Insight into the bronchodilator activity ofVitex negundo

Abstract

Context: Vitex negundo Linn. (Verbenaceae) is traditionally used in hyperactive respiratory disorders.Objective: This study explored the mechanisms underlying the effectiveness of Vitex negundo in hyperactive respiratory disorders. Materials and methods: Crude extract of V. negundo leaves was obtained. For in vivo bronchodilatory activity in anesthetized rats, different doses (1, 3, 10, 30, and 50 mg/kg) of the crude extract of V. negundo (Vn.Cr) were tested. The underlying mechanisms were studied in isolated guinea pig tracheal strips, suspended in organ baths at 37 C. Results: Intravenous doses of the crude extract of Vn.Cr showed dose-dependent bronchodilatory effect (9-50%) against carbachol (CCh; 100 mg/kg)-induced bronchoconstriction, similar to aminophylline. In isolated guinea-pig tracheal strips, Vn.Crrelaxed CCh (1 mM) and high K + pre-contractions with respective EC 50 values of 0.72 (0.48-1.10; n ¼ 5) and 3.38 mg/mL (1.84-6.21; n ¼ 4), similar to papaverine. Diltiazem also relaxed both contractions with more potency against high K + pre-contraction (p50.05). Pre-incubation of the tracheal strips with Vn.Cr potentiated the isoprenaline inhibitory concentration response curves (CRCs), similar to papaverine. Discussion: The inhibitory effect against CCh and high K + suggests involvement of phosphodiesterase (PDE) inhibitory pathway(s), in addition to an inhibitory effect on Ca ++ entry. This finding was further strengthened when pre-treatment of the tracheal strips potentiated the isoprenaline CRCs. Conclusion: Results suggest Vn.Cr possesses a combination of papaverine-like PDE inhibitor and diltiazem-like Ca ++ entry blocking constituents, which partly explain its bronchodilatory effect, thus validating its medicinal importance in asthma.

Natural Products Useful in Respiratory Disorders: Focus on Side-Effect Neutralizing Combinations

“…Interestingly, one of its known constituents, chrysoeriol, was found to exhibit high selectivity for its inhibitory effect on airways compared with other smooth muscles (Khan and Gilani, ), thus showing potential to be developed for airways disorders. Interestingly, few recent studies on Morus alba , Salvia officinalis (Sage) and Vitex negun showed that their bronchodilator action is mediated through a combination of predominant K + channel activation, PDE inhibition and reasonable Ca ++ channel blockade (Khan et al , ; Gilani et al , ; Khan et al , ).…”

A Systematic Review on Vitex negundo (NIRPROMP formulations) for the Treatment of Acute Cough of Mild to Moderate Severity in Pediatric Patients

“…12 Patel et al in 2009 utilizing normotensive anesthetized rats showed that the lagundi extract stabilized mast cells showing inhibitory effects on immediate hypersensitivity reactions and exhibited anti-eosinophilic activity which was considered the underlying mechanism involved in the anti-asthmatic effect of Vitex negundo. 13 Khan, Shah et al in 2015 explored the mechanism underlying the effectiveness of Vitex negundo in hyperactive respiratory disorders using crude extract of the leaves and found that Vitex negundo possesses a combination of papaverine-like phosphodiesterase inhibitors (PPE) and diltiazem-like Ca ++ entry blocking constituents which partly explains its bronchodilating effect. 14 Plant extracts tend to exhibit numerous pharmacological actions with multiple mechanisms, which are activated by several different types of compounds.…”

Study on the mechanisms of the bronchodilator effects ofFolium Eriobotryaeand the selected active ingredient on isolated guinea pig tracheal strips

“…Tracheal strips were placed in an organ bath of 10 mL capacity containing the Krebs solution with the following composition (mM): NaCl 118.1, KCl 4.7, CaCl 2 2.5, MgSO 4 1.2, KH 2 PO 4 1.2, NaHCO 3 25.0 and glucose 11.1, bubbled with 95% O 2 and 5% CO 2 at 37 C. Tissue was suspended under an isotonic tension of 1 g and allowed to equilibrate for at least 1 h, while it was washed with the Krebs solution for every 15 min. After equilibration, it was stimulated with 2 lM His to test their contractile responses and isometric contractions were measured by a force transducer connected to a computerized data acquisition system (BL-420F analyzer, Chengdu Instrument Corporation, Chengdu, China) (Khan et al 2015).…”

“…Incidence of asthma has climbed dramatically, despite an increased use of medications that suppress airway inflammation and repress contraction of smooth muscle that encircles the airways. Asthmatic patients exhibit episodes of airway inflammation that potentiates reversible airway smooth muscle spasm (Khan et al 2015). Current pharmacological management for controlling asthma is mainly based on corticoids as antiinflammatory agents in combination with b 2 -adrenergic agonists as bronchodilators (Chung et al 2009).…”