Anti-hyperglycemic action of apigenin-6-C-ß-fucopyranoside from Averrhoa carambola.

A stimulatory effect of apigenin-6-C-ß-fucopyranoside (1) on glucose uptake was observed when rat soleus muscle was incubated with 1, 10 and 100 µM of this flavonoid glycoside. The presence of specific insulin signaling inhibitors, such as wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), RO318220, an inhibitor of protein kinase C (PKC), PD98059, an inhibitor of mitogen-activated protein kinase (MEK), and HNMPA(AM)3, an insulin receptor tyrosine kinase activity inhibitor showed that apigenin-6-C-ß-fucopyranoside triggers different metabolic pathways in skeletal muscle. The oral administration of crude extract, fractions and isolated flavonoids (apigenin-6-C-ß-fucopyranoside (1) and apigenin-6-C-(2″-O-α-rhamnopyranosyl)-ß-fucopyranoside (2)) from Averrhoa carambola leaves exhibited a potential hypoglycemic activity in hyperglycemic normal rats. Additionally, both flavonoids significantly increased the muscle and liver glycogen content after an acute treatment. The results indicate that A. carambola can be regarded as a potent antihyperglycemic agent with insulin secretagogue and insulin mimetic properties.

Protected effect of Esenbeckia leiocarpa upon the inflammatory response induced by carrageenan in a murine air pouch model.

UNLABELLED: This study was conducted to investigate the anti-inflammatory efficacy of Esenbeckia leiocarpa against the inflammation caused by the carrageenan using a murine air pouch model. MATERIAL AND METHODS: The effects of the crude hydroalcoholic extract (CHE), fractions (n-hexane (Hex) and ethyl acetate (AcOEt)), subfractions (polar (Pol) and nonpolar (Nonpol)), or isolated compounds (dihydrocorynantheol (DHC) and beta-sitosterol (ß-Sit)) isolated from CHE upon leukocytes, exudate, myeloperoxidase (MPO) adenosine-deaminase (ADA), nitrate/nitrite (NO(x)), interleukin-1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α), and inhibitory kappa-B-alpha (IκB-α) degradation were evaluated. The CHE, Alk, Pol, Nonpol, DHC and ß-Sit, inhibited leukocytes, exudate, MPO and ADA, NO(x), IL-1ß, and TNF-α (P<0.05). The Hex and AcOEt fractions inhibited all of the proinflammatory parameters, except the exudate. The compound DHC prevented the IκB-α degradation. CONCLUSION: E. leiocarpa possesses important anti-inflammatory properties. These inhibitory effects occurred along with the downregulation of nitric oxide, IL-1ß and TNF-α levels. The isolated compounds DHC and ß-Sit may be partially responsible for these anti-inflammatory effects.

Esenbeckia leiocarpa Engl. inhibits inflammation in a carrageenan-induced murine model of pleurisy.

OBJECTIVES: The aim of this study was to investigate the anti-inflammatory effects of the crude hydroalcoholic extract (CHE) isolated from Esenbeckia leiocarpa Engl., and fractions and subfractions derived from it. METHODS: Dried E. leiocarpa Engl. bark was macerated and extracted with ethanol to obtain the CHE. The n-hexane, ethyl acetate, aqueous and alkaloid fractions, as well as two alkaloid subfractions (polar and nonpolar) were obtained from the CHE. A preliminary analysis using thin-layer chromatography was performed. Capillary electrophoresis, physical characteristics and spectral data produced by IR analysis and nuclear magnetic resonance (¹H and ¹³C NMR), and mass spectrometry analysis were used to identify and elucidate the structure of the major compounds. Swiss mice were used in a carrageenan-induced pleurisy model. Pro-inflammatory parameters (leukocyte and exudate concentrations, myeloperoxidase and adenosine-deaminase activity, and nitrate/nitrite, interleukin 1ß and tumour necrosis factor α levels) were quantified in exudates at 4 h after carrageenan-induced pleurisy in mice. KEY FINDINGS: The dihydrocorynantheol alkaloid was isolated as the majority compound in the CHE, ethyl acetate and alkaloid fractions, and in the polar and nonpolar alkaloid subfractions. The CHE, fractions and subfractions inhibited the increases in leukocyte and exudate concentrations, myeloperoxidase and adenosine-deaminase activity, and nitrite/nitrate, interleukin 1ß, and tumour necrosis factor α levels (P<0.05) in the fluid secreted from the pleural cavity of the carrageenan-treated mice. CONCLUSIONS: E. leiocarpa Engl. showed significant in vivo anti-inflammatory action by inhibiting the inflammation caused by carrageenan. This effect may be, in part, due to the dihydrocorynantheol alkaloid, which was identified as the majority compound isolated from E. leiocarpa bark.