Cassminic Acid, a Minor Constituent from the Bark of Erythrophleum guineense

Abstract

A structure (I: R1 = R2 = H) is suggested for cassminic acid, a minor constituent from the bark of Erythrophleurn guineense.THE relationship of cassminic acid (I; R1 = R2 = H) C2,H3,,0,) to cassanic acid is shown by a sequence of standard reactions:The presence of a hydroxy-group intramolecularly hydrogen bonded is indicated by i.r. absorption at 3500 cm.-l, unchanged on dilution. Oxidation of the ester (I; R1 = Me, R2 = H) with chromic anhydride or (more specifically) with bismuth trioxide 2 yields a diosphenol (11; R1 = Me or the alternative 5,6-unsaturated structure) (ferric reaction) which shows pH-sensitive absorption at 283 nm. (E 4900). This band moves to 337 nm. (E 2400) in alkali, a shift reversed on reacidification. A diosphenol structure is thus indicated and is confirmed by formation of an enol acetate in the U.V. spectrum of which the main band has moved to 246 nm. and is no longer pH-sensitive. Cassminic acid itself thus contains

Antioxidant stilbenoid and flavanonol from stem of Erythrophleum suaveolens (Guill. & Perr.)

“…suaveolens against Basidiobolus haptosporus , Basidiobolus ranarum , Trichophyton rubrum and Trichophyton mentagrophytes was also demonstrated . In prior studies on the genus Erythrophleum , cassaine diterpenoid amines and amides were found as the main constituents with minor amounts of cassaine acids also present . We report herein the isolation and structure elucidation of compounds from this species, including a new stilbenoid, suaveolensone A ( 1 ), a new flavanonol, suaveolensone B ( 2 ) and five known compounds.…”

“…[5] In prior studies on the genus Erythrophleum, cassaine diterpenoid amines and amides were found as the main constituents with minor amounts of cassaine acids also present. [6][7][8][9][10][11][12] We report herein the isolation and structure elucidation of compounds from this species, including a new stilbenoid, suaveolensone A (1), a new flavanonol, suaveolensone B (2) and five known compounds. The radical scavenging activity of compounds (1-2) is also reported ( Fig.1).…”