Article: SMOOTH MUSCLE RELAXANT ACTIVITY OF ESSENTIAL OIL OF PISTACIA INTEGERRIMA J.L. STEWART EX BRANDIS GALLS ON RAT UTERUS

Article Category: Original Research articles

DOI: 10.7897/2277-4343.15383

Pages: 124-128

Author: Shirole RL *, Shirole NL, Saraf MN

Abstract: Ethnopharmacological relevance: Pistacia integerrima J.L. Stewart ex Brandis is valued in traditional medicine used in India for the treatment of asthma, chronic bronchitis, diarrhoea, and fever and incorporated in Ayurvedic formulations like ‘Chvyanprash Avaleha’, ‘Kumari Asava’, ‘Kumari Kalp’ prescribed in weakness as rejuvenating agent and tonic. However, in vitro studies providing new insights into its pharmacological properties on isolated rat uteruses have not been thoroughly investigated. Aim: The present investigation aimed to elucidate the effect of the essential oil of Pistacia integerrima on isolated rat uterus and to find the probable mechanism. Methods: The essential oil of Pistacia integerrima was characterised by GCMS analysis and tested using in vitro studies to relax the contraction of rat uterus rings induced by KCl (60 mM) and oxytocin. We also investigated the effect of the essential oil of Pistacia integerrima on extracellular calcium uptake. In order to study the effect of β-adrenergic antagonist and NO-synthase inhibitor in the relaxing effect of essential oil of Pistacia integerrima, the uterine rings were incubated with L-NAME (100 µM) and propranolol (10µM) prior to addition of essential oil of Pistacia integerrima. The effect of the essential oil of Pistacia integerrima on extracellular calcium uptake was studied in a Ca²⁺ free medium. Results: The essential oil of Pistacia integerrima (10, 30 and 100µg/mL) showed a relaxant effect on both KCl and oxytocin-induced tonic contractions of isolated rat uterus separately. Preincubation of L-NAME, a classical NO-synthase inhibitor (100 µM), did not alter the relaxation induced by the essential oil of Pistacia integerrima. Pre-treatment of the uterine rings with essential oil of Pistacia integerrima (5, 10 and 20 µg/mL) and Nifedipine (10^-7 M) inhibited the cumulative response curve of CaCl₂ (10^-4 to 10^-2 M) in Ca²⁺ free medium. Conclusion: The present investigation indicates that the essential oil of Pistacia integerrima J.L. Stewart ex Brandis shows uterine relaxant effect in vitro in a concentration-dependent manner attributed to tetracyclic triterpenoids. The effect is mediated inhibition of the cumulative Ca²⁺-induced contraction in the depolarised uterus rings and does not depend on NO or/and β-adrenergic receptors. These findings suggest that the essential oil of Pistacia integerrima acts on voltage-sensitive calcium channels.

Keyword: Pistacia integerrima J.L. Stewart ex Brandis, tocolytic, essential oil