Monoterpene Constituents from Cistanche tubulosa—Chemical Structures of Kankanosides A—E and Kankanol—

Abstract

Four new iridoid glycosides, kankanosides A (1), B (2), C (3), and D (4), a chlorinated iridoid, kankanol (5), and an acyclic monoterpene glycoside, kankanoside E (6), were isolated from the methanolic extract of dried stems of Cistanche tubulosa (SCHRENK) R. WIGHT (Orobanchaceae) together with 16 known compounds. The structures of these new compounds (1—6) were determined on the basis of the chemical and physicochemical evidence.