions (n-hexane, dichloromethane, ethyl ethanoate, n-butyl alcohol and distilled water). The antihyperglycemic activity of all the fractions was investigated in vitro by α-glucosidase inhibition (using two types of enzyme sources) and in vivo in normal rats by evaluating the blood glucose lowering effect after maltose administration (1 g/kg bw). In addition, all these fractions were also evaluated by five diverse in vitro antioxidant assay systems, which include, ferrous ion chelating (FIC), 1,1diphenyl-2-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), 2,20-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and lipid peroxidation inhibition (using rat liver) assays. We also examined the total phenolic and flavonoid contents for all of these fractions. In all, ethyl ethanoate and dichloromethane fractions exhibited potent antihyperglycemic and antioxidant effects in vitroand in vivo.   Key words: Rhododendron sclippenbachii, α-glucosidase, oral glucose tolerance test (OGTT), rats, antioxidant.

[1]  B. Mayur,et al.  Antioxidant and α-glucosidase inhibitory properties of Carpesium abrotanoides L. , 2010 .

[2]  O. Sağdıç,et al.  Total phenolic content, antiradical, antioxidant and antimicrobial activities of Rhododendron honeys , 2010 .

[3]  A. Peksel,et al.  EVALUATION OF ANTIOXIDANT AND ANTIACETYLCHOLINESTERASE ACTIVITIES OF THE EXTRACTS OF PISTACIA ATLANTICA DESF. LEAVES , 2010 .

[4]  B. Um,et al.  1,2,3,4,6-penta-O-galloyl-β-d-glucose: A cholinesterase inhibitor from Terminalia chebula , 2010 .

[5]  S. Nabavi,et al.  ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITY , 2010 .

[6]  S. Nabavi,et al.  Antioxidant and free radical scavenging activity of H. officinalis L. var. angustifolius, V. odorata, B. hyrcana and C. speciosum. , 2010, Pakistan journal of pharmaceutical sciences.

[7]  H.-S. Lee,et al.  Comparison of Antioxidant Potential and Rat intestinal a-Glucosidases inhibitory Activities of Quercetin, Rutin, and Isoquercetin , 2009 .

[8]  H. Jang,et al.  Antioxidant and antidiabetic activity of Dangyuja (Citrus grandis Osbeck) extract treated with Aspergillus saitoi , 2009 .

[9]  J. Eloff,et al.  Can MTT be used to quantify the antioxidant activity of plant extracts? , 2009, Phytomedicine : international journal of phytotherapy and phytopharmacology.

[10]  Y. Furuichi,et al.  Hypoglycemic effect of hot-water extract of adzuki (Vigna angularis) in spontaneously diabetic KK-A(y) mice. , 2009, Nutrition.

[11]  A. Tiwari,et al.  Reduction in Post‐Prandial Hyperglycemic Excursion Through α‐Glucosidase Inhibition by β‐Acetamido Carbonyl Compounds. , 2008 .

[12]  A. Tiwari,et al.  Reduction in post-prandial hyperglycemic excursion through alpha-glucosidase inhibition by beta-acetamido carbonyl compounds. , 2008, Bioorganic & medicinal chemistry letters.

[13]  Michelle M. Cartagena,et al.  Fatty Acid Composition of Turkish Rhododendron Species , 2008 .

[14]  M. Ebrahimzadeh,et al.  DETERMINATION OF ANTIOXIDANT ACTIVITY, PHENOL AND FLAVONOID CONTENT OF PARROTIA PERSICA MEY , 2008 .

[15]  M. Öztürk,et al.  Antioxidant activity of stem and root extracts of Rhubarb (Rheum ribes) : An edible medicinal plant , 2007 .

[16]  L. Leong,et al.  Antioxidant activities of aqueous extracts of selected plants , 2006 .

[17]  Malaya Gupta,et al.  In Vitro Lipid Peroxidation and Antimicrobial Activity of Mucuna Pruriens Seeds , 2005 .

[18]  A. Ceriello.  Postprandial hyperglycemia and diabetes complications: is it time to treat? , 2005, Diabetes.

[19]  E. Gulve,et al.  Chemistry and biochemistry of type 2 diabetes. , 2004, Chemical reviews.

[20]  L. McCune,et al.  Antioxidant activity in medicinal plants associated with the symptoms of diabetes mellitus used by the indigenous peoples of the North American boreal forest. , 2002, Journal of ethnopharmacology.

[21]  R. Kuttan,et al.  Anti-diabetic activity of medicinal plants and its relationship with their antioxidant property. , 2002, Journal of ethnopharmacology.

[22]  Chi-Tang Ho,et al.  ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITIES OF EDIBLE MUSHROOMS , 2002 .

[23]  E. Bonora,et al.  Postprandial blood glucose as a risk factor for cardiovascular disease in Type II diabetes: the epidemiological evidence , 2001, Diabetologia.

[24]  G. Kusano,et al.  Studies on the Constituents of Broussonetia Species. Part 8. Four New Pyrrolidine Alkaloids, Broussonetines R, S, T, and V and a New Pyrroline Alkaloid, Broussonetine U, from Broussonetia kazinoki SIEB. , 2001 .

[25]  G. Kusano,et al.  Studies on the constituents of Broussonetia species. II. Six new pyrrolidine alkaloids, broussonetine A, B, E, F and broussonetinine A and B, as inhibitors of glycosidases from Broussonetia kazinoki Sieb. , 1997, Chemical & pharmaceutical bulletin.

[26]  G. Fleet,et al.  Amino-sugar glycosidase inhibitors: versatile tools for glycobiologists. , 1992, Glycobiology.

[27]  H. Ploegh,et al.  Interference with HIV-induced syncytium formation and viral infectivity by inhibitors of trimming glucosidase , 1987, Nature.

[28]  R. Kerbel,et al.  Beta 1-6 branching of Asn-linked oligosaccharides is directly associated with metastasis. , 1987, Science.