LC-MS metabolomic evidence metabolites from Oenothera rosea L´ Hér. ex Ait with antiproliferative properties on DU145 human prostate cancer cell line.

Prostate cancer remains one of the leading health issues without a fully effective treatment. Medicinal plants are one of the primary sources of compounds for treating numerous ailments. In this sense, the Oenothera genus contains metabolites with antiproliferative activity on cancer cells. For this, the study aimed to explore the antiproliferative activity of its extracts against prostate cancer and identify its metabolites (under metabolomics analyses) associated with anticancer and/or antiproliferative properties. For this reason, a LC-MS/MS-based metabolomic analysis was performed to demonstrate the possible metabolites present in O. rosea. In addition, the antiproliferative activity of different extracts in the human prostate cancer cell line DU145 was evaluated. All extracts have antiproliferative effects on DU145 cells at 72 h, with moderate activity being the best ethanolic either 48 or 72 h. Finally, by LC-MS/MS-based metabolomics, 307 compounds from aqueous, methanolic, ethanolic, and ethyl acetate extracts from which 40 putative metabolites identified were organized as anti-inflammatory, anticancer, and/or antiproliferative activities according to previously reported. These results provide evidence that O. rosea could be used as an antiproliferative agent due to its chemical contents used as polypharmacy with low concentration levels.

1,2,3,4,6-Penta-O-galloyl-ß-d-glucose modulates perivascular inflammation and prevents vascular dysfunction in angiotensin II-induced hypertension.

BACKGROUND AND PURPOSE: Hypertension is a multifactorial disease, manifested by vascular dysfunction, increased superoxide production, and perivascular inflammation. In this study, we have hypothesized that 1,2,3,4,6-penta-O-galloyl-ß-d-glucose (PGG) would inhibit vascular inflammation and protect from vascular dysfunction in an experimental model of hypertension. EXPERIMENTAL APPROACH: PGG was administered to mice every 2 days at a dose of 10 mg·kg-1 i.p during 14 days of Ang II infusion. It was used at a final concentration of 20 µM for in vitro studies in cultured cells. KEY RESULTS: Ang II administration increased leukocyte and T-cell content in perivascular adipose tissue (pVAT), and administration of PGG significantly decreased total leukocyte and T-cell infiltration in pVAT. This effect was observed in relation to all T-cell subsets. PGG also decreased the content of T-cells bearing CD25, CCR5, and CD44 receptors and the expression of both monocyte chemoattractant protein 1 (CCL2) in aorta and RANTES (CCL5) in pVAT. PGG administration decreased the content of TNF+ and IFN-γ+ CD8 T-cells and IL-17A+ CD4+ and CD3+ CD4- CD8- cells. Importantly, these effects of PGG were associated with improved vascular function and decreased ROS production in the aortas of Ang II-infused animals independently of the BP increase. Mechanistically, PGG (20 µM) directly inhibited CD25 and CCR5 expression in cultured T-cells. It also decreased the content of IFN-γ+ CD8+ and CD3+ CD4- CD8- cells and IL-17A+ CD3+ CD4- CD8- cells. CONCLUSION AND IMPLICATION: PGG may constitute an interesting immunomodulating strategy in the regulation of vascular dysfunction and hypertension. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

Oenothein B, dimeric hydrolysable tannin inhibiting HCV invasion from Oenothera erythrosepala.

The envelope proteins of the hepatitis C virus (HCV), E1 and E2, have been revealed to be essential for invasion of HCV. Thus, we were engaged in the search for the inhibitors against HCV invasion through the assay system using the model virus expressing recombinant HCV envelopes, E1 and E2. Now, we disclosed dimeric hydrolysable tannin oenothein B (1) from MeOH extract of Oenothera erythrosepala as an active principle for inhibition of HCV invasion and its potency was almost the same as that of monomeric hydrolysable tannin, tellimagrandin I (2). Furthermore, by use of stereoselectively prepared 1-ß- and 1-α-O-methyl tellimagrandin Is (4 and 5), the introduction of methyl moiety into 1-hydroxy group of 2 was clarified to result in slightly reduction of activity and ß-isomer was revealed to exhibit a little stronger activity than α-one.

Oenothera rosea L´Hér. ex Ait attenuates acute colonic inflammation in TNBS-induced colitis model in rats: in vivo and in silico myeloperoxidase role.

Oenothera rosea L´Hér. ex Ait is a species traditionally used in the treatment of inflammation, headache, stomach pain, infections, among others. The aim of this study was evaluating the acute anti-inflammatory activity of the aqueous extract of O. rosea by 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Rats were randomized into six groups: (I) Sham; (II) EtOH; (III) TNBS; and (IV-VI) 250, 500 and 750 mg/Kg, respectively. The colonic injury was induced (groups III-VI) by intrarectal instillation of 0.25 mL of TNBS (10 mg) in 50% ethanol. Groups I and II received an enema (0.25 mL) of physiological saline solution or 50% ethanol, respectively. Treatments were administered by oral gavage 48, 24 and 1 h prior, and 24 h after the induction. The inflammatory response was assessed considering the macroscopic and microscopic damage, the serum nitric oxide (NO), the colonic IL-1ß levels, and the myeloperoxidase (MPO) activity. Moreover, we performed an LC-MS-based metabolite profiling, and a docking on the MPO. Doses of 500 and 750 mg/Kg showed a protective effect in the TNBS-induced colonic damage. This activity was related to the downregulation of evaluated parameters. Also, considering previous reports, 29 metabolites of 91 detected were selected for the docking, of which Isolimonic acid (29) and Kaempferol 3-(2'',4''-diacetylrhamnoside) (10) showed the highest affinity to MPO. The aqueous extract of O. rosea protected the TNBS-induced colonic damage in rats, an effect that could be associated with the presence of polyphenolic compounds, alkaloids, and terpenes; as well as their ability to down-regulate MPO activity.

Change of Petals' Color and Chemical Components in Oenothera Flowers during Senescence.

Oenothera flower petals change color during senescence. When in full bloom, the flowers of O. tetraptera are white and those of O. laciniata and O. stricta are yellow. However, the colors change to pink and orange, respectively, when the petals fade. We analyzed the flavonoid components in these petals as a function of senescence using HPLC-DAD and LC-MS. In all three species, cyanidin 3-glucoside (Cy3G) was found in faded petals. The content of Cy3G increased in senescence. In full bloom (0 h), no Cy3G was detected in any of the petals. However, after 12 h, the content of Cy3G in O. tetraptera was 0.97 µmol/g fresh weight (FW) and the content of Cy3G in O. laciniata was 1.82 µmol/g FW. Together with anthocyanins, major flavonoid components in petals were identified. Quercitrin was detected in the petals of O. tetraptera and isosalipurposide was found in the petals of O. laciniata and O. stricta. The content of quercitrin did not change during senescence, but the content of isosalipurposide in O. laciniata increased from 3.4 µmol/g FW at 0 h to 4.8 µmol/g FW at 12 h. The color change in all three Oenothera flowers was confirmed to be due to the de novo biosynthesis of Cy3G.

Floral nectary, nectar production dynamics and chemical composition in five nocturnal Oenothera species (Onagraceae) in relation to floral visitors.

Main conclusion The floral nectars were sucrose-dominant; however, nectar protein and amino acid contents differed, indicating that composition of nitrogenous compounds may vary considerably even between closely related plant species, irrespectively of nectary structure. Numerous zoophilous plants attract their pollinators by offering floral nectar; an aqueous solution produced by specialized secretory tissues, known as floral nectaries. Although many papers on nectaries and nectar already exist, there has been a little research into the structure of nectaries and/or nectar production and composition in species belonging to the same genus. To redress this imbalance, we sought, in the present paper, to describe the floral nectary, nectar production, and nectar composition in five nocturnal Oenothera species with respect to their floral visitors. The structure of nectaries was similar for all the species investigated, and comprised the epidermis (with nectarostomata), numerous layers of nectary parenchyma, and subsecretory parenchyma. Anthesis for a single flower was short (ca. 10-12 h), and flowers lasted only one night. The release of floral nectar commenced at the bud stage (approx. 4 h before anthesis) and nectar was available to pollinators until petal closure. Nectar concentration was relatively low (ca. 27%) and the nectar was sucrose-dominant, and composed mainly of sucrose, glucose and fructose. The protein content of the nectar was also relatively low (on average, 0.31 µg ml-1). Nevertheless, a great variety of amino acids, including both protein and non-protein types, was detected in the nectar profile of the investigated taxa. We noted both diurnal and nocturnal generalist, opportunistic floral insect visitors.

In Vitro Biological Screening of Hartmannia rosea Extracts.

The present study is focused on the assessment of the medicinal therapeutic potential extracts of H. rosea to investigate their pharmacological implications based upon science proofs. The antioxidant activity of fraction of H. rosea, namely, n-hexane (HR-1), ethyl acetate (HR-2), chloroform (HR-3), and n-butanol (HR-4), was performed by using the DPPH radical scavenging method. The cytotoxicity and enzyme inhibition assessment were also performed. All the extracts showed significant antioxidant, antibacterial, and protein kinase inhibition but none of the extracts exhibited α-amylase inhibition activity. The chloroform extract HR-3 may block a kinase receptor from binding to ATP; the lead molecule will be isolated, which may stop cancerous cell growth and demotion of cell division. It is predicted that ethyl acetate, chloroform, and n-butanol extracts of H. rosea contain polyphenolics, flavonoids, and alkaloids that are biologically effective candidates exhibiting significant cytotoxicity, antioxidant, and antimicrobial activities. They may control oxidative damage in the body tissues and act as potential antidiabetic and anticancer agents. These studies will also be helpful for future drug designing and drug development research.

Biomolecular Interactions of Tannin Isolated from Oenothera gigas with Liposomes.

We have examined the interaction between hydrolysable tannin 1-O-galloyl-4,6-hexahydroxydiphenoyl-ß-D-glucose (OGßDG) with neutral liposomes as a model of cell membranes composed of three lipids: lecithin, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) at different mass ratios. OGßDG in the concentration range 0.5-15 µg/ml (0.4-12 µM) strongly interacts with liposomal membranes by changing their structure, surface charge and fluidity. Used OGßDG molecules decrease and increase the rigidity of hydrophilic surface and hydrophobic parts of liposomes, respectively. At higher concentrations of tannin (>15 µM), liposomes are aggregated. Fourier Transform Infra-Red (FTIR) analysis showed that mainly -OH groups from OGßDG and also PO(2-) groups from phospholipids are responsible for the interaction. Obtained data indicate the importance of membrane lipid composition in interactions between tannins and cells.

Anti-skeletal muscle atrophy effect of Oenothera odorata root extract via reactive oxygen species-dependent signaling pathways in cellular and mouse model.

Skeletal muscle atrophy can be defined as a decrease of muscle volume caused by injury or lack of use. This condition is associated with reactive oxygen species (ROS), resulting in various muscular disorders. We acquired 2D and 3D images using micro-computed tomography in gastrocnemius and soleus muscles of sciatic-denervated mice. We confirmed that sciatic denervation-small animal model reduced muscle volume. However, the intraperitoneal injection of Oenothera odorata root extract (EVP) delayed muscle atrophy compared to a control group. We also investigated the mechanism of muscle atrophy's relationship with ROS. EVP suppressed expression of SOD1, and increased expression of HSP70, in both H2O2-treated C2C12 myoblasts and sciatic-denervated mice. Moreover, EVP regulated apoptotic signals, including caspase-3, Bax, Bcl-2, and ceramide. These results indicate that EVP has a positive effect on reducing the effect of ROS on muscle atrophy.

Antidiabetic effect of polyphenolic extracts from selected edible plants as α-amylase, α -glucosidase and PTP1B inhibitors, and ß pancreatic cells cytoprotective agents - a comparative study.

Type 2 diabetes mellitus, which is usually a result of wrong dietary habits and reduced physical activity, represents 85-95% of all diabetes cases and among other diet related diseases is the major cause of deaths. The disease is characterized mainly by hyperglycemia, which is associated with attenuated insulin sensitivity or beta cells dysfunction caused by multiple stimuli, including oxidative stress and loss of insulin secretion. Since polyphenols possess multiple biological activities and constitute an important part of the human diet, they have recently emerged as critical phytochemicals in type 2 diabetes prevention and treatment. Their hypoglycemic action results from their antioxidative effect involved in recovering of altered antioxidant defenses and restoring insulin secreting machinery in pancreatic cells, or abilities to inhibit the activity of carbohydrates hydrolyzing enzymes (α-amylase and α-glucosidase) or protein tyrosine phosphatase 1B (PTP1B), which is known as the major negative regulator in insulin signaling. This study investigates the total phenolic content (Folin-Ciocalteu and HPLC methods) and antioxidant capacity (ABTS) of 20 polyphenolic extracts obtained from selected edible plants, which were screened in terms of α -amylase, α - glucosidase and protein tyrosine phosphatase 1B inhibitors or protective agents against oxidative stress induced by tertbutylhydroperoxide (t-BOOH) in ßTC3 pancreatic beta cells used as a model target for antidiabetes drugs. The study concludes that Chaenomeles japonica, Oenothera paradoxa and Viburnum opulus may be promising natural sources for active compounds with antidiabetic properties.

Biophysical studies of interaction between hydrolysable tannins isolated from Oenothera gigas and Geranium sanguineum with human serum albumin.

Tannins, secondary plant metabolites, possess diverse biological activities and can interact with biopolymers such as lipids or proteins. Interactions between tannins and proteins depend on the structures of both and can result in changes in protein structure and activity. Because human serum albumin is the most abundant protein in plasma and responsible for interactions with important biological compounds (e.g. bilirubin) and proper blood pressure, therefore, it is very important to investigate reactions between HSA and tannins. This paper describes the interaction between human serum albumin (HSA) and two tannins: bihexahydroxydiphenoyl-trigalloylglucose (BDTG) and 1-O-galloyl-4,6-hexahydroxydiphenoyl-ß-d-glucose (OGßDG), isolated from Geranium sanguineum and Oenothera gigas leafs, respectively. Optical (spectrofluorimetric) and chiral optical (circular dichroism) methods were used in this study. Fluorescence analysis demonstrated that OGßDG quenched HSA fluorescence more strongly than BDTG. Both OGßDG and BDTG formed complexes with albumin and caused a red shift of the fluorescence spectra but did not significantly change the protein secondary structure. Our studies clearly demonstrate that the tested tannins interact very strongly with human serum albumin (quenching constant K=88,277.26±407.04 M(-1) and K=55,552.67±583.07 M(-1) respectively for OGßDG and BDTG) in a manner depending on their chemical structure.

Dual stimulus-dependent effect of Oenothera paradoxa extract on the respiratory burst in human leukocytes: suppressing for Escherichia coli and phorbol myristate acetate and stimulating for formyl-methionyl-leucyl-phenylalanine.

Although a growing body of evidence suggests that plant polyphenols can modulate human immune responses, their simultaneous action on monocyte and neutrophil oxidative burst is currently poorly understood. Based on the hypothesis that various polyphenols contained in plant extracts might affect the oxidative burst of phagocytes, we evaluated the effects of ethanolic O. paradoxa extract polyphenols on monocyte and neutrophil oxidative burst in vitro activated by different stimuli, including opsonized bacteria E. coli, phorbol 12-myristate 13-acetate (PMA), and formyl-methionyl-leucyl-phenylalanine (fMLP). Samples were analyzed by the dihydrorhodamine flow cytometry assay. Our results showed that the extract repressed significantly and dose-dependently reactive oxygen species production in both cell types stimulated with E. coli and PMA (P < 0.05) and its inhibitory efficiency was stimulus- and cell-type-dependent. Interestingly, there was significant stimulatory effect of the extract on bursting phagocytes induced by fMLP (P < 0.05). Additionally, several flavonoids and phenolic compounds as well as penta-galloyl-ß-(D)-glucose (PGG), the representative of hydrolyzable tannins, were identified in the 60% extract by high-performance liquid chromatography (HPLC) coupled to electrospray ionization in negative ion mode. In summary, the ethanolic O. paradoxa extract, rich in flavonoids and phenolic compounds, exhibits dual stimulus-dependent effect on the respiratory burst in human leukocytes; hence, it might affect immune responses in humans.

Macroevolution of plant defenses against herbivores in the evening primroses.

Plant species vary greatly in defenses against herbivores, but existing theory has struggled to explain this variation. Here, we test how phylogenetic relatedness, tradeoffs, trait syndromes, and sexual reproduction affect the macroevolution of defense. To examine the macroevolution of defenses, we studied 26 Oenothera (Onagraceae) species, combining chemistry, comparative phylogenetics and experimental assays of resistance against generalist and specialist herbivores. We detected dozens of phenolic metabolites within leaves, including ellagitannins (ETs), flavonoids, and caffeic acid derivatives (CAs). The concentration and composition of phenolics exhibited low to moderate phylogenetic signal. There were clear negative correlations between multiple traits, supporting the prediction of allocation tradeoffs. There were also positively covarying suites of traits, but these suites did not strongly predict resistance to herbivores and thus did not act as defensive syndromes. By contrast, specific metabolites did correlate with the performance of generalist and specialist herbivores. Finally, that repeated losses of sex in Oenothera was associated with the evolution of increased flavonoid diversity and altered phenolic composition. These results show that secondary chemistry has evolved rapidly during the diversification of Oenothera. This evolution has been marked by allocation tradeoffs between traits, some of which are related to herbivore performance. The repeated loss of sex appears also to have constrained the evolution of plant secondary chemistry, which may help to explain variation in defense among plants.

Procyanidins from evening primrose (Oenothera paradoxa) defatted seeds inhibit invasiveness of breast cancer cells and modulate the expression of selected genes involved in angiogenesis, metastasis, and apoptosis.

There is a growing interest in plant polyphenols (including flavanols) that exhibit pleiotropic biological activities such as antiinflammatory, antioxidant, and anticancer effects. Here, we report for the first time the inhibition of MDA-MB-231 breast cancer cell viability and invasiveness by an evening primrose flavanol preparation (EPFP). We observed a decrease in MDA-MB-231 viability of 50% vs. a control after 72 h of incubation with EPFP at a concentration of 58 µM gallic acid equivalents (GAE) and an inhibition of their invasiveness of 65% vs. a control at 75 µM GAE after 48 h of incubation. EPFP caused a 10-fold reduction in matrix metalloproteinase-9 (MMP-9) activity at 100 µM GAE. Furthermore, through modulation of mRNA expression, EPFP reduced the expression levels of the following proteins: antiapoptotic Bcl-2, angiogenic vascular endothelial growth factor (VEGF), and 2 transcription factors (c-Jun, c-Fos). Moreover, analysis by flow cytometry revealed that EPFP induced apoptosis in MDA-MB-231 cells. In conclusion, our data shows that EPFP inhibits cell viability by increasing apoptosis and decreases cell invasiveness by decreasing angiogenesis.

UVA-induced ROS generation inhibition by Oenothera paradoxa defatted seeds extract and subsequent cell death in human dermal fibroblasts.

UVA radiation stimulates the production of reactive oxygen species (ROS), which react with lipids, proteins and other intracellular molecules leading to oxidative stress, cellular damage and ultimately cell death. There is, therefore, a growing need for substances exhibiting antioxidant activity, which may support repair mechanisms of the skin. This study evaluates the protective effect of the aqueous Oenothera paradoxa Hudziok defatted seeds extract, rich in polyphenolic compounds, against UVA (25 and 50J/cm(2))-induced changes in normal human dermal fibroblasts (NHDFs). The tested extract (0.1-10µg/ml) has decreased, in a concentration-dependent fashion, the UVA-induced release of lactate dehydrogenase (LDH) into the culture medium, the ROS production (with the use of 2',7'-dichlorodihydrofluorescein diacetate) and lipid peroxidation (utilizing redox reactions with ferrous ions) as compared to the control cells (incubated without the extract). Moreover, the extract increased the number of viable (calcein positive) cells decreasing the number of cells in late apoptosis (annexin V-FITC and propidium iodide positive). Thus our results show that O. paradoxa defatted seeds extract may be beneficial for the prevention of UVA skin damage.

Flavanols from evening primrose (Oenothera paradoxa) defatted seeds inhibit prostate cells invasiveness and cause changes in Bcl-2/Bax mRNA ratio.

In this study, we assessed the influence of an evening primrose flavanol preparation (EPFP) on proliferation and invasiveness of human prostate cancer cells (DU 145) and immortalized prostate epithelial cells (PNT1A). We report for the first time that EPFP reduces DU 145 cell proliferation (IC50 = 97 µM GAE for 72 h incubation) and invasiveness (by 24% versus control at 75 µM GAE). EPFP strongly inhibited PNT1A invasiveness in a concentration-dependent manner (by 67% versus control at 75 µM GAE) and did not cause a reduction in their proliferation. Furthermore, EPFP inhibited the activities of MMP-2 and MMP-9 secreted to culture medium by PNT1A cells by 84% and 34% versus control at 100 µM GAE, respectively. In the case of DU 145, MMP-9 activity at 100 µM GAE was reduced by 37% versus control. Moreover, the evening primrose seed flavanols suppressed the expression of selected genes (MMP-1, MMP-9, MMP-14, c-Fos, c-Jun, and VEGF) and also caused favorable changes in Bcl-2/Bax mRNA ratio which render DU 145 cells more sensitive to apoptosis-triggering agents. An additional confirmation of the proapoptotic activity of EPFP toward DU 145 was visualization of characteristic apoptotic bodies by DAPI staining. In conclusion, this study suggests that EPFP may increase apoptosis and reduce angiogenesis of prostate cancer cells.

Chemical composition, antioxidative and anti-inflammatory activity of extracts prepared from aerial parts of Oenothera biennis L. and Oenothera paradoxa Hudziok obtained after seeds cultivation.

In the present study we investigated the chemical composition of extracts prepared from aerial parts of Oenothera paradoxa Hudziok and Oenothera biennis L. and their antioxidative and anti-inflammatory activities. Ultra high pressure liquid chromatography (UHPLC)-DAD-MS/MS studies showed that both extracts contain a wide variety of polyphenols (39 identified constituents) among which macrocyclic ellagitannin turned out to be the main constituent. During the in vitro studies, using noncellular models, both extracts scavenged reactive oxygen species (ROS) in a concentration-dependent manner, and the lowest SC(50) values were obtained for O(2)(-) and H(2)O(2). Both extracts inhibited ROS production by stimulated human neutrophils. The stronger activity in the case of formyl-met-leu-phenylalanine stimulation suggests that both extracts may act through the receptor-dependent pathway. O. paradoxa extract and O. biennis extract exhibited anti-inflammatory activity by the inhibition of hyaluronidase and lipoxygenase in a concentration-dependent manner. The stronger activity of O.biennis extract toward lipoxygenase may be explained by its higher oenothein B content.

An updated review on the Oenothera genus.

Oenothera genus (Onagraceae) has been used as a folk remedy since ancient times for the treatment of asthma, gastrointestinal disorders, neuralgia, skin diseases, and hepatic and kidney diseases. Different chemical constituents like lipids, flavonoids, tannins, steroids and triterpenes have been isolated from this genus. The various notable pharmacological activities reported from the genus are antioxidant, cytotoxic, antibacterial, antiviral, anti-inflammatory, antihyperlipidaemic, thrombolytic and antidiarrhoeal. The present paper is to summarize the worldwide reported biological activities and phytoconstituents associated with this genus for about 50 years and highlight the medicinally important species belonging to this genus so that these species can be further explored and used as therapeutic agents for various diseases.

Ex vivo effects of an Oenothera paradoxa extract on the reactive oxygen species generation and neutral endopeptidase activity in neutrophils from patients after acute myocardial infarction.

Oxidative stress induced by reactive oxygen species (ROS) is considered to play an important part in the aetiology of coronary heart disease. Apart from ROS, neutrophils are a source of neutral endopeptidase (NEP) that inactivates protective natriuretic peptides. The aim of the present study was to evaluate the in vitro ROS generation and inhibition of NEP activity in neutrophils obtained from healthy volunteers and from patients after acute myocardial infarction (AMI) by an aqueous extract of Oenothera paradoxa. Neutrophils isolated from AMI patients showed two-fold higher ROS generation compared with cells from healthy donors, especially in the lucigenin-enhanced luminescence model, which suggests intensive O2⁻ generation. The addition of O. paradoxa extract at concentrations of 0.2, 2 and 20 µg/mL resulted in a significant reduction in ROS generation. The extracellular NEP activity was higher in patients after AMI compared with healthy individuals (15.0 ± 0.9 versus 10.3 ± 0.5 nmol AMC/10(6) cells/60 min; p = 0.001). The addition of O. paradoxa extract at concentrations of 20, 50 and 100 µg/mL resulted in a significant reduction in NEP activity in both groups. O. paradoxa extract appears to be an interesting candidate for supplementation in the prevention of cardiovascular diseases.

Ethanol extract of seeds of Oenothera odorata induces vasorelaxation via endothelium-dependent NO-cGMP signaling through activation of Akt-eNOS-sGC pathway.

AIM OF STUDY: The vasorelaxant effect of ethanol extract of seeds of Oenothera odorata (Onagraceae) (one species of evening primroses) (ESOO) and its mechanisms involved were defined. MATERIALS AND METHODS: Changes in vascular tension, guanosine 3',5'-cyclic monophosphate (cGMP) levels, and Akt expression were measured in carotid arterial rings from rats. Seeds of Oenothera odorata were extracted with ethanol (94%) and the extract was filtered, concentrated and stored at -70°C. RESULTS: ESOO relaxed endothelium-intact, but not endothelium-denuded, carotid arterial rings in a concentration-dependent manner. Similarly, ESOO increased cGMP levels of the carotid arterial rings. Pretreatment of endothelium-intact arterial rings with L-NAME, an inhibitor of nitric oxide synthase (NOS), or ODQ, an inhibitor of soluble guanylyl cyclase (sGC), blocked the ESOO-induced vasorelaxation and increase in cGMP levels. Nominally Ca(2+)-free but not L-typed Ca(2+) channel inhibition attenuated the ESOO-induced vasorelaxation. Thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate, modulators of store-operated Ca(2+) entry (SOCE), significantly attenuated the ESOO-induced vasorelaxation and increase in cGMP levels. Further, wortmannin, an inhibitor of Akt, attenuated the ESOO-induced vasorelaxation and increases in cGMP levels and phosphorylated Akt2 expression. K(+) channel blockade with TEA, 4-aminopyridine, and glibenclamide attenuated the ESOO-induced vascular relaxation. CONCLUSION: Taken together, the present study demonstrates that ESOO relaxes vascular smooth muscle via endothelium-dependent NO-cGMP signaling through activation of the Akt-eNOS-sGC pathway.