Planta Med 2014; 80 - SL23
DOI: 10.1055/s-0034-1394511

Hypoglycemic effect of the extract of Myrcia bella Cambess. through modulation of protein expression involved on glucose metabolism in liver of streptozotocin diabetic mice

PM Ponce Vareda 1, LL Saldanha 1, N De Paula Camaforte 1, NM Violato 1, AL Dokkedal 2, JR Bosqueiro 3
  • 1UNESP – São Paulo State University, Institute of Biosciences, Rubião Jr. District, 18618 – 970, Botucatu, SP, Brazil
  • 2UNESP – São Paulo State University, Department of Biology Science, Eng. Luiz Edmundo Carrijo Coube Avenue, 14 – 01, Vargem Limpa, 17033 – 360, Bauru, SP, Brazil
  • 3UNESP – São Paulo State University, Department of Physical Education, Eng. Luiz Edmundo Carrijo Coube Avenue, 14 – 01, Vargem Limpa, 17033 – 360, Bauru, SP, Brazil

Diabetes is a metabolic disorder characterized by chronic hyperglycemia as a result of defects in insulin action, insulin secretion or both [1]. Species of Myrcia have been used by indigenous people and in traditional communities in Brazil for the treatment of diabetes [2,3]. The aim of this study was to investigate the molecular mechanisms involved in hypoglycemic activity of the extract of M. bella in liver of streptozotocin diabetic mice. Powdered leaves were extracted with EtOH/Water (7:3) by percolation and the chemical profile made using Accela (Thermo Scietific®) FIA-ESI-IT-MSn as described by Saldanha et al. [4]. Male albino Swiss mice (90 days, 40 g) had diabetes induced by a single injection of Streptozotocin® (150 mg/Kg). The mice were divided into 4 groups and treated by gavage during 21 days with saline or the extract of M. bella at 600 mg/Kg: CTL SAL (normoglycemic mice treated with saline), CTL EXT (normoglycemic mice treated with extract), STZ SAL (diabetic mice treated with saline) and STZ EXT (diabetic mice treated with extract). Proteins involved in glycogenesis, gluconeogenesis and glycogenolysis like glycogen synthase, AMPK, PEPCK and glucose-6-phosphatase (G6Pase) had their expression measured in liver. The results were expressed as Means ± SEM and statistical analyses were performed using ANOVA followed by Tukey post test. The FIA-ESI-IT-MSn analysis of the M. bella hydroalcoholic extract confirms the presence of flavonoid-O-glycosides, mainly derivatives of quercetin and myricetin [4]. The analysis of protein expression showed a significant increase of glycogen synthase (0.77 ± 0.06) and AMPK (2.04 ± 0.25) in liver of STZ EXT while G6Pase (0.43 ± 0.03) and PEPCK (0.29 ± 0.07) were decreased when compared with STZ SAL (0.34 ± 0.05; 0.91 ± 0.09; 0.71 ± 0.07; 0.7 ± 0.1 respectively) (p < 0.05, n = 6). The extract seems to be a valuable source of natural products that can act as hypoglycemic agent through modulation of key proteins in liver.

References:

[1] American Diabetes Association (2011) Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 34: S62-S69.

[2] Russo, EM., et al. (1990) Clinical trial of Myrcia uniflora and Bauhinia forficata leaf extracts in normal and diabetic patients. Brazilian J. Med. Biol. Res 23: 11 – 20.

[3] Hashimoto, G. Illustrade Cyclopedia of Brazilian Medicinal Plants. Aboc-Sha: Kamakura, Japan, 1996.

[4] Saldanha, L. L., Vilegas, W., Dokkedal, A.L. (2013) Characterization of Flavonoids and Phenolic Acids in Myrcia bella Cambess. using FIA-ESI-IT-MSn and HPLC-PAD-ESI-IT-MS Combined with NMR. Molecules 18: 8402 – 8416.