Procyanidin-rich fractions from Parkia biglobosa (Mimosaceae) leaves cause redox-sensitive endothelium-dependent relaxation involving NO and EDHF in porcine coronary artery

Contemporary Insights into the Biological Mechanisms of Parkia biglobosa

For a long time, traditional medicine has relied on the use of medicinal plants and herbal products which have served as the basis for numerous pharmaceuticals. Parkia biglobosa (Jacq) R.Br.ex. G. Don., commonly called the African locust bean tree, is a perennial deciduous plant native to West Africa where it is highly esteemed for its nutritional and traditional medicinal benefits. Parkia biglobosa's ethnomedicinal uses include microbial infections such as diarrhea and chronic diseases like hypertension and type 2 diabetes mellitus. This article presents the current understanding of the molecular mechanisms underlying Parkia biglobosa's biological effects. An electronic database search was conducted using P. biglobosa and its synonyms as keywords in Scientific Electronic Library Online, ISI Web of Knowledge, PubMed, Scopus, Science Direct, and Google Scholar. Consistently, scientific research has confirmed the medicinal effects of the plant's extracts and active phytochemicals, including antimicrobial, analgesic, antidiabetic, antihypertensive, hypolipidemic, and neuroprotective properties, among others. It highlights the contributions of identified innate phytochemicals and existing limitations to therapeutic applications, as well as the need for and prospects for further research. Advancing our understanding of the medicinal plant's biological mechanisms and the contributions of the active phytochemicals would allow for more effective exploration of its vast pharmacological potential and facilitate clinical applications.

Carissa edulis Vahl (Apocynaceae) extract, a medicinal plant of Benin pharmacopoeia, induces potent endothelium-dependent relaxation of coronary artery rings involving nitric oxide

BACKGROUND

Hypertension is a major cardiovascular risk factor that affects most countries including those of Africa. Although Carissa edulis Vahl, Diodia scandens Sw. and Cleome gynandra L. are traditionally used in Benin as antihypertensive treatments with some efficacy mentioned by the local population, their biological activity on the cardiovascular system remains poorly studied.

AIM

The study investigated the vasoreactivity of the plants and assessed the underlying mechanisms using isolated arteries.

STUDY DESIGN

Aqueous-ethanolic extracts of aerial parts of C. edulis, D. scandens and C. gynandra were prepared by maceration before being subjected to multi-step liquid-liquid fractionation with solvents of increasing polarity. The vasoreactivity of the extracts and fractions were assessed on isolated porcine coronary artery and rat aorta using organ chambers, the role of nitric oxide (NO) using N^G-nitro-L-arginine (NO synthase inhibitor), prostanoids using indomethacin (cyclooxygenases inhibitor) and endothelium-dependent hyperpolarization using TRAM-34 plus UCL 1684 (inhibitors of calcium-dependent K⁺ channels), and the vascular uptake of polyphenols using Neu reagent.

RESULTS

The aqueous-ethanolic crude extract of C. edulis (CECE) induced potent relaxations that were exclusively endothelium-dependent and more pronounced than those to D. scandens and C. gynandra. The n-butanolic fraction of C. edulis (CEBF) was more active than the cyclohexane, dichloromethane, and ethyl acetate fractions. The relaxation induced by CECE and CEBF were inhibited by N^G-nitro-L-arginine and affected neither by TRAM-34 plus UCL 1684 nor by indomethacin. CEBF induced sustained endothelium-dependent relaxations for at least 60 min, and inhibited, in a concentration-dependent manner, contractions to KCl, CaCl₂, U46619 and serotonin in rings with endothelium. Analysis of CEBF by LCHRMS indicated the presence of polyphenols, terpenes, and alkaloids. Exposure of coronary artery and aorta rings to CEBF caused the accumulation of polyphenols predominantly in the endothelium.

CONCLUSION

C. edulis leaf extract induced pronounced endothelium-dependent relaxations and inhibited contractile responses by stimulating the endothelial formation of NO. LCHRMS analysis of the most active fraction, the butanolic fraction, revealed the presence of numerous compounds including polyphenols, terpenes, and alkaloids. The polyphenols of CEBF accumulated preferentially in the endothelium of the arterial wall. Thus, these observations support the folkloric use of C. edulis in hypertension.

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services.

Phytochemicals and Amino Acids Profiles of Selected sub-Saharan African Medicinal Plants' Parts Used for Cardiovascular Diseases' Treatment

For years, the focus on the lipid-atherosclerosis relationship has limited the consideration of the possible contribution of other key dietary components, such as amino acids (AAs), to cardiovascular disease (CVD) development. Notwithstanding, the potential of plant-based diets, some AAs and phytochemicals to reduce CVDs' risk has been reported. Therefore, in this study, the phytochemical and AA profiles of different medicinal plants' (MPs) parts used for CVDs' treatment in sub-Saharan Africa were investigated. Fourier-transform infrared analysis confirmed the presence of hydroxyl, amino and other bioactive compounds' functional groups in the samples. In most of them, glutamic and aspartic acids were the most abundant AAs, while lysine was the most limiting. P. biglobosa leaf, had the richest total branched-chain AAs (BCAAs) level, followed by A. cepa bulb. However, A. cepa bulb had the highest total AAs content and an encouraging nutraceutical use for adults based on its amino acid score. Principal component analysis revealed no sharp distinction between the AAs composition of MPs that have found food applications and those only used medicinally. Overall, the presence of medicinally important phytochemicals and AAs levels in the selected MPs' parts support their use for CVDs treatment as they might not add to the AAs (e.g., the BCAAs) burden in the human body.

Review of Natural Resources With Vasodilation: Traditional Medicinal Plants, Natural Products, and Their Mechanism and Clinical Efficacy

For decades, chronic diseases including cardiovascular and cerebrovascular diseases (CCVDs) have plagued the world. Meanwhile, we have noticed a close association between CCVDs and vascular lesions, such as hypertension. More focus has been placed on TMPs and natural products with vasodilation and hypotension. TMPs with vasodilatory and hypotensive activities are mainly from Compositae, Lamiaceae, and Orchidaceae (such as V. amygdalina Del., T. procuinbens L., M. glomerata Spreng., K. galanga L., etc.) whereas natural products eliciting vasorelaxant potentials were primarily from flavonoids, phenolic acids and alkaloids (such as apigenin, puerarin, curcumin, sinomenine, etc.). Furthermore, the data analysis showed that the vasodilatory function of TMPs was mainly concerned with the activation of eNOS, while the natural products were primarily correlated with the blockage of calcium channel. Thus, TMPs will be used as alternative drugs and nutritional supplements, while natural products will be considered as potential therapies for CCVDs in the future. This study provides comprehensive and valuable references for the prevention and treatment of hypertension and CCVDs and sheds light on the further studies in this regard. However, since most studies are in vitro and preclinical, there is a need for more in-depth researches and clinical trials to understand the potential of these substances.

Chenopodium ambrosioides induces an endothelium-dependent relaxation of rat isolated aorta

OBJECTIVE

This study aims to evaluate the vasodilatory effect of Chenopodium ambrosioides on the isolated rat aorta, and to explore its mechanism of action.

METHODS

The vasorelaxant effect and the mode of action of various extracts from the leaves of C. ambrosioides were evaluated on thoracic aortic rings isolated from Wistar rats. In addition, ethyl acetate and methanol fractions were analyzed, using thin-layer chromatography and high-performance liquid chromatography techniques, for their polyphenolic content.

RESULTS

The various active extracts of C. ambrosioides at four concentrations (10^-3, 10^-2, 10^-1 and 1 mg/mL) relaxed the contraction elicited by phenylephrine, in a concentration-dependent manner. This effect seems to be endothelium-dependent, since the vasodilatory effect was entirely absent in denuded aortic rings. The vasorelaxant effect of the methanol fraction (MF) of C. ambrosioides at 1 mg/mL was also inhibited by atropine and tetraethylammonium. This effect remained unchanged by Nω-nitro-l-arginine methyl ester hydrochloride and glibenclamide. The preliminary phytochemical analysis showed that the leaves of C. ambrosioides are rich in phenolic and flavonoid derivatives.

CONCLUSION

These results suggest that the MF of C. ambrosioides produces an endothelium-dependent relaxation of the isolated rat aorta, which is thought to be mediated mainly through stimulation of the muscarinic receptors, and probably involving the opening of Ca²⁺-activated potassium channels.

An aqueous extract of the Anogeissus leiocarpus bark (AEAL) induces the endothelium-dependent relaxation of porcine coronary artery rings involving predominantly nitric oxide

BACKGROUND

Anogeissus leiocarpus is a Sahel tree traditionally used by the residents of Burkina Faso for its antihypertensive properties. In this study, experiments were conducted to evaluate whether an aqueous extract of the Anogeissus leiocarpus (AEAL) trunk bark induces a vasorelaxant effect on porcine coronary artery rings and to investigate the underlying mechanism.

METHODS

AEAL-induced relaxations were assessed using porcine coronary artery rings suspended in organ chambers. The phosphorylation levels of Src, Akt and endothelial nitric oxide synthase (eNOS) were assessed in a primary endothelial cell culture by Western blot. The reactive oxygen species (ROS) formation was assessed using dihydroethidine.

RESULTS

In porcine coronary artery rings, AEAL at 0.1-300 μg/mL induced endothelium-dependent relaxations, which were inhibited in the presence of inhibitors of nitric oxide (NO) and the endothelium-derived hyperpolarization pathways. Moreover, the AEAL-induced NO-mediated relaxations were significantly reduced by the inhibitors of Src and PI3-kinase as well as by the membrane-permeant ROS scavengers. In cultured porcine coronary artery endothelial cells, treatment with AEAL is associated with an intracellular generation of ROS. Moreover, the AEAL induced the phosphorylations of Akt (Ser473), eNOS (Ser1177) and a transient phosphorylation of Src (Ser17) in a time-dependent manner.

CONCLUSIONS

These findings indicate that AEAL is a potent inducer of endothelium-dependent NO-mediated relaxations in porcine coronary arteries through the redox-sensitive Src/PI3-kinase/Akt pathway-dependent activation of eNOS.

Procyanidins Mitigate Osteoarthritis Pathogenesis by, at Least in Part, Suppressing Vascular Endothelial Growth Factor Signaling

Procyanidins are a family of plant metabolites that have been suggested to mitigate osteoarthritis pathogenesis in mice. However, the underlying mechanism is largely unknown. This study aimed to determine whether procyanidins mitigate traumatic injury-induced osteoarthritis (OA) disease progression, and whether procyanidins exert a chondroprotective effect by, at least in part, suppressing vascular endothelial growth factor signaling. Procyanidins (extracts from pine bark), orally administered to mice subjected to surgery for destabilization of the medial meniscus, significantly slowed OA disease progression. Real-time polymerase chain reaction revealed that procyanidin treatment reduced expression of vascular endothelial growth factor and effectors in OA pathogenesis that are regulated by vascular endothelial growth factor. Procyanidin-suppressed vascular endothelial growth factor expression was correlated with reduced phosphorylation of vascular endothelial growth factor receptor 2 in human OA primary chondrocytes. Moreover, components of procyanidins, procyanidin B2 and procyanidin B3 exerted effects similar to those of total procyanidins in mitigating the OA-related gene expression profile in the primary culture of human OA chondrocytes in the presence of vascular endothelial growth factor. Together, these findings suggest procyanidins mitigate OA pathogenesis, which is mediated, at least in part, by suppressing vascular endothelial growth factor signaling.

Endothelium-independent vasorelaxant effect of a Berberis orthobotrys root extract via inhibition of phosphodiesterases in the porcine coronary artery

BACKGROUND

Berberis orthobotrys Bien ex Aitch. (Berberidaceae) is a plant indigenous of Pakistan that is locally used for the treatment of hypertension.

HYPOTHESIS

This study evaluated the vasoactive properties of a Berberis orthobotrys root extract and its fractions, and investigated the role of the endothelium and the underlying mechanism.

STUDY DESIGN

An aqueous methanolic extract of Berberis orthobotrys roots was prepared and submitted to a multi-step liquid-liquid fractionation with solvents of increasing polarity. Vascular reactivity of the different fractions was assessed using porcine coronary artery rings either with or without endothelium, and in the presence or absence of specific pharmacological tools. The ability of Berberis orthobotrys extracts to affect phosphodiesterase (PDE) activity was evaluated using a radioenzymatic method and purified phosphodiesterases.

RESULTS

The aqueous methanol extract induced similar relaxations in coronary artery rings with and without endothelium, and, amongst the three derived preparations, the butanol fraction (BFBO) was slightly but significantly more effective than the ethyl acetate fraction and the aqueous residue in rings without endothelium. Analysis of the butanol fraction (BFBO) by LC-ELSD-MS indicated the presence of four major isoquinoline alkaloids including berberine. BFBO significantly potentiated the relaxations induced by cyclic GMP- and cyclic AMP-dependent relaxing agonists, and inhibited contractions to KCl, CaCl2, and U46619 in endothelium denuded rings. In contrast, BFBO did not affect relaxations to endothelium-dependent vasodilators. BFBO concentration-dependently inhibited the cyclic GMP-hydrolyzing activity of basal PDE1, calmodulin-activated PDE1 and PDE5, and of cyclic AMP-hydrolyzing activity of PDE3 and PDE4 with IC50 values ranging from 40 to 130µg/ml.

CONCLUSION

The butanol fraction of the aqueous methanol extract of Berberis orthobotrys roots induced pronounced endothelium-independent relaxations and inhibited contractile responses by acting directly at the vascular smooth muscle in the coronary artery. Moreover, BFBO potentiated relaxations induced by both cyclic GMP- and cyclic AMP-dependent vasodilators most likely due to its ability to inhibit several vascular PDEs, and in particular PDE4 and PDE5.

Butanol fraction of Parkia biglobosa (Jacq.) G. Don leaves enhance pancreatic β-cell functions, stimulates insulin secretion and ameliorates other type 2 diabetes-associated complications in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological surveys have reported that Parkia biglobosa (Jacq.) G. Don (Leguminosae) is among the plants commonly used in the traditional management of diabetes mellitus in Nigeria and Togo.

AIM OF THE STUDY

This study investigated the anti-diabetic activity of the butanol fraction of P. biglobosa leaves (PBBF) in a type 2 diabetes (T2D) model of rats and a possible bioactive compound in the fraction.

MATERIALS AND METHODS

T2D was induced by feeding rats with a 10% fructose solution ad libitum for two weeks followed by an intraperitoneal injection of 40mg/kg body weight streptozotocin and the animals were orally treated with 150 and 300mg/kg BW of the PBBF for five days in a week. Another group of rats was non-diabetic but similarly administered with 300mg/kg BW of the PBBF. Food and fluid intakes, body weight changes and blood glucose levels were monitored during the experiment while other relevant diabetes-associated parameters were measured at the end of the experiment.

RESULTS

The PBBF treatments significantly (P<0.05) decreased the blood glucose levels and improved the glucose tolerance ability compared to untreated diabetic rats. Furthermore, the treatments were found to improve pancreatic β cell function (HOMA-β), stimulate insulin secretions, decrease insulin resistance (HOMA-IR), restore liver glycogen, ameliorate serum dyslipidaemia and prevent hepatic and renal damages compared to untreated diabetic rats. Phytochemical analysis of the fraction led to the isolation of lupeol which inhibited α-glucosidase and α-amylase in non-competitive and uncompetitive inhibition patterns respectively.

CONCLUSION

It was concluded that PBBF possessed remarkable anti-T2D activity which is mediated through modulation of β-cell function and stimulation of insulin secretion and the lower dose (150mg/kg BW) was found optimum for anti-T2D activity compared to the high dose (300mg/kg BW) in this study.

Bioactive-rich extracts of persimmon, but not nettle, Sideritis, dill or kale, increase eNOS activation and NO bioavailability and decrease endothelin-1 secretion by human vascular endothelial cells

BACKGROUND

There is increasing evidence that consumption of plant bioactives such as polyphenols and glucosinolates reduces cardiovascular disease risk and improves endothelial function. In the Black Sea area, a number of plants are consumed alone and as ingredients in traditional foods, and dill, nettle, kale, Sideritis and persimmon were identified as bioactive-rich traditional food plants. The present study investigated the effects of plant extracts on cellular markers of endothelial function (eNOS activation and expression and ET-1 secretion).

RESULTS

Treatment of human umbilical vein endothelial cells with persimmon extract significantly increased Akt and eNOS phosphorylation and nitric oxide metabolites and significantly decreased secretion of ET-1 to the media after 24 h compared with a vehicle control (all P < 0.01). None of the other plant extracts significantly altered any markers of endothelial function.

CONCLUSION

These findings suggest that persimmon fruit contains bioactives that can improve endothelial function via activation of eNOS and reduction in ET-1 secretion, but that dill, kale, Sideritis and nettle do not.

2,3-cis-procyanidins elicit endothelium-dependent relaxation in porcine coronary arteries via activation of the PI3/Akt kinase signaling pathway

Polyphenols including procyanidins have been reported to reduce the risk of cardiovascular diseases. However, polyphenolic extracts represent complex mixtures, and detailed information on their chemical composition is commonly lacking. The aim of this study was to investigate the potential of a highly purified and chemically defined 2,3-cis-procyanidin sample (di- to hexameric [4β,8]-linked oligomers) from Nelia meyeri to relax coronary arteries and to get insight into the underlying mechanisms. The procyanidins produced a concentration-dependent relaxation in endothelium-intact vascular rings by activation of the NO and endothelium-derived hyperpolarizing factor (EDHF)-signaling pathway via PI3/Akt kinase in a redox-sensitive manner, with O2(-) as key species predominantly produced by xanthine oxidase and NADPH oxidase. Our observations in tissue bath studies were confirmed by Western blotting; 2,3-cis-procyanidins induced phosphorylation of eNOS and Akt in a ROS-dependent manner. These findings provide a basis for comparing the relaxant response and mode of action with that of structurally related proanthocyanidins. Our results may contribute to a better understanding of the potential link between the beneficial effects of proanthocyanidins on vascular health and their broad distribution in many fruits, natural food sources, and foodstuffs.

Vasodilator compounds derived from plants and their mechanisms of action

The present paper reviews vasodilator compounds isolated from plants that were reported in the past 22 years (1990 to 2012) and the different mechanisms of action involved in their vasodilator effects. The search for reports was conducted in a comprehensive manner, intending to encompass those metabolites with a vasodilator effect whose mechanism of action involved both vascular endothelium and arterial smooth muscle. The results obtained from our bibliographic search showed that over half of the isolated compounds have a mechanism of action involving the endothelium. Most of these bioactive metabolites cause vasodilation either by activating the nitric oxide/cGMP pathway or by blocking voltage-dependent calcium channels. Moreover, it was found that many compounds induced vasodilation by more than one mechanism. This review confirms that secondary metabolites, which include a significant group of compounds with extensive chemical diversity, are a valuable source of new pharmaceuticals useful for the treatment and prevention of cardiovascular diseases.

Flavan 3-ols improve metabolic syndrome risk factors: evidence and mechanisms

Flavan 3-ols, a type of polyphenolic substance, are distributed in a number of plant foods. Of these foods, chocolate is very rich in flavan 3-ols as flavan 3-ol monomers, (+)-catechin and (−)-epicatechin, and the oligomers as procyanidins. There is evidence that cacao products containing flavan 3-ols have the potential to contribute to the risk reduction of cardiometabolic disorders according to recent epidemiological or intervention studies. This review focuses on recent advances in research on the ability of flavan 3-ols to reduce the risk of cardiovascular disease as a result of improving metabolic syndrome risk factors and these mechanisms.

Vasorelaxant and antihypertensive effects of methanolic extracts from Hymenocardia acida Tul

ETHNOPHARMACOLOGICAL RELEVANCE

In Congolese traditional medicine, decoctions of Hymenocardia acida root bark (HaRB) and trunk bark (HaTrB) are used for the treatment of conditions assumed to be hypertension. In this work, we propose to study the vasorelaxant effect of HaRB and HaTrB methanolic extracts on isolated rat thoracic aorta, to characterize the group of molecules responsible for the observed vasorelaxant activity, to evaluate the in vitro antioxidant activity of these extracts and to determine the antihypertensive activity of the HaRB extract on spontaneously hypertensive rats (SHR).

MATERIALS AND METHODS

The vasorelaxant effect of the HaRB and HaTrB methanolic extracts was studied on endothelium-intact aortic rings pre-contracted with phenylephrine (PE, 1μM). The mechanism of this vasorelaxant effect was investigated on endothelium-denuded vessels and on endothelium-intact aortic rings in the presence of three inhibitors: l-N(G)-nitroarginine methyl ester (100μM), indomethacin (10μM) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10μM). To determine the nature of the compounds responsible for the vasorelaxant activity, we carried out a fractionation of the extracts and a thiolysis of the most active fraction followed by a liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) analysis. The extracts antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay. In vivo anti-hypertensive activity of the HaRB extract was conducted on SHR.

RESULTS

HaRB and HaTrB methanolic extracts produced a concentration-dependent vasorelaxation on intact aortic rings pre-contracted with PE (1μM). The vasorelaxant responses obtained were 95.3±1.5% (5μg/ml) and 100.6±3.0% (1μg/ml), respectively. The effect was markedly attenuated by removal of endothelium or pretreatment of aortic rings with all inhibitors except indomethacin. The LC/ESI-MS analysis of the thiolysis products indicated that the fraction which caused the most important vasorelaxation (97.9±2.5% at 3μg/ml) was a mixture of procyanidins and prodelphinidins, with a predominance of procyanidins. Both extracts and all fractions from HaRB extract showed a DPPH scavenging activity, ranging from 0.4 to 0.8 quercetin-equivalents. The HaRB methanolic extract reduced the systolic blood pressure in SHR (from 214±3mmHg to 194±4mmHg) after a 5-week treatment.

CONCLUSIONS

The methanolic extracts of Hymenocardia acida root and trunk bark have vasorelaxant activity. The vasorelaxant effect observed is endothelium-dependent and seems mainly mediated through the NO-cGMP pathway. The COX pathway is not involved. The vasorelaxant activity appears to be due to polymeric procyanidins and prodelphinidins. These extracts also have an antioxidant effect. The extract of Hymenocardia acida root bark shows a significant but weak antihypertensive activity in SHR.

Effect of procyanidin C1 on nitric oxide production and hyperpolarization through Ca(2+)-dependent pathway in endothelial cells

Polyphenol-rich foods, such as fruits and vegetables, are protective against cardiovascular diseases, but the mechanisms of the beneficial effects are still unknown. The goal of this research was to clarify actions of procyanidin trimer (C1) in rat aortic endothelial cells (RAECs). Procyanidin C1 at concentrations up to 50 μM was not cytotoxic to the RAECs. The addition of procyanidin C1 to RAECs exerted a time-dependent hyperpolarization measured using a membrane potential-dependent fluorescent probe, bis-(1,3-dibutylbarbituric acid) trimethine oxonol, whereas the hyperpolarization was significantly inhibited by the nonspecific K(+) channel inhibitor tetraethylammonium chloride (TEA). Moreover, procyanidin C1 elevated intracellular Ca(2+) influx, which was totally abolished in the presence of Ca(2+)-free solution with EGTA. Procyanidin C1 caused a significant increase in nitric oxide (NO) production. The effect was significantly inhibited by an NO synthase inhibitor, N(G)-monomethyl-l-arginine, or TEA. In conclusion, we demonstrated for the first time that procyanidin C1 plays a potent role in promoting Ca(2+)-mediated signals such as the hyperpolarization via multiple K(+) channel activations and the NO release in RAECs, suggesting that procyanidin C1 may represent novel and effective therapy for the treatment of cardiovascular diseases.

Acute toxicity and vascular properties of seed of Parkia biglobosa (JACQ) R. Br Gift (Mimosaceae) on rat aorta

The authors report here the results of study on Parkia biglobosa seeds used in Burkina Faso for arterial hypertension treatment. Investigations were done on acute toxicity and vascular properties of fermented and roasted seeds. Acute toxicity test using mice, revealed by the intraperitoneal route a lethal dose 50 (LD50) of 1800 mg/kg and 1600 mg/kg of body weight for aqueous extract from roasted and fermented seeds respectively. According to the scale of Hodge and Sterner and that of the World Health Organization, such drugs would be classified lightly toxic. Oral administration (up to 3000 mg/kg) did not induce any death of animal. For the vascular properties, the effects of these products were tested on the aorta isolated from rats. The cumulative administration of extract from roasted and fermented seeds (0.1-10 mg/mL) in an organ bath induced a concentration-dependent relaxation of the aorta pre contracted by phenylephrine, with or without functional endothelium. The extracts (10 mg/mL) inhibited for 100% the contraction induced by phenylephrine. The EC50 values in presence and absence of endothelium were respectively of 5.37 ± 0.12 and 4.19 ± 1.02 mg/mL for fermented seeds; for roasted seeds these values were respectively, 5.39 ± 1.12 and 5.93 ± 0.95 mg/mL. Nevertheless, low concentration of roasted seeds (1-4 mg/mL) induced endothelium-dependent relaxation and this effect was inhibited by indomethacin (10⁻⁵M), and not by L-NAME (310⁻⁴M). These experimental results revealed a vasorelaxant effect of P. biglobosa seeds. P. biglobosa seems to act directly on the smooth muscle and via endothelium involving the generation of vasodilatating prostaglandins. This vasodilator effect would be in favor of an anti hypertensive property of P. biglobosa seeds.

Effects of freeze-dried cranberry powder on serum lipids and inflammatory markers in lipopolysaccharide treated rats fed an atherogenic diet

This study investigated the effects of freeze-dried cranberry powder on anti-inflammation and lipid profiles of lipopolysaccharide (LPS)-treated rats fed an atherogenic diet for 6 weeks. Forty Sprague-Dawley male rats (6-weeks-old) were equally divided into the following five groups: 1) normal diet group + saline (NC); 2) atherogenic diet + saline (HFC); 3) atherogenic diet + LPS (HL); 4) atherogenic diet with 5% cranberry power + LPS (C5); 5) atherogenic diet with 10% cranberry power + LPS (C10). LPS (0.5 mg/kg) was injected into the abdominal cavities of rats 18 hours prior to sacrifice. At the end of the experimental period, we measured serum lipid profiles as well as levels of serum C-reactive protein (CRP), nitric oxide (NO), and pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10 as an anti-inflammatory cytokine. The mean serum high density lipoprotein (HDL)-cholesterol level in C5 rats was significantly higher than that in NC and HL rats (P < 0.05). The mean serum levels of CRP and IL-1β were significantly lower (P < 0.05) in the cranberry powder groups compared to those in HL rats. Additionally, mean serum IL-6 levels tended to be lower in the cranberry groups than that in the HL group, whereas serum IL-10 and NO showed 29% and 88% higher mean values in the C5 group and 49% and 24% higher in the C10 group than those in the HL group, respectively. These results suggest that freeze-dried cranberry powder may have beneficial effects on cardiovascular diseases by modifying serum lipids and the early inflammatory response.