American ginseng (Panax quinquefolius L) reduces postprandial glycemia in nondiabetic subjects and subjects with type 2 diabetes mellitus

MDR- and CYP3A4-mediated drug–herbal interactions

According to recent epidemiological reports, almost 40% of American population use complimentary and alternative medicine (CAM) during their lifetime. Patients detected with HIV or cancer often consume herbal products especially St. John's wort (SJW) for antidepressants in combination with prescription medicines. Such self-administered herbal products along with prescribed medicines raise concerns of therapeutic activity due to possible drug-herbal interactions. P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4) together constitute a highly efficient barrier for many orally absorbed drugs. Available literature, clinical reports and in vitro studies from our laboratory indicate that many drugs and herbal active constituents are substrates for both P-gp and CYP3A4. Results from clinical studies and case reports indicate that self-administered SJW reduce steady state plasma concentrations of amitriptyline, cyclosporine, digoxin, fexofenadine, amprenavir, indonavir, lopinavir, ritonavir, saquinavir, benzodiazepines, theophyline, irinotecan, midazolan and warfarin. This herbal agent has been also reported to cause bleeding and unwanted pregnancies when concomitantly administered with oral contraceptives. Most of these medicinal agents and SJW are substrates for P-gp and/or CYP3A4. In vitro studies from our laboratory suggest that short-term exposure with pure herbal agents such as hypericin, kaempferol and quercetin or extract of SJW resulted in higher uptake or influx of ritonavir and erythromycin. Hypericin, kaempferol and quercetin also caused a remarkable inhibition of cortisol metabolism with the percent intact cortisol values of 64.58%, 89.6% and 90.1%, respectively, during short-term in vitro experiments. Conversely, long-term exposure of herbal agents (hyperforin, kaempferol and quercetin) showed enhanced expression of CYP3A4 mRNA in Caco-2 cells. In another study, we observed that long-term exposure of hypericin, kaempferol, quercetin and silibinin resulted in higher MDR-1 mRNA expression in Caco-2 cells. Therefore, herbs can pharmacokinetically act as inhibitors or inducers. Medicinal agents that are substrates P-gp-mediated efflux and/or CYP-mediated metabolism are likely to be potential candidates for drug-herbal interactions. The duration of exposure of cells/healthy volunteers/animals to herbals appears to be critical for drug-herbal interaction. An increase in plasma drug concentration is possible during concomitant administration of SJW and prescribed drugs. In contrast, prolonged intake of herbal supplement followed by drug administration may result in subtherapeutic concentrations. Therefore, clinical implications of such drug herbal interactions depend on a variety of factors such as dose, frequency and timing of herbal intake, dosing regimen, route of drug administration and therapeutic range. In vitro screening techniques will play a major role in identifying possible herb-drug interactions and thus create a platform for clinical studies to emerge. Mechanisms of drug-herbal interaction have been discussed in this review article.

Ginseng extract inhibits lipolysis in rat adipocytes in vitro by activating phosphodiesterase 4

Elevated concentrations of plasma free fatty acids (FFA) may cause insulin resistance. Inhibition of lipolysis reduces FFA availability and improves insulin sensitivity. Ginseng extract (Panax spp., GE) was shown to improve glycemia in Type 2 diabetes. In the present study, the antilipolytic effect of GE in rat adipocytes and the signaling pathway for GE antilipolysis were investigated. Adipocytes were isolated from rat fat tissue by collagenase digestion. The ability of GE to inhibit lipolysis was assessed by measuring glycerol and FFA release into the incubation medium. Phosphatidylinositol 3-kinase (PI3-K) inhibitor and various phosphodiesterase (PDE) inhibitors were applied to investigate the signaling pathway for GE antilipolysis. The present study showed that insulin and GE inhibited lipolysis by 42.4 and 49% compared with basal, respectively (P < 0.05). Unlike insulin, the PI3-K inhibitor wortmannin did not reverse GE antilipolysis, and GE did not affect phosphorylation of protein kinase B (PKB). The nonselective PDE inhibitor enprofylline reversed both insulin and GE antilipolysis. The specific phosphodiesterase 3 (PDE3) inhibitor cilostamide reversed insulin antilipolysis completely, but did not significantly affect GE antilipolysis. The specific phosphodiesterase 4 (PDE4) inhibitor rolipram did not significantly affect insulin antilipolysis, but almost completely reversed GE antilipolysis. Moreover, the combination of PDE3 and PDE4 inhibitors completely reversed GE antilipolysis. None of the ginsenosides (Rb1, Re, Rg1, Rc, Rb2, and Rd) were responsible for GE antilipolysis. The results suggest that ginseng exerts its antilipolytic effect through a signaling pathway different from that of insulin. GE antilipolysis is mediated in part by activating PDE4 in rat adipocytes.

Ginseng and diabetes

Ginseng is a well-known medicinal plant used in traditional Oriental medicine. In recent decades, ginseng root has gained popularity as a dietary supplement in the United States. Ginseng has also been commonly used in Oriental medicine to treat diabetes-like conditions. The present review discusses the research on the anti-diabetic effects of ginseng and the possible mechanisms of its anti-diabetic actions.

Systematic review of the effects of ginseng on cardiovascular risk factors

OBJECTIVE

To examine the evidence for the efficacy of ginseng (Panax spp.) on cardiovascular risk factors, including blood pressure, lipid profiles, and blood glucose, and to summarize reported cardiovascular adverse events.

DATA SOURCES

We searched MEDLINE, AMED, BIOSIS, CAB, EMBASE, and the Cochrane Controlled Trials databases through July 2005 and performed hand searches of bibliographies.

STUDY SELECTION AND DATA EXTRACTION

Short- or long-term, randomized, controlled trials and nonrandomized studies published in English were included. Data were extracted in a standardized manner, and 2 independent investigators assessed methodologic quality of the studies. Thirty-four studies were identified with results for blood pressure, lipids, and/or blood glucose. Due to heterogeneity of the studies, we were unable to perform a meta-analysis. Data on cardiovascular adverse events were extracted from events reported in identified studies and from case reports.

DATA SYNTHESIS

The majority of studies were short term. Ginseng may slightly decrease blood pressure compared with placebo (range 0-4%). We found mixed results for an effect on lipids, with 5 of 9 studies showing improvement in one or more lipid parameters compared with baseline (range 7-44%). We identified several studies showing that ginseng lowers blood glucose, but overall studies were inconsistent.

CONCLUSIONS

Current evidence does not support the use of ginseng to treat cardiovascular risk factors. Some studies suggest a small reduction in blood pressure. Despite some evidence showing that ginseng lowers blood glucose and improves lipid profiles, well-designed, randomized, controlled trials evaluating its effects are lacking.

Conduite à tenir concernant le traitement médicamenteux des patients adressés pour chirurgie programmée

This review focuses on potential drug interactions between anaesthetic drugs or techniques and chronic medications in patients scheduled for surgery. The vast majority of therapeutics can be continued until the morning of surgery. However, for some drugs such as ACE inhibitors, there is strong evidence to recommend their discontinuation prior to surgery. When juged necessary, interruption of chronic therapeutic needs to be anticipated and planned. In the other hand, for other drugs such as beta-blockers or L-Dopa, acute withdrawal is associated with documented adverse outcome. As a result, such drugs have to be continuing throughout the operative period. Although a general consensus exists for many medications, there are still controverses as to the management of antithrombotic drugs and some central nervous system agents. Advances in anaesthesia include knowledge on the mechanisms involved in drug interactions, which allows us to improve the preoperative management of chronic therapeutics.

The systemic theory of living systems and relevance to CAM: the theory (Part III)

Western medical science lacks a solid philosophical and theoretical approach to disease cognition and therapeutics. My first two articles provided a framework for a humane medicine based on Modern Biophysics. Its precepts encompass modern therapeutics and CAM. Modern Biophysics and its concepts are presently missing in medicine, whether orthodox or CAM, albeit they probably provide the long sought explanation that bridges the abyss between East and West. Key points that differentiate Systemic from other systems' approaches are ‘Intelligence’, ‘Energy’ and the objective ‘to survive’. The General System Theory (GST) took a forward step by proposing a departure from the mechanistic biological concept—of analyzing parts and processes in isolation—and brought us towards an organismic model. GST examines the system's components and results of their interaction. However, GST still does not go far enough. GST assumes ‘Self-Organization’ as a spontaneous phenomenon, ignoring a causative entity or central controller to all systems: Intelligence. It also neglects ‘Survive’ as the directional motivation common to any living system, and scarcely assigns ‘Energy’ its true inherent value. These three parameters, Intelligence, Energy and Survive, are vital variables to be considered, in our human quest, if we are to achieve a unified theory of life.

Botanical dietary supplements and the treatment of diabetes: what is the evidence?

With the increase in cases of diabetes, many patients are using dietary supplements in an attempt to improve diabetes control. It is estimated that one third of patients with diabetes use some type of dietary supplement or complementary and alternative medicine treatment. Dietary supplements have active pharmacologic ingredients that are not only responsible for their theorized mechanisms in lowering blood glucose, but that are also responsible for adverse effects and drug interactions. Clinicians and patients alike should be aware of which botanical products are currently being used in diabetes care and what adverse effects and monitoring parameters should be considered.

Antihyperglycemic effects of total ginsenosides from leaves and stem of Panax ginseng

AIM

The antihyperglycemic effects of the total ginsenosides in Chinese ginseng (TGCG), extracted from leaves and the stem, were evaluated in diabetic C57BL/6J ob/ob mice.

METHODS

Animals received daily intraperitoneal injections of TGCG (100 and 200 mg/kg) or oral administration (150 and 300 mg/kg) for 12 d. Fasting blood glucose levels and body weight were measured after fasting the animals for 4 h. Peripheral glucose use was also measured using an intraperitoneal glucose tolerance test.

RESULTS

In the injection group, a high dose of TGCG (200 mg/kg) significantly lowered the fasting blood glucose levels in ob/ob mice on d 12 (153+/-16 mg/dL vs 203+/-9.8 mg/dL, P<0.01, compared to vehicle-treated group). In the oral group, blood glucose decreased notably with a dose of TGCG (300 mg/kg) on d 12 (169.1+/-12.6 mg/dL vs 211.6+/-13.8 mg/dL, P<0.05, compared to the vehicle-treated group). Glucose tolerance was also improved markedly in ob/ob mice. Furthermore, a significant reduction in bodyweight (P<0.05) was observed after 12 d of TGCG (300 mg/kg) treatment in mice from the oral group.

CONCLUSION

The results indicated that in a diabetic ob/ob mouse model TGCG was endowed with significant anti-hyperglycemic and anti-obesity properties. Therefore, the total ginsenosides extracted from Chinese ginseng leaves and the stem may have some potential for treating diabetes.

North American ginseng exerts a neutral effect on blood pressure in individuals with hypertension

An early observational study suggested that ginseng could elevate blood pressure. This caused concern because 4.5% of American adults use ginseng, with a popular choice being North American ginseng. To date, North American ginseng lacks hemodynamic evaluation; therefore, we conducted a randomized, double-blinded, controlled trial to investigate its effect on blood pressure in 16 hypertensive individuals (mean+/-SD age 61.1+/-8.1 years; systolic/diastolic blood pressure 132.4+/-12.8/83.3+/-8.1 mm Hg; 13 on antihypertensives). We used 6 batches of North American ginseng root that varied in quality and ginsenoside content, representing the spectrum of this ginseng on the market. On 8 mornings, each participant was fitted with an ambulatory blood pressure monitor, which measured blood pressure during a 30-minute baseline period. Each participant then consumed in a randomized and double-blind fashion 3 g of encapsulated treatment: placebo (on 2 mornings) or powdered North American ginseng (on 6 mornings). After treatment, blood pressure was measured every 10 minutes for 160 minutes, and its change at each post-treatment time point relative to baseline was determined per individual and averaged, and the mean was obtained for the overall 160-minute period. None of the North American ginsengs or their mean differed from placebo in their effect on overall (160 minutes) mean blood pressure change. None affected blood pressure versus placebo at the 10-minute intervals; but their mean versus placebo increased systolic and diastolic blood pressure at 140 and 160 minutes, respectively, and lowered diastolic blood pressure at 100 minutes. The findings together suggested that North American ginseng exerts a neutral acute effect on blood pressure in hypertensive individuals.

Use of alternative medicine by patients with stage 5 chronic kidney disease

The use of complementary and alternative medicine (CAM) in the United States is growing at a remarkable speed. Herbal products and dietary supplements are CAM therapies that have grown faster than any other CAM treatments. Little information is available about herbs and dietary supplement use in the stage 5 chronic kidney disease population. These products contain a myriad of pharmacologically active compounds that, when used by people with kidney disease, may be hazardous. Members of the renal dietitian listserv were queried about herbs and dietary supplements reportedly used by dialysis patients. Up-to-date information on the use, safety, efficacy, adverse effects, and recommended dosages in the nondialysis population are presented for 24 products. In the dialysis population, Noni juice should be avoided because of its high potassium content. In addition, bulk-forming laxatives such as flaxseed should be used with caution because of the need for increased fluid intake. Dialysis practitioners should include specific questions about herbs and dietary supplement use in medical and nutrition histories, and they should increase their knowledge about these products to advise patients appropriately. A list of reliable sources of information for the health care provider on herbs and dietary supplements is also presented.

Single doses of Panax ginseng (G115) reduce blood glucose levels and improve cognitive performance during sustained mental activity

Single doses of the traditional herbal treatment Panax ginseng have recently been shown to elicit cognitive improvements in healthy young volunteers. The mechanisms by which ginseng improves cognitive performance are not known. However, they may be related to the glycaemic properties of some Panax species. Using a double-blind, placebo-controlled, balanced crossover design, 30 healthy young adults completed a 10 min test battery at baseline, and then six times in immediate succession commencing 60 min after the day's treatment (placebo, 200mg G115 or 400mg G115). The 10 min battery comprised a Serial Threes subtraction task (2 min); a Serial Sevens task (2 min); a Rapid Visual Information Processing task (5 min); then a 'mental fatigue' visual analogue scale. Blood glucose was measured prior to each day's treatment, and before, during and after the post-dose completions of the battery. Both the 200mg and 400mg treatments led to significant reductions in blood glucose levels at all three post-treatment measurements (p 0.005 in all cases). The most notable behavioural effects were associated with 200mg of ginseng and included significantly improved Serial Sevens subtraction task performance and significantly reduced subjective mental fatigue throughout all (with the exception of one time point in each case) of the post-dose completions of the 10 min battery (p 0.05). Overall these data suggest that Panax ginseng can improve performance and subjective feelings of mental fatigue during sustained mental activity. This effect may be related to the acute gluco-regulatory properties of the extract.

Herbal remedies in the management of diabetes: lessons learned from the study of ginseng

The only example of an approved antidiabetic drug that was developed from a herbal source with a long history of use for diabetes is the biguanide Metformin from French lilac (Galega officinalis). Clinical data are beginning to emerge that support antidiabetic indications for several other herbs. This viewpoint discusses the state of the evidence for their clinical antidiabetic efficacy. One of the most studied herbs, ginseng (Panax spp.), is used as a model to illustrate the challenges associated with achieving reproducible clinical efficacy. It is concluded that the best evidence for clinical efficacy in diabetes remains for ginseng. But overall insufficient evidence exists to claim a diabetes indication for herbs. The experience with ginseng suggests that although reproducible efficacy may be achieved using an acute postprandial clinical screening model to select an efficacious ginseng batch, dose, and time of administration, there is a need to develop a basis for standardization that ties the composition of herbs to efficacy. In absence of such standardization, the use of herbs in diabetes must be approached cautiously.

Anti-diabetic effect of ginsenoside Re in ob/ob mice

We evaluated the anti-diabetic effects of ginsenoside Re in adult male C57BL/6J ob/ob mice. Diabetic ob/ob mice with fasting blood glucose levels of approximately 230 mg/dl received daily intraperitoneal injections of 7, 20 and 60 mg/kg ginsenoside Re for 12 consecutive days. Dose-related effects of ginsenoside Re on fasting blood glucose levels were observed. After the 20 mg/kg treatment, fasting blood glucose levels were reduced to 188+/-9.2 and 180+/-10.8 mg/dl on Day 5 and Day 12, respectively (both P<0.01 compared to vehicle group, 229+/-9.5 and 235+/-13.4 mg/dl, respectively). The EC(70) of ginsenoside Re was calculated to be 10.3 mg/kg and was used for subsequent studies. Consistent with the reduction in blood glucose, there were significant decreases in both fed and fasting serum insulin levels in mice treated with ginsenoside Re. With 12 days of ginsenoside treatment, glucose tolerance of ob/ob mice increased significantly, and the area under the curve for glucose decreased by 17.8% (P<0.05 compared to vehicle treatment). The hypoglycemic effect of the ginsenoside persisted even at 3 days of treatment cessation (blood glucose levels: 198+/-13.1 with ginsenoside treatment vs. 253+/-20.3 mg/dl with vehicle, P<0.01). There were no significant changes in body weight or body temperature. Preliminary microarray analysis revealed differential expression of skeletal muscle genes associated with lipid metabolism and muscle function. The results suggest that ginsenoside Re may prove to be useful in treating type 2 diabetes.

Mycotoxins in root extracts of American and Asian ginseng bind estrogen receptors alpha and beta

The estrogenic activity of ginseng has been the subject of conflicting reports. Cell proliferation, induction of estrogen-responsive genes, and isolated cases of adverse reactions such as postmenopausal vaginal bleeding and gynecomastia have been reported after ginseng treatment. Other studies report antiproliferative effects with no induction of estrogen-responsive genes. We developed estrogen receptor (ER) alpha and ER alpha competitive binding assays using recombinant receptors and [(3)H]-17 alpha-estradiol to detect phytoestrogens in extracts of Asian ginseng root (Panax ginseng C. A. Meyer) and American ginseng root (Panax quinquefolius L.). Root extracts contained substances that bound both receptor isoforms. These substances had a two to three times greater affinity for ER alpha. Significantly higher binding was found in methanol extracts than in hot water extracts. Subsequent analysis of the extracts revealed significant ER binding attributable to zearalenone, the estrogenic mycotoxin produced by several Fusarium species. The ER showed no binding affinity for Rb1 and Rg1, the major ginsenosides found in P. quinquefolius and P. ginseng, respectively. Thus, ginseng extraction methods, plant species tested, and mycotoxin contaminants may help to explain the disparate literature reports. The prevalence and health significance of fungal contamination in herbal products used for medicinal purposes should be further investigated.

Decreasing, Null and Increasing Effects of Eight Popular Types of Ginseng on Acute Postprandial Glycemic Indices in Healthy Humans: The Role of Ginsenosides

BACKGROUND

It is unclear whether other ginseng sources can replicate the glycemic-lowering efficacy observed previously with American ginseng and whether ginsenosides are mediators. We assessed the effect of eight popular ginseng types on postprandial plasma glucose (PG) and insulin (PI) indices, linking effects to ginsenoside profiles.

METHODS

Using a double-blind, randomized, multiple-crossover design, 12 healthy participants (gender: 6M:6F, age: 34 +/- 3 y, BMI: 25.8 +/- 1.2 kg/m(2)) received 10 3g treatments: American, American-wild, Asian, Asian-red, Vietnamese-wild, Siberian, Japanese-rhizome, and Sanchi ginsengs and two placebos. Each treatment was given 40-minutes before a 75g-oral-glucose-tolerance-test (75g-OGTT) with blood drawn at -40, 0, 15, 30, 45, 60, 90, 120-minutes. HPLC-UV analysis quantified seven principal ginsenosides.

RESULTS

Two-factor analysis showed the main effects of ginseng-type and time were significant for PG and PI, with an interaction for PG (p < 0.05). Subsequent one-factor analysis showed an effect of ginseng-type on 90-min-PG and 90-min-PI (p < 0.05). This was reflected in effects on peak-PG, area under the curve (AUC)-PG and AUC-PI (p < 0.05). But the effect on 90-min-PI and AUC-PI were significant (p < 0.05) only in overweight participants (BMI > 25 kg/m(2), n = 6). Planned comparisons with placebo showed a tendency for American ginseng and Vietnamese ginseng to lower 90-min-PG (p < 0.06), while Asian ginseng raised peak-PG and AUC-PG, American-wild ginseng raised 120-min-PG, and Siberian ginseng raised 90-min-PG, 120-min-PG, and AUC-PG (p < 0.05). Stepwise-multiple-regression assessed the protopanaxadiol:protopanaxatriol (PPD:PPT)-ginsenoside ratio as the sole predictor (p < 0.05) for 90-min-PG (beta = -0.43, r(2) = 0.072), AUC-PG (beta = -0.25, r(2) = 0.06), 90-min-PI (beta = -0.26, r(2) = 0.065), AUC-PI (beta = -0.20, r(2) = 0.04).

CONCLUSIONS

Ginseng has variable glycemic effects, in which the PPD:PPT-ginsenoside ratio might be involved. But the low variance explained suggests the involvement of other unmeasured ginsenoside or non-ginsenoside components.

Effect and putative mechanism of action of ginseng on the formation of glycated hemoglobin in vitro

As a non-enzymatic, covalent binding between glucose and protein, glycation is a well-known cause of various forms of diabetic complications. This study was undertaken to determine the effect and mechanism of action of ginseng on the formation of glycated protein. A solution containing hemoglobin and glucose was incubated for 5 days by adding ginseng extract or glutathione. The quantitative measurement of glycated hemoglobin was determined using the ion capture component set. The anti-oxidative effect of ginseng and quercetin was determined through the TBA method. The amount of glycated hemoglobin (%GHb) significantly increased with the addition of glucose (27.8 mM) compared to the non-addition group. Nonetheless, this significantly decreased when ginseng extract (2 g/dl) was added and further dropped when glutathione (50 mM) was added. The amount of hemoglobin A1c (%HbA1c), a sub-fraction of glycated hemoglobin, was lower than that of glycated hemoglobin, but it showed a similar tendency. Compared to a non-addition group, the optical density of the organic layer that was separated through the addition of chloroform in oxidized linoleic acid significantly and dose-dependently decreased when ginseng extract or quercetin was added. These results suggest that the inhibitory effect of ginseng on the formation of glycated hemoglobin could be attributed to the anti-oxidative activity of ginseng.

Anti-hyperglycemic effect of the polysaccharides fraction from American ginseng berry extract in ob/ob mice

In this study, we evaluated the anti-hyperglycemic effect of a polysaccharides fraction from American ginseng berry extract in diabetic ob/ob mice. All animals received daily intraperitoneal injections of polysaccharides at 150 mg/kg body wt. (n = 5), polysaccharides at 50 mg/kg body wt. (n = 5), or vehicle (n = 5) for 10 consecutive days. On Day 5, as compared to the vehicle-treated mice (230.5 +/- 13.5 mg/dl, mean +/- S.E), mice from both treated groups showed significantly lower fasting blood glucose levels (187.4 +/- 20.5 mg/dl and 187.4 +/- 17.1 mg/dl), respectively (both P < 0.05). On Day 10, compared to the vehicle group (240.1 +/- 12.3 mg/dl), the 50 mg/kg dose group were at 188.4 +/- 12.6 mg/dl (P < 0.05), and the 150 mg/kg dose group were normoglycemic (148.8 +/- 17.6 mg/dl, P < 0.01). Those ob/ob mice treated with vehicle did not, however, show significant changes in fasting blood glucose levels. Data from the intraperitoneal glucose tolerance test (IPGTT) showed that, compared to Day 0, there was a significant improvement in glucose tolerance in animals who received the 50 and 150 mg/kg polysaccharide doses, and the area under the curve (AUC) decreased 15.5% (P < 0.05) and 28.2% (P < 0.01), respectively. Interestingly, after cessation of polysaccharide treatment, the fasting blood glucose levels stayed lower, and returned to control concentration on Day 30. We also observed that the polysaccharides fraction did not affect body weight changes in ob/ob mice. Our data suggest that the polysaccharides fraction from American ginseng berry extract has a potential clinical utility in treating diabetic patients.

Chinese herbal medicines for type 2 diabetes mellitus

BACKGROUND

Traditional Chinese herbal medicines have been used for a long time to treat diabetes, and many controlled trials have been done to investigate their efficacy.

OBJECTIVES

To assess the effects of Chinese herbal medicines in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

We searched the following electronic databases: The Cochrane Library (CENTRAL), the Chinese BioMedical Database, MEDLINE, EMBASE, and LILACS, combined with hand searches on Chinese journals and conference proceedings. Date of last search was April 2004. No language restriction was used.

SELECTION CRITERIA

Randomised trials of herbal medicines (with at least two months treatment duration) compared with placebo, pharmacological or non-pharmacological interventions were included.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers. The methodological quality of trials was evaluated using the parameters of randomisation, allocation concealment, double blinding, and drop-out rates. Meta-analyses were performed where data were available.

MAIN RESULTS

Sixty-six randomised trials, involving 8302 participants, met the inclusion criteria. Methodological quality was generally low. Sixty-nine different herbal medicines were tested in the included trials, which compared herbal medicines with placebo, hypoglycaemic drugs, or herbal medicines plus hypoglycaemic drugs. Compared with placebo, Holy basil leaves, Xianzhen Pian, Qidan Tongmai, traditional Chinese formulae (TCT), Huoxue Jiangtang Pingzhi, and Inolter showed significantly hypoglycaemic response. Compared with hypoglycaemic drugs including glibenclamide, tolbutamide, or gliclazide, seven herbal medicines demonstrated a significant better metabolic control, including Bushen Jiangtang Tang, Composite Trichosanthis, Jiangtang Kang, Ketang Ling, Shenqi Jiangtang Yin, Xiaoke Tang, and Yishen Huoxue Tiaogan. In 29 trials that evaluated herbal medicines combined with hypoglycaemic drugs, 15 different herbal preparations showed additional better effects than hypoglycaemic drugs monotherapy. Two herbal therapies combined with diet and behaviour change showed better hypoglycaemic effects than diet and behaviour change alone. No serious adverse effects from the herbal medicines were reported.

REVIEWERS' CONCLUSIONS

Some herbal medicines show hypoglycaemic effects in type 2 diabetes. However, these findings should be carefully interpreted due to the low methodological quality, small sample size, and limited number of trials. In the light of some positive findings, some herbal medicines deserve further examination in high-quality trials.

Null and Opposing Effects of Asian Ginseng (Panax ginsengC.A. Meyer) on Acute Glycemia: Results of Two Acute Dose Escalation Studies

OBJECTIVE

We have repeatedly reported that a batch of American ginseng with a specific ginsenoside (glycosidal saponin) profile decreases acute postprandial glycemia. We investigated whether Asian ginseng is able to replicate this glycemia-lowering efficacy in two separate acute dose escalation studies.

METHODS

Each study was conducted in a separate sample of 11 healthy subjects (gender: 8M:3F and 6M:5F, age: 29 +/- 2y and 27 +/- 3y, BMI: 28.5 +/- 2.1 kg/m(2) and 26.9 +/- 1.4 kg/m(2)) using a randomized, single-blind, placebo-controlled, multiple-crossover design. Treatments consisted of 0 (placebo), 1, 2, and 3 g of Asian ginseng for the first study and 0 (placebo), 3, 6, and 9 g Asian ginseng for the second study administered 40 minutes before a 75g-OGTT protocol with blood drawn at -40, 0, 15, 30, 45, 60, 90, and 120 minutes. Ginsenosides were analyzed by HPLC-UV.

RESULTS

Neither the main effect of pooled-treatment, nor dose, nor either factors interaction with time was significant for incremental plasma glucose and insulin. But the diagnostically and therapeutically relevant two-hour plasma glucose (2h-PG) value was significantly higher for pooled Asian ginseng treatment than placebo (5.46 +/- 0.31 versus 4.99 +/- 0.30 mmol/L, p = 0.050). Ginsenoside analyses showed that the Asian ginseng contained up to 96% lower and sevenfold higher quantities of various ginsenosides and their ratios than our previous efficacious batch of American ginseng.

CONCLUSIONS

Asian ginseng showed both null and opposing effects on indices of acute postprandial plasma glucose and insulin. This is in contrast to our findings with American ginseng. One explanation may be the marked ginsenoside differences. Practitioners and consumers should be aware of ginseng's variable effects.

Herb use in critical care: what to watch for

The use of herbal remedies for well-being and treatment of illness has occurred for thousands of years. Although herbal remedies frequently are misconceptually considered to be safe because they are natural, herbal medicines can cause severe or toxic effects if not used appropriately. This article discusses implications that healthcare providers need to consider when patients are admitted to critical care units due to herbal interactions or when patients and families request to maintain patients' herbal regimens during a critical illness.

Ginseng: potential for the enhancement of cognitive performance and mood

Ginseng has been used medicinally in the Far East for several millennia and is currently one of the most widely taken herbal products throughout the world. It has been attributed with a plethora of physiological effects that could potentially benefit cognitive performance or mood. Studies involving animals show that ginseng and its constituent ginsenosides can modulate indices of stress, fatigue, and learning. However, there is a lack of adequately controlled research showing behavioural effects following chronic administration to humans. Recent research has demonstrated that single doses of ginseng most notably engender cognitive benefits in terms of improved memory, but can also be associated with 'costs' in terms of attention task deficits following less mnemonically beneficial doses. A single dose of ginseng has also been shown to modulate cerebroelectrical (EEG) activity. It is suggested that ginseng would benefit from rigorous research further delineating its acute effects and exploring the relationship between acute effects and those seen during and following chronic administration regimens.

Effects of American ginseng berry extract on blood glucose levels in ob/ob mice

In this study, we evaluated antihyperglycemic effects of American ginseng berry extract in diabetic ob/ob mice. Animals received daily intraperitoneal (IP) injections of the extract 150 mg/kg for 12 days. On days 5 and 12, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to day 0 (both p < 0.05). Glucose tolerance improved significantly, which was shown by overall glucose excursion, calculated as area under the curve (AUC) during the two-hour IP glucose tolerance test. The AUC decreased by 31.8% on day 12 compared to day 0 (p < 0.01). In addition, after 12 days of the berry extract treatment, a significant reduction in body weight (p < 0.01 compared to day 0) and a significant increase in body temperature (p < 0.01 compared to day 0) was noticeable. Our results support in vivo antihyperglycemic and antiobese activity of American ginseng berry extract that may prove to be of clinical importance in the prevention and treatment of Type 2 diabetes.

Herbs commonly used by women: an evidence-based review

OBJECTIVE

To review the evidence of herbs commonly used by women.

DATA SOURCES

Articles were located by searching Medline, Cochrane Database of Systemic Reviews, and the Combined Health Information Database and by hand searching the reference lists of recent systematic reviews. The databases were searched in January 2000 and October 2000 by using the Latin and common name of each herb.

METHODS OF STUDY SELECTION

Preference was given to randomized, placebo-controlled trials. When available, English language studies were reviewed. If not, data are presented from review articles that summarize the foreign study.

RESULTS

Many women use herbal therapies. In the United States, herbs are considered dietary supplements. The Food and Drug Administration (FDA) cannot remove them from the market unless they are proven unsafe. The herb industry plans to improve monitoring. Many prospective randomized controlled trials are being funded. Gingko biloba seems to slow the progression of dementia but increases the risk of bleeding. St John's Wort is efficacious for treating mild to moderate depression but has many drug interactions. Ginseng seems to improve well being in perimenopausal women, but it is often impure and has side effects and drug interactions. Garlic slightly lowers blood pressure and lipids. Echinacea slightly decreases the duration of colds but does not prevent them. Valerian is beneficial for insomnia, but there is no long-term safety data. Black cohosh may help the symptoms of perimenopause, and chasteberry may improve premenstrual syndrome. More study is needed on both herbs.

CONCLUSION

Some herbs are medically useful, but the American public would benefit from increased regulation. Manufacturers should be able to ensure that herbs contain pure ingredients. Side effects and drug interactions should be listed. Well-designed studies are being conducted. The results will be helpful to physicians and patients when the clinical evidence becomes available.

Dietary supplements and functional foods: 2 sides of a coin?

Dietary supplements are used by more than one-half of the adult US population. In contrast to pharmaceuticals, dietary supplements may be sold in the United States with little regulation other than listing of ingredients and the potential health benefits. By contrast, herbal products in Germany are carefully regulated by the same standards as drugs, and efforts are under way to standardize their regulation in the entire European Union. Most herbal users do not inform their physicians that they are taking these supplements, and most physicians do not inquire. Although some herbal products have clinically proven benefits, it is increasingly apparent that many contain potentially toxic substances, particularly in relation to interactions with drugs. Hence, it is essential that practicing physicians develop a working knowledge of herbals-specifically, about claims for their usage and potential or proven efficacies and toxicities-and that they incorporate such knowledge into the evaluation and management of their patients. By contrast, functional foods-integral components of the diet that are understood to contribute added health benefits-are the subject of intense and widespread research in food and nutritional science. Examples include many polyphenolic substances, carotenoids, soy isoflavones, fish oils, and components of nuts that possess antioxidant and other properties that decrease the risk of vascular diseases and cancer. Practicing physicians are advised to stay abreast of these emerging findings in order to best advise their patients on the value of health-promoting diets in disease prevention.

Systematic review of herbs and dietary supplements for glycemic control in diabetes

OBJECTIVE

To conduct a systematic review of the published literature on the efficacy and safety of herbal therapies and vitamin/mineral supplements for glucose control in patients with diabetes.

RESEARCH DESIGN AND METHODS

We conducted an electronic literature search of MEDLINE, OLDMEDLINE, Cochrane Library Database, and HealthSTAR, from database inception to May 2002, in addition to performing hand searches and consulting with experts in the field. Available clinical studies published in the English language that used human participants and examined glycemic control were included. Data were extracted in a standardized manner, and two independent investigators assessed methodological quality of randomized controlled trials using the Jadad scale.

RESULTS

A total of 108 trials examining 36 herbs (single or in combination) and 9 vitamin/mineral supplements, involving 4,565 patients with diabetes or impaired glucose tolerance, met the inclusion criteria and were analyzed. There were 58 controlled clinical trials involving individuals with diabetes or impaired glucose tolerance (42 randomized and 16 nonrandomized trials). Most studies involved patients with type 2 diabetes. Heterogeneity and the small number of studies per supplement precluded formal meta-analyses. Of these 58 trials, the direction of the evidence for improved glucose control was positive in 76% (44 of 58). Very few adverse effects were reported.

CONCLUSIONS

There is still insufficient evidence to draw definitive conclusions about the efficacy of individual herbs and supplements for diabetes; however, they appear to be generally safe. The available data suggest that several supplements may warrant further study. The best evidence for efficacy from adequately designed randomized controlled trials (RCTs) is available for Coccinia indica and American ginseng. Chromium has been the most widely studied supplement. Other supplements with positive preliminary results include Gymnema sylvestre, Aloe vera, vanadium, Momordica charantia, and nopal.

A survey of herbal product use in a dialysis population in Northwest Ohio

OBJECTIVE

To identify herbal product use in a dialysis population.

DESIGN AND SETTING

Cross-sectional survey conducted at 2 freestanding dialysis centers in Northwest Ohio.

PATIENTS

Two hundred and sixteen hemodialysis and peritoneal dialysis patients who provided informed consent.

INTERVENTION

All patients were surveyed by personal interview regarding use of herbal products. Patients identified as current users were asked questions about specific agents. Respondents reporting past but not current use were questioned about specific agents and reasons for discontinuation.

RESULTS

Thirty-one patients reported taking herbal therapies. Twenty-six patients discontinued use before the survey. Sixteen different herbal products were reported being used in our study population. Those who reported ever using an herbal product were more likely to be employed or disabled and have higher education when compared with nonusers.

CONCLUSION

Our data suggest a lower frequency of herbal product use in the dialysis population as compared with the general population and other chronically ill populations. Education and employment are factors associated with use. Many of the herbal therapies used potentially could have significant adverse effects in dialysis patients. These include effects on blood pressure, blood glucose, coagulation parameters, and electrolyte disturbances. Dialysis patients currently taking herbal products may not be reevaluating their need for continuation and may not be informing members of the nephrology care team about their use.

Panax ginseng: a role in cancer therapy?

Panax ginseng is a plant that has been used in traditional medicine in China for thousands of years. It is used as a general tonic or adaptogen with chronically ill patients and is frequently featured in traditional medicine prescriptions from China, Japan, and Korea used by cancer patients. The putative active compounds are the ginsenosides, of which there are more than two dozen. These compounds are found in both Panax ginseng and in other Panax species that are used in herbal medicine. Analysis of ginsenosides is being used in developing quality control assessments for ginseng, which has frequently been adulterated due to its high cost; many currently available standardized extracts do appear to contain the amounts of ginsenosides listed on package labeling. The toxicity of ginseng appears to be low: some of the reports of toxic episodes of ginseng may actually pertain to other components of multicomponent preparations. Very low incidence of toxicity has been observed in ginseng clinical trials using well-characterized preparations. Numerous pharmacological activities of ginseng and the ginsenosides have been explored: the authors review here the activities relating to cancer. Immune system modulation, antistress activities, and antihyperglycemic activities are among the most notable features of ginseng noted in laboratory and clinical analyses. Much testing has been done in humans to explore ginseng's purported antifatigue properties, but this area remains controversial. A number of investigations point to antitumor properties and other pharmacological activities related to cancer, but no trials have yet confirmed a clinically significant anticancer activity. Cancer patients may empirically find ginseng to be useful when they are fatigued, although clinical trials should be conducted to confirm its benefits.

Variable effects of American ginseng: a batch of American ginseng (Panax quinquefolius L.) with a depressed ginsenoside profile does not affect postprandial glycemia

BACKGROUND

We have repeatedly reported that American ginseng (AG) with a specific ginsenoside profile significantly decreases postprandial glycemia. Whether this effect is reproducible using AG with a different profile is unknown. We therefore investigated the effect of a different batch of AG on glycemia following a 75 g oral glucose tolerance test (OGTT).

METHODS

Using a randomized, single blind design, 12 normal subjects (six males and six females, aged 31+/-3 y, body mass index (BMI) 28+/-2 kg/m(2)) received 6 g AG or placebo 40 min before a 75 g OGTT. The protocol followed the guidelines for the OGTT, with venous blood samples drawn at -40, 0, 15, 30, 45, 60, 90 and 120 min. Ginsenosides in the AG were assessed by established methods for HPLC-UV.

RESULTS

Repeated measures analysis of variance demonstrated that there was no significant effect of the AG on incremental plasma glucose (PG) or insulin (PI) or their areas under the curve Indices of insulin sensitivity (insulin sensitivity index (ISI)) and release (deltaPI(30-0)/deltaPG(30-0)) calculated from the OGTT were also unaffected. The AG contained 1.66% total ginsenosides, 0.90% (20S)-protopanaxadiol (PPD) ginsenosides, and 0.75% (20S)-protopanaxatriol (PPT) ginsenosides, with the following key ratios: PPD:PPT of 1.2, Rb(1):Rg(1) of 8.1, and Rb(2):Rc of 0.18.

CONCLUSIONS

The present batch of AG was unable to reproduce the postprandial hypoglycemic effects we observed previously. Possible explanations for this discrepancy include marked decrements in total ginsenosides and the key ratios PPD:PPT, Rb(1):Rg(1), and Rb(2):Rc. These data suggest that the ginsenoside profile of AG might play a role in its hypoglycemic effects. The involvement of other components cannot, however, be precluded.

Anti-hyperglycemic effects of ginseng: comparison between root and berry

Previous studies demonstrated that both ginseng root and ginseng berry possess anti-diabetic activity. However, a direct comparison between the root and the berry under the same experimental conditions has not been conducted. In the present study, we compared anti-hyperglycemic effect between Panax ginseng root and Panax ginseng berry in ob/ob mice, which exhibit profound obesity and hyperglycemia that phenotypically resemble human type-2 diabetes. We observed that ob/ob mice had high baseline glucose levels (195 mg/dl). Ginseng root extract (150 mg/kg body wt.) and ginseng berry extract (150 mg/kg body wt.) significantly decreased fasting blood glucose to 143 +/- 9.3 mg/dl and 150 +/- 9.5 mg/dl on day 5, respectively (both P < 0.01 compared with the vehicle). On day 12, although fasting blood glucose level did not continue to decrease in the root group (155 +/- 12.7 mg/dl), the berry group became normoglycemic (129 +/- 7.3 mg/dl; P < 0.01). We further evaluated glucose tolerance using the intraperitoneal glucose tolerance test. On day 0, basal hyperglycemia was exacerbated by intraperitoneal glucose load, and failed to return to baseline after 120 min. After 12 days of treatment with ginseng root extract (150 mg/kg body wt.), the area under the curve (AUC) showed some decrease (9.6%). However, after 12 days of treatment with ginseng berry extract (150 mg/kg body wt.), overall glucose exposure improved significantly, and the AUC decreased 31.0% (P < 0.01). In addition, we observed that body weight did not change significantly after ginseng root extract (150 mg/kg body wt.) treatment, but the same concentration of ginseng berry extract significantly decreased body weight (P < 0.01). These data suggest that, compared to ginseng root, ginseng berry exhibits more potent anti-hyperglycemic activity, and only ginseng berry shows marked anti-obesity effects in ob/ob mice.

Ginseng radix increases cell proliferation in dentate gyrus of rats with streptozotocin-induced diabetes

In the present study, the effect of Ginseng radix on cell proliferation in the dentate gyrus of rats with streptozotocin-induced diabetes was investigated via immunohistochemistry. Aqueous extract of Ginseng radix was shown to exert no significant effect on weight in normal rats, while it prevented weight loss in rats with streptozotocin-induced diabetes. Cell proliferation in the dentate gyrus of diabetic rats was increased by Ginseng radix treatment, but it had no effect on cell proliferation in normal rats. These results suggest that Ginseng radix may help in improve the central nervous system complications of diabetes mellitus.

Use of complementary and alternative medicine among persons with diabetes mellitus: results of a national survey

OBJECTIVES

This study sought to characterize the use of complementary and alternative medicine (CAM) among persons with diabetes mellitus residing in the United States.

METHODS

Data from a 1997-1998 national survey (n = 2055) on CAM use were examined.

RESULTS

Ninety-five respondents reported having diabetes, of whom 57% reported CAM use in the past year; fewer respondents (35%) reported use specifically for diabetes. Therapies used for diabetes included solitary prayer/spiritual practices (28%), herbal remedies (7%), commercial diets (6%), and folk remedies (3%). Excluding solitary prayer, only 20% of respondents used CAM to treat diabetes.

CONCLUSIONS

The prevalence of CAM therapy use among persons with diabetes is comparable to that among the general population. Use of CAM therapies specifically to treat diabetes, however, is much less common.

Antidiabetic effects of Panax ginseng berry extract and the identification of an effective component

We evaluated antihyperglycemic and anti-obese effects of Panax ginseng berry extract and its major constituent, ginsenoside Re, in obese diabetic C57BL/6J ob/ ob mice and their lean littermates. Animals received daily intraperitoneal injections of Panax ginseng berry extract for 12 days. On day 12, 150 mg/kg extract-treated ob/ob mice became normoglycemic (137 +/- 6.7 mg/dl) and had significantly improved glucose tolerance. The overall glucose excursion during the 2-h intraperitoneal glucose tolerance test decreased by 46% (P < 0.01) compared with vehicle-treated ob/ob mice. The improvement in blood glucose levels in the extract-treated ob/ ob mice was associated with a significant reduction in serum insulin levels in fed and fasting mice. A hyperinsulinemic-euglycemic clamp study revealed a more than twofold increase in the rate of insulin-stimulated glucose disposal in treated ob/ ob mice (112 +/- 19.1 vs. 52 +/- 11.8 micromol x kg(-1) x min(-1) for the vehicle group, P < 0.01). In addition, the extract-treated ob/ob mice lost a significant amount of weight (from 51.7 +/- 1.9 g on day 0 to 45.7 +/- 1.2 on day 12, P < 0.01 vs. vehicle-treated ob/ob mice), associated with a significant reduction in food intake (P < 0.05) and a very significant increase in energy expenditure (P < 0.01) and body temperature (P < 0.01). Treatment with the extract also significantly reduced plasma cholesterol levels in ob/ob mice. Additional studies demonstrated that ginsenoside Re plays a significant role in antihyperglycemic action. This antidiabetic effect of ginsenoside Re was not associated with body weight changes, suggesting that other constituents in the extract have distinct pharmacological mechanisms on energy metabolism.

Modulation of cognition and mood following administration of single doses of Ginkgo biloba, ginseng, and a ginkgo/ginseng combination to healthy young adults

It has previously been demonstrated in separate studies that single doses of Ginkgo biloba, Panax ginseng, and a combination of the two extracts can improve different aspects of cognitive performance in healthy young volunteers. The present study directly compared the effects of single doses of G. biloba, ginseng, and a product combining the two on aspects of mood and cognitive performance in the same cohort of healthy, young adult volunteers. The study followed a randomised placebo-controlled, double-blind, balanced, cross-over design. Twenty participants received 360 mg of ginkgo, 400 mg of ginseng, 960 mg of a product combining the two extracts, and a matching placebo. Treatment order was dictated by random allocation to a Latin square, with a 7-day wash-out period between treatments. Cognitive testing comprised completion of the Cognitive Drug Research (CDR) computerised assessment battery and two serial subtraction mental arithmetic tasks. Mood was assessed with Bond-Lader visual analogue scales. Following a baseline cognitive assessment, further test sessions took place 1, 2.5, 4, and 6 h after the day's treatment was taken. The results largely supported previous findings. All three treatments were associated with improved secondary memory performance on the CDR battery, with the ginseng condition evincing some improvement in the speed of performing memory tasks and in the accuracy of attentional tasks. Following ginkgo and the ginkgo/ginseng combination performance of both the Serial Threes and Serial Sevens, subtraction tasks was also improved at the later testing sessions. No modulation of the speed of performing attention tasks was evident. Improvements in self-rated mood was also found following ginkgo and to a lesser extent the combination product.

Complementary/alternative therapies for reducing hot flashes in prostate cancer patients: reevaluating the existing indirect data from studies of breast cancer and postmenopausal women

Vasomotor hot flashes are a common problem in women who are postmenopausal or receiving antiestrogen treatment for breast cancer. Hot flashes are also a common problem after orchiectomy/luteinizing hormone-releasing hormone therapy, occurring generally in 50% to 66% of these men. Prescribed treatments for hot flashes for men on hormonal ablation treatment for prostate cancer are well documented. These conventional agents have shown good results, but their long-term efficacy, safety, and cost are still questioned. Therefore, the search for other viable agents, including nontraditional treatments, continues. Complementary/alternative treatments to alleviate hot flashes in women have generated an enormous amount of interest. However, these options have received little attention in men with hot flashes. Research with vitamin E, soy, black cohosh, red clover, and numerous other alternative treatments in women may provide some indirect but valuable insight on their potential effectiveness in men. Many of these alternatives have been a disappointment in recent randomized trials of women, and it is likely that there will be similar results with men. However, numerous supplements have yet to be tested in a clinical trial against a placebo, and clinicians should become aware of this ever-increasing list. Patients should be made aware of the primary importance of lifestyle interventions that could partially affect hot flashes and immediately affect overall health, especially during the period of androgen suppression, when it is not uncommon to observe accelerated weight changes and insulin insensitivity. Otherwise, recent research with older and newer conventional agents, such as antidepressants or estrogen/progesterone, should be emphasized at this time for moderate-to-severe hot flashes that profoundly affect daily activities and/or sleep. Antidepressant supplements (St. John's wort) or acupuncture could also be an attractive option in future investigations. Low-dose estrogen seems particularly attractive, because it is inexpensive and may simultaneously reduce hot flashes and the risk of osteoporosis in men receiving long-term androgen suppression therapy; however, the potential for cardiovascular complications must be further investigated. Ultimately, adequate research (vs placebo) should determine the fate of the alternative supplements proposed for hot flash reduction.

Ginseng berry reduces blood glucose and body weight in db/db mice

In this study, we observed anti-diabetic and anti-obesity effects of Panax ginseng berry in adult C57BL/Ks db/db mice and their lean littermates. Animals received daily intraperitoneal injections of Panax ginseng berry extract at 150 mg/kg body wt. for 12 consecutive days. On Day 5, the extract-treated db/db mice had significantly lower fasting blood glucose levels as compared to vehicle-treated mice (180.5+/-10.2 mg/dl vs. 226.0+/-15.3 mg/dl, P < 0.01). On day 12, the extract-treated db/db mice were normoglycemic (134.3+/-7.3 mg/dl) as compared to vehicle-treated mice (254.8+/-24.1 mg/dl; P < 0.01). Fasting blood glucose levels of lean mice did not decrease significantly after treatment with extract. After 12 days of treatment with the extract, glucose tolerance increased significantly, and overall blood glucose exposure calculated as area under the curve (AUC) decreased 53.4% (P < 0.01) in db/db mice. Furthermore, db/db mice treated with extract (150 mg/kg body wt.) showed weight loss from 51.0+/-1.9 g on Day 0, to 46.6+/-1.7 g on Day 5, and to 45.2+/-1.4 g on Day 12 (P < 0.05 and P < 0.01 compared to Day 0, respectively). The body weight of lean littermates also decreased at the same dose of extract. These data suggest that Panax ginseng berry extract may have therapeutic value in treating diabetic and obese patients.

Herbal and nonherbal supplements in medical-psychiatric patient populations

Nutritional supplements remain a popular choice for patients seeking relief or prevention from a wide range of physical and mental disorders. Review of available literature finds support for some therapeutic uses, but flaws in study design (e.g., small sample sizes) and methodology (e.g., inadequate blinding and a lack of placebo control) limit the possibility of making strong recommendations. Quality-control issues also raise concerns about the safety of supplement use (see previous list). In addition, potential interactions with prescription drugs are another consideration (Table 1). By becoming more knowledgeable about the risks and benefits of nutritional supplements, psychiatrists can assist patients in making informed choices and avoiding unnecessary harm.

Natural products used for diabetes

OBJECTIVE

To review the efficacy and safety of natural products commonly used for diabetes.

DATA SOURCES

English and Spanish-language journals retrieved through a MEDLINE search of articles published between 1960 and December 2001 using these index terms: Opuntia, karela, gymnema, tecoma, alpha lipoic acid, thioctic acid, ginseng, panaxans, and diabetes.

DATA SYNTHESIS

Natural products have long been used in traditional systems of medicine for diabetes. Products in common use include nopal (prickly pear cactus), fenu-greek, karela (bitter melon), gymnema, ginseng, tronadora, chromium, and alpha-lipoic acid. The popularity of these products varies among people of different ethnicities. Nopal is the most commonly used herbal hypoglycemic among persons of Mexican descent. Karela is more commonly used by persons from Asian countries. Some of these agents have gained universal appeal. For a select number of products, studies have revealed single or multiple mechanisms of action. For several of these, high soluble fiber content is a contributing factor.

CONCLUSION

Based on the available evidence, several natural products in common use can lower blood glucose in patients with diabetes. Commonly used natural products often have a long history of traditional use, and pharmacists who have a stronger understanding of these products are better positioned to counsel patients on their appropriate use.

Lifestyle/dietary supplement partial androgen suppression and/or estrogen manipulation. A novel PSA reducer and preventive/treatment option for prostate cancer?

There is a large interest in prostate cancer prevention and/or slowing the progression of this disease via dietary/lifestyle/supplement interventions. Numerous mechanisms have been suggested as to how these interventions may lower PSA levels. However, it is possible that the primary mechanism of action is partial androgen suppression and/or estrogen manipulation.

Acute, dose-dependent cognitive effects of Ginkgo biloba, Panax ginseng and their combination in healthy young volunteers: differential interactions with cognitive demand

The present paper describes three studies examining the acute effects of single doses of Ginkgo biloba (GK501), Ginseng (G115) and their combination (Ginkoba M/E, Pharmaton SA) on the performance of healthy young adults (mean age 21 years) during serial arithmetic tasks with differing cognitive load. In each double-blind, placebo-controlled study three different treatment doses and a placebo were administered, according to a balanced crossover design, with a 7-day washout period between each dose. Participants' scores on two computerised serial subtraction tasks (Serial Threes and Serial Sevens) were assessed pre-dosing and at 1, 2.5, 4 and 6 h thereafter. A number of significant time, dose and task-specific effects were associated with each treatment. There was a dose-dependent improvement in speed of responding during Serial Threes following Ginkgo biloba. Different doses of Ginseng improved accuracy and slowed responses during Serial Sevens. The most striking result, however, was a highly significant and sustained increase in the number of Serial Sevens responses following 320 mg of the Ginkgo-Ginseng combination at all post-treatment testing times. This was accompanied by improved accuracy during Serial Sevens and Serial Threes following the 640 mg and the 960 mg dose, respectively. The paper concludes with speculation into the possible mechanisms underlying these effects.

Konjac-Mannan and American ginsing: emerging alternative therapies for type 2 diabetes mellitus

Despite significant achievements in treatment modalities and preventive measures, the prevalence of diabetes has risen exponentially in the last decade. Because of these limitations there is a continued need for new and more effective therapies. An increasing number of people are using dietary and herbal supplements, even though there is a general lack of evidence for their safety and efficacy. Consequently, science based medical and government regulators are calling for more randomized clinical studies to provide evidence of efficacy and safety. Our research group has selected two such promising and functionally complementary therapies for further investigation as potentially emerging alternative therapies for type 2 diabetes: Konjac-mannan (KJM) and American ginseng (AG). We have generated a mounting body of evidence to support the claim that rheologically-selected, highly-viscous KJM, and AG with a specific composition may be useful in improving diabetes control, reducing associated risk factors such as hyperlipidemia and hypertension, and ameliorating insulin resistance. KJM has a demonstrated ability to modulate the rate of absorption of nutrients from the small bowel, whereas AG has post-absorptive effects. Consequently, it appears that KJM and AG are acting through different, yet complementary, mechanisms: KJM by increasing insulin sensitivity and AG likely by enhancing insulin secretion. Before the therapeutic potential of KJM and AG as novel prandial agents for treatment of diabetes can be fully realized, further controlled trials with larger sample sizes and of longer duration are required. A determination of the active ingredients in AG, and the rheology-biology relationship of KJM are also warranted.