An ingredient in chocolate could be used to stop persistent coughs and lead to more effective medicines, researchers say. The study found that theobromine, found in cocoa, was nearly a third more effective in stopping persistent coughs than codeine, currently considered the best cough medicine

ingredient n.成分　theobromine n.可可碱　cocoa n.可可粉　codeine n.可待因

The researchers, from Imperial College London (ICL), said the discovery could lead to more effective cough treatments. Ten healthy volunteers were either given theobromine, codeine or a dummy pill during the trial, which also involved Royal Brompton Hospital and St Bartholomew's Hospital.

treatment n. 治疗　volunteer n. 志愿者

The researchers, writing in the online FASEB Journal, said that theobromine worked by suppressing vagus nerve activity, which is responsible for causing coughing. They also found that unlike standard cough treatments, theobromine caused no adverse effects on the cardiovascular or central nervous systems, such as drowsiness.

vagus nerve 迷走神经　adverse effect 反作用、副作用　

cardiovascular adj. 心脏血管的　drowsiness n. 睡意

辅助阅读：

伦敦帝国学院的科学家发现，巧克力中含有的可可碱成分的止咳效果优于常用止咳药可待因30%以上。从事该研究的彼得·巴内斯教授认为，此发现有望改进现在普遍采用的止咳方法。

科学家们让10位志愿者分别服用了可可碱、可待因或者安慰剂。为了检验上述三种物质的作用，研究人员让志愿者吸入了可以诱发咳嗽的辣椒素。通过对辣椒素水平进行分析，研究人员发现，服用可可碱的志愿者与服用安慰剂的志愿者相比，前者要吸入浓度高三分之一的辣椒素才能引发咳嗽；服用可待因的志愿者与服用安慰剂的志愿者相比，前者需要吸入的辣椒素浓度要稍高于后者即可引发咳嗽。研究者还表示，与通常的止咳方法不同，可可碱对心血管和中枢神经系统不会产生任何副作用。