Temperature and Different Organs Create Volatile Profile Differences of Edible Gynura [Gynura bicolor (Roxb. ex Willd.) DC]

The volatile profile of the edible vegetable Gynura bicolor [Gynura bicolor (Roxb. ex Willd.) DC] was analyzed using gas chromatography-mass spectrometry (GC-MS). Isocaryophyllene (23.2%), α-pinene (16.8%), α-humulene (9.1%), β-pinene (7.3%), and copaene (7.0%) were identified as the major compounds in the leaves. In the stems, α-pinene (27.1%), β-pinene (13.0%), isocaryophyllene (7.8%), β-myrceneb (7.8%), 1-undecene (5.7%), and copaene (5.3%) were the main components. G. bicolor grows best at 25 °C. When cultivated at different temperatures (20 to 35 °C in incements of 5 °C), the volatile profiles shifted. The proportion of isocaryophyllene was lower at 20 °C than at the other temperatures. The relative amounts of α-pinene and α-humulene were highest at 20 °C, whereas copaene was highest at 35 °C. Principal component analysis (PCA) was used to explore the correlation between volatile compounds identified from the vegetative tissues and temperature treatments. It reveals the same trend with the previous statements and the first principal component (PC1) and the second principal component (PC2) explains up to 90% of the variance. Experimental results revealed that both temperature and vegetative organ correlate with the volatile emission profile of G. bicolor.

Effects of Gynura bicolor on Glycemic Control and Antioxidant Ability in Prediabetes

There exists an intermediate group of individuals whose glucose levels do not meet the criteria for diabetes yet are higher than those considered normal (prediabetes mellitus (preDM)). Those people have a higher risk of developing diabetes in the future. Gynura bicolor (GB) is a red-purple-colored vegetable, which is common in Taiwan. GB has shown antioxidant, anti-inflammatory and anti-hyperglycemic effects in previous studies. The aim of this study was to assess the effects of serving two serving sizes of GB every day on the glycemic control and antioxidant ability of preDM subjects. According to the age and anthropometry data of the participates, we assigned them into a control or GB group for the 8-week intervention and 4-week washout period. Data of anthropometry and biochemical analysis were collected at 0, 8 and 12 weeks. Oral glucose tolerance tests were performed, and we collected dietary records on the baseline and Week 8. Both groups received nutrition education and a diet plan individually. After intervention, the fasting glucose and malondialdehyde (MDA) values were significantly decreased in the GB group. HOMA-IR and QUICKI values were improved, and antioxidant activity was increased in the GB group. GB could improve glycemic control and decrease oxidative stress because of its large amounts of polyphenols.

Protective Effect of Gynura Bicolor Alcohol Extracts on Rat Kidney Epithelial NRK-52E Cells Induced by Tert-Butyl Hydroperoxide

Background: Gynura bicolor is a common vegetable in the Asia and has many physiological effects. We aimed to investigate the renoprotective effects of G. bicolor alcohol extracts (GBAEs). Methods: Rat kidney epithelial NRK-52E cell culture and kidney damage induction by tert-butyl hydroperoxide (t-BHP) were used as experimental models. In this study, the antioxidative and anti-inflammatory activities, the levels of apoptosis and apoptosis-related molecules were analyzed in NRK-52E cells following t-BHP-induced injury. Results: The results showed the levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) decreased by levels by 61-71% and 41-59%, respectively, in NRK-52E cells treated with 0.5, 1, or 5 mg/ml GBAE combined with t-BHP compared with t-BHP-induced cells (p<0.05). The GSH levels and GSH-to-GSSG ratio were increased in NRK-52E cells treated with 0.5, 1, and 5 mg/ml GBAE combined with t-BHP compared to t-BHT-induced cells (p<0.05). The nitrite (NO), prostaglandin E2 (PGE2), IL-6, and TNF-α levels of NRK-52E cells treated with 0.5, 1, and 5 mg/ml GBAE combined with t-BHP were decreased compared with t-BHP-induced cells (p<0.05). In addition, Bcl-2 levels were increased after treatment with 5 mg/ml GBAE combined with t-BHP, and the levels of Bax and poly (ADP-ribose) polymerase (PARP) and the apoptosis percentage were decreased after treatment with 1 or 5 mg/ml GBAE combined with t-BHP induction compared to after t-BHP induction alone (p<0.05). Conclusions: These data showed that 5 mg/ml GBAE can protect against kidney cell damage induced by t-BHP. The mechanism involves reducing cell damage and apoptosis through decreasing oxidative stress and inflammation.

Suppressive Effects of the Gynura bicolor Ether Extract on Endothelial Permeability and Leukocyte Transmigration in Human Endothelial Cells Induced by TNF-α

Gynura bicolor (Roxb. and Willd.) DC (G. bicolor) is generally used as a dietary vegetable and traditional herb in Taiwan and the Far East. G. bicolor exerts antioxidant and anti-inflammatory effects and regulates blood lipids and cholesterol. However, the effects of G. bicolor on endothelial transmigration and atherosclerosis are not clear. The present study investigated the effects of G. bicolor on endothelial permeability and transmigration in human endothelial cells. We prepared G. bicolor ether extract (GBEE) for use as the experimental material. Under TNF-α stimulation, HL-60 cell adherence to EA.hy926 cells, the shape of EA.hy926 cells, and the expression of adhesion molecules and transmigration-related regulatory molecules were analysed after pretreatment with GBEE for 24 h. GBEE inhibited leukocyte adhesion to endothelial cells, reduced intercellular adhesion molecule-1 (ICAM-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) expressions, and decreased endothelial monolayer permeability. GBEE also reduced paracellular transmigration by reducing the levels of reactive oxygen species (ROS), Src phosphorylation, and vascular endothelial-cadherin (VE-cadherin) phosphorylation. GBEE reduced transcellular migration via inhibition of Ras homolog family member A (RhoA) and Rho-associated protein kinase (ROCK) expression and phosphorylation of the ezrin-radixin-moesin (ERM) protein. Incubation of EA.hy926 cells with GBEE for 8 h and stimulation with TNF-α for 3 h reduced the phosphorylation of the inhibitor of kappa B (IĸB) and DNA-binding activity of nuclear factor-ĸB (NF-ĸB). These results suggest that GBEE has a protective effect against endothelial dysfunction via suppression of leukocyte-endothelium adhesion and transmigration.

Potential Effects of Antioxidant and Serum Cholesterol-Lowering Effects of Gynura bicolor Water Extracts in Syrian Hamster

Gynura bicolor (Roxb. and Willd.) DC (G. bicolor) is a dietary vegetable in the Far East. The aims of the present study were to investigate the antioxidant effects of the G. bicolor water extract (GBWE) and its ability to regulate the blood lipid and lipoprotein profiles. In this study, the pigment composition and antioxidant ability of the GBWE were analyzed. Syrian hamsters were fed a high-fat diet (HFD) and the GBWE for 12 weeks, and the blood lipid levels, lipoprotein profiles, and cholesterol metabolism-related enzyme levels were then examined. The results showed that the GBWE exhibited excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and ferrous-ion-chelating ability. The hepatic glutathione levels in the hamsters were increased after the administration of low (0.4 g/kg BW, GBWE-L) or high (0.8 g/kg BW, GBWE-H) levels of the GBWE. The GBWE-H-treated hamsters exhibited significantly decreased serum levels of total cholesterols (TC) and low-density lipoprotein-cholesterol (LDL-C) and significantly increased levels of lectin-cholesterol acetyltransferase (LCAT). These results showed that GBWE-H can reduce the total cholesterol and LDL-C levels in HFD-fed hamsters, and this reduction might be involved in the regulation of LCAT expression.

Gynura bicolor aqueous extract attenuated H2O2 induced injury in PC12 cells

Background: Protective effects of Gynura bicolor aqueous extract (GAE) at three concentrations upon nerve growth factor (NGF) differentiated-PC12 cells against H2O2 induced injury were examined. Methods: NGF differentiated-PC12 cells were treated with GAE at 0.25%, 0.5% or 1%. 100 μM H2O2 was used to treat cells with GAE pre-treatments. After incubating at 37 °C for 12 hr, experimental analyses were processed. Results: H2O2 exposure decreased cell viability, increased plasma membrane damage, suppressed Bcl-2 mRNA expression and enhanced Bax mRNA expression. GAE pre-treatments reversed these changes. H2O2 exposure reduced mitochondrial membrane potential, lowered Na+-K+-ATPase activity, and increased DNA fragmentation and Ca2+ release. GAE pre-treatments attenuated these alterations. H2O2 stimulated the production of reactive oxygen species (ROS), interleukin (IL)-1beta, IL-6 and tumor necrosis factor-alpha, lowered glutathione content, and reduced glutathione peroxidase (GPX) and catalase activities. GAE pretreatments maintained GPX and catalase activities; and concentration-dependently diminished the generation of ROS and inflammatory cytokines. H2O2 enhanced mRNA expression of nuclear factor kappa (NF-κ) B and p38. GAE pre-treatments decreased mRNA expression of NF-κB and p38. Conclusion: These findings suggested that GAE might be a potent neuronal protective agent.