Spiciferum are shrubs of Ericaceae and Rhododendron, the main production area is westen part of GUIZHOU, central and south east region of YUNNAN in China. Proanthocyanidin A-1 (PAA-1) extracted from Rhododendron spiciferum in ethylacetate is a Dimer compound of Proanthocyanidins. Proanthocyanidins (PAs) are general of Polyphenols. Recently researchs have found that PAs have many medical benefits including antioxidant, cardiovascular protection, anti-cancer, anti-platelet aggregation, immunomodulation...