中美联合研究的一个重要发现（见内）

Researchers in the US and China studied ginkgo trees aged 15 to 667, extracting tree-rings and analysing cells, bark, leaves and seeds. They found both young and old trees produce protective chemicals to fight off stresses caused by pathogens or drought.

我不知道银杏叶治疗老年痴呆的功效是否与此有关。