Unique vascular protective properties of natural products: supplements or future main-line drugs with significant anti-atherosclerotic potential?

Research Progress on Natural Plant Molecules in Regulating the Blood-Brain Barrier in Alzheimer's Disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder. With the aging population and the continuous development of risk factors associated with AD, it will impose a significant burden on individuals, families, and society. Currently, commonly used therapeutic drugs such as Cholinesterase inhibitors, N-methyl-D-aspartate antagonists, and multiple AD pathology removal drugs have been shown to have beneficial effects on certain pathological conditions of AD. However, their clinical efficacy is minimal and they are associated with certain adverse reactions. Furthermore, the underlying pathological mechanism of AD remains unclear, posing a challenge for drug development. In contrast, natural plant molecules, widely available, offer multiple targeting pathways and demonstrate inherent advantages in modifying the typical pathologic features of AD by influencing the blood-brain barrier (BBB). We provide a comprehensive review of recent in vivo and in vitro studies on natural plant molecules that impact the BBB in the treatment of AD. Additionally, we analyze their specific mechanisms to offer novel insights for the development of safe and effective targeted drugs as well as guidance for experimental research and the clinical application of drugs for the prevention and treatment of AD.

Potential antiplatelet aggregation metabolites from the discarded sorghum (Sorghum bicolor L.) root

Sorghum (Sorghum bicolor L.) is the fifth largest crop in the world and has potential health benefits, but vast quantities of sorghum roots are discarded after harvest. Based on the previous antiplatelet aggregation for this species, two new multi-substituted 3H-indole alkaloids sorghumine A (1) and sorghumine B (2), together with 14 known compounds (3-16), were found from the water extract of sorghum roots. Compounds 1-2 were identified by analyzing their spectroscopic data and physic and chemical properties, and the absolute configuration was further determined by electronic circular dichroism (ECD) analysis and calculations. 1-2, 4, 6-8 and 13-15 showed significant inhibition of platelet aggregation induced by adenosine diphosphate. 2-4, 6-9 and 11 showed significant inhibition of platelet aggregation induced by collagen. 4-6, 8, 10-11 and 16 showed significant inhibition on platelet aggregation induced by thrombin. Furthermore, molecular docking showed that active compounds can bind to P2Y12 and COX-1 receptors in platelet.

Aronia melanocarpa Fruit Juice Modulates ACE2 Immunoexpression and Diminishes Age-Related Remodeling of Coronary Arteries in Rats

The aim of the study is to evaluate the effect of Aronia melanocarpa fruit juice (AMJ) supplementation on age-related coronary arteries remodeled in aged rat hearts. Male Wistar rats (n = 24) were divided into three groups: (1) young controls (CY), aged 2 months, without AMJ supplementation; (2) old controls (CO), aged 27 months, without AMJ supplementation; and (3) the AMJ group (A), which used 27-month old animals, supplemented orally with AMJ for 105 days. AMJ supplementation did not influence the wall-to-diameter parameter (Kernohan index) of the coronary arteries of test animals. Aged rats supplemented with AMJ showed a significant decrease in the amount of collagen fibers in their coronary tunica media, as compared with the old controls. The intensity of the immunoreaction for alpha smooth muscle actin (αSMA) in the coronary tunica media was significantly lower in the supplemented group than in the old controls. The intensity of the angiotensin-converting enzyme 2 (ACE2) immunoreaction in the coronary tunica media of the supplemented group was significantly higher than the one observed in the old controls. These results indicate the positive effects of AMJ supplementation on the age-dependent remodeling of coronary arteries and support for the preventive potential of antioxidant-rich functional food supplementation in age-related diseases.

Secondary Metabolites from the Leather Coral-Derived Fungal Strain Xylaria sp. FM1005 and Their Glycoprotein IIb/IIIa Inhibitory Activity

Five new tyrosine derivatives (1-5), one new phenylacetic acid derivative (6), two new quinazolinone analogues (7 and 8), one new naphthalenedicarboxylic acid (9), and one new 3,4-dihydroisocoumarin derivative (10), together with seven known compounds, were isolated from the fungus Xylaria sp. FM1005, which was isolated from Sinularia densa (leather coral) collected in the offshore region of the Big Island, Hawaii. The structures of compounds 1-10 were elucidated by extensive analysis of NMR spectroscopy, HRESIMS, and ECD data. Due to their structure similarity to the antiplatelet drug tirofiban, compounds 1-5 together with 6 were investigated for their antithrombotic activities. Compounds 1 and 2 strongly inhibited the binding of fibrinogen to purified integrin IIIb/IIa in a dose-dependent manner with the IC50 values of 0.89 and 0.61 μM, respectively, and compounds 1 and 2 did not show any cytotoxicity against A2780 and HEK 293 at 40 μM.

Nanoformulations to Enhance the Bioavailability and Physiological Functions of Polyphenols

Polyphenols are micronutrients that are widely present in human daily diets. Numerous studies have demonstrated their potential as antioxidants and anti-inflammatory agents, and for cancer prevention, heart protection and the treatment of neurodegenerative diseases. However, due to their vulnerability to environmental conditions and low bioavailability, their application in the food and medical fields is greatly limited. Nanoformulations, as excellent drug delivery systems, can overcome these limitations and maximize the pharmacological effects of polyphenols. In this review, we summarize the biological activities of polyphenols, together with systems for their delivery, including phospholipid complexes, lipid-based nanoparticles, protein-based nanoparticles, niosomes, polymers, micelles, emulsions and metal nanoparticles. The application of polyphenol nanoparticles in food and medicine is also discussed. Although loading into nanoparticles solves the main limitation to application of polyphenolic compounds, there are some concerns about their toxicological safety after entry into the human body. It is therefore necessary to conduct toxicity studies and residue analysis on the carrier.

Anti-Aggregatory Potential of Selected Vegetables-Promising Dietary Components for the Prevention and Treatment of Cardiovascular Disease

Increased blood platelet activation, especially platelet aggregation, plays an important function in cardiovascular disease; however, various dietary components may inhibit platelet activation. Recent clinical and epidemiologic studies indicate that both fruits and vegetables, and their products, contain various phytoprotective substances possessing biological properties such as antiplatelet and antioxidant effects that may work synergistically to ameliorate the effect of cardiovascular disease. In addition, the consumption of vegetables and their products may also play an important role in prevention. However, the mechanisms involved have not been clearly defined. Various studies clearly indicate that certain vegetables (e.g., onions, garlic, and tomatoes) have beneficial effects on blood platelet hyperactivity, an important cardiovascular risk factor, and hence may offer new prophylactic and therapeutic possibilities for the treatment of blood platelet hyperactivation and cardiovascular disease. This mini-review evaluates the current literature on the relationship between the consumption of onion (Allium cepa L.), garlic (Allium sativum L.), tomato (Solanum lycopersicum L.), and beetroot (Beta vulgaris L.), and blood platelet activation, which may have important implications for the prophylaxis and treatment of cardiovascular disease.

Resveratrol Brain Delivery for Neurological Disorders Prevention and Treatment

Resveratrol (RES) is a natural polyphenolic non-flavonoid compound present in grapes, mulberries, peanuts, rhubarb and in several other plants. Numerous health effects have been related with its intake, such as anti-carcinogenic, anti-inflammatory and brain protective effects. The neuroprotective effects of RES in neurological diseases, such as Alzheimer's (AD) and Parkinson's (PD) diseases, are related to the protection of neurons against oxidative damage and toxicity, and to the prevention of apoptotic neuronal death. In brain cancer, RES induces cell apoptotic death and inhibits angiogenesis and tumor invasion. Despite its great potential as therapeutic agent for the treatment of several diseases, RES exhibits some limitations. It has poor water solubility and it is chemically instable, being degraded by isomerization once exposed to high temperatures, pH changes, UV light, or certain types of enzymes. Thus, RES has low bioavailability, limiting its biological and pharmacological benefits. To overcome these limitations, RES can be delivered by nanocarriers. This field of nanomedicine studies how the drug administration, pharmacokinetics, and pharmacodynamics are affected by the use of nanosized materials. The role of nanotechnology, in the prevention and treatment of neurological diseases, arises from the necessity to mask the physicochemical properties of therapeutic drugs to prolong the half-life and to be able to cross the blood-brain barrier (BBB). This can be achieved by encapsulating the drug in a nanoparticle (NP), which can be made of different kinds of materials. An increasing trend to encapsulate and direct RES to the brain has been observed. RES has been encapsulated in many different types of nanosystems, as liposomes, lipid and polymeric NPs. Furthermore, some of these nanocarriers have been modified with targeting molecules able to recognize the brain areas. Then, this article aims to overview the RES benefits and limitations in the treatment of neurological diseases, as the different nanotechnology strategies to overcome these limitations.

Resveratrol and Amyloid-Beta: Mechanistic Insights

The amyloid-beta (Aβ) hypothesis that dyshomeostasis between Aβ production and clearance is a very early, key molecular factor in the etiology of Alzheimer’s disease (AD) has been proposed and examined in the AD research field. Scientists have focused on seeking natural products or drugs to influence the dynamic equilibrium of Aβ, targeting production and clearance of Aβ. There is emerging evidence that resveratrol (Res), a naturally occurring polyphenol mainly found in grapes and red wine, acts on AD in numerous in vivo and in vitro models. Res decreases the amyloidogenic cleavage of the amyloid precursor protein (APP), enhances clearance of amyloid beta-peptides, and reduces Aβ aggregation. Moreover, Res also protects neuronal functions through its antioxidant properties. This review discusses the action of Res on Aβ production, clearance and aggregation and multiple potential mechanisms, providing evidence of the useful of Res for AD treatment.

Preliminary assessment of free radical scavenging, thrombolytic and membrane stabilizing capabilities of organic fractions of Callistemon citrinus (Curtis.) skeels leaves

Background

Callistemon citrinus (Curtis.) (Family- Myrtaceae) is a popular evergreen shrub in Bangladesh. In the present study, the leaves of this plant have been assessed comprehensively for free radical scavenging, thrombolytic and membrane stabilizing activities.

Methods

The leaves were collected, powdered and extracted with methanol. The extract was then concentrated and successively fractionated into petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions. The extractives were investigated for free radical scavenging, thrombolytic and membrane stabilizing activities.

Results

In case of 1,1 diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide radical scavenging assays, the crude methanol extract of the leaves showed the highest free radical scavenging activity among the tested materials including standard ascorbic acid (p = 0.0000). Besides, this extract was also found significantly rich (p = 0.0000) in phenolics and flavonoids compared to other organic fractions. In thrombolytic study, the petroleum ether fraction exhibited significantly stronger thrombolysis (p = 0.024) than other leaf extractives but was weaker than the standard streptokinase. In membrane stabilizing assay, the activity of chloroform fraction was similar to that of standard acetylsalicylic acid (p = 1.000) in hypotonic solution induced hemolysis. However, membrane stabilization activity of this chloroform fraction was found significantly stronger than that of the standard (p = 0.0000) in heat induced hemolysis.

Conclusion

This study has revealed the medicinal capabilities of different organic fractions of C. citrinus displaying free radical scavenging, thrombolysis and membrane stabilizing antiinflammatory potentials. Further bioactivity guided isolation is required to obtain pharmacologically secondary metabolites.

Anti-hypertensive Herbs and their Mechanisms of Action: Part I

The use of herbal therapies for treatment and management of cardiovascular diseases (CVDs) is increasing. Plants contain a bounty of phytochemicals that have proven to be protective by reducing the risk of various ailments and diseases. Indeed, accumulating literature provides the scientific evidence and hence reason d'etre for the application of herbal therapy in relation to CVDs. Slowly, but absolutely, herbal remedies are being entrenched into evidence-based medical practice. This is partly due to the supporting clinical trials and epidemiological studies. The rationale for this expanding interest and use of plant based treatments being that a significant proportion of hypertensive patients do not respond to Modern therapeutic medication. Other elements to this equation are the cost of medication, side-effects, accessibility, and availability of drugs. Therefore, we believe it is pertinent to review the literature on the beneficial effects of herbs and their isolated compounds as medication for treatment of hypertension, a prevalent risk factor for CVDs. Our search utilized the PubMed and ScienceDirect databases, and the criterion for inclusion was based on the following keywords and phrases: hypertension, high blood pressure, herbal medicine, complementary and alternative medicine (CAM), nitric oxide, vascular smooth muscle cell (VSMC) proliferation, hydrogen sulfide, nuclear factor kappa-B, oxidative stress, and epigenetics/epigenomics. Each of the aforementioned keywords was co-joined with herb in question, and where possible with its constituent molecule(s). In this first of a two-part review, we provide a brief introduction of hypertension, followed by a discussion of the molecular and cellular mechanisms. We then present and discuss the plants that are most commonly used in the treatment and management of hypertension.

Potential interaction of green tea extract with hydrochlorothiazide against doxorubicin-induced myocardial damage

BACKGROUND

Treatment of ischemic hypertensive patients with hydrochlorothiazide can precipitate cardiac arrhythmias. Green tea, by virtue of its antioxidant potential, is responsible for cardio-protective activity.

OBJECTIVE

The present study was under taken to evaluate the pharmacodynamic interaction of green tea extract with hydrochlorothiazide (HCTZ) against doxorubicin (DOX)-induced myocardial toxicity.

MATERIALS AND METHODS

Rats were treated with high (500 mg/kg, p.o.) and low (100 mg/kg, p.o.) dose of green tea extract in alone and interactive groups for 28 days. Standard, high and low dose of interactive groups received hydrochlorothiazide (10 mg/kg, p.o.) for the last 7 days. Apart from normal controls, all other groups were subjected to DOX (3 mg/kg, i.p.) toxicity on Days 1, 7, 14, 21 and 28, and the effect of different treatments was evaluated by changes in electrocardiographic parameters, serum biomarkers and tissue antioxidant levels. Apart from that, lipid profile and histological studies were also carried out.

RESULTS

Compared with the DOX control group, both high and low dose of green tea exhibited a significant decrease in serum biomarkers and increase in tissue antioxidant levels. Green tea treatment was also responsible for significant improvement in ECG parameter, lipid profile and histological score. Incorporation of high and low dose of green tea with HCTZ exhibited significant protection compared with the HCTZ alone treated group.

CONCLUSION

The present findings clearly suggest that the green tea extract dose-dependently reduces DOX-induced myocardial toxicity. Green tea when combined with HCTZ can reduce the associated side-effects and exhibits myocardial protection.

Natural Products for Antithrombosis

Thrombosis is considered to be closely related to several diseases such as atherosclerosis, ischemic heart disease and stroke, as well as rheumatoid arthritis, hyperuricemia, and various inflammatory conditions. More and more studies have been focused on understanding the mechanism of molecular and cellular basis of thrombus formation as well as preventing thrombosis for the treatment of thrombotic diseases. In reality, there is considerable interest in the role of natural products and their bioactive components in the prevention and treatment of thrombosis related disorders. This paper briefly describes the mechanisms of thrombus formation on three aspects, including coagulation system, platelet activation, and aggregation, and change of blood flow conditions. Furthermore, the natural products for antithrombosis by anticoagulation, antiplatelet aggregation, and fibrinolysis were summarized, respectively.

Cross-sectional associations of medication and supplement use with retinal vascular diameter in the Beaver Dam Eye Study

IMPORTANCE

Retinal vessel diameters are being measured to examine their relationship with ocular and systemic disease and, in some studies, to calculate the risk of disease. Important factors that directly affect retinal vessel diameters, such as medication use, should be considered when estimating these associations.

OBJECTIVE

To quantify the association between selected medications and supplements and retinal vessel diameters.

DESIGN, SETTING, AND PARTICIPANTS

In a prospective cohort investigation, 4926 participants (aged 43-86 years at baseline) in the Beaver Dam Eye Study were evaluated every 5 years during 20 years of follow-up from 1988 to 2010.

MAIN OUTCOMES AND MEASURES

Central retinal arteriolar equivalent and central retinal venular equivalent measured from the Early Treatment Diabetic Retinopathy Study fundus photograph field 1.

RESULTS

After Bonferroni correction, the use of any blood pressure medication (β = 0.75; P = .04), specifically calcium channel blockers (β = -1.02; P < .001), was significantly associated with wider central retinal arteriolar equivalent adjusting for refraction, photograph focus, age, systolic blood pressure, height, examination phase, educational level, smoking and drinking histories, and presence of diabetes mellitus and emphysema. Use of prostaglandin analogues was marginally associated with narrower central retinal arteriolar equivalent (β = -2.04; P = .09); β-blockers (β = -1.02; P = .10) and oral corticosteroids (β = 2.13; P = .07) were marginally associated with changes in the central retinal venular equivalent.

CONCLUSIONS AND RELEVANCE

Several medications are associated with central retinal arteriolar and venular equivalents. Prostaglandin analogues, calcium channel blockers, and oral corticosteroids have the largest relative effects. After Bonferroni correction was applied, the use of calcium channel blockers was most strongly associated with change in the central retinal arteriolar equivalent. The presence of factors that are associated with retinal vessel diameters should be considered when using retinal vessel diameter as an outcome or when using these measures to assess the risk of systemic or ocular disease.

Anti-atherosclerotic therapy based on botanicals

Natural products including botanicals for both therapy of clinical manifestations of atherosclerosis and reduction of atherosclerosis risk factors are topics of recent patents. Only a few recent patents are relevant to the direct antiatherosclerotic therapy leading to regression of atherosclerotic lesions. Earlier, using a cellular model we have developed and patented several anti-atherosclerotic drugs. The AMAR (Atherosclerosis Monitoring and Atherogenicity Reduction) study was designed to estimate the effect of two-year treatment with time-released garlic-based drug Allicor on the progression of carotid atherosclerosis in 196 asymptomatic men aged 40-74 in double-blinded placebo-controlled randomized clinical study. The primary outcome was the rate of atherosclerosis progression, measured by high-resolution B-mode ultrasonography as the increase in carotid intima-media thickness (IMT) of the far wall of common carotid arteries. The mean rate of IMT changes in Allicor-treated group (-0.022±0.007 mm per year) was significantly different (P = 0.002) from the placebo group in which there was a moderate progression of 0.015±0.008 mm at the overall mean baseline IMT of 0.931±0.009 mm. A significant correlation was found between the changes in blood serum atherogenicity (the ability of serum to induce cholesterol accumulation in cultured cells) during the study and the changes in intima-media thickness of common carotid arteries (r = 0.144, P = 0.045). Thus, the results of AMAR study demonstrate that long-term treatment with Allicor has a direct anti-atherosclerotic effect on carotid atherosclerosis and this effect is likely to be due to serum atherogenicity inhibition. The beneficial effects of other botanicals including Inflaminat (calendula, elder and violet), phytoestrogen- rich Karinat (garlic powder, extract of grape seeds, green tea leafs, hop cones, β-carotene, α-tocopherol and ascorbic acid) on atherosclerosis have also been revealed in clinical studies which enforces a view that botanicals might represent promising drugs for anti-atherosclerotic therapy.