Current Pharmaceutical Design - Volume 23, Issue 17, 2017

Background: Compounds and extracts derived from natural sources continue to stand in the spotlight of drug design owing to their versatile interaction with enzymes, receptors and metabolic pathways. Nanomedicine offers an operative tool for the efficient delivery of natural products, in terms of increased bioavailability, targeting, and controlled release while protecting active constituents against physico-chemical alterations. The interest of the scientific community in the field of nanosized delivery of natural compounds is demonstrated by the exponential growth of the publications in this field. Aim: Beyond the presentation of successful examples of nanoscale delivery systems containing natural products, the scope of this review is to point out the yet underexplored capacities of this field with relevance for the pharmaceutical and nutraceutical market. Review: Departing from a short presentation of plant-derived natural products and strategies to obtain nanoformulations, the current work discusses nanoparticulate drug delivery systems targeting diseases of various organs and systems: skin, central nervous system, skeletal tissue, cardiovascular apparatus, and diabetes. Conclusions: While notable progress has been achieved in the preparation of nanomedicines containing selected dietary polyphenols, works dealing with crude extracts or standardized fractions are much less frequent. In fact, most of the plants with solidly documented therapeutic properties and registered in pharmacopoeias still wait to benefit from advances in the field of nanotechnology. At least for some of them, adequate nanoformulation shall contribute to their removal from the group of dietary supplements and pharmaceutical preparations with suboptimal bioavailability and efficacy.

Background: Oxidative stress is implicated in the pathogenesis of a lot of age-related pathologies and some types of cancers. Carotenoids have shown antioxidant properties, due to the ability to quench singlet oxygen and to scavenge free radicals that may prevent and treat a wide range of chronic diseases. The aim of this review is to discuss the clinical evidence present in literature about the effects of carotenoids on human health and to evaluate their effectiveness in the prevention and treatment of many chronic diseases. Method: We reviewed studies on carotenoids claiming to show an effect in the prevention and treatment of many chronic diseases. In particular, we focused our attention on clinical trials published on Natural Medicine Comprehensive Database and PubMed. Results: A great number of clinical trials reported the beneficial effects of carotenoids on human health, in particular against skin, eye, hepatic, cardiovascular diseases and some types of cancer. Nevertheless, a few study evaluated the intake of carotenoids alone and sometimes the results are discording. Furthermore, irrational or excessive use of antioxidants may produce risk of potential toxicity. Conclusion: The antioxidant activity of carotenoids, taken with the diet or through nutritional supplements, seems to benefit human health. Therefore, it is necessary to test them alone and to evaluate their safety in longterm clinical trials on a large and heterogeneous sample of people.

Background: Cardiovascular disease (CVD) is a spectrum of diseases involving the heart and blood vessels, and the first cause of mortality worldwide. Medicinal plants have been used for thousands of years to treat CVD. In Traditional Persian Medicine (TPM), there is a special focus on heart diseases. Avicenna, a Persian physician of the eleventh century compiled a book devoted to this field named “The treatise on cardiac drugs” which is a compendium of TPM knowledge on CVD. Avicenna mentioned 50 cardiovascular active plants and described their therapeutic effects in the treatment of CVDs. Methods: Here, we perform a detailed search in scientific databases to verify the cardiovascular activities of the medicinal plants suggested by Avicenna. Also, we discussed cardiovascular activities of a number of the most important suggested plants as well as their efficacy in clinical studies. Major bioactive compounds identified from these plants are also discussed. Results: Pharmacological studies have revealed that the majority of these plants are effective in cardiovascular health with various mechanisms. Among them, Crocus sativus L., Cinnamomum cassia (L.) J. Presl, Punica granatum L., Ocimum basilicum L., Elettaria cardamomum (L.) Maton, Melissa officinalis L. and Phyllanthus emblica L. have proved to be more effective. Conclusion: The above-mentioned plants can be rich sources for developing new and effective pharmaceuticals for the treatment of CVDs.

The chemical structure of polyphenols consisting of aromatic rings, capable of quenching free radicals, makes them ideal candidates to protect against oxidation. Polyphenols are present in a variety of foods including grapes, berries, dark chocolate, coffee and tea to mention a few. A number of studies have shown that dietary polyphenols exert a protective effect against hypertension, dyslipidemias, inflammation, endothelial function and atherosclerosis, conditions associated with increased risk for cardiovascular disease. Studies indicate that by decreasing cholesterol absorption, polyphenols alter hepatic cholesterol homeostasis resulting in decreases in plasma lipids and reduction in atherogenic lipoproteins thus having a protective effect against atherosclerosis; polyphenols have also been shown to decrease the activity of enzymes involved in the renin-angiotensinaldosterone system and improve blood pressure. Further, they have been recognized to increase nitric oxide production and to improve endothelial function. In this review we will present some of the evidence derived from epidemiological studies, clinical interventions as well as animal and cell studies supporting the cardioprotective effects of dietary polyphenols.

The prevalence of hypertension (HTN) worldwide is high and is constantly rising. HTN is considered to be a silent killer since often there are no obvious symptoms but long-term, HTN significantly increases the risk of coronary heart disease and cerebrovascular diseases. Those with diagnosed HTN or at high risk of its development, should start blood pressure (BP) lowering therapy based on natural methods including: lifestyle, regular physical activity, respiratory training, reducing body mass, lowering sodium intake with food, potassium supplementation, balanced diet enriched with herbs, reducing caffeine and alcohol intake, smoking cessation, stress avoidance and regular monitoring of the BP. This review focuses on several most common methods of natural BP lowering since it is not possible to consider all of them.

Background: The endothelium is a large paracrine organ regulating cell growth, vascular tone and thrombogenicity as well as platelet and leukocyte interactions. Endothelial function can be assessed by noninvasive techniques [e.g. flow-mediated vasodilation, nitroglycerin-mediated dilation and pulse wave velocity] and measuring specific circulating biomarkers [cell adhesion molecules, endothelial microparticles and endothelial progenitor cells]. Impaired endothelial function plays a key role in the development of atherosclerosis, arterial hypertension, heart failure, ischemia-reperfusion injury, Alzheimer’s disease and other conditions. Endothelial function is also involved in growth and proliferation of tumor cells. Methods: We performed a literature review and assessed the role of the natural polyphenol, curcumin, as a potential inexpensive, well-tolerated, and safe agent for improving endothelial function. Results: Curcumin exerts several positive pharmacological effects; these include anti-inflammatory, antioxidant, anti-hypertensive, anti-cancer, antiviral, anti-infective and wound-healing properties. Specifically, curcumin’s anti-inflammatory effects are thought to be caused by reducing trans-endothelial monocyte migration by reduction of mRNA and protein expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and P-selectin and by modulating NFΚB, JNK, p38 and STAT-3 in endothelial cells. Dietary curcumin supplementation can also increase antioxidant activity through the induction of heme oxygenase-1, a scavenger of free radicals, and by reduction of reactive oxygen species and Nox-2. Conclusions: Curcumin appears to improve endothelial function but additional research is needed to determine the precise mechanism(s) and biomarkers involved in curcumin’s therapeutic effects on endothelial dysfunction.

Background: Tea and coffee are the second and third most consumed beverages after water, respectively. The high consumption of these beverages is due to the sensorial properties and effects on psychological and physiological functions, induced by caffeine and many other bioactive components responsible for the protective effects on human health generally ascribed to these beverages. Methods: The goal of this review article is to collect the scientific data obtained from clinical trials published in the last five years on the role of tea and coffee consumption against cardiovascular diseases (CVDs) and CVD risk factors such as hypertension, hyperglicemia, and hyperlipidaemia. Results: In normal weight subjects, clinical trials showed that the consumption of tea is inversely associated to CVD risk factors or no association was found. Differently, in overweight subjects, the clinical trials and the metaanalyses showed an inverse correlation between tea consumption and CVDs. As regards coffee, it has long been suspected to be associated to high risk of CVDs. Nevertheless, some recent investigations reported that moderate coffee consumption have no effect or even protective effects against CVDs risk factors. The results of the metaanalyses confirm this trend suggesting that moderate coffee drinkers could be associated to a lower risk of CVDs than non- or occasional coffee drinkers or no association can be demonstrated between coffee consumption and CVDs. Conclusion: Literature data on tea consumption and CVD risk factors support that tea consumption reduces some risk factors especially in overweight people and obese subjects. Therefore, these results seem to suggest that tea could exert a protective effects against CVD development. As regards coffee, the results are controversial and did not allow to draw conclusions. Therefore, further research is needed before definitive recommendations for coffee consumption against CVD development can be made.

Background: The prevalence of premature atherosclerosis and cardiovascular disease (CVD) is constantly increasing worldwide. It has been proved that LDL-cholesterol (LDL-C) plays causal role in the development of coronary atherosclerosis. The fact that atherosclerosis is a chronic and progressive disease which onsets during the first three decades of life bores questions what to do to maintain LDL-C at low levels throughout life and thus to delay and/or prevent the progress this disease. Currently, most of public health expenses are spared on treatment, but not on prophylaxis. Methods: This is a review article summarizing novel reports concerning the efficacy of sterols/stanols as lipidlowering agents, assessing their influence on cardiovascular risk and safety. Results: It has been suggested that sterols and stanols are effective in the lowering of low-density cholesterol levels and diminishing cardiovascular risk. However, the results of other studies suggest that phytosterols may not exert positive effects during atherogenesis. Firstly, patients with phytosterolaemia (genetic disease in which high plant sterol plasma concentrations are observed) develop malignant premature atherosclerosis. Moreover, several epidemiological studies demonstrated the association between upper normal plasma concentrations of plant sterols and increased risk of cardiovascular events. Finally, the supplementation with plant stanols and plant sterols may be not beneficial due to their incorporation in various tissues and potentially resulting in adverse effects. Conclusion: Despite the worldwide promotion of sterols as health improving supplements, it seems that in some people responding with relatively high phytosterol serum levels after its consumption such additives may turn out to be as good as it has been believed.

Several risk factors such as abnormality of lipid metabolism (e.g. high levels of low-density lipoprotein cholesterol (LDL-C), elevated triglycerides and low levels of high-density lipoprotein cholesterol (HDL-C)) play a central role in the aetiology of cardiovascular disease (CVD). Nutraceutical combination together with a cholesterol- lowering action, when associated with suitable lifestyle, should furnish an alternative to pharmacotherapy in patients reporting statin-intolerance and in subjects at low cardiovascular risk. The present review is focused on nutraceuticals and their synergetic combinations demonstrating a beneficial effect in the management of dyslipidaemia. Several nutraceuticals have been shown to positively modulate lipid metabolism having different functions. Plant sterols and soluble fibres can, for example, decrease the intestinal assimilation of lipids and increase their elimination. Furthermore, berberine and soybean proteins improve the cholesterol uptake in the liver. Policosanols, monacolins and bergamot inhibit hydroxy-methyl-glutaryl coenzyme A reductase (HMGCoA reductase) enzyme action determining the cholesterol hepatic synthesis. Moreover, pomegranate can decrease LDL oxidation and positively affect subclinical atherosclerosis; red yeast rice and berberine play, instead, an important role on endothelial dysfunction and psyllium, plant sterols and bergamot have positive effects on LDL subclasses. To the best of our knowledge, there are no long-term large-scale studies on the anti-atherogenic effect of the nutraceuticals that are available on the market. Thus, further clinical studies should investigate in order to achieve long term tolerability and safety and to provide a better nutraceutical combination tailored to the patient needs.

Background: Most of the active pharmaceutical ingredients discovered recently in pharmaceutical field exhibits poor aqueous solubility that pose major problem in their oral administration. The oral administration of these drugs gets further complicated due to their short bioavailability, inconsistent absorption and inter/intra subject variability. Methods: Pharmaceutical emulsion holds a significant place as a primary choice of oral drug delivery system for lipophilic drugs used in pediatric and geriatric patients. Pharmacokinetic studies on nanoemulsion mediated drugs delivery approach indicates practical feasibility in regards to their clinical translation and commercialization. Results: This review article is to provide an updated understanding on pharmacokinetic and pharmacodynamic features of nanoemulsion delivered via oral, intravenous, topical and nasal route. Conclusion: The article is of huge interest to formulation scientists working on range of lipophilic drug molecules intended to be administered through oral, intravenous, topical and nasal routes for vivid medical benefits.

Metformin, a synthetic biguanide, is currently one of the most frequently recommended medications for type 2 diabetes treatment around the world. This review presents the latest discoveries in the pharmacokinetics of metformin, especially the role of transporters (e.g. Organic Cation Transporters OCTs, Multidrug and Toxin Extrusion transporters MATE) in oral absorption, distribution, elimination and biochemical effects of metformin in humans. We also review the associations between genetic variations of metformin transporters, their pharmacokinetics and drug efficacy or drug responses. In the second part of this paper, we highlight the current knowledge on novel metformin actions including favourable effects on lipid profile (e.g. decreasing plasma triglycerides (TG) and low density lipoprotein (LDL) cholesterol levels) and the cardiovascular system (e.g. decline in systolic and diastolic blood pressure, and vasoprotective effects). Furthermore, we provide an up-to-date overview of multidirectional activities of metformin, including the effects on coagulation and fibrinolysis, polycystic ovary syndrome, as well as the anti-ageing and antiinflammatory properties. Over the past two decades, metformin’s antineoplastic properties have been drawing increasing attention of scientists; herein, we outline the state-of-the-art discoveries concerning metformin use in the field of oncology. Finally, we review the newly synthesized derivatives and pro-drugs of metformin and other biguanides.