Effects of onopordia, a novel isolated compound from Onopordon acanthium, on pentylenetetrazole-induced seizures in mice: Possible involvement of nitric oxide pathway.

Epilepsy is identified as a brain disorder and characterized by unpredictable disruption of normal brain function. Due to adverse side effect associated with antiepileptic drugs and also resistance profile, improvement of antiepileptic medications with more beneficial anticonvulsant activity is essential. Natural products have demonstrated their therapeutic properties such as anxiolytic, antidepressant and anticonvulsant activities and a source for identification of novel lead compounds. Therefore, the purpose of this study was to evaluate the effects of Onopordon acanthium secondary metabolite, onopordia, on pentylenetetrazole (PTZ)-induced seizure in male mice and investigate the possible role of nitric oxide pathway. Different doses of onopordia (0.1, 1 and 10 mg/kg) and phenobarbital (20 mg/kg) were administered intraperitoneally (i.p., 30, 60 and 120 min) prior to induction of epileptic seizure and compared to control groups. Onopordia demonstrated anticonvulsant effects when administrated at dose of 10 mg/kg, i.p. and optimum time 60 min prior to induction of seizure. Anticonvulsant effect of onopordia was blocked by applying a single dose of a non-selective nitric oxide synthase (NOS) inhibitor, Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; 10 mg/kg, i.p.), and also a single dose of a selective neuronal NOS (nNOS) inhibitor, 7-nitroindazole (7-NI; 30 mg/kg, i.p.). Administration of ketamine as a N-Methyl-d-aspartic acid (NMDA) receptor antagonist (0.5 mg/kg; i.p.) with onopordia did not change the anticonvulsant effect of onopordia. The results of the present study demonstrated the anticonvulsant effect of onopordia as a new lead compound and also contribution of NO/nNOS pathway on PTZ-induced seizure in mice.

Effect of Onopordon acanthium L. as Add on Antihypertensive Therapy in Patients with Primary Hypertension Taking Losartan: a Pilot Study.

Purpose: Onopordon acanthium L. is known for its medicinal properties. Our recent study showed that its seed extract is a novel natura angiotensin-converting-enzyme inhibitor (ACEI). This study was carried out to investigate its possible antihypertensive effects in patients receiving losartan. Methods: This uncontrolled clinical trial was carried out among 20 patients (30-60y) with uncontrolled hypertension despite receiving 50 mg losartan (stage I & II) in two hospitals in Iran. After completing informed consent, patients were treated by 2 capsules [each 1g of Onopordon acanthium seed extract (OSE)] as add-on therapy, two times per day. Results: 18 patients completed the study (50.94 ±8.37y). Mean systolic blood pressure (SBP) at the baseline was 151.9 ± 13.74mmHg and at the end of the study, it was 134.6 ± 18.25 mmHg and mean diastolic blood pressure (DBP) was 97.41 ± 10.36 at the baseline and was 85.71 ± 7.481 after 8 weeks. OSE significantly reduced SBP and DBP at the end of 8 weeks (P=0.003, 95% CI: -19.7, -15.1; P=0.0006, 95% CI: -10.23, -13.15; respectively). No evidence of hepatic or renal toxicity was detected. Conclusion: Based on the results of this study OSE has antihypertensive property with no significant adverse effects. However, because of the low number of samples, this medication may be not safely administered. The results of this study could be the basis for further studies with larger sample size. IRCT registration number: IRCT2013020712391N.

Identification of a New Isoindole-2-yl Scaffold as a Qo and Qi Dual Inhibitor of Cytochrome bc 1 Complex: Virtual Screening, Synthesis, and Biochemical Assay.

Respiratory chain ubiquinol-cytochrome (cyt) c oxidoreductase (cyt bc 1 or complex III) has been demonstrated as a promising target for numerous antibiotics and fungicide applications. In this study, a virtual screening of NCI diversity database was carried out in order to find novel Qo/Qi cyt bc 1 complex inhibitors. Structure-based virtual screening and molecular docking methodology were employed to further screen compounds with inhibition activity against cyt bc 1 complex after extensive reliability validation protocol with cross-docking method and identification of the best score functions. Subsequently, the application of rational filtering procedure over the target database resulted in the elucidation of a novel class of cyt bc 1 complex potent inhibitors with comparable binding energies and biological activities to those of the standard inhibitor, antimycin.

Structure-based pharmacophore design and virtual screening for novel potential inhibitors of epidermal growth factor receptor as an approach to breast cancer chemotherapy.

Cancer cells are described with features of uncontrolled growth, invasion and metastasis. The epidermal growth factor receptor subfamily of tyrosine kinases (EGFR-TK) plays a crucial regulatory role in the control of cellular proliferation and progression of various cancers. Therefore, its inhibition might lead to the discovery of a new generation of anticancer drugs. In the present study, structure-based pharmacophore modeling, molecular docking and molecular dynamics simulations were applied to identify potential hits, which exhibited good inhibition on the proliferation of MCF-7 breast cancer cell line and favorable binding interactions on EGFR-TK. Selected compounds were examined for their anticancer activity against the Michigan Cancer Foundation-7 (MCF-7) breast cancer cell line which overexpresses EGFR using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay. Compounds 1 and 2, with an isoindoline-1-one core, induced significant inhibition of breast cancer cells proliferation with IC[Formula: see text] values 327 and 370 nM, respectively.

Palladium Catalysis Enables Benzylation of α,α-Difluoroketone Enolates.

A palladium-catalyzed decarboxylative benzylation reaction of α,α-difluoroketone enolates is reported, in which the key C(α)-C(sp(3) ) bond is generated by reductive elimination from a palladium intermediate. The transformation provides convergent access to α-benzyl-α,α-difluoroketone-based products, and should be useful for accessing biological probes.

Discovery of new angiotensin converting enzyme (ACE) inhibitors from medicinal plants to treat hypertension using an in vitro assay.

BACKGROUND AND PURPOSE OF THE STUDY: Angiotensin converting enzyme (ACE) inhibitors plays a critical role in treating hypertension. The purpose of the present investigation was to evaluate ACE inhibition activity of 50 Iranian medicinal plants using an in vitro assay. METHODS: The ACE activity was evaluated by determining the hydrolysis rate of substrate, hippuryl-L-histidyl-L-leucine (HHL), using reverse phase high performance liquid chromatography (RP-HPLC). Total phenolic content and antioxidant activity were determined by Folin-Ciocalteu colorimetric method and DPPH radical scavenging assay respectively. RESULTS: Six extracts revealed > 50% ACE inhibition activity at 330 µg/ml concentration. They were Berberis integerrima Bunge. (Berberidaceae) (88.2 ± 1.7%), Crataegus microphylla C. Koch (Rosaceae) (80.9 ± 1.3%), Nymphaea alba L. (Nymphaeaceae) (66.3 ± 1.2%), Onopordon acanthium L. (Asteraceae) (80.2 ± 2.0%), Quercus infectoria G. Olivier. (Fagaceae) (93.9 ± 2.5%) and Rubus sp. (Rosaceae) (51.3 ± 1.0%). Q. infectoria possessed the highest total phenolic content with 7410 ± 101 mg gallic acid/100 g dry plant. Antioxidant activity of Q. infectoria (IC50 value 1.7 ± 0.03 µg/ml) was more than that of BHT (IC50 value of 10.3 ± 0.15 µg/ml) and Trolox (IC50 value of 3.2 ± 0.06 µg/ml) as the positive controls. CONCLUSIONS: In this study, we introduced six medicinal plants with ACE inhibition activity. Despite the high ACE inhibition and antioxidant activity of Q. infectoria, due to its tannin content (tannins interfere in ACE activity), another plant, O. acanthium, which also had high ACE inhibition and antioxidant activity, but contained no tannin, could be utilized in further studies for isolation of active compounds.

Isolation, identification and molecular docking studies of a new isolated compound, from Onopordon acanthium: a novel angiotensin converting enzyme (ACE) inhibitor.

ETHNOPHARMACOLOGICAL RELEVANCE: Onopordon acanthium (also known as Scotch thistle) is a medicinal plant of the Asteraceae family that is widely distributed in Europe and Asia. This plant has been long used in traditional medicine as a hypotensive, cardiotonic and diuretic agent. AIM OF THE STUDY: The present study is designed to isolate an active compound with ACE inhibition activity from O. acanthium, measure antioxidant activity, predict domain specificity and pharmacokinetic properties of the isolated compound. MATERIALS AND METHODS: Methanolic extract of O. acanthium seeds, has been subjected to a repeated column chromatography to give a pure compound with Angiotensin Converting Enzyme (ACE) inhibition activity. The ACE inhibition activity was determined using hippuryl-L-histidyl-L-leucine (HHL) as substrate in an in vitro ACE assay. Structure of the pure compound, isolated from O. acanthium has been established by spectroscopic methods, including Infrared (IR), Nuclear Magnetic Resonance (NMR) and Mass spectrum analysis. In addition, antioxidant activity of the new isolated compound, was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and compared with those of BHT and Trolox as positive controls. Enzyme type inhibition and ACE-C or N domain specificity of the new compound was further evaluated through molecular modeling and docking studies. RESULTS: Structure of the pure compound, isolated from O. acanthium (83±1% ACE inhibition activity at concentration of 330 µg/ml), has been established. The isolated compound possessed acceptable antioxidant activity (IC50 value of 2.6±0.04 µg/ml) in comparison with BHT (IC50 value of 10.3±0.15 µg/ml) and Trolox (IC50 value of 3.2±0.06 µg/ml). Molecular docking predicted competitive type enzyme inhibition and approximately similar affinity of the isolated compound for ACE-C and N domains. CONCLUSION: The results derived from computational and in vitro experiments, confirm the potential of the isolated compound, from O. acanthium as a new antihypertensive compound and give additional scientific support to an anecdotal use of O. acanthium in traditional medicine to treat cardiovascular disease such as hypertension.