Decrease of Plasma Glucose byHibiscus taiwanensisin Type-1-Like Diabetic Rats

Abstract

Hibiscus taiwanensis (Malvaceae) is widely used as an alternative herb to treat disorders in Taiwan. In the present study, it is used to screen the effect on diabetic hyperglycemia in streptozotocin-induced diabetic rats (STZ-diabetic rats). The extract of Hibiscus taiwanensis showed a significant plasma glucose-lowering action in STZ-diabetic rats. Stems of Hibiscus taiwanensis are more effective than other parts to decrease the plasma glucose in a dose-dependent manner. Oral administration of Hibiscus taiwanensis three times daily for 3 days into STZ-diabetic rats increased the sensitivity to exogenous insulin showing an increase in insulin sensitivity. Moreover, similar repeated administration of Hibiscus taiwanensis for 3 days in STZ-diabetic rats produced a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver and an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle. Taken together, our results suggest that Hibiscus taiwanensis has the ability to lower plasma glucose through an increase in glucose utilization via elevation of skeletal GLUT 4 and decrease of hepatic PEPCK in STZ-diabetic rats.

Antihyperglycemic Action of Sinapic Acid in Diabetic Rats

“…Thus, 25 mg/kg of sinapic acid or the same volume of vehicle was applied to oral intake into normal rats. After 45 min, the plasma glucose values were indicated as 0 min as described previously . Then oral intake of glucose solution (1 g glucose per mL saline) at 5 mL/kg of body weight was used to mimic the food consumption.…”

“…After 45 min, the plasma glucose values were indicated as 0 min as described previously. 22 Then oral intake of glucose solution (1 g glucose per mL saline) at 5 mL/kg of body weight was used to mimic the food consumption. Different from the vehicle, as shown in Figure 2A, sinapic acid at 25 mg/kg markedly lowered the plasma glucose at 10, 60, 120, and 180 min.…”

“…Effect of Sinapic Acid on Expressions of GLUT4 in Soleus Muscle of STZ-diabetic Rats. Sinapic acid treated STZ-diabetic rats at the effective dose (25 mg/kg) through oral intake three times daily for 3 days, as described previously, 22 may result in a reduction of plasma glucose from 411.6 ± 5.5 to 325.8 ± 5.2 mg/dL. Then, the soleus muscle was isolated from these STZ-diabetic rats.…”

Supercritical Carbon Dioxide Extraction Process for Hibiscus taiwanensis S. Y. Hu and Tyrosinase Inhibitory Activity of Its Extract

“…In recent years, th extraction of natural plant components and their whitening effects has bec hotspot [8,9]. At present, the extraction methods by water and organic solvents (su or acetone) are mainly employed to obtain the extracts of Hibiscus taiwa [3,6,10,11]. For example, using methanol as a solvent, Wu's team extracte three new phenylpropionates from the stem of Hibiscus taiwanensis S. Y. their cytotoxic activity against human lung and breast cancer cells [6].…”

“…Usi solvent, Lee et al isolated 56 chemical components, including ferulic acid taiwanensis S. Y. Hu, among which five compounds, namely hibicuslide A hibicuslide C, hibicutaiwanin, and hibicusin were newly discovered employed water as a solvent to extract Hibiscus taiwanensis S. Y. Hu fou phenolic compounds, namely ferulic acid, p-coumaric acid, gallic acid, chlorogenic acid, vanillic acid, and caffeic acid, and detected their ant activity to lps-induced RAW264.7 cells and carr-induced mouse foot edem al. used an acetone aqueous solution to immerse and extract Hibiscus taiwa and described the hypoglycemic effect of the extracts, including syringal plasma of streptozotocin-induced diabetic rats [11]. The use of a large amo solvents has the disadvantages of negative environmental impact as well and tedious processes.…”