5‐Hydroxyferulic acid methyl ester isolated from wasabi leaves inhibits 3T3‐L1 adipocyte differentiation

To investigate the compounds present in wasabi leaves (Wasabia japonica Matsumura) that inhibit the adipocyte differentiation, activity‐guided fractionation was performed on these leaves. 5‐Hydroxyferulic acid methyl ester ( 1 : 5‐HFA ester), one of the phenylpropanoids, was isolated from wasabi leaves as a compound that inhibits the adipocyte differentiation. Compound 1 suppressed the intracellular lipid accumulation of 3T3‐L1 cells without significant cytotoxicity. Gene expression analysis revealed that 1 suppressed the mRNA expression of 2 master regulators of adipocyte differentiation, PPARγ and C/EBPα. Furthermore, 1 downregulated the expression of adipogenesis‐related genes, GLUT4, LPL, SREBP‐1c, ACC, and FAS. Protein expression analysis revealed that 1 suppressed PPARγ protein expression. Moreover, to investigate the relationship between the structure and activity of inhibiting the adipocyte differentiation, we synthesized 12 kinds of phenylpropanoid analog. Comparison of the activity among 1 and its analogs suggested that the compound containing the substructure that possess a common functional group at the ortho position such as a catechol group exhibits the activity of inhibiting the adipocyte differentiation. Taken together, our findings suggest that 1 from wasabi leaves inhibits adipocyte differentiation via the downregulation of PPARγ.     

Effects of Lonicera japonica Thunb. on Type 2 Diabetes via PPAR‐γ Activation in Rats

Lonicera japonica Thunb. (Caprifoliaceae) is a traditional herbal medicine and has been used to treat diabetic symptoms. Notwithstanding its use, the scientific basis on anti‐diabetic properties of L. japonica is not yet established. This study is designed to investigate anti‐diabetic effects of L. japonica in type 2 diabetic rats. L. japonica was orally administered at the dose of 100 mg/kg in high‐fat diet‐fed and low‐dose streptozotocin‐induced rats. After the treatment of 4 weeks, L. japonica reduced high blood glucose level and homeostatic model assessment of insulin resistance in diabetic rats. In addition, body weight and food intake were restored by the L. japonica treatment. In the histopathologic examination, the amelioration of damaged β‐islet in pancreas was observed in L. japonica‐treated diabetic rats. The administration of L. japonica elevated peroxisome proliferator‐activated receptor gamma and insulin receptor subunit‐1 protein expressions. The results demonstrated that L. japonica had anti‐diabetic effects in type 2 diabetic rats via the peroxisome proliferator‐activated receptor gamma regulatory action of L. japonica as a potential mechanism. Copyright © 2015 John Wiley & Sons, Ltd.     

Protective Effects of Turbinaria ornata and Padina pavonia against Azoxymethane‐Induced Colon Carcinogenesis through Modulation of PPAR Gamma,NF‐κB and Oxidative Stress

The aim of this study was to investigate the antiproliferative and protective effects of the brown seaweeds, Turbinaria ornata and Padina pavonia, against azoxymethane (AOM)‐induced colon carcinogenesis in mice. Both algal extracts showed anti‐proliferative effects on the human carcinoma cell line HCT‐116 in vitro, with T. ornata demonstrating a more potent effect. Male albino Swiss mice received intraperitoneal injections of AOM (10 mg/kg) once a week for two consecutive weeks and 100 mg/kg of either T. ornata or P. pavonia extracts. AOM‐induced mice exhibited alterations in the histological structure of the colon, elevated lipid peroxidation and nitric oxide, declined glutathione content and reduced activity of superoxide dismutase and glutathione peroxidase. In addition, AOM induced downregulation of peroxisome proliferator activated receptor gamma (PPARγ) and p53 mRNA expression, with concomitant upregulation of nuclear factor‐kappa B (NF‐κB) in colon tissue. Administration of either algal extract markedly alleviated the recorded alterations. In conclusion, the current study suggests that T. ornata and P. pavonia, through their antioxidant and anti‐inflammatory effects, are able to attenuate colon inflammation by downregulating NF‐κB expression. Furthermore, the protective effects of both algae against AOM‐initiated carcinogenesis were attributed, at least in part, to their ability to upregulate colonic PPARγ and p53 expression. Copyright © 2015 John Wiley & Sons, Ltd.     

Anti‐Ulcerative Colitis Activity of Compounds from Euphorbia granuleta Forssk

The aim of the present study was to evaluate the anti‐ulcerative colitis (UC) activity of the total alcohol extracts of Euphorbia granuleta Forssk. (Euphorpiaceae), isolate and identify the active compounds that could be responsible for the activity, in addition to determination of the possible mechanism of action. Six compounds were isolated and identified from this plant: three phenolic compounds (kampferol, kampferol‐3‐glucoside and kampferol‐3‐galactoside) in addition to three steroidal compounds (1‐ethoxypentacosane, heptacosan‐1‐ol and β‐sitosterol). Three compounds (heptacosan‐1‐ol, β‐sitosterol and kampferol‐3‐galactoside) were found to be responsible for the anti‐UC activity of E. granuleta extract. The anti‐UC activity of these compounds may be explained by reducing the pro‐inflammatory cytokine tumor necrosis factor‐alpha (TNF‐α), in addition to reduction of colonic malondialdehyde (MDA) contents. No side effects were reported on liver and kidney functions. The active compounds reduced both serum TNF‐α and mucosal MDA levels. Copyright © 2013 John Wiley & Sons, Ltd.     

In Vitro Inhibition of the Transcription Factor NF‐κB and Cyclooxygenase by Bamboo Extracts

Several bamboo species have been used in traditional medicine for the treatment of inflammatory conditions. The present study evaluates the in vitro anti‐inflammatory properties of the traditionally used bamboo species Phyllostachys nigra (Lodd.) Munro and Sasa veitchii (Carr.) Rehder to explore their future research opportunities and therapeutic potential as anti‐inflammatory agents. The extracts were evaluated for their potential inhibitory activity at the level of NF‐κB‐induced gene expression and suppression of cyclooxygenase (COX)‐1 and COX‐2 enzyme activities, representative pharmacological targets for the anti‐inflammatory action of glucocorticoids and non‐steroidal anti‐inflammatory drugs, respectively. The activity of P. nigra (Lodd.) Munro and S. veitchii (Carr.) Rehder was compared with bamboo species without traditional anti‐inflammatory indications. High‐performance liquid chromatography with diode‐array detection and liquid chromatography–tandem mass spectrometry analyses were performed to phytochemically characterize the extracts. P. nigra (Lodd.) Munro leaf extract potently inhibited NF‐κB‐induced gene expression, while S. veitchii (Carr.) Rehder leaf extract exerted a selective COX‐2 inhibition. The crude extracts consistently showed a more potent bioactivity than the solid phase extraction fractions. P. nigra (Lodd.) Munro and S. veitchii (Carr.) Rehder both exert anti‐inflammatory properties, but act via a different molecular mechanism. Copyright © 2013 John Wiley & Sons, Ltd.     

Inhibition of Prostaglandin D2 Production by Trihydroxy Fatty Acids Isolated from Ulmus davidiana var. japonica

The stem and root barks of Ulmus davidiana var. japonica (Ulmaceae) have been used to treat inflammatory diseases including mastitis, rhinitis, sinusitis, and enteritis. In an ongoing study focused on the discovery of natural anti‐inflammatory compounds from natural products, a methanol extract of the stem and root barks of U. davidiana var. japonica showed anti‐inflammatory activities. Activity‐guided fractionation of the methanol extract yielded a new trihydroxy fatty acid, 9,12,13‐trihydroxyoctadeca‐10(Z),15(Z)‐dienoic acid (1), and a known compound, pinellic acid (2). These two trihydroxy fatty acids 1 and 2 inhibited prostaglandin D₂ production with IC₅₀ values of 25.8 and 40.8 μM, respectively. These results suggest that 9,12,13‐trihydroxyoctadeca‐10(Z),15(Z)‐dienoic acid (1) and pinellic acid (2) are among the anti‐inflammatory principles in this medicinal plant. Copyright © 2012 John Wiley & Sons, Ltd.     

Aged garlic extract inhibits CD36 expression in human macrophages via modulation of the PPARγ pathway

Expression of CD36 scavenger receptors on macrophages is involved in oxidized low‐density lipoprotein uptake and foam cell formation during atherosclerotic lesion development. We examined the effects of aged garlic extract (AGE), a garlic preparation enriched in water‐soluble cysteinyl moieties that increases cellular total thiols and glutathione concentrations, on CD36 expression in human monocytes/macrophages (THP‐1 cells and primary human monocytes). Compared to control, AGE (1–5 mg/mL) dose‐dependently and significantly suppressed CD36 expression up to by 61.8 ± 7.4% in THP‐1‐derived macrophages and up to 50.5 ± 7.1% in primary human macrophages, respectively. Furthermore, AGE prevented induction of CD36 expression by the peroxisome proliferator activator receptor (PPAR) γ agonist troglitazone, and decreased binding of nuclear proteins to a PPARγ response element. AGE showed a stronger inhibitory effect on CD36 expression in THP‐1 cells during simultaneous incubation with phorbol 12‐myristate 13‐acetate (PMA) compared to cells that had been pre‐incubated with PMA. Furthermore, AGE decreased CD11b expression in a dose‐dependent manner. These data indicate that AGE inhibits CD36 expression by modulating the PPARγ pathway in human macrophages and monocytes differentiation into macrophages, and suggests that the extract could be useful for the prevention of atherosclerotic lesions. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of Penta‐O‐galloyl‐β‐D‐glucose on Human Neutrophil Function: significant Down‐Regulation of L‐selectin Expression

Penta‐O‐galloyl‐β‐D‐glucose (PGG) occurrs in high concentrations in medicinal herbs such as Rhus chinensis, Paeonia suffruticosa, Acer truncatum and Terminalia chebula, which demonstrate anti‐inflammatory activity. We investigated the effect of PGG on stimulated and non‐stimulated neutrophils in processes which included reactive oxygen species generation (ROS), metalloproteinase‐9 and interleukin‐8 secretion (IL‐8), β₂ integrin (CD11b) and L‐selectin (CD62L) expression and apoptosis. In concentrations of 5 μM–20 μM, PGG demonstrated statistically significant inhibition of ROS generation, IL‐8 secretion and β₂ integrin expression in stimulated neutrophils. The inhibition of L‐selectin expression by PGG resulted in prevention in neutrophils’ endothelial attachment. The result obtained may explain the anti‐inflammatory activity of this compound and underline the contribution of PGG in the activity of PGG rich plant extracts. Copyright © 2012 John Wiley & Sons, Ltd.     

Antioxidant and Anti‐α‐glucosidase Compounds from the Rhizome of Peltiphyllum peltatum (Torr.) Engl

The antioxidant, anti‐α‐glucosidase and anticholinesterase effects of the alcohol extract of fresh underground rhizomes of Peltiphyllum peltatum were studied. A potent antioxidant activity accompanied by a selective α‐glucosidase effect was observed for the crude extract. Further activity‐guided fractionation (petroleum ether, chloroform, ethyl acetate, n‐butanol and water) resulted in the identification of the ethyl acetate fraction with the highest antioxidant effect. Gallic acid, methyl‐3‐O‐methyl gallate, catechin, gallocatechin, bergenin and 11‐O‐galloylbergenin were isolated from the ethyl acetate fraction. While all the isolated compounds did show a variable degree of radical scavenging effect, 11‐O‐galloylbergenin was identified as the selective α‐glucosidase inhibitor. The isolation, structural elucidation and biological effects of these compounds are discussed. Copyright © 2012 John Wiley & Sons, Ltd.