Acetylenic glucosides from Microglossa pyrifolia.

From the leaves of Microglossa pyrifolia Lam. (Asteraceae) four new acetylenic glucosides (1-4) have been isolated. The aglucones 2a and 4a are new polyynes. The aglucone 3a could only be isolated as a mixture of E/Z-isomers in a ratio of 4:1. The structures of 1-4 were elucidated by spectroscopic and biochemical methods. Compound 1 shows antibacterial activity.