Nutraceuticals: vitamins and other nutrients in coronary heart disease

Antarctic microorganisms as source of the omega-3 polyunsaturated fatty acids

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are long-chain polyunsaturated fatty acids (PUFAs) that belong to the omega-3 group. They are essential fatty acids found in phospholipid of cell membranes. There is strong evidence that these nutrients may also favorably modulate many diseases. Primary sources of omega-3 PUFAs in the human diet are fish and fish-derived products. The fishing industry worldwide, however, is becoming unable to satisfy the growing demand for these PUFAs. A promising cost-effective alternative source of PUFAs is bacterial production. We identified 40 Antarctic marine bacterial isolates by 16S rRNA gene sequence analysis. Fifteen genera in three phyla were represented in the collection. Isolates were tested for ability to produce EPA using a method in which their ability to reduce 2,3,5-triphenyltetrazolium chloride (TTC) is determined and by gas chromatography coupled to mass spectrometry (GC-MS). All isolates could reduce TTC, and GC-MS analysis showed that four produced EPA and that six produced DHA. We show for the first time that isolates identified as Cellulophaga, Pibocella and Polaribacter can produce EPA and DHA, only DHA or only EPA, respectively. One isolate, Shewanella sp. (strain 8-5), is indicated to be a good candidate for further study to optimize growth and EPA production. In conclusion, a rapid method was tested for identification of new EPA producing strains from marine environments. New EPA and DHA producing strains were found as well as a potentially useful PUFA production strain.

Combined effects of niacin and chromium treatment on heart of hyperlipidemic rats

The present study was undertaken to investigate the effects of the combination of niacin and chromium(III)-chloride on heart glutathione (GSH), lipid peroxidation (LPO) levels, serum paraoxonase (PON), gamma-glutamyl transferase (GGT) activities and protein carbonyl contents (PCC) of hyperlipidemic rats. In this study, female Swiss albino rats were used. They were divided into four groups. The animals of the first group (group I) were fed with pellet chow. The rats (group II) were fed with a lipogenic diet consisting of 2% cholesterol, 0.5% cholic acid and 20% sunflower oil added to the pellet chow, and given 3% alcoholic water for 60 days. The rats (group III) were fed with the same lipogenic diet and treated by gavage technique with CrCl(3) 6H(2)O to a dose of 250 µg/kg and 100 mg/kg niacin for 45 days, 15 days after experimental animals were done hyperlipidemic. Group IV was fed with pellet chow and treated with 250 µg/kg CrCl(3) 6H(2)O and 100 mg/kg niacin for 45 days. On the 60th day, the heart tissue and blood samples were taken from animals. As a result, heart LPO, serum GGT activity and serum PCC were increased; serum PON activity and heart GSH levels were decreased in hyperlipidemic rats. Treatment with combined niacin and chromium reversed these effects. In conclusion, the combined treatment with niacin and chromium might induce a protective effect on heart tissue.

Bacteria Coated by Polyphenols Acquire Potent Oxidant-Scavenging Capacities

Several microbial species, including probiotic lactic acid bacteria, have the ability to irreversibly bind a large variety of polyphenols (flavonoids) and anthocyanidins found in many colored fruits and vegetables and to enhance their total oxidant-scavenging capacities (TOSC). The binding of flavonoids to microbial surfaces was further increased by the cationic polyelectrolytes ligands poly-L-histidine, chlorhexidine and Copaxone®. This phenomenon was confirmed visually, by the FRAP, DPPH, cyclic voltammetry, Folin-Ciocalteu as well as by luminol-dependent chemiluminescence techniques employed to assay TOSC. The possibility is considered that clinically, microbial cells in the oral cavity and in the gastro intestinal tract, complexed with antioxidant polyphenols from nutrients and with cationic ligands, might increase the protection of mammalian cells against damage induced by excessive generation of reactive oxygen species during infections and inflammation.

Inhibitory effect of aqueous extracts of some herbs on human platelet aggregation in vitro

Effect of aqueous extract of several herbs on human platelet aggregation in vitro was investigated. Out of 28 herbs/nutriceuticals investigated, camomile, nettle alfalfa, garlic and onion exhibited most significant anti-platelet activity (>or=45% inhibition). Aqueous extracts of alfalfa, fresh nettle, and camomile inhibited ADP induced-platelet aggregation by 73, 65 and 60%, respectively, compared with control (P < 0.05). Camomile and alfalfa inhibited collagen-induced platelet aggregation by 84 and 65%, respectively, but nettle could not inhibit collagen-induced aggregation. In contrast, nettle was the most potent inhibitor (66%) of whole blood aggregation induced by collagen, followed by alfalfa (52%), and camomile (30%) compared with control (P < 0.05). None of these three herbs however could inhibit arachidonic acid or thrombin induced platelet aggregation. Camomile and alfalfa strongly inhibited thromboxane B2 synthesis induced by ADP or collagen, but nettle had no effect. Alfalfa and nettle increased cGMP levels in platelets by 50 and 35%, respectively, compared with the control (1.85 +/- 0.23 nM) (P < 0.005). All these data indicate that camomile, nettle and alfalfa have potent anti-platelet properties, and their inhibitory actions are mediated via different mechanisms.

The Effect of Combined Treatment with Niacin and Chromium (III) Chloride on the Different Tissues of Hyperlipemic Rats

We investigated the effects of a combined treatment with chromium (Cr) and niacin on the spleen, tongue, and lens tissues in terms of lipid peroxidation (LPO), glutathione (GSH), serum catalase (CAT), lactate dehydrogenase (LDH), serum cholesterol, and total lipid levels in normal and hyperlipemic rats. In this study, female 1-year-old Swiss albino rats were used. The rats were randomly divided into four groups. Group I rats (control) were fed with standard pellet chow. Group II rats were fed a lipogenic diet in which 2% cholesterol, 0.5% cholic acid, and 20% sunflower oil were added and were given 3% alcoholic water for 60 days. Group III rats were fed with the same lipogenic diet and were treated with a dose of 250 microg/kg body weight CrCI3 x 6H2O and 100 mg/kg body weight niacin, for 45 days, by gavage. The rats in group IV were fed with pellet chow and treated with 250 microg/kg body weight CrCI3 x 6H2O and 100 mg/kg body weight niacin, by gavage, for 45 days. After 2 weeks, the animals showed symptoms of hyperlipemia. On the 60th day, tissue and blood samples were taken. We have observed decreased CAT activity and GSH levels, increased LDH activity, cholesterol, total lipid, and LPO levels in hyperlipemic rats. Niacin and Cr administration to hyperlipemic rats increased tissue GSH levels and CAT activity and decreased tissue LPO levels and LDH activity, cholesterol, and total lipid levels compared with hyperlipemic rats. We conclude that the administration of a combination of niacin and chromium has a protective effect against oxidative damage to tongue, lens, and spleen tissues as a result of hyperlipemia.

Vitamin E in human health and disease

Vitamin E in nature is comprised of a family of tocopherols and tocotrienols. The most studied of these is alpha-tocopherol (alpha-TOH), because this form is retained within the body, and vitamin E deficiency is corrected with this supplement. alpha-TOH is a lipid-soluble antioxidant required for the preservation of cell membranes, and it potentially acts as a defense against oxidative stress. Many studies have investigated the metabolism, transport, and efficacy alpha-TOH in the prevention of sequelae associated with cardiovascular disease (CVD). Supplementation with vitamin E is considered to provide health benefits against CVD through its antioxidant activity, the prevention of lipoprotein oxidation, and the inhibition of platelet aggregation. However, the results from large prospective, randomized, placebo-controlled clinical trials with alpha-TOH have been largely negative. A recent meta-analysis suggests that alpha-TOH supplements may actually increase all-cause mortality; however, the mechanism for this increased risk is unknown. In vitro studies performed in human cell cultures and animal models suggest that vitamin E might increase the hepatic production of cytochrome P450s and MDR1. Induction of CYP3A4 or MDR1 by vitamin E could potentially lower the efficacy of any drug metabolized by CYP3A4 or MDR1. Other possibilities include an adverse effect of alpha-TOH on blood pressure in high-risk populations. Because of the wide popularity and use of vitamin E supplements, further research into potential adverse effects is clearly warranted.

High-value oils from plants

The seed oils of domesticated oilseed crops are major agricultural commodities that are used primarily for nutritional applications, but in recent years there has been increasing use of these oils for production of biofuels and chemical feedstocks. This is being driven in part by the rapidly rising costs of petroleum, increased concern about the environmental impact of using fossil oil, and the need to develop renewable domestic sources of fuel and industrial raw materials. There is also a need to develop sustainable sources of nutritionally important fatty acids such as those that are typically derived from fish oil. Plant oils can provide renewable sources of high-value fatty acids for both the chemical and health-related industries. The value and application of an oil are determined largely by its fatty acid composition, and while most vegetable oils contain just five basic fatty acid structures, there is a rich diversity of fatty acids present in nature, many of which have potential usage in industry. In this review, we describe several areas where plant oils can have a significant impact on the emerging bioeconomy and the types of fatty acids that are required in these various applications. We also outline the current understanding of the underlying biochemical and molecular mechanisms of seed oil production, and the challenges and potential in translating this knowledge into the rational design and engineering of crop plants to produce high-value oils in plant seeds.

Role of oxidants and antioxidants in atherosclerosis: results of in vitro and in vivo investigations

Both in vitro and in vivo studies have shown that oxidants are central in the development of atherosclerosis. Consequently, additional studies evaluated the protective effects of various natural and synthetic antioxidants, alone and in combination, with most studies focusing on alpha-tocopherol (vitamin E). Here, we summarize the role of oxidants in the pathomechanism of atherosclerosis. We also discuss epidemiological studies and others focused on the protective effect of vitamin E against atherosclerosis. Other antioxidants are also considered if they were included in studies involving vitamin E. The protective effect of antioxidants on atherosclerotic pathomechanisms has been confirmed in vitro, but only in some animal studies. Various epidemiological and observational studies have produced conflicting results on the protective effect of antioxidants. Most studies of primary or secondary prevention failed to show a protective effect. These conflicting results are biased by a number of factors, including differences between the study groups. Therefore, we describe these studies in detail.

Naturally derived micelles for rapid in vitro screening of potential cholesterol-lowering bioactives

A high plasma cholesterol level, especially low-density lipoprotein cholesterol, indicates increased risk of cardiovascular diseases. Plasma cholesterol levels are influenced by diet and cholesterol biosynthesis, uptake, and secretion. Cholesterol uptake involves solubilization into complex phospholipid spherical bodies termed micelles that facilitate the transport of lipids through the gut brush border membrane into enterocytes. In vitro assays reported to date to determine potential cholesterol-lowering effects of various compounds require artificial micelle preparations that are elaborate and time-consuming to prepare. The aims of this study were to compare the efficacy of artificially prepared micelles with naturally derived micelles from pig's bile and to test their ability to assess potential inhibitors of cholesterol uptake. The suitability of pig's bile-derived micelles was tested both at the level of the micelle and at cellular uptake using cultured Caco-2 cells. Known cholesterol uptake inhibitors at the micelle (green tea catechins) and at the Caco-2 cell (beta-lactoglobulin-derived peptide, IIAEK) were used as reference inhibitory compounds. It was concluded that pig's bile was a rapid, reproducible, convenient, and cost-effective source of micelles for cholesterol micelle solubility and cellular uptake assay systems and is suitable for screening purposes focused on identifying potential cholesterol-lowering agents.

Marine pharmacology in 2001--2002: marine compounds with anthelmintic, antibacterial, anticoagulant, antidiabetic, antifungal, anti-inflammatory, antimalarial, antiplatelet, antiprotozoal, antituberculosis, and antiviral activities; affecting the cardiovascular, immune and nervous systems and other miscellaneous mechanisms of action

During 2001--2002, research on the pharmacology of marine chemicals continued to be global in nature involving investigators from Argentina, Australia, Brazil, Canada, China, Denmark, France, Germany, India, Indonesia, Israel, Italy, Japan, Mexico, Netherlands, New Zealand, Pakistan, the Philippines, Russia, Singapore, Slovenia, South Africa, South Korea, Spain, Sweden, Switzerland, Thailand, United Kingdom, and the United States. This current article, a sequel to the authors' 1998, 1999 and 2000 marine pharmacology reviews, classifies 106 marine chemicals derived from a diverse group of marine animals, algae, fungi and bacteria, on the basis of peer-reviewed preclinical pharmacology. Anthelmintic, antibacterial, anticoagulant, antifungal, antimalarial, antiplatelet, antiprotozoal, antituberculosis or antiviral activities were reported for 56 marine chemicals. An additional 19 marine compounds were shown to have significant effects on the cardiovascular, immune and nervous system as well as to possess anti-inflammatory and antidiabetic effects. Finally, 31 marine compounds were reported to act on a variety of molecular targets and thus may potentially contribute to several pharmacological classes. Thus, during 2001--2002 pharmacological research with marine chemicals continued to contribute potentially novel chemical leads for the ongoing global search for therapeutic agents for the treatment of multiple disease categories.

Neuroprotection by flavonoids

The high morbidity, high socioeconomic costs and lack of specific treatments are key factors that define the relevance of brain pathology for human health and the importance of research on neuronal protective agents. Epidemiological studies have shown beneficial effects of flavonoids on arteriosclerosis-related pathology in general and neurodegeneration in particular. Flavonoids can protect the brain by their ability to modulate intracellular signals promoting cellular survival. Quercetin and structurally related flavonoids (myricetin, fisetin, luteolin) showed a marked cytoprotective capacity in in vitro experimental conditions in models of predominantly apoptotic death such as that induced by medium concentrations (200 M) of H2O2 added to PC12 cells in culture. Nevertheless, quercetin did not protect substantia nigra neurons in vivo from an oxidative insult (6-hydroxydopamine), probably due to difficulties in crossing the blood-brain barrier. On the other hand, treatment of permanent focal ischemia with a lecithin/quercetin preparation decreased lesion volume, showing that preparations that help to cross the blood-brain barrier may be critical for the expression of the effects of flavonoids on the brain. The hypothesis is advanced that a group of quercetin-related flavonoids could become lead molecules for the development of neuroprotective compounds with multitarget anti-ischemic effects.

Nutraceuticals: a pharmaceutical viewpoint: I

PURPOSE OF REVIEW

To review pharmaceutical aspects of selected amino acids, antioxidants and related nutraceuticals, deemed to be important for clinical nutrition.

RECENT FINDINGS

New clinical applications of nutraceuticals are increasingly being reported, but there are fundamental differences between formulation, production and the evidence supporting clinical use. Nutraceuticals generally fall within the novel foods and ingredients regulations but their purity, dosage requirements and clinical consequences exceed those of most 'healthfoods'. Replacement of one nutrient or antioxidant is unlikely to correct the cascade of interconnected metabolic abnormalities associated with many diseases. However, it is difficult to ascertain whether the reported benefits of complex mixtures, with little published stability data, are due to one or more individual substrates or some in-vitro interaction between them. Many clinical studies have suffered from inconsistencies of dose, formulation discrepancies and unproven outcome. These contradictory results weaken any firm evidence base to substantiate their effectiveness.

SUMMARY

Nutraceuticals are destined to play an important role in future therapeutic developments but their success will be governed by control of purity, safety and efficacy without inhibiting innovation. The straightforward application of pharmaceutical standards, especially across national borders, is likely to be a difficult challenge and could effectively paralyse the industry. Nevertheless more standardized formulations, dosage forms and production controls are called for. A place for nutraceuticals in clinical practice is emerging, but important pharmaceutical and clinical issues need to be addressed by further research.

Polyunsaturated fatty acid synthesis: what will they think of next?

Polyunsaturated fatty acids have crucial roles in membrane biology and signaling processes in most living organisms. However, it is only recently that molecular genetic approaches have allowed detailed studies of the enzymes involved in their synthesis. New evidence has revealed a range of pathways in different organisms. These include a complex sequence for synthesis of docosahexaenoic acid (22:6) in mammals and a polyketide synthase pathway in marine microbes.