Chemical composition and spasmolytic activity of Cymbopogon nervatus (Hochst.) Chiov. (Poaceae) essential oil

Abstract

The composition of essential oils obtained by hydrodistillation from dried stems and inflorescences of Cymbopogon nervatus (Hochst.) Chiov. (Poaceae) growing wild in Western and Eastern Sudan and collected at two different periods, was analyzed by GC and GC MS. The most dominant constituents in the oils were p-menthadienols, trans-p-mentha-1(7),8-dien-2-ol (19.9-32.6%), cis-p-mentha-1(7),8-dien-2-ol (18.9-23.3%), trans-p-mentha-2,8-dien-l-ol (10.6-21.0%) and cis-p-mentha-2,8-dien-1-ol (8.1-10.4%). The essential oil of inflorescence from the Western Sudan was tested for spasmolytic activity using three different experimental models: against spontaneous contractions, and contractions induced with ACh and KCI. The oil exhibited strong, significant and concentration-dependent spasmolytic activity. Applied in concentration of 200 mu g/ml, the oil showed 88.44 +/- 16.78% of maximal spasmolytic effect of atropine (6.4 p,,M) against spontaneous contraction. Essential oil (90 mu g/ml) inhibited ACh-induced contractions as well, and reduced the effect of the highest applied concentration of ACh to 37.29 +/- 16.16%. Additionally, the oil exhibited strong activity against contractions induced with KCI (80 mM) and in concentration of 200 mu g/ml, completely abolished the contractile effect of KCI. The essential oil of inflorescence from the Western Sudan was also tested for antioxidant activity by DPPH assay and showed moderate anti-DPPH activity (SC50 23.8 mu l/ml).