BACKGROUND
The leaf of Malus toringoides (Rehd.) Hughes is a traditional folk medicine in Tibet, China, which is called "E Se" in Tibetan language. This original plant grows on snow mountains at an attitude of 3000 to 3700 m. It is primarily used to treat hypertension, hyperlipidemia, hyperglycemia,
Three dihydrochalcone-derived polyphenols, huperolides A-C (1-3), along with thirteen known compounds (4-16) were isolated from the leaves of Malus hupehensis, the well-known tea crab apple in China. Their chemical structures were elucidated by extensive spectroscopic analysis including NMR (HSQC,