Vinti Goel

Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial

Background: Upper respiratory tract infections are a major source of morbidity throughout the world. Extracts of the root of North American ginseng (Panax quinquefolium) have been found to have the potential to modulate both natural and acquired immune responses. We sought to examine the efficacy of an extract of North American ginseng root in preventing colds. Methods: We conducted a randomized, double-blind, placebo-controlled study at the onset of the influenza season. A total of 323 subjects 18–65 years of age with a history of at least 2 colds in the previous year were recruited from the general population in Edmonton, Alberta. The participants were instructed to take 2 capsules per day of either the North American ginseng extract or a placebo for a period of 4 months. The primary outcome measure was the number of Jackson-verified colds. Secondary variables measured included symptom severity, total number of days of symptoms and duration of all colds. Cold symptoms were scored by subjects using a 4-point scale. Results: Subjects who did not start treatment were excluded from the analysis (23 in the ginseng group and 21 in the placebo group), leaving 130 in the ginseng group and 149 in the placebo group. The mean number of colds per person was lower in the ginseng group than in the placebo group (0.68 [standard deviation (SD) 0.82] v. 0.93 [SD 0.91], difference 0.25%, 95% confidence interval [CI] 0.04–0.45). The proportion of subjects with 2 or more Jackson-verified colds during the 4-month period (10.0% v. 22.8%, 12.8% difference, 95% CI 4.3–21.3) was significantly lower in the ginseng group than in the placebo group, as were the total symptom score (77.5 [SD 84.6] v. 112.3 [SD 102.5], difference 1.5%, 95% CI 1.2–2.0) and the total number of days cold symptoms were reported (10.8 [SD 9.7] v. 16.5 [SD 13.8] days, difference 1.6%, 95% CI 1.3–2.0) for all colds. Interpretation: Ingestion of a poly-furanosyl-pyranosyl-saccharide–rich extract of the roots of North American ginseng in a moderate dose over 4 months reduced the mean number of colds per person, the proportion of subjects who experienced 2 or more colds, the severity of symptoms and the number of days cold symptoms were reported.

Alkylamides of Echinacea purpurea stimulate alveolar macrophage function in normal rats.

Echinacea plant extract is widely used for the prevention and the treatment of upper respiratory tract infections. However, the active components in the herb, their optimal dosages and their in vivo effects are still undefined. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of various dose levels of three components, isolated and purified from Echinacea purpurea. The components were cichoric acid, polysaccharides and alkylamides. The rats were gavaged orally two times/day for 4 days with three different concentrations of each of the Echinacea components. Among the components, alkylamides at the dose level of 12 microg/kg body weight/day significantly increased the phagocytic activity as well as phagocytic index of the alveolar macrophages. The alveolar macrophages obtained from this group of rats also produced significantly more TNF-alpha and nitric oxide after an in vitro stimulation with LPS than any other active component or the control. None of the components at any concentration had any effect on the release of TNF-alpha, IFN-gamma and IL-2 by the splenocytes. These results suggest that the alkylamides are one of the active constituents of E. purpurea plant. At a dose level of approximately 12 microg/kg body weight/day they effectively stimulate alveolar macrophage function in healthy rats. The immunomodulatory effects of alkylamides appear to be more pronounced in lungs than in spleen.

Efficacy of a standardized echinacea preparation (EchinilinTM) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial

Background:  Recently, echinacea has regained popularity as one of the treatments chosen most commonly by consumers with the expectation that it will reduce the severity and duration of the common cold. However, the results from a limited number of clinical trials for this application have thus far been inconclusive. This incongruity may be the result of investigators utilizing poorly standardized echinacea products, likely devoid of sufficient quantities of active constituents necessary to exert a definitive clinical effect. Therefore, a formulation containing alkamides, cichoric acid, and polysaccharides at concentrations of 0·25, 2·5, and 25 mg/mL, respectively, was prepared from freshly harvested Echinacea purpurea plants (commercially available as Echinilin, Natural Factors Nutritional Products, Inc., Vancouver, BC, Canada). The objective of this study was to test the efficacy of this highly standardized formulation in reducing the severity and duration of symptoms of a naturally acquired common cold.

Echinacea stimulates macrophage function in the lung and spleen of normal rats.

Echinacea plant extract has been used for immunostimulation for many years but the evidence supporting its therapeutic potential is still controversial. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of preparations of Echinacea containing its components cichoric acid, polysaccharides and alkylamides in different concentrations. The rats were gavaged orally with these preparations, two times/day for 4 days. Phagocytic activity of alveolar macrophage was increased with increasing concentrations of the Echinacea components. A trend of increase in TNF-alpha and nitric oxide release by the alveolar macrophages following an in vitro stimulation with LPS was also evident. An enhanced release of cytokines (such as TNF-alpha and IFN-gamma) in response to Echinacea components, was also apparent in rats spleen macrophage, but at higher concentrations. These results suggest that the Echinacea preparations containing optimal concentrations of cichoric acid, polysaccharides and alkylamides are potentially effective in stimulating an in vivo, non-specific immune response in normal rats.

Dietary rhubarb ( Rheum rhaponticum ) stalk fibre stimulates cholesterol 7α-hydroxylase gene expression and bile acid excretion in cholesterol-fed C57BL/6J mice

Both experimental and clinical studies have indicated that a novel source of dietary fibre, produced from rhubarb (Rheum rhaponticum) stalks, is potentially hypolipidaemic. The present study, using C57BL/6J mice, was undertaken to examine if this fibre source affects cholesterol degradation. Mice were maintained on semi-purified diets containing 50 g rhubarb fibre or cellulose/kg with or without 5 g cholesterol/kg for 4 weeks. In cholesterol-supplemented mice, rhubarb fibre caused significant lowering of plasma cholesterol (-13%) and the hepatic concentrations of total cholesterol (-34%) and cholesteryl esters (-34%). In parallel to the reduction of hepatic cholesteryl ester content, animals fed on rhubarb fibre had significantly lower activity of acyl CoA: cholesterol acyltransferase (EC 2.3.1.26) than the mice maintained on a diet containing cellulose and cholesterol. Rhubarb-fibre feeding accelerated the faecal bile-acid loss and diminished the gall-bladder bile-acid pool in both the normal and the cholesterol-fed mice. The increase in the bile-acid excretion was positively correlated with an increased activity as well as mRNA abundance of cholesterol 7 alpha-hydroxylase (EC 1.14.13.17). The increased excretion of bile acids and induction of cholesterol 7 alpha-hydroxylase activity may account for the hypocholesterolaemic effect of rhubarb fibre.

Cholesterol lowering effects of rhubarb stalk fiber in hypercholesterolemic men

OBJECTIVE The present study was undertaken to examine the lipid lowering effects of rhubarb fiber prepared by blanching and drying fresh rhubarb stalks. The new fiber source contained 74% dietary fiber, on dry weight basis, with 66% insoluble and 8% soluble fiber. DESIGN Ten hypercholesterolemic men were assigned to consume 27 g of ground rhubarb stalk fiber per day for 4 weeks. The dietary intake in terms of total energy, lipid and cholesterol was kept unaltered during the study period. Changes in serum lipid profile were monitored by obtaining blood samples before and after the fiber intervention. RESULTS Rhubarb fiber supplementation resulted in significant lowering of serum total cholesterol (8%) and low-density lipoprotein (LDL) cholesterol (9%), while high-density lipoprotein cholesterol (HDL) concentrations remained unchanged. The depressed total and LDL cholesterol levels returned to baseline after the fiber supplementation was withdrawn for 1 month. CONCLUSION The rhubarb stalk fiber is effective in lowering serum cholesterol concentrations, especially LDL cholesterol, in hypercholesterolemic men. These results signify the potential use of underutilized rhubarb crop.

In vitro binding of bile salt to rhubarb stalk powder

Abstract A new fiber source was developed by blanching, drying and grinding the fresh stalks of rhubarb, an underutilized and universal crop. The product was found to contain 74% total dietary fiber (66% insoluble and 8% soluble dietary fiber), on dry weight basis. Preliminary studies involving experimental animals and hypercholesterolemic subjects revealed that this fiber source is potentially hypolipidemic, though the underlying mechanism still remains unknown. To investigate its mechanism of action, this study was undertaken to determine its potential to complex with bile salts in vitro . Comparison of various fiber sources showed that the rhubarb fiber had the maximum ability to bind taurocholate, and bound 11 and 2.5 fold more bile salt than cellulose and wheat bran respectively. The binding increased linearly with increasing rhubarb fiber concentration. Increasing the bile salt concentration also increased the binding in a dose dependent manner and showed a saturation at a concentration greater than 10mM. The rhubarb fiber had a binding capacity of 40 μmol of taurocholate per gram. Cholate competed taurocholate for binding indicating that conjugation of bile salt was not a mandatory requirement for the binding Based on the chemical composition of rhubarb stalk powder, the bile salt binding property appears to be due to a combination of factors present in this product such as its high fiber content (insoluble with pectin), hydrophilic nature and high ash content. The ability to bind bile salts might be responsible for its hypocholesterolemic action observed in experimental animals and humans.

Dietary rhubarb (Rheum rhaponticum ) stalk fibre does not lower plasma cholesterol levels in diabetic rats

Rhubarb (Rheum rhapontiam) stalk fibre was previously shown to be hypolipidaemic under clinical and experimental conditions. The present study was undertaken to investigate whether rhubarb stalk fibre has a hypolipidaemic effect under diabetic conditions. Two models of diabetic rats were used: streptozotocin-induced diabetic rats, and diabetes-prone BB (BBdp) rats. The plasma cholesterol and triacylglycerol concentrations were elevated after the onset of diabetes in BBdp rats, but not in sterptozotocin-induced diabetic rats. The rhubarb-fibre diet had no effect on the plasma cholesterol or triacylglycerol concentrations of diabetic rats. The hypolipidaemic effect of rhubarb stalk fibre has been suggested to be due to the bile-acid-binding capacity of rhubarb fibre, which in turn up regulates cholesterol 7alpha-hydroxylase (cyp7a) activity. cyp7a is the first and the rate-limiting enzyme in the breakdown of cholesterol to bile acids. We measured the cyp7a activity and mRNA levels in control and diabetic rats fed rhubarb- and cellulose-fibre diets. The cyp7a activity and mRNA abundance were increased in both diabetic rat models, indicating that bile acid synthesis is enhanced in diabetes. Feeding a diet enriched with rhubarb fibre caused a slight but significant increase (P<0.05) in cyp7a enzyme activity in BBdp rats, but no change in cyp7a mRNA abundance was detected. These results suggest that although a rhubarb-fibre-enriched diet increased cyp7a activity in BBdp rats, there was no apparent therapeutic benefit in terms of lowering plasma cholesterol concentrations.

Effect of dietary rhubarb stalk fiber on the bioavailability of calcium in rats

Ground rhubarb stalk fiber containing, on a dry weight basis, 74% total dietary fiber (66% insoluble and 8% soluble) was prepared from rhubarb plants. This fiber source has been shown to have a pronounced lipid lowering effect in mice. Its high oxalic acid content may, however, be a limiting factor for its use. The present study was undertaken to determine the safe dose level of the fiber in terms of its effect on calcium bioavailability. Male weanling Sprague-Dawley rats were fed a semi-purified diet (AIN 76) for 4 weeks containing 0, 1, 3, or 5% rhubarb fiber, or pure oxalic acid equivalent to 5% rhubarb fiber. The fiber content of each diet was brought to 5% by adding cellulose, and the calcium level of all diets was the same. As the rhubarb stalk fiber content of the diet increased, a consistent trend of increasing total retention and apparent absorption of calcium was manifested. In contrast, however, cellulose, due to its increased effect on intestinal motility resulted in a decreased calcium bioavailability. Overall results suggest that an addition of rhubarb stalk powder up to the level of 5% in a diet does not have detrimental effect on calcium bioavailability.