Methods for the synthesis, isolation, and purification of procyanidin B2 are disclosed. The synthetic methods utilize epicatechin as a starting material and produce procyanidin B2 in high yields. The isolation methods extract procyanidin B2 from a sample of bark powder from plant matter of the genus Uncaria. The isolated and/or synthesized procyanidin B2 is used to treat amyloid disease, such as Alzheimer's disease and Parkinson's disease as well as improve cognitive performance and increase learning and memory in Alzheimer's patients. Pharmaceutical compositions containing the synthesized and/or isolated procyanidin B2 are also disclosed.