Polycycloiridals with a Cyclopentane Ring from <i>Iris tectorum</i>

Six new iridal-type triterpenoids containing an unprecedented cyclopentane ring, polycycloiridals E–J (<b>1</b>–<b>6</b>), were isolated from a large-scale re-extraction of <i>Iris tectorum</i>. A possible biosynthesis pathway is postulated. The known spirioiridotectal D (<b>7</b>) was also obtained in the current investigation, and its structure was unequivocally defined using X-ray diffraction data. Compound <b>7</b> suppressed LPS-activated NO production in the BV2 cell line with an IC₅₀ value of 0.54 μM

Polycycloiridals A–D, Four Iridal-Type Triterpenoids with an α‑Terpineol Moiety from <i>Iris tectorum</i>

Polycycloiridals A–D, four novel iridals with an unprecedented α-terpineol moiety resulting from cyclization of the homofarnesylside chain, were isolated from the ethanol extract of rhizomes of <i>Iris tectorum</i>. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configuration of <b>1</b> was determined by the modified Mosher’s method and comparison of experimental and calculated electronic circular dichroism (ECD) spectrum. A possible biosynthetic pathway was postulated