One of the most popular plants in herbal medicine, ginseng contains anti-inflammatory chemicals called ginsenosides. According to a review published in 2018, scientists have observed that ginsenosides may help reduce brain levels of beta-amyloid in preliminary lab studies. What's more, the review says preliminary studies have indicated that ashwagandha may benefit the brain by reducing oxidative stress (a factor that may contribute to the development and progression of Alzheimer's disease). Another Ayurvedic herb, ashwagandha has been found to inhibit the formation of beta-amyloid plaques in preliminary research, according to a review study published in 2010. It contains a compound called curcumin, which has antioxidant and anti-inflammatory effects .