Astaxanthin: sources, extraction, stability, biological activities and its commercial applications--a review

There is currently much interest in biological active compounds derived from natural resources, especially compounds that can efficiently act on molecular targets, which are involved in various diseases. Astaxanthin (3,3'-dihydroxy-β, β'-carotene-4,4'-dione) is a xanthophyll carotenoid, contained in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum, and Phaffia rhodozyma. It accumulates up to 3.8% on the dry weight basis in H. pluvialis. Our recent published data on astaxanthin extraction, analysis, stability studies, and its biological activities results were added to this review paper. Based on our results and current literature, astaxanthin showed potential biological activity in in vitro and in vivo models. These studies emphasize the influence of astaxanthin and its beneficial effects on the metabolism in animals and humans. Bioavailability of astaxanthin in animals was enhanced after feeding Haematococcus biomass as a source of astaxanthin. Astaxanthin, used as a nutritional supplement, antioxidant and anticancer agent, prevents diabetes, cardiovascular diseases, and neurodegenerative disorders, and also stimulates immunization. Astaxanthin products are used for commercial applications in the dosage forms as tablets, capsules, syrups, oils, soft gels, creams, biomass and granulated powders. Astaxanthin patent applications are available in food, feed and nutraceutical applications. The current review provides up-to-date information on astaxanthin sources, extraction, analysis, stability, biological activities, health benefits and special attention paid to its commercial applications.

Effects of calcium ions and local anesthetics on electrical properties of Purkinje fibres

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Peripartum cardiomyopathy: National Heart, Lung, and Blood Institute and Office of Rare Diseases (National Institutes of Health) workshop recommendations and review

OBJECTIVE

Peripartum cardiomyopathy (PPCM) is a rare life-threatening cardiomyopathy of unknown cause that occurs in the peripartum period in previously healthy women. In April 1997, the National Heart, Lung, and Blood Institute (NHLBI) and the Office of Rare Diseases of the National Institutes of Health (NIH) convened a Workshop on Peripartum Cardiomyopathy to foster a systematic review of information and to develop recommendations for research and education.

PARTICIPANTS

Fourteen workshop participants were selected by NHLBI staff and represented cardiovascular medicine, obstetrics, immunology, and pathology. A representative subgroup of 8 participants and NHLBI staff formed the writing group for this article and updated the literature on which the conclusions were based. The workshop was an open meeting, consistent with NIH policy.

EVIDENCE

Data presented at the workshop were augmented by a MEDLINE search for English-language articles published from 1966 to July 1999, using the terms peripartum cardiomyopathy, cardiomyopathy, and pregnancy. Articles on the epidemiology, pathogenesis, pathophysiology, diagnosis, treatment, and prognosis of PPCM were included. RECOMMENDATION PROCESS: After discussion of data presented, workshop participants agreed on a standardized definition of PPCM, a general clinical approach, and the need for a registry to provide an infrastructure for future research.

CONCLUSIONS

Peripartum cardiomyopathy is a rare lethal disease about which little is known. Diagnosis is confined to a narrow period and requires echocardiographic evidence of left ventricular systolic dysfunction. Symptomatic patients should receive standard therapy for heart failure, managed by a multidisciplinary team. If subsequent pregnancies occur, they should be managed in collaboration with a high-risk perinatal center. Systematic data collection is required to answer important questions about incidence, treatment, and prognosis.

George E. Brown memorial lecture. Oxygen radicals in cerebral vascular injury

Acute, severe increases in arterial blood pressure cause sustained cerebral arteriolar dilation, abnormal reactivity to carbon dioxide and to changes in blood pressure, abolition of endothelium-dependent dilation from acetylcholine, discrete morphological lesions of the endothelium and vascular smooth muscle, and breakdown of the blood-brain barrier to plasma proteins. The dilation, abnormal reactivity, and morphological abnormalities are inhibited by pretreatment with cyclooxygenase inhibitors or with free radical scavengers. Superoxide dismutase-inhibitable reduction of nitroblue tetrazolium applied to the brain surface was detectable both during hypertension and one hour after hypertension subsided. Nitroblue tetrazolium reduction is also reduced by inhibitors of the anion channel. The abnormalities seen after hypertension are reproduced by topical application of arachidonate. The results are consistent with the view that acute hypertension induces generation of superoxide anion radical in association with accelerated arachidonate metabolism via cyclooxygenase. This radical enters cerebral extracellular space via the anion channel and gives rise to hydrogen peroxide and hydroxyl radical. All three radicals are capable of causing vasodilation by relaxation of cerebral vascular smooth muscle. The hydroxyl radical is the most likely candidate for vascular wall damage. The significance of this mechanism in chronic experimental hypertension or its relevance to human disease is not known.

Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography

Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

Geographic variation in the treatment of acute myocardial infarction: the Cooperative Cardiovascular Project

CONTEXT

Quality indicators for the treatment of acute myocardial infarction include pharmacologic therapy, reperfusion, and smoking cessation advice, but these therapies may not be administered to all patients who could benefit from them.

OBJECTIVE

To assess geographic variation in adherence to quality indicators for treatment of acute myocardial infarction.

DESIGN

Inception cohort using data from the Health Care Financing Administration Cooperative Cardiovascular Project.

SETTING

Acute care hospitals in the United States.

PATIENTS

A total of 186800 Medicare beneficiaries hospitalized for treatment of confirmed acute myocardial infarction from February 1994 through July 1995.

MAIN OUTCOME MEASURES

Adherence to quality indicators for pharmacologic therapy, reperfusion, and smoking cessation advice for patients judged to be ideal candidates for these therapies. The mean rates of adherence to these quality indicators for the entire United States were determined, and the 20th and 80th percentiles of the age- and sex-adjusted rates for each of 306 hospital referral regions were contrasted (mean rate [20th-80th percentiles]).

RESULTS

Aspirin was used frequently both during hospitalization (86.2% [82.6%-90.1%]) and at discharge (77.8% [72.5% -83.9%]). Calcium channel blockers were withheld from most patients with impaired left ventricular function (81.9% [73.6%-90.8%]). Lower rates were seen in the use of angiotensin-converting enzyme inhibitors at discharge (59.3% [49.2%-69.2%]); reperfusion, using thrombolytic therapy or coronary angioplasty (67.2% [59.8%-75.1%]); prescription of beta-blockers at discharge (49.5% [35.8%-61.5%]); and for smoking cessation advice (41.9% [32.8%-51.3%]).

CONCLUSIONS

Substantial geographic variation exists in the treatment of patients with acute myocardial infarction, and these gaps between knowledge and practice have important consequences. Therapies with proven benefit for AMI are underused despite strong evidence that their use will result in better patient outcomes.

Rho-kinase inhibition with intracoronary fasudil prevents myocardial ischemia in patients with coronary microvascular spasm

OBJECTIVES

We sought to determine whether a potent Rho-kinase inhibitor fasudil prevents the occurrence of myocardial ischemia in patients with microvascular angina attributable to coronary microvascular spasm.

BACKGROUND

Effective treatment of patients with angina who have normal coronary arteriograms (microvascular angina) has not yet been established. Rho-kinase-mediated calcium sensitization of the myosin light chain in smooth muscle cells has been implicated as substantially contributing to vascular hyperconstriction.

METHODS

We studied consecutive 18 patients with angina and normal epicardial coronaries in whom intracoronary acetylcholine (ACh) induced myocardial ischemia (ischemic electrocardiographic changes, myocardial lactate production, or both) without angiographically demonstrable epicardial coronary vasospasm. All patients underwent a second ACh challenge test after pretreatment with either saline (n = 5) or fasudil (4.5 mg intracoronarily, n = 13).

RESULTS

Myocardial ischemia was reproducibly induced by ACh in the saline group. In contrast, 11 of the 13 patients pretreated with fasudil had no evidence of myocardial ischemia during the second infusion of ACh (p < 0.01). The lactate extraction ratio (median value [interquartile range]) during ACh infusion was improved by fasudil pretreatment, from -0.16 (-0.25 to 0.04) to 0.09 (0.05 to 0.18) (p = 0.0125).

CONCLUSIONS

Fasudil ameliorated myocardial ischemia in patients who were most likely having coronary microvascular spasm. The inhibition of Rho-kinase may be a novel therapeutic strategy for this group of patients with microvascular angina.

Studies on the control of hypertension by hyphex. II. Toxic reactions and side effects

Although effective in maintaining relatively normal levels of blood pressure in hypertensive patients and retarding some of the serious and fatal secondary consequences of the disease, hexamethonium ion and 1-hydrazinophthalazine can cause severe immediate and late reactions. The latter drug has produced collagen diseases of varying degrees of severity, all of which have regressed on cessation of medication, in 14 of 253 patients. The combination has given rise to fatal interstitial pneumonia in 5 of 89 in malignant stages of hypertension. Less serious side effects of each agent are also discussed.

Motor end-plate differences as a determining factor in the mode of action of neuromuscular blocking substances

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Potential for biodegradation and sorption of acetaminophen, caffeine, propranolol and acebutolol in lab-scale aqueous environments

Sorption and combined sorption-biodegradation experiments were conducted in laboratory batch studies with 100 g soil/sediments and 500 mL water to investigate the fates in aqueous environments of acetaminophen, caffeine, propranolol, and acebutolol, four frequently used and often-detected pharmaceuticals. All four compounds have demonstrated significant potential for degradation and sorption in natural aqueous systems. For acetaminophen, biodegradation was found to be a primary mechanism for degradation, with a half-life (t(1/2)) for combined sorption-biodegradation of 2.1 days; in contrast, sorption alone was responsible only for a 30% loss of aqueous-phase acetaminophen after 15 days. For caffeine, both biodegradation and sorption were important (t(1/2) for combined sorption-biodegradation was 1.5 days). However, for propranolol and acebutolol, sorption was found to be the most significant removal mechanism and was not affected by biodegradation. Desorption experiments revealed that the sorption process was mostly irreversible. High values were found for K(d) for caffeine, propranolol, and acebutolol, ranging from 250 to 1900 L kg(-1), which explained their greater tendency for sorption onto sediments, compared to the more hydrophilic acetaminophen. Experimentally derived values for logK(oc) differed markedly from values calculated from correlation equations. This discrepancy was attributed to the fact that these equations are well suited for hydrophobic interactions but may fail to predict the sorption of polar and ionic compounds. These results suggest that mechanisms other than hydrophobic interactions played an important role in the sorption process.

Coronary Heart Disease in Patients With Diabetes

Diabetes mellitus (DM) is a worldwide epidemic. Its prevalence is rapidly increasing in both developing and developed countries. Coronary heart disease (CHD) is highly prevalent and is the major cause of morbidity and mortality in diabetic patients. The purpose of this review is to assess the clinical impact of recent advances in the epidemiology, prevention, and management of CHD in diabetic patients. A systematic review of publications in this area, referenced in MEDLINE in the past 5 years (2000 to 2005), was undertaken. Patients with CHD and prediabetic states should undergo lifestyle modifications aimed at preventing DM. Pharmacological prevention of DM is also promising but requires further study. In patients with CHD and DM, routine use of aspirin and an angiotensin-converting enzyme inhibitor (ACE-I)--unless contraindicated or not tolerated-and strict glycemic, blood pressure, and lipid control are strongly recommended. The targets for secondary prevention in these patients are relatively well defined, but the strategies to achieve them vary and must be individualized. Intense insulin therapy might be needed for glycemic control, and high-dose statin therapy might be needed for lipid control. For blood pressure control, ACE-Is and angiotensin receptor blockers are considered as first-line therapy. Noncompliance, particularly with lifestyle measures, and underprescription of evidence-based therapies remain important unsolved problems.

Cardiovascular effects of ginger aqueous extract and its phenolic constituents are mediated through multiple pathways

Ginger is a world known food plant which is equally reputed for its medicinal properties. We report here the hypotensive, endothelium-dependent and independent vasodilator and cardio-suppressant and stimulant effects of its aqueous extract (Zo.Cr). Zo.Cr, which tested positive for saponins, flavonoids, amines, alkaloids and terpenoids, induced a dose-dependent (3.0-10.0 mg/kg) fall in the arterial blood pressure (BP) of anaesthetized rats which was partially blocked by atropine (1 mg/kg). In isolated endothelium-intact rat aorta, Zo.Cr (0.01-5.0 mg/ml) relaxed the phenylephrine (1 microM)-induced contractions, effect partially blocked by atropine (1 microM). Zo.Cr inhibited the K+ (80 mM)-induced contractions and also shifted the Ca++ dose-response curves to the right, similar to verapamil, indicating Ca++ antagonist activity. An atropine-resistant and l-NAME-sensitive vasodilator activity was also noted from ginger phenolic constituents 6-, 8- and 10-gingerol, while 6-shogaol showed a mild vasodilator effect. In guinea-pig atria, Zo.Cr (0.1-5.0 mg/ml) inhibited the force and rate of atrial contractions. Pretreatment with atropine blocked the inhibitory effect and a stimulatory effect was unmasked which was resistant to propranolol and verapamil but sensitive to ryanodine, blocker of Ca++ release from intracellular stores. Later at doses >or=1.0 mg/ml, the extract completely suppressed the atrial tissue, effect resistant to glibenclamide, pyrilamine, aminophylline and L-NAME. These data indicate that the aqueous ginger extract lowers BP through a dual inhibitory effect mediated via stimulation of muscarinic receptors and blockade of Ca++ channels and this study provides sound mechanistic basis for the use of ginger in hypertension and palpitations.