Three cyclooctapeptides and one glycoside from Microtoena prainiana.

Three new cyclic octapeptides, microtoenins A-C (1-3), and a new glycoside, 3'''-O-methylcrenatoside (4), along with several known compounds, were isolated from the ethanolic extract of the stems of Microtoena prainiana. Their structures were determined by spectral and chemical evidence. At a concentration of 0.