Mechanism of vasorelaxation induced by Achillea wilhelmsii in rat isolated thoracic aorta

Experimental and clinical studies on pharmacological actions of the genus Achillea: A comprehensive and updated review

Objective

Species of the genus Achillea (from the family Compositae or Asteraceae) are widely used for their numerous pharmacological properties. The present paper reviews pharmacological actions and their possible underlying molecular mechanisms reported for various species of Achillea.

Materials and Methods

Various databases including PubMed, Science Direct, and Scopus were used.

Results

Immunosuppressive, anti-inflammatory and anti-oxidant effects were shown for these plants. In addition, it was shown that these plants pose wound-healing properties and antimicrobial effects on various bacteria as well as antitumor effects on different cell lines. Achillea species showed anti-arrhythmic, anti-thrombotic, vasorelaxant, anti-hyperlipidemic, anti-hypertensive, hepatoprotective and gastroprotective effects. In addition, the plants showed different endocrine effects such as anti-diabetic, estrogenic and anti-spermatogenic properties. Neurological effects of the plants also included anti-nociceptive and anti-anxiety actions. Clinical studies also indicated therapeutic effect of A. millefolium on multiple sclerosis, chemotherapy-induced oral mucositis in cancer patients, and dysmenorrhea but did not affect atopic dermatitis.

Conclusion

Achillea species could be of therapeutic potential for treating of a wide range of diseases but further investigations are needed regarding the other properties of Achillea plants.

Relieving the tension in hypertension: Food-drug interactions and anti-hypertensive mechanisms of food bioactive compounds

Hypertension is a global health problem. Statistics report from the World Health Organization reveals its prevalence in about a quarter of the world global population. Due to the complications associated with hypertension, it is required to be well managed or prevented pharmacologically or non-pharmacologically. Pharmacologically, the major antihypertensive drugs used are centrally acting sympatholytic drugs, diuretics, vasodilators, angiotensin converting enzyme inhibitors, and angiotensin II receptor blockers while non-pharmacological means of management include lifestyle changes, intake of diet or supplements with antihypertensive effects. Interestingly, the use of diet as a complement with drug intake has become very popular due to occurring side effects over time. Recent research efforts have revealed that foods such as fruits and vegetables contain bioactive substances that modulate the activities of macromolecules involved in the development, complications, and management of hypertension. PRACTICAL APPLICATIONS: Recent research efforts have suggested the efficacy of diets rich in fruits and vegetables in the management of hypertension. This review examines some of the mechanisms involved in the dietary management or prevention of hypertension by bioactive compounds found in foods. This review promotes the use of diet in the management of the condition and also suggests that precautions to be taken in the combined use of food and drugs.

Endothelial-Dependent and Independent Vascular Relaxation Effect of Tetrahydropalmatine on Rat Aorta

Tetrahydropalmatine (THP) is an active natural alkaloid isolated from Corydalis yanhusuo W.T. Wang which has been widely used for treating pain and cardiovascular disease in traditional Chinese medicine. Previous studies suggested THP have various pharmacological effects in neural and cardio tissue while the vascular reactivity of THP was not fully established. The present study found that THP relaxed rat aorta which contracted by phenylephrine (Phe), KCl, and U46619. The vascular relaxation effect of THP was partially attenuated by PI3K inhibitor wortmannin, Akt inhibitor IV, endothelial nitric oxide synthetase (eNOS) inhibitor L-NAME, guanylate cyclase inhibitors and the mechanical removal of endothelium. Also, the eNOS substrate L-arginine reversed the inhibition effect of L-NAME on THP-induced vascular relaxation. THP also induced intracellular NO production in human umbilical vein endothelial cells. However, Pre-incubation with β-adrenergic receptor blocker propranolol, angiotensin II receptor 1 (AT1) inhibitor losartan, angiotensin II receptor 2 (AT1) inhibitor PD123319 or angiotensin converting enzyme inhibitor enalapril enhanced the vascular relaxation effect of THP. THP did not affect the angiotensin II induced vascular contraction. Cyclooxygenase-2 (COX2) inhibitor indomethacin did not affect the vascular relaxation effect of THP. Furthermore, pre-treatment THP attenuated KCl and Phe induced rat aorta contraction in standard Krebs solution. In Ca²⁺ free Krebs solution, THP inhibited the Ca²⁺ induced vascular contraction under KCl or Phe stress and reduced KCl stressed Ca²⁺ influx in rat vascular smooth muscle cells. THP also inhibited intracellular Ca²⁺ release induced vascular contraction by blocking Ryr or IP3 receptors. In addition, the voltage-dependent K⁺ channel (Kv) blocker 4-aminopyridine, ATP-sensitive K⁺ channel (KATP) blocker glibenclamide and inward rectifying K⁺ channel blocker BaCl₂ attenuated THP induced vascular relaxation regardless of the Ca²⁺-activated K⁺ channel (KCa) blocker tetraethylammonium. Thus, we could conclude that THP relaxed rat aorta in an endothelium-dependent and independent manner. The underlying mechanism of THP relaxing rat aorta involved PI3K/Akt/eNOS/NO/cGMP signaling path-way, Ca²⁺ channels and K⁺ channels rather than COX2, β-adrenergic receptor and renin-angiotensin system (RAS). These findings indicated that THP might be a potent treatment of diseases with vascular dysfunction like hypertension.

Effect of Achillea wilhelmsii extract on expression of the human telomerase reverse transcriptase mRNA in the PC3 prostate cancer cell line

Evidence has indicated that human telomerase reverse transcriptase (hTERT) was overexpressed in prostate cancer (PCa). Achillea wilhelmsii (AW) is a plant that has been traditionally used for its medicinal properties. The aim of current study was to evaluate the effects of AW extract on a PCa cell line. The cytotoxic activity of the hydroalcoholic extract of AW was studied on the PCa PC3 cell line using MTT assay. Flow cytometry was used to evaluate the effects of the extract on the apoptosis. The expression of hTERT mRNA was analyzed by the reverse transcription-quantitative polymerase chain reaction method. The ELISA method was used to measure the levels of telomerase enzyme. The hydroalcoholic AW extract demonstrated the appropriate inhibitory effect in 150 µg/ml concentration (IC₅₀) on PC3 cell line following 48 h treatment. Treatment of the PC3 cells with AW resulted in a significant increase in early and late apoptotic cells and a decrease in live cells (P<0.001), in a dose-dependent manner. Moreover, the early apoptotic cells were significantly higher than late apoptotic cells. The hTERT mRNA expression was decreased following 24 h treatment of AW extract, although it was not different between 2, 4, 8 and 12 h treatments or 24, 48 and 72 h treatments. In addition, the hTERT concentration was significantly decreased following 24 h treatment of AW extract with the marginal P-value. There was no significant difference regarding hTERT concentration between 2, 4, 8 and 12 h treatments or 24, 48 and 72 h treatments. The hydroalcoholic extract of AW induced potent antiproliferative and apoptotic effects in PC3 cell line, which could be explainable by its high potency to inhibit expression of the prominent oncogene hTERT in PCa. Therefore, targeting telomerase represents a promising strategy for PCa therapy, and AW may have considerable potential for development as a novel natural anticancer agent.

Cardioprotective effects of Achillea wilhelmsii on the isolated rat heart in ischemia-reperfusion

Context

There are some reports about protective effects of Achillea on the heart.

Objective

We investigated the effect of Achillea wilhelmsii extract on cardiac function during ischemia–reperfusion (I/R) injury in the isolated rat heart.

Materials and methods

60 male Wistar rats were randomly divided into 6 groups; 1: Control group, 2: Control-ischemia (CI) 3: vitamin C (10 mg/kg), 4–6: Extract groups (E 100, E 200 and E 400 mg/kg). The animals received normal saline, vitamin C or A. wilhelmsii extract orally for 4 weeks. At the end of the treatment, the hearts were subjected to in vitro I/R Injury (20 min of global ischemia, followed by 40 min of reperfusion, Langendorff's mode). Heart rate (HR) and left ventricular pressure (LVP) were measured using a pressure transducer connected to a data acquisition system. Lactate dehydrogenase (LDH) and creatine kinase (CK) activities in the effluent were measured to determine the myocardial injury degree. The malondialdehyde (MDA), total thiol groups (-SH), superoxide anion dismutase (SOD) and catalase (CAT) in myocardial tissue were detected to determine the oxidative stress degree.

Results

Pretreatment with Achillea wilhlemsii significantly decreased the LDH, CK activities, and MDA level, while it increased the LVDP, ±dp/dt_max, rate-pressure product (RPP), SH groups, SOD and CAT activities, and also the coronary artery flow.

Discussion and conclusion

Our findings indicated that Achillea wilhelmsii could provide protection for heart against the I/R injury which may be related to the improvement of myocardial oxidative stress states.