The 80% ethanol extract of Alstonia yunnanensis afforded five new monoterpenoid indole alkaloids: 11-hydroxy-6. 7-epoxy-8-oxo-vincadifformine (1). 14-chloro-15-hydroxy- vincadifformine (2). perakine N4-oxide (3). https://sportshutes.shop/product-category/hearing-protection/