Roselle (Hibiscus sabdariffa L.) from Malvaceae family is an annual crop with potential for use by many industries including food, animal feed, neutraceutical, cosmeticeutical and pharmaceutical industries. Its origin is not fully known but it is believed to be from West Africa, although the plant is found native from India to Southeast Asia. The calyxes, stems and leaves are acid in flavour. The juice is produced from the calyces, and it is claimed to be a prohealth drink due to its high contents of ascorbic acid, anthocyanins and other antioxidants.
Noninvasive transcranial direct current stimulation (tDCS) and methylphenidate (MP) are associated with motor recovery after stroke. Based on the potentially complementary mechanisms of these interventions, we examined whether there is an interactive effect between MP and tDCS. In this preliminary study, we randomized subacute stroke subjects to receive tDCS alone, MP alone or combination of tDCS and MP. A blinded rater measured safety, hand function, and cortical excitability before and after treatment. None of the treatments caused any major or severe adverse effects or induced significant differences in cortical excitability. Analysis of variance of gain score, as measured by Purdue pegboard test, showed a significant between-group difference (F(2,6)=12.167, p=0.008). Post hoc analysis showed that the combination treatment effected greater Purdue pegboard gain scores than tDCS alone (p=0.017) or MP alone (p=0.01). Our preliminary data with nine subjects shows an interesting dissociation between motor function improvement and lack of motor corticospinal plasticity changes as indexed by transcranial magnetic stimulation in subacute stroke subjects.