Stimulation of low density lipoprotein receptor activity in liver membrane of guggulsterone treated rats

In-vivo anti-diabetic and anti-hyperlipidemic effects of natural metabolites from resin of Commiphora mukul and their in-silico to in-vitro target fishing

Diabetes mellitus is a rapidly spreading global metabolic disorder that has serious social, health, and economic consequences. Herein, we have evaluated in vivo antidiabetic and antihyperlipidemic effects of myrrhanone-B and myrrhanol-B (isolated from Commiphora mukul Hook). We observed that treatment with myrrhanone-B and myrrhanol-B at a dose of 5 and 10 mg/kg body weight for 21 days significantly improved body weight loss, water consumption, and the concentration of blood glucose level (BGL) in alloxan (120 mg/kg) induced diabetic mice, which indicates that the compounds possess strong anti-diabetic activities. In the biochemical analysis, these compounds improved an abnormal level of total cholesterol (TC), triacylglycerol (TG), and low-density lipoprotein cholesterol (LDL-C) to a normal level and increased the high-density lipoprotein cholesterol level (HDLC). Later, drug target of compounds was predicted through in-silico docking which shows that these compounds nicely fit in the active site of α-glucosidase enzyme and mediates excellent interactions with the catalytic residues, Asp214 and Asp349. The in-silico results were confirmed by in-vitro testing of myrrhanone-B and myrrhanol-B against α-glucosidase where both the compounds exhibited excellent inhibitory potency with IC50 values of 19.50 ± 0.71, and 16.11 ± 0.69 µM, respectively. Furthermore, mechanistic study was conducted to observe their binding mechanism, which reflect that myrrhanol-B has mixed type of inhibition (ki = 12.33 ± 0.030 µM), while myrrhanone-B demonstrates competitive type of inhibition (ki =14.53 ± 0.040 µM).

Myrrhanone B and Myrrhanol B from resin of Commipohora mukul exhibit hepatoprotective effects in-vivo

Despite a large number of liver disorders, clinically useful drugs are scarce. Moreover, the available therapies are facing the challenges of efficacy and safety. Commipohora mukul has been used in folk medicine globally for millennia for the treatment of several ailments. The current study was designed to evaluate the possible hepatoprotective activity of Myrrhanone B (MN) and Myrrhanol B (ML) isolated from C. mukul using an animal model. The animals (Swiss albino mice) were segregated into seven groups, each comprising six mice. The first group was treated with normal saline at a dose of 1 ML/kg daily intraperitoneally (i.p.) for one week. The second group was treated with acetaminophen (APAP) (250 mg/kg, i.p.), it was taken as a negative control. Group 3 was used as a positive control (treated with Silymarin (100 mg/kg, i.p.)). While groups 4-7 were used as experimental groups (termed as groups II to IV), which were treated with ML and MN at a dose of 0.6 mg/kg, and 1.2 mg/kg (i.p.) for one week. Subsequently, blood serum and liver tissue samples were collected for biochemical and histopathological analysis. Both compounds significantly improved the levels of liver biomarkers including aspartate transaminase (AST), alkaline phosphatase (ALP), bilirubin, lactate dehydrogenase (LDH), and alanine transaminase (ALT) as compared to the normal saline-treated group in APAP-induced hepatotoxic mice. Moreover, both compounds significantly modulated the expression of oxidative biomarkers including superoxide dismutase (SOD), reduced glutathione (GSH), and catalase (CAT) at the same doses. Additionally, ML and MN showed a remarkable improvement in histological changes with only mild inflammation, mild hemorrhage, no necrosis, and no pyknosis as compared to the control groups. In conclusion, MN and ML exhibited significant hepatoprotective effects in the animal model used in this study.

Therapeutic Effect of Guggulsterone in Primary Cultured Orbital Fibroblasts Obtained From Patients with Graves' Orbitopathy

Purpose

Inflammation, hyaluronan production, and adipogenesis are the main pathological events leading to Graves' orbitopathy (GO). Guggulsterone (GS), a phytosterol found in the resin of the guggul plant, is a well-known treatment for several inflammatory disorders, such as arthritis, obesity, and hyperlipidemia. Here we investigated the effects of GS treatment on GO pathology.

Methods

Using primary cultures of orbital fibroblasts from GO patients and non-GO controls, we examined the effects of GS on hyaluronan production and the production of proinflammatory cytokines induced by interleukin (IL)-1β, using real-time reverse transcription-polymerase chain reaction analysis, western blots, and enzyme-linked immunosorbent assays. Further, adipogenic differentiation was evaluated by quantification of Oil Red O staining and assessment of protein levels of peroxisome proliferator activator gamma (PPARγ), CCAAT-enhancer-binding proteins (C/EBP) α and β, and sterol regulatory element-binding protein-1 (SREBP-1).

Results

Treatment with noncytotoxic concentrations of GS resulted in the dose-dependent inhibition of IL-1β-induced inflammatory cytokines, including IL-6, IL-8, MCP-1, and COX-2, at both mRNA and protein levels. The hyaluronan level was also significantly suppressed by GS. Moreover, GS significantly decreased the formation of lipid droplets and expression of PPARγ, C/EBP α/β, and SREBP-1 in a dose-dependent manner. GS pretreatment attenuated the phosphorylation of nuclear factor-kappa B induced by IL-1β.

Conclusions

Our data show significant inhibitory effects of GS on inflammation, production of hyaluronan, and adipogenesis in orbital fibroblasts. To our knowledge, this is the first in vitro preclinical evidence of the therapeutic effect of GS in GO.

Potential Anti-obesity and Lipid Lowering Natural Products: A Review

Obesity has reached epidemic proportions globally, with more than 1 billion adults overweight - at least 300 million of them clinically obese. In Ayurveda, obesity is called ‘medoroga’. The detailed features and treatments of the disease have been described in an old Ayurvedic text, Charak and Sushrut Samhita. There are some native plants that are commonly used for the treatment of obesity in Ayurveda. Unfortunately, only few medications are available in the market, with side effects and unacceptable efficacy. With the current view that botanical drugs can be developed faster and more cheaply than conventional single entity pharmaceuticals, the review mainly focuses on the rationality of their use with appropriate literature data support.

Medicinal plants in treatment of hypertriglyceridemia: A review based on their mechanisms and effectiveness

BACKGROUND

Hypertriglyceridemia (HTg) defines as high amounts of triglyceride (TG) in the blood which can lead to serious complications over time. HTg is usually a part of metabolic disorders such as diabetes mellitus, metabolic syndrome, and dyslipidemia. Different medications have been used to treat HTg but experimentally, many herbs have been recommended for treating HTg as an adjuvant therapy. In most cases, the recommendations are based on animal studies and limited evidences exist about their mechanisms and clinical usefulness.

PURPOSE

This review focused on the herbs which have been shown TG lowering effect.

METHOD

The search was done in PubMed, Science Direct, Scopus, Web of Science and Google Scholar databases a 20-year period between 1997 to 2017 with keywords search of medicinal plant, plant extract, hypertriglyceridemia, dyslipidemia, hyperlipidemia, lipoprotein lipase and apolipoprotein.

RESULTS

According to the results, many plants showed positive effects but Allium sativum, Nigella sativa, Curcuma longa, Anethum graveolens and Commiphora mukul had the best TG lowering effect with exact mechanisms of action.

CONCLUSION

It seems that use of these plants as complementary therapeutics or extraction of their active ingredients along with currently available drugs will improve the management of HTg in patients.

Googling the Guggul (Commiphora and Boswellia) for Prevention of Chronic Diseases

Extensive research during last 2 decades has revealed that most drugs discovered today, although costs billions of dollars for discovery, and yet they are highly ineffective in their clinical response. For instance, the European Medicines Agency has approved 68 anti-cancer drugs, and out of which 39 has reached the market level with no indication of increased survival nor betterment of quality of life. Even when drugs did improve survival rate compared to available treatment strategies, most of these were found to be clinically insignificant. This is a fundamental problem with modern drug discovery which is based on thinking that most chronic diseases are caused by alteration of a single gene and thus most therapies are single gene-targeted therapies. However, extensive research has revealed that most chronic diseases are caused by multiple gene products. Although most drugs designed by man are mono-targeted therapies, however, those designed by "mother nature" and have been used for thousands of years, are "multi-targeted" therapies. In this review, we examine two agents that have been around for thousands of years, namely "guggul" from Commiphora and Boswellia. Although we are all familiar with the search engine "google," this is another type of "guggul" that has been used for centuries and being explored for its various biological activities. The current review summarizes the traditional uses, chemistry, in vitro and in vivo biological activities, molecular targets, and clinical trials performed with these agents.

Gugulipid causes hypercholesterolemia leading to endothelial dysfunction, increased atherosclerosis, and premature death by ischemic heart disease in male mice

For proper cholesterol metabolism, normal expression and function of scavenger receptor class B type I (SR-BI), a high-density lipoprotein (HDL) receptor, is required. Among the factors that regulate overall cholesterol homeostasis and HDL metabolism, the nuclear farnesoid X receptor plays an important role. Guggulsterone, a bioactive compound present in the natural product gugulipid, is an antagonist of this receptor. This natural product is widely used globally as a natural lipid-lowering agent, although its anti-atherogenic cardiovascular benefit in animal models or humans is unknown. The aim of this study was to determine the effects of gugulipid on cholesterol homeostasis and development of mild and severe atherosclerosis in male mice. For this purpose, we evaluated the impact of gugulipid treatment on liver histology, plasma lipoprotein cholesterol, endothelial function, and development of atherosclerosis and/or ischemic heart disease in wild-type mice; apolipoprotein E knockout mice, a model of atherosclerosis without ischemic complications; and SR-B1 knockout and atherogenic–diet-fed apolipoprotein E hypomorphic (SR-BI KO/ApoER61^h/h) mice, a model of lethal ischemic heart disease due to severe atherosclerosis. Gugulipid administration was associated with histological abnormalities in liver, increased alanine aminotransferase levels, lower hepatic SR-BI content, hypercholesterolemia due to increased HDL cholesterol levels, endothelial dysfunction, enhanced atherosclerosis, and accelerated death in animals with severe ischemic heart disease. In conclusion, our data show important adverse effects of gugulipid intake on HDL metabolism and atherosclerosis in male mice, suggesting potential and unknown deleterious effects on cardiovascular health in humans. In addition, these findings reemphasize the need for rigorous preclinical and clinical studies to provide guidance on the consumption of natural products and regulation of their use in the general population.

Acute toxicity and antihyperlipidemic activity of rhizome of Tectaria coadunata (Kukkutnakhi): A folklore herb

Background:

Tectaria coadunata (Wall. Ex Hook and Grev.) C. Chr (Kukkutnakhi) is a pteridophyte fern which is found in Western Ghats, Kerala Ghats, and Mahendragiri forest region. It is used by many Vaidyas in hyperlipidemic conditions and obesity.

Aim:

This study aimed to evaluate the acute toxicity and antihyperlipidemic activity of T. coadunata in experimental animals.

Materials and Methods:

Oral acute toxicity study was carried out in female Wistar rats as per OECD 425 guideline. Antihyperlipidemic activity of powder of T. coadunata (540 mg/kg) was carried out in high-fat diet–induced hyperlipidemia in Wistar albino rats.

Results:

T. coadunata rhizome powder at the dose of 2000 mg/kg did not produce any mortality and toxic effects during acute toxicity study in female rats. Test drug produced highly significant (P < 0.001) reversal in the triglycerides and very-low-density lipoprotein (VLDL)-cholesterol along with nonsignificant decrease in the cholesterol level in rats fed with hyperlipidemic diet. Further, T. coadunata has shown nonsignificant decrease in serum urea, serum glutamic pyruvic transaminase, alkaline phosphatase, and bilirubin direct while statistically significant decrease in bilirubin total in comparison to cholesterol control group. Histopathological study has shown reversal of adverse changes induced by hyperlipidemic diet in heart, liver, and kidney.

Conclusion:

It is concluded that drug is safe up to the dose level of 2000 mg/kg in rats. Rhizome of T. coadunata has shown antihyperlipidemic activity in rats, which suggest its potential role in hyperlipidemia and associated conditions.

A Comparative Study of Lipid-Lowering Effects of Guggul and Atorvastatin Monotherapy in Comparison to Their Combination in High Cholesterol Diet-Induced Hyperlipidemia in Rabbits

BACKGROUND

Hypolipidemic activity of gugulipid has been widely described in traditional literature.

OBJECTIVE

This study was done to evaluate hypolipidemic activity of guggul and atorvaststin monotherapy in comparison to their combination in rabbits.

MATERIALS AND METHODS

Male New Zealand White rabbits (body weight 1.3-1.8 kg and age 8-10 weeks) were made hyperlipidemic by feeding cholesterol (0.5 g/kg) for three weeks and randomly divided into a control and three treatment groups receiving: atorvastatin (3.7 mg/kg), guggul (3.5 mg/kg) and their combination (same dose) for the next three weeks. Body weight measurements, estimation of serum lipid profile were done at the beginning, after three and six weeks, respectively. Histopathological examination of liver, heart and aorta was done after six weeks. Statistical analysis was done with SPSS version 16.0 using one-way and repeated measures analysis of variance (ANOVA) followed by post-hoc multiple comparison test with two tailed P value < 0.05 as significant.

RESULTS

All treated groups had significant reduction in cholesterol, triglyceride, low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) in comparison to pre-treatment values and control group, and had significant increase in high-density lipoprotein (HDL) in comparison to pre-treatment values.

CONCLUSION

Combination of atorvastatin and guggul was comparable to their monotherapies in improving lipid profile.

Guggulsterone and Its Role in Chronic Diseases

Guggulsterone is a plant sterol derived from gum resin of Commiphora wightii. The gum resin from guggul plants has been used for thousand years in Ayurveda to treat various disorders, including internal tumors, obesity, liver disorders, malignant sores and ulcers, urinary complaints, intestinal worms, leucoderma, sinuses, edema, and sudden paralytic seizures. Guggulsterone has been identified a bioactive components of this gum resin. This plant steroid has been reported to work as an antagonist of certain nuclear receptors, especially farnesoid X receptor, which regulates bile acids and cholesterol metabolism. Guggulsterone also mediates gene expression through the regulation of transcription factors, including nuclear factor-kappa B and signal transducer and activator of transcription 3, which plays important roles in the development of inflammation and tumorigenesis. Guggulsterone has been shown to downregulate the expression of proteins involved in anti-apoptotic, cell survival, cell proliferation, angiogenic, metastatic, and chemoresistant activities in tumor cells. This review aimed to clarify the cell signal pathways targeted by guggulsterone and the bioactivities of guggulsterone in animal models and humans.

Hypolipidemic Effects of a Proprietary Commiphora Mukul Gum Resin Extract and Medium-Chain Triglyceride Preparation (GU-MCT810)

The hypolipidemic effects of the poorly soluble ayurvedic resin guggul, especially the molecular targets and mechanism, have not been well investigated to date. In the present study, we have formulated a liquid product, GU-MCT810, composed of a proprietary Commiphora mukul gum resin extract and medium-chain triglyceride and investigated its hypolipidemic effects in vitro. Treatment of HepG2 cells significantly reduced low-density lipoprotein cholesterol and increased the high-density lipoprotein/low-density lipoprotein ratio. GU-MCT810 showed direct inhibition of HMG-CoA reductase activity in a dose-dependent manner and compared very well with the inhibitory effect of statins like Pravastatin and Mevastatin. The adipocyte differentiation was also inhibited by GU-MCT810 treatment. GU-MCT810 increased the AMPKα phosphorylation and AMPK kinase activity and inhibited the phosphorylated form of mTOR expression, indicating the molecular targets affected by the nutraceutical compound. The preparation also highly upregulated the expression of LXR and PPARα genes and moderately upregulated BABP and SHP genes.

Pharmacological properties of guggulsterones, the major active components of gum guggul

Oleo gum resin secreted by Commiphora mukul, also known as gum guggul, has been used widely as an ayurvedic drug. Commiphora mukul is a short thorny shrub that is native to the Indian subcontinent. Oleo gum resin extracted by incision of the bark is a very complex mixture of gum, minerals, essential oils, terpenes, sterols, ferrulates, flavanones and sterones. Its active constituents, the Z- and E-guggulsterones, have been demonstrated to exhibit their biological activities by binding to nuclear receptors and modulating the expression of proteins involved in carcinogenic activities. Guggulsterones have also been reported to regulate gene expression by exhibiting control over other molecular targets including transcription factors such as nuclear factor (NF)-κB, signal transducer and activator of transcription (STAT) and steroid receptors. Considerable scientific evidence indicates the use of gum guggul as a therapeutic agent in the treatment of inflammation, nervous disorders, hyperlipidaemia and associated cardiac disorders such as hypertension and ischaemia, skin disorders, cancer and urinary disorders. This review highlights the taxonomic details, phytochemical properties and pharmacological profile of gum guggul.

Indole-based fibrates as potential hypolipidemic and antiobesity agents

Hypolipidemic and antiobesity effects of the newly synthesized indole-based fibrates were evaluated in Triton WR-1339 and high fat diet (HFD)-induced hyperlipidemic rats. Preliminary screening of all the synthesized compounds was done by using an acute model (Triton model), in which compounds 3f and 3l showed significant antidyslipidemic activity. Furthermore, these compounds 3f and 3l were found to induce significant weight loss in the visceral fat mass of HFD-fed hyperlipidemic rats without affecting the normal feeding behavior. Histological examination of the liver of rats supplemented with 3f and 3l revealed a significant decrease in steatosis when compared to the effect of the standard drug fenofibrate. Additional effects such as an increase in lecithin cholesterol acyl-transferase (LCAT) enzyme level and increased receptor mediated catabolism of I(131)-low density lipoproteins (LDL) confirm and reinforce the efficacy of both of these compounds as a new class of dual-acting hypolipidemic and antiobesity agents.

Polysaccharide from fuzi (FPS) prevents hypercholesterolemia in rats

BACKGROUND AND AIM

Polysaccharide from fuzi (FPS), a Chinese herbal medicine extract, has been demonstrated to exert lipid lowering affects. In this study we examined potential mechanisms underlying this affect, specifically alterations in expression of the LDL-receptor (LDL-R), 3-hydroxy-3-methyl glutaryl (HMG)-CoA reductase and cytochrome P450 7alpha-1 (CYP7alpha-1), using a rat model of hypercholesterolemia.

METHODS AND RESULTS

Male rats were fed either a normal or high cholesterol (HC) diet for two-weeks. Half of the rats on the HC diet were orally gavaged with FPS (224 mg/kg, 448 mg/kg or 896 mg/kg diet) daily. Serum lipid levels were quantified at end of the study period as were liver levels of LDL-R protein and mRNA expression of CYP7alpha-1 and HMG-CoA. Serum cholesterol and LDL-C concentrations were significantly elevated from control in HC rats, but not in those treated with FPS (P < 0.05). LDL-R expression was significantly decreased in the HC group compared to control (P < 0.05), but significantly increased in the FPS group (P < 0.05). HMG-CoA mRNA levels were significantly increased in the HC group compared both other groups (P < 0.05), while CYP7alpha-1 expression was significantly higher in the FPS group compared to both other groups (P < 0.05).

CONCLUSION

These findings suggest that the cholesterol lowering effect of FPS in hypercholesteremic rats is caused at least in part by increased hepatic LDL-R and CYP7alpha-1 expression and decreased HMG-CoA expression. Further study is needed to determine precisely where and how FPS exerts these effects. FPS offers potential as a therapeutic agent for the treatment of hypercholesterolemia.

Anti-obesity effects of xanthohumol plus guggulsterone in 3T3-L1 adipocytes

Xanthohumol (XN) and guggulsterone (GS) have each been shown to inhibit adipogenesis and induce apoptosis in adipocytes. In the present study effects of the combination of XN + GS on 3T3-L1 adipocyte apoptosis and adipogenesis were investigated. Mature adipocytes were treated with XN and GS individually and in combination. XN and GS individually decreased cell viability, but XN + GS caused an enhanced decrease in viability and potentiated induction of apoptosis. Likewise, XN + GS caused a potentiated increase in caspase-3/7 activation, whereas neither of the compounds showed any effect individually. In addition, western blot analysis revealed that XN + GS increased Bax expression and decreased Bcl-2 expression, whereas individual compounds did not show any significant effect. XN and GS both decreased lipid accumulation. Individually, XN at 1.5 microM and GS at 3.12 microM decreased lipid accumulation by 26 +/- 4.5% (P < .001) each, whereas XN1.5 + GS3.12 decreased lipid accumulation by 78.2 +/- 1.8% (P < .001). Moreover, expression of the adipocyte-specific proteins was down-regulated with XN1.5 + GS3.12, but no effect was observed with the individual compounds. Finally, XN + GS caused an enhanced stimulation of lipolysis. Thus, combination of XN and GS is more potent in exerting anti-obesity effects than additive effects of the individual compounds.

Therapeutic effects of guggul and its constituent guggulsterone: cardiovascular benefits

Oleogum resin (known as guggul) from the guggul tree, Commiphora mukul, found in India, Bangladesh, and Pakistan, has been used to treat various diseases including hyper-cholesterolemia, atherosclerosis, rheumatism, and obesity over several thousands of years. Guggulsterone isolated from guggul has been identified as the bioactive constituent responsible for guggul's therapeutic effects. Since the first study demonstrating the therapeutic effects of guggul in an animal model in 1966, numerous preclinical and clinical trails have been carried out. Although differences in study design, methodological quality, statistical analysis, sample size, and subject population result in certain inconsistencies in the response to therapy, the cumulative data from in vitro, preclinical, and clinical studies largely support the therapeutic claims for guggul described in the ancient Ayurvedic text. However, future clinical studies with much larger size and longer term are required to confirm these claims. The cardiovascular benefits of the therapy are derived from the multiple pharmacological activities associated with guggul or guggulsterone, notably its hypolipidemic, antioxidant, and antiinflammatory activities. It has been established that guggulsterone is an antagonist at farnesoid x receptor (FXR), a key transcriptional regulator for the maintenance of cholesterol and bile acid homeostasis. The FXR antagonism by guggulsterone has been proposed as a mechanism for its hypolipidemic effect. A recent study demonstrates that guggulsterone upregulates the bile salt export pump (BSEP), an efflux transporter responsible for removal of cholesterol metabolites, bile acids from the liver. Such upregulation of BSEP expression by guggulsterone favors cholesterol metabolism into bile acids, and thus represents another possible mechanism for its hypolipidemic activity. Guggulsterone has been found to potently inhibit the activation of nuclear factor-kappaB (NF-kappaB), a critical regulator of inflammatory responses. Such repression of NF-kappaB activation by guggulsterone has been proposed as a mechanism of the antiinflammatory effect of guggulsterone.

Pregnane X receptor and natural products: beyond drug-drug interactions

The pregnane X receptor (PXR, NR1I2) is a member of the nuclear receptor superfamily that is activated by a myriad of compounds and natural products in clinical use. Activation of PXR represents the basis for several clinically important drug-drug interactions. Although PXR activation has undesirable effects in patients on combination therapy, it also mediates the hepatoprotective effects exhibited by some herbal remedies. This review focuses on PXR activation by natural products and the potential therapeutic opportunities presented. In particular, the biological effects of St. John's Wort, gugulipid, kava kava, Coleus forskolii, Hypoxis, Sutherlandia, qing hao, wu wei zi, gan cao and other natural products are discussed. The impact of these natural products on drug metabolism and hepatoprotection is highlighted in the context of activation and antagonism of PXR.

Enhanced pro-apoptotic and anti-adipogenic effects of genistein plus guggulsterone in 3T3-L1 adipocytes

Genistein (G), an isoflavone, and guggulsterone (GS), the active substance in guggulipid, have been reported to possess therapeutic effects for obesity. In the present study, we investigated the effects of combinations of G plus GS on apoptosis and adipogenesis in 3T3-L1 cells. In mature adipocytes, G and GS individually caused apoptosis, but combination of G plus GS significantly increased apoptosis, more than either compound alone. Furthermore, G plus GS caused a greater increase in procaspase-3 cleavage, Bax expression, cytochrome c release, and proteolytic cleavage of PARP than either compound alone. In maturing preadipocytes G and GS each suppressed lipid accumulation, but the combination potentiated the inhibition of lipid accumulation. These results suggest that combination of genistein and guggulsterone may exert anti-obesity effects by inhibiting adipogenesis and inducing apoptosis in adipocytes.

Dietary Supplements for The Prevention and Treatment of Coronary Artery Disease

PURPOSE

With the recent growth in the use of dietary supplements, it is increasingly important for clinicians to be familiar with the evidence for and against their efficacy. We set out to systematically review the dietary supplements available for the prevention and treatment of coronary artery disease.

METHODS

Between May 2004 and May 2006, we searched MEDLINE, the Cochrane Library, and Pro-Quest using the MeSH terms hypertension, hypercholesterolemia, myocardial infarction, dietary supplements, and herb-drug interactions. The MeSH terms of individual supplements identified were then added to the search. Reference lists of pertinent papers were also searched to find appropriate papers for inclusion. We included randomized controlled trials published in English of at least 1 week's duration that studied the efficacy of supplements in the treatment of hypercholesterolemia, or hypertension, or in the prevention of cardiac events. Qualifying papers were identified and assigned a Jadad quality score. In areas of uncertainty, a second investigator independently scored the trial.

RESULTS

Fifteen (15) supplements were identified. Of these, most had little data available and most of the data were of poor quality. The supplements with the most supporting data were policosanol and garlic, both for hyperlipidemia.

CONCLUSIONS

A growing body of literature exists for numerous supplements in the prevention of coronary artery disease, but much of these data are inconclusive. Clinicians should become familiar with the extent and limitations of this literature so that they may counsel their patients better.

Guggul for hyperlipidemia: A review by the Natural Standard Research Collaboration

OBJECTIVE

To evaluate the scientific evidence on guggul for hyperlipidemia including expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

METHODS

Electronic searches were conducted in nine databases, 20 additional journals (not indexed in common databases), and bibliographies from 50 selected secondary references. No restrictions were placed on language or quality of publications. All literature collected pertained to efficacy in humans, dosing, precautions, adverse effects, use in pregnancy/lactation, interactions, alteration of laboratory assays, and mechanism of action. Standardized inclusion/exclusion criteria were utilized for selection.

RESULTS

Before 2003, most scientific evidence suggested that guggulipid elicits significant reductions in serum total cholesterol, low-density lipoprotein (LDL), and triglycerides, as well as elevations in high-density lipoprotein (HDL) [Kotiyal JP, Bisht DB, Singh DS. Double blind cross-over trial of gum guggulu (Commiphora mukul) Fraction A in hypercholesterolemia. J Res Indian Med Yoga Hom 1979;14(2):11-6; Kotiyal JP, Singh DS, Bisht DB. Gum guggulu (Commiphora mukul) fraction 'A' in obesity-a double-blind clinical trial. J Res Ayur Siddha 1985;6(1, 3, 4):20-35; Gaur SP, Garg RK, Kar AM, et al. Gugulipid, a new hypolipidaemic agent, in patients of acute ischaemic stroke: effect on clinical outcome, platelet function and serum lipids. Asia Pacif J Pharm 1997;12:65-9; Urizar NL, Liverman AB, Dodds DT, et al. A natural product that lowers cholesterol as an antagonist ligand for the FXR. Science 3 May 2002 [Science Express Reports]; Nityanand S, Srivastava JS, Asthana OP. Clinical trials with gugulipid. A new hypolipidaemic agent. J Assoc Physicians India 1989;37(5):323-8; Kuppurajan K, Rajagopalan SS, Rao TK, et al. Effect of guggulu (Commiphora mukul-Engl.) on serum lipids in obese, hypercholesterolemic and hyperlipemic cases. J Assoc Physicians India 1978;26(5):367-73; Gopal K, Saran RK, Nityanand S, et al. Clinical trial of ethyl acetate extract of gum gugulu (gugulipid) in primary hyperlipidemia. J Assoc Physicians India 1986;34(4):249-51; Agarwal RC, Singh SP, Saran RK, et al. Clinical trial of gugulipid-a new hypolipidemic agent of plant origin in primary hyperlipidemia. Indian J Med Res 1986;84:626-34; Verma SK, Bordia A. Effect of Commiphora mukul (gum guggulu) in patients of hyperlipidemia with special reference to HDL-cholesterol. Indian J Med Res 1988;87:356-60; Singh RB, Niaz MA, Ghosh S. Hypolipidemic and antioxidant effects of Commiphora mukul as an adjunct to dietary therapy in patients with hypercholesterolemia. Cardiovasc Drugs Ther 1994;8(4):659-64; Ghorai M, Mandal SC, Pal M, et al. A comparative study on hypocholesterolaemic effect of allicin, whole germinated seeds of bengal gram and guggulipid of gum gugglu. Phytother Res 2000;14(3):200-02]. However, most published studies were small and methodologically flawed. In August 2003, a well-designed trial reported small significant increases in serum LDL levels associated with the use of guggul compared to placebo [Szapary PO, Wolfe ML, Bloedon LT, et al. Guggulipid for the treatment of hypercholesterolemia: a randomized controlled trial. JAMA 2003;290(6):765-72]. No significant changes in total cholesterol, high-density lipoprotein (HDL), or triglycerides were measured. These results are consistent with two prior published case reports [Das Gupta R. Gugulipid: pro-lipaemic effect. J Assoc Physicians India 1990;38(12):346].

CONCLUSION

The effects of guggulipid in patients with high cholesterol are not clear, with some studies finding cholesterol-lowering effects, and other research suggesting no benefits. At this time, there is not enough scientific evidence to support the use of guggul for any medical condition. Guggul may cause stomach discomfort or allergic rash as well as other serious side effects and interactions. It should be avoided in pregnant or breast-feeding women and in children. Safety of use beyond 4 months has not been well studied.

Loss of functional farnesoid X receptor increases atherosclerotic lesions in apolipoprotein E-deficient mice

The farnesoid X receptor (FXR) is a bile acid-activated transcription factor that regulates the expression of genes critical for bile acid and lipid homeostasis. This study was undertaken to investigate the pathological consequences of the loss of FXR function on the risk and severity of atherosclerosis. For this purpose, FXR-deficient (FXR-/-) mice were crossed with apolipoprotein E-deficient (ApoE-/-) mice to generate FXR-/- ApoE-/- mice. Challenging these mice with a high-fat, high-cholesterol (HF/HC) diet resulted in reduced weight gain and decreased survival compared with wild-type, FXR-/-, and ApoE-/- mice. FXR-/- ApoE-/- mice also had the highest total plasma lipids and the most atherogenic lipoprotein profile. Livers from FXR-/- and FXR-/- ApoE-/- mice exhibited marked lipid accumulation, focal necrosis (accompanied by increased levels of plasma aspartate aminotransferase), and increased inflammatory gene expression. Measurement of en face lesion area of HF/HC-challenged mice revealed that although FXR-/- mice did not develop atherosclerosis, FXR-/- ApoE-/- mice had approximately double the lesion area compared with ApoE-/- mice. In conclusion, loss of FXR function is associated with decreased survival, increased severity of defects in lipid metabolism, and more extensive aortic plaque formation in a mouse model of atherosclerotic disease.

Isohumulones, bitter acids derived from hops, activate both peroxisome proliferator-activated receptor alpha and gamma and reduce insulin resistance

The peroxisome proliferator-activated receptors (PPARs) are dietary lipid sensors that regulate fatty acid and carbohydrate metabolism. The hypolipidemic effects of fibrate drugs and the therapeutic benefits of the thiazolidinedione drugs are due to their activation of PPARalpha and -gamma, respectively. In this study, isohumulones, the bitter compounds derived from hops that are present in beer, were found to activate PPARalpha and -gamma in transient co-transfection studies. Among the three major isohumulone homologs, isohumulone and isocohumulone were found to activate PPARalpha and -gamma. Diabetic KK-Ay mice that were treated with isohumulones (isohumulone and isocohumulone) showed reduced plasma glucose, triglyceride, and free fatty acid levels (65.3, 62.6, and 73.1%, respectively, for isohumulone); similar reductions were found following treatment with the thiazolidinedione drug, pioglitazone. Isohumulone treatment did not result in significant body weight gain, although pioglitazone treatment did increase body weight (10.6% increase versus control group). C57BL/6N mice fed a high fat diet that were treated with isohumulones showed improved glucose tolerance and reduced insulin resistance. Furthermore, these animals showed increased liver fatty acid oxidation and a decrease in size and an increase in apoptosis of their hypertrophic adipocytes. A double-blind, placebo-controlled pilot study for studying the effect of isohumulones on diabetes suggested that isohumulones significantly decreased blood glucose and hemoglobin A1c levels after 8 weeks (by 10.1 and 6.4%, respectively, versus week 0). These results suggest that isohumulones can improve insulin sensitivity in high fat diet-fed mice with insulin resistance and in patients with type 2 diabetes.

Lipid lowering activity of Phyllanthus niruri in hyperlipemic rats

The lipid lowering activity (LLA) of Phyllanthus niruri has been studied in triton and cholesterol fed hyperlipemic rats. Serum lipids were lowered by P. niruri extract orally fed (250 mg/kg b.w.) to the triton WR-1339 induced hyperlipemic rats. Chronic feeding of this drugs (100 mg/kg b.w.) in animals simultaneously fed with cholesterol (25 mg/kg b.w.) for 30 days caused lowering in the lipids and apoprotein levels of VLDL and LDL in experimental animals. The LLA of this drug is mediated through inhibition of hepatic cholesterol biosynthesis, increased faecal bile acids excretion and enhanced plasma lecithin: cholesterol acyltransferase activity.

Hypolipidaemic activity of seaweed from Karachi coast

During the present study, ethanol extracts of five seaweed species Solieria robusta, Iyengaria stellata, Colpomenia sinuosa, Spatoglossum asperum and Caulerpa racemosa at 10 mg/ 200 g body weight were tested for their hypolipidaemic activity. All the species significantly decreased the serum total cholesterol, triglyceride and low density lipoprotein cholesterol levels in normal, triton-induced and diet-induced hyperlipidaemic rats. Solieria robusta was found to be the most effective in reducing the lipid profile, particularly in diet-induced hyperlipidaemic rats. A beneficial effect of the ethanol extract of S. asperum was also found on cardiac and liver enzymes in diet-induced hyperlipidaemic rats.

Effect of tincture of Crataegus on the LDL-receptor activity of hepatic plasma membrane of rats fed an atherogenic diet

Tincture of Crataegus, (TCR), is a hypocholesterolemic and antiatherosclerotic drug made from berries of hawthorn, Crataegus oxyacantha. Its main constituents are flavonoids, triterpene saponins and a few cardioactive amines. TCR, when administered simultaneously to rats fed an atherogenic diet, significantly increased the binding of 125I-LDL to the liver plasma membranes, in vitro. Scatchard analysis of the specific binding data revealed that under the influence of TCR treatment the liver membranes bound to a greater number of 125I-LDL molecules indicating an enhancement in the LDL-receptor activity. TCR was also shown to increase bile acid excretion and to depress hepatic cholesterol synthesis in atherogenic diet fed rats. With these observations in view, the hypocholesterolemic action of TCR appears to be due to an upregulation of hepatic LDL-receptors resulting in greater influx of plasma cholesterol into the liver. TCR also prevents the accumulation of cholesterol in the liver by enhancing cholesterol degradation to bile acids and by simultaneously suppressing cholesterol biosynthesis. The various constituents of TCR may act synergistically to bring about the observed effects.