A study involving more than 3,000 participants has led researchers to conclude that Ginkgo biloba(イチョウの葉の粉末薬)does not slow the rate of cognitive decline in healthy older people or those with mild cognitive impairment. Scientists had speculated that ginkgo extract might have anti-inflammatory(抗炎症の)properties that promote the flow of nutrients to neurons and that, as a strong antioxidant, it might inhibit oxidative damage to brain cells. If that were the case, researchers would have seen a difference between test performance of those taking the substance and those in the placebo group. Instead, the data showed no notable differences in scores on brain-function tests.