Iridoid Constituents of <i>Tarenna </i><i>a</i><i>ttenuata</i>

Members of a rare type of iridoid with two α,β-unsaturated acid units were isolated from the whole plant of Tarenna attenuata, including a new compound, tarennin (1), an extraction artifact, and seven new glucosides, tarenninosides A−G (2−8), together with two known iridoid glucosides, ixoside and 10-methylixoside. The structures of 1−8 were elucidated by analysis of spectroscopic data including HMQC, HMBC, 1H−H COSY, and ROESY NMR spectra and by comparison with known analogues. Antioxidant and cytotoxic activities were evaluated for these 10 compounds, but none showed positive activity.