Effects of total flavonoids of Hippophae rhamnoides L. on intracellular free calcium in cultured vascular smooth muscle cells of spontaneously hypertensive rats and Wistar-Kyoto rats

Novel preventive effect of isorhamnetin on electrical and structural remodeling in atrial fibrillation

Isorhamnetin, a natural flavonoid, has strong antioxidant and antifibrotic effects, and a regulatory effect against Ca2+-handling. Atrial remodeling due to fibrosis and abnormal intracellular Ca2+ activities contributes to initiation and persistence of atrial fibrillation (AF). The present study investigated the effect of isorhamnetin on angiotensin II (AngII)-induced AF in mice. Wild-type male mice (C57BL/6J, 8 weeks old) were assigned to three groups: (1) control group, (2) AngII-treated group, and (3) AngII- and isorhamnetin-treated group. AngII (1000 ng/kg/min) and isorhamnetin (5 mg/kg) were administered continuously via an implantable osmotic pump for two weeks and intraperitoneally one week before initiating AngII administration, respectively. AF induction and electrophysiological studies, Ca2+ imaging with isolated atrial myocytes and HL-1 cells, and action potential duration (APD) measurements using atrial tissue and HL-1 cells were performed. AF-related molecule expression was assessed and histopathological examination was performed. Isorhamnetin decreased AF inducibility compared with the AngII group and restored AngII-induced atrial effective refractory period prolongation. Isorhamnetin eliminated abnormal diastolic intracellular Ca2+ activities induced by AngII. Isorhamnetin also abrogated AngII-induced APD prolongation and abnormal Ca2+ loading in HL-1 cells. Furthermore, isorhamnetin strongly attenuated AngII-induced left atrial enlargement and atrial fibrosis. AngII-induced elevated expression of AF-associated molecules, such as ox-CaMKII, p-RyR2, p-JNK, p-ERK, and TRPC3/6, was improved by isorhamnetin treatment. The findings of the present study suggest that isorhamnetin prevents AngII-induced AF vulnerability and arrhythmogenic atrial remodeling, highlighting its therapeutic potential as an anti-arrhythmogenic pharmaceutical or dietary supplement.

Herbs and their bioactive ingredients in cardio-protection: Underlying molecular mechanisms and evidences from clinical studies

BACKGROUND

Medicinal plants or herbs produce a bounty of bioactive phytochemicals. These phytochemicals can influence a variety of physiological events related to cardiovascular health through multiple underlying mechanisms, such as their role as antioxidative, anti-ischemic, anti-proliferative, hypotensive, anti-thrombotic, and anti-hypercholesterolemic agents.

PURPOSE

The purpose of this review is to summarize and connect evidences supporting the use of phytotherapy in the management of some of the most common cardiovascular impairments, molecular mechanisms underlying cardio-protection mediated by herbs, and clinical studies which are positively linked with the use of herbs in cardiovascular biology. Additionally, we also describe several adverse effects associated with some of the herbal plants and their products to provide a balanced set of studies in favor or against phytotherapy in cardiovascular health that may help global discourses on this matter.

METHODS

Studies relating to the use of medicinal plants were mined by strategically searching scientific databases including Google Scholar, PubMed and Science Direct. Investigations involving approximately 175 articles including reviews, research articles, meta-analyses, and cross-sectional and observational studies were retrieved and analyzed in line with the stated purpose of this study.

RESULTS

A positive correlation between the use of medicinal plants and cardiovascular health was observed. While maintaining cardiovascular physiology, medicinal plants and their derivatives seem to govern a variety of cellular mechanisms involved in vasoconstriction and vasorelaxation, which in turn, are important aspects of cardiovascular homeostasis. Furthermore, a variety of studies including clinical trials, cross-sectional studies, and meta-analyses have also supported the anti-hypertensive and thus, cardio-protective effects, of medicinal plants. Apart from this, evidence is also available for the potential drawbacks of several herbs and their products indicating that the unsupervised use of many herbs may lead to severe health issues.

CONCLUSIONS

The cardio-protective outcomes of medicinal plants and their derivatives are supported by ever-increasing studies, while evidences exist for the potential drawbacks of some of the herbs. A balanced view about the use of medicinal plants and their derivative in cardiovascular biology thus needs to be outlined by researchers and the medical community. The novelty and exhaustiveness of the present manuscript is reflected by the detailed outline of the molecular basis of "herbal cardio-protection", active involvement of several herbs in ameliorating the cardiovascular status, adverse effects of medicinal plants, and the clinical studies considering the use of phytotherapy, all on a single platform.

Flavonoids from sea buckthorn: A review on phytochemistry, pharmacokinetics and role in metabolic diseases

Sea buckthorn (Hippophae rhamnoides L., SBT) is being used as a folk medicine for their diverse medicinal properties. Flavonoids are generally considered as the main bioactive and characteristic ingredients in SBT. This review was conducted using a comprehensive literature search on the chemical components, quality control, pharmacokinetics of flavonoids from SBT (FSBT). Particularly, we highlighted the therapeutic potential in metabolic diseases and clinical applications of FSBT. More than 95 flavonoids have been identified from SBT. Although the oral bioavailability of FSBT was relatively low, FSBT displays significant effect on the regulation of metabolism to ameliorate metabolic disorders and their complications. There is a heightened need to explore the bioactive compounds in SBT and mechanism(s) of action of FSBT in order to fully understand the pathways of their activities. PRACTICAL APPLICATIONS: For years, due to the increasing emergence of metabolic syndrome and diverse functions of FSBT in regulating metabolism, they can be efficiently utilized for human health and have an urgent need to become a hotspot for research. This review will broaden the understanding of FSBT, providing some directions for further development and expanding the therapeutic applications of FSBT.

Evaluation of biomarkers in liver following Solanum melongena green calyx administration in diabetic rats

Background

Solanum melongena green calyx (SMGC) has antioxidant properties. Diabetes mellitus (DM) increases oxidative stress and causes cellular damages in liver. This study attempts to show the protective effects of SMGC against morphometric, inflammatory, oxidative, and apoptotic changes in liver following DM induction.

Methods

For DM induction, the streptozotocin (60 mg/kg) was injected intraperitoneally. After the preparation of the SMGC extract, phytochemical content was analyzed. Sixty-four rats were categorized into 8 groups (n = 8); control, diabetic, SMGC, and diabetic + SMGC. SMGC administration was applied orally with doses of 100, 300, 500 mg/kg for 4 weeks. The assays of nitrite oxide, lipid peroxidation (LP), and Ferric Reducing Ability of Plasma (FRAP) were conducted for sample analysis. P53, Bcl2, and Bax genes expression, inflammatory cytokines, enzymes, and morphological features were measured. Apoptotic cell index, body weight, and levels of glucose and insulin were also analyzed. A one-way ANOVA test was used for statistical analysis.

Result

According to the phytochemical analysis, the SMGC is rich in Tannins and Saponins. Antioxidant values, p53 and Bax genes expression, inflammatory cytokines, enzymes, body weight, serum glucose, and morphometrical features were increased significantly (except insulin and FRAP levels and Bcl2 gene expression which were decreased) in diabetic group compared to the control group (P < 0.05). Also, evaluated parameters were reduced significantly (except insulin and FRAP levels and Bcl2 gene expression which were increased) in SMGC and diabetic + SMGC groups in comparison with the diabetic group (P < 0.05).

Conclusion

These findings revealed that the SMGC attenuates blood glucose levels in diabetic animals and also eliminates destructive effects of DM on liver through antioxidant features.

Chinese Herbal Medicine on Cardiovascular Diseases and the Mechanisms of Action

Cardiovascular diseases are the principal cause of death worldwide. The potentially serious adverse effects of therapeutic drugs lead to growing awareness of the role of Chinese herbal medicine in the treatment of cardiovascular diseases. Chinese herbal medicine has been widely used in many countries especially in China from antiquity; however, the mechanisms by which herbal medicine acts in the prevention and treatment of cardiovascular diseases are far from clear. In this review, we briefly describe the characteristics of Chinese herbal medicine by comparing with western medicine. Then we summarize the formulae and herbs/natural products applied in the clinic and animal studies being sorted according to the specific cardiovascular diseases. Most importantly, we elaborate the existing investigations into mechanisms by which herbal compounds act at the cellular levels, including vascular smooth muscle cells, endothelial cells, cardiomyocytes and immune cells. Future research should focus on well-designed clinic trial, in-depth mechanic study, investigations on side effects of herbs and drug interactions. Studies on developing new agents with effectiveness and safety from traditional Chinese medicine is a promising way for prevention and treatment of patients with cardiovascular diseases.

Intestinal and vascular smooth muscle relaxant effect of Viscum album explains its medicinal use in hyperactive gut disorders and hypertension

Background

Viscum album has shown inhibitory effect on different smooth muscles but underlying mechanisms in gut and vascular smooth muscles are not well defined. Additionally, the plant has also importance in managing hyperactive gut and cardiovascular disorders. The current study was aimed to probe a pharmacological base of the smooth muscle relaxant effect of V. album in gut and vascular preparations.

Methods

V. album crude extract (Va. Cr) and its ethyl acetate fraction (Va. EtAc) were studied using in vitro techniques. The antispasmodic activity was performed using isolated rabbit jejunum while the vasorelaxant effects were studied in rabbit aortic rings.

Results

Va. Cr and Va. EtAc inhibited spontaneous and high K⁺-induced contractions with EC₅₀ values of 0.31 mg/mL (0.15–0.57) and 0.62 mg/mL (0.3–0.95), respectively. This advocates an antispasmodic effect probably operated through calcium channels blockade (CBB). The proposed mechanism was confirmed by a pretreatment of the tissue with Va. Cr (0.01–0.3 mg/mL), which shifted the Ca⁺⁺ concentration-response curves (CRCs) rightward, similar to verapamil. Moreover, Va. Cr showed a partial relaxation against high K⁺ and PE (1 μM) induced contractions in isolated rabbit aorta rings. Va. EtAc caused complete relaxation of high K⁺ precontraction and partially relaxed PE (1 μM) induced contractions, suggesting inhibitory effect on Ca⁺⁺ entry, in addition to other possible mechanisms. CRCs were shifted to the right correspondingly to verapamil when the aortic rings were pretreated with Va. Cr and Va. EtAc.

Conclusions

These data indicated that Va. Cr possesses smooth muscle relaxant effect mediated through voltage-dependent Ca⁺⁺ channel blockade (CCB), which explains its spasmolytic and vasorelaxant activity. The CCB activity is concentrated more in Va. EtAc. This study provides an evidence for the medicinal importance of V. album in gut spasm and possibly hypertension.

Studies on antidiarrhoeal, antispasmodic and bronchodilator activities of Operculina turpethum Linn

Background

Traditionally, Operculina turpethum has been used in a wide range of ailments such as, gastrointestinal disturbances and asthma. It is found in China, South Asia, Pacific Islands, and Australia. This study was aimed to provide a possible pharmacological basis for the medicinal use of O. turpethum in gut and airways disorders.

Methods

Castor oil-induced diarrhoeal mice model and isolated tissue preparations such as, rabbit jejunum and guinea-pig tracheal preparations were used to test the antidiarrhoeal, antispasmodic and bronchodilator effects and the possible mode of action(s) of the 70% aqueous-ethanolic extract of O. turpethum black variety (OTB).

Results

In the castor oil-induced diarrhoea in mice, the crude extract of OTB caused a dose-dependent (300–1000 mg/kg) protection from diarrhoea, similar to that of loperamide. In isolated rabbit jejunum preparations, OTB produced a dose-dependent inhibition of spontaneous and high K⁺(80 mM)-induced contractions with resultant median effective concentrations (EC₅₀ with 95% confidence interval) of 1.04 mg/ml (0.59-1.54) and 0.12 mg/ml (0.10-0.15; n = 4) respectively, thus showing more potency against K⁺. Pretreatment of the tissue with OTB (0.01 and 0.03 mg/ml) caused a rightward shift in the concentration response curves of Ca⁺⁺, similar to that of verapamil. In isolated guinea-pig tracheal preparations, OTB caused inhibition of carbachol and high K⁺-induced constriction at similar concentrations with respective EC₅₀ value of 0.66 mg/ml (0.53-0.82) and 0.59 mg/ml (0.45-0.62). Activity-directed fractionation revealed that the ethyl acetate fraction was more potent than the parent crude extract and hexane fraction.

Conclusion

These results suggest that the crude extract of O. turpethum possesses antidiarrhoeal, antispasmodic and bronchodilator activities, mediated possibly through the presence of Ca⁺⁺ antagonist like constituent(s), though additional mechanism(s) cannot be ruled out. Thus, this study provides the evidence for the medicinal use of plant in diarrhoea and asthma.

Antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. in sucrose-fed rats

The study was designed to investigate the antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. (TFH-SR) and its underlying mechanism in chronic sucrose-fed rats by evaluating its ability to regulate insulin and angiotensin || levels. Feeding of high-sucrose diet (HS: 77% of kcal from carbohydrate, 16% from protein and 6% from lipid, respectively) for 6 weeks resulted in significant rise in systolic blood pressure (SBP) by 25.60%, plasma insulin by 114.24%, triglycerides by 85.14% and activated angiotensin || contents in heart and kidney. However, TFH-SR treatment significantly suppressed the elevated hypertension, hyperinsulinemia and dyslipidemia. Furthermore, TFH-SR (especially at the dose of 150mg/kg/day) increased the circulatory blood angiotensin || level as effective as angiotensin || receptor blocker. These results indicated that TFH-SR exerted its antihypertensive effects at least in part by improving insulin sensitivity and blocking angiotensin || signal pathway. Findings of the present study suggested that TFH-SR might prove to be of potential use in the management of hyperinsulinemia in non-diabetic state with cardiovascular diseases.