The Effect of Alpinia zerumbet Essential Oil on Post-Stroke Muscle Spasticity.

The essential oil of Alpinia zerumbet (EOAz) presents myorelaxant and antispasmodic actions on cardiac and smooth muscles. The aim of this study was to investigate the effect of EOAz on the skeletal muscle contraction in post-stroke spasticity. Fifteen adults with unilateral hemiparesis and spasticity resulting from stroke were submitted to surface electromyography readings of the gastrocnemius muscle, before and after 10 daily applications (dermal 0.05 mL per muscle belly) of EOAz. The healthy contralateral muscles without applying the oil were used as controls. The analysis showed that, in both lateral and medial gastrocnemius, the values of all studied variables (root mean square, maximum amplitude and median power frequency) were significantly decreased in pathological legs during muscle contraction (Wilcoxon test, p < 0.05). Moreover, spastic muscles presented different results before and after dermal application of EOAz: The mean values of root mean square and median power frequency were significantly increased in lateral and medial gastrocnemius, and also, the maximum amplitude increased in medial gastrocnemius (Mann-Whitney test, p < 0.05). The results suggest that EOAz acts in the skeletal spastic muscle contraction by promoting relaxation and improvement of the muscular performance. Thus, the EOAz can be useful for the clinical management of secondary effects in patients with cerebral vascular disease.