Endothelium-dependent potentiation of prostaglandin F2alpha-induced contractions by (+/-)-[6]-gingerol is inhibited by cyclooxygenase- but not lipoxygenase-inhibitors in mouse mesenteric veins

Vasculoprotective effects of ginger (Zingiber officinale Roscoe) and underlying molecular mechanisms

Ginger (Zingiber officinale Roscoe) is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. Herein, we reviewed its effects on the vascular system. Studies utilizing cell cultures or animal models showed that ginger constituents alleviate oxidative stress and inflammation, increase nitric oxide synthesis, suppress vascular smooth muscle cell proliferation, promote cholesterol efflux from macrophages, inhibit angiogenesis, block voltage-dependent Ca2+ channels, and induce autophagy. In clinical trials, ginger was shown to have a favorable effect on serum lipids, inflammatory cytokines, blood pressure, and platelet aggregation. Taken together, these studies point to the potential benefits of ginger and its constituents in the treatment of hypertension, coronary artery disease, peripheral arterial diseases, and other vascular diseases.

Gingerols and shogaols: Important nutraceutical principles from ginger

Gingerols are the major pungent compounds present in the rhizomes of ginger (Zingiber officinale Roscoe) and are renowned for their contribution to human health and nutrition. Medicinal properties of ginger, including the alleviation of nausea, arthritis and pain, have been associated with the gingerols. Gingerol analogues are thermally labile and easily undergo dehydration reactions to form the corresponding shogaols, which impart the characteristic pungent taste to dried ginger. Both gingerols and shogaols exhibit a host of biological activities, ranging from anticancer, anti-oxidant, antimicrobial, anti-inflammatory and anti-allergic to various central nervous system activities. Shogaols are important biomarkers used for the quality control of many ginger-containing products, due to their diverse biological activities. In this review, a large body of available knowledge on the biosynthesis, chemical synthesis and pharmacological activities, as well as on the structure-activity relationships of various gingerols and shogaols, have been collated, coherently summarised and discussed. The manuscript highlights convincing evidence indicating that these phenolic compounds could serve as important lead molecules for the development of therapeutic agents to treat various life-threatening human diseases, particularly cancer. Inclusion of ginger or ginger extracts in nutraceutical formulations could provide valuable protection against diabetes, cardiac and hepatic disorders.

The contractile response of the mesenteric resistance arteries to prostaglandin F2alpha; effects of simultaneous hyperlipemia-diabetes

The effect of hyperlipemia associated with diabetes on the contractility of resistance arteries to prostaglandin F2alpha (PGF2alpha) was investigated employing 4 weeks simultaneously hyperlipemic-diabetic (HD), hyperlipemic (H), diabetic (D) and normal hamsters (controls, C). The isometric force produced by explanted arteries in the presence of 10(-8) to 10(-5) M PGF2alpha was recorded by the myograph technique. The results showed that compared with controls, the contractile response to 10(-5) M PGF2alpha was approx. 2 fold increased in HD group, and approx. 1.75 and 1.62-fold enhanced in H and D groups, respectively. Activation of protein kinase C with 10(-6) M phorbol 12-myristate 13-acetate increased the contractility to PGF2alpha in all groups and particularly in HD hamsters (approx. 10.16-fold). Inhibition of cyclooxygenase by indomethacin increased approx. 1.81-fold the arterial contractility to PGF2alpha in C group, whereas in H, D and HD hamsters had no effect. Blockage of Ca(2+)-activated K(+)-channels with 10(-3) M tetraethylammonium augmented the contraction to PGF2alpha approx. 6.43-fold in C group, and at significantly lower levels in H, D and HD groups, i.e. approx. 3.84, 3.72 and 3.33-fold, respectively. The results validate two conclusions: (i) simultaneous insult of hyperlipemia-hyperglycemia is associated with the highest contractility of the resistance arteries to PGF2alpha; the highest circulating glucose and cholesterol levels, and the enhancement in the protein kinase C pathway underlay the augmented contractility; (ii) no matter the pathology induced (hyperlipemia, diabetes or both simultaneously) a common dysfunctional response to PGF2alpha was installed; this consists in a reduced effect of cyclooxygenase inhibition, and a altered activity of Ca(2+) dependent K(+) channels.

Modifications of capsaicin-sensitive neurons in isolated guinea pig ileum by [6]-gingerol and lafutidine

A segment of guinea pig ileum was used to confirm the hypothesis that [6]-gingerol and lafutidine interact with capsaicin-sensitive neurons. Addition of 30 and 100 microM [6]-gingerol (a pungent constituent of ginger) induced contraction of the ileum immediately. Like capsaicin, [6]-gingerol-induced contraction was inhibited by antagonists of the vanilloid receptor (capsazepine and ruthenium red), tetrodotoxin, and atropine. Treatment with [6]-gingerol up to 0.3 microM, which alone had no effect, enhanced 3 microM capsaicin-induced contraction, but greater than 3 microM [6]-gingerol significantly inhibited capsaicin-induced contraction. Treatment with lafutidine (a new type of antagonist of the histamine H(2) receptor), which was suggested to interact with capsaicin-sensitive neurons in vivo, also showed both stimulatory and inhibitory effects on capsaicin-induced contraction depending on the concentrations. Lafutidine alone had no effect. The enhanced contraction induced by capsaicin in the [6]-gingerol- or lafutidine-treated ileum was also inhibited by antagonists of the vanilloid receptor, tetrodotoxin, and atropine. Capsaicin and [6]-gingerol, but not lafutidine, at 30 microM stimulated [(3)H]choline release from the prelabeled slices of the ileum. These findings suggest that [6]-gingerol and lafutidine act on capsaicin-sensitive cholinergic neurons and modulate the contraction in isolated guinea pig ileum.