Diterpenes from Grangea maderaspatana

Phytochemical investigation of the ethanolic extract of Grangea maderaspatana led to isolation of gramaderins A–D, together with thirteen known compounds. All isolates were assayed for their anti-inflammatory activities. Consequently, 5,7-dihydroxy-3,6,3′,4′,5′-pentamethoxyflavone and 5,3′-dihydroxy-3,6,7,4′,5′-pentamethoxyflavone showed significant bioactivities by inhibiting superoxide anion generation. 8-Acetoxy-pentadeca-1,9Z,14-trien-4,6-diyne-3-ol also demonstrated potent inhibition on elastase release. The gramaderins A/C (β-alkyl linked γ-lactone) and gramaderins B/D (α-alkyl linked γ-lactone) co-exist in this plant material, of which the latter derivatives are few in nature. Gramaderins C/D possess a special linear dilactone diterpene skeleton, which never been reported.