Analysis of chemical constituents and antinociceptive potential of essential oil of <it>Teucrium Stocksianum</it> bioss collected from the North West of Pakistan

<p>Abstract</p> <p>Background</p> <p>Medicinal plants are used for the treatment of different diseases in almost all cultures. Teucrium species grow wildly at different geographical locations around the world. <it>Teucrium stocksianum</it> is used in folk medicine for the treatment of diarrhea, cough, jaundice and abdominal pain. Scientific study on <it>Teucrium stocksianum</it> shows that it possesses anthelmintic, cytotoxic and antispasmodic activity. The aim of our present study is to identify the chemical composition and antinociceptive potential of the essential oil extracted from <it>Teucrium stocksianum</it> bioss.</p> <p>Method</p> <p>Essential oil (EO) from the aerial parts of <it>Teucrium stocksianum</it> were extracted by hydrodistillation process. The qualitative and quantitative composition of essential oil was determined with Gas chromatography/Mass spectrometer. Antinociceptive activity was determined by acetic acid induced writhing method. Percent inhibition of writhes of the test concentration was determined by comparing it with that of control. Tween-80 emulsion 2.5% (5 ml/kg b.w) was used as a control while Diclofenic sodium 50 mg/kg (b.w) was used as a standard drug.</p> <p>Results</p> <p>The chromatogram of the essential oil of <it>Teucrium stocksianum</it> shows differences both qualitatively and quantatively from essential oil composition reported in other countries. Hydrodistillation of <it>Teucrium stocksianum</it> yielded 0.4% (v/w), pale yellowish oil on dry basis. A total of 26 chemicals were identified by GC-MS accounting for 90.28% of the oil. The major components of essential oil were δ-cadinene (12.92%), α-pinene (10.3%), myrcene (8.64%), β-caryophyllene (8.23%), germacrene D (5.18%) and limonene (2.36%). Essential oil of <it>Teucrium stocksianum</it> has shown outstanding antinociceptive activity. It has been observed that increase in percent writhe inhibition (PWI) occurred from 20-80 mg/kg (b.w) and maximum writhe inhibition has been noted at a concentration of 80 mg/kg (b.w), but PWI decreased at 160 mg/kg, which may be due to some toxic effect of higher dose. ED₅₀ value for <it>Teucrium stocksianum</it> was calculated as 31.5 ± 1.72415 mg/kg (b.w).</p> <p>Conclusion</p> <p>Our results indicate that there is a lot of variation in the composition of essential oil of <it>Teucrium stocksianum boiss,</it> which may be due to different climatic and experimental conditions. Secondly, the essential oil possesses strong antinociceptive activity and could be used in analgesic preparations especially for topical use.</p