Synthesis, structural revision, and antioxidant activities of antimutagenic homoisoflavonoids from Hoffmanosseggia intricata

Intricatinol and intricatin, the two homoisoflavonoids isolated from Hoffmanosseggia intricata, and two analogs have been synthesized from pyrogallol in three steps. The spectral data of synthetic intricatinol are in good agreement with those of natural metabolite, but the spectral data of intricatin are not corroborative with those of the natural product. The structure of intricatin has been thus revised to 8-methoxybonducellin, a compound isolated from Caesalpinia pulcherrima. The antioxidant activity of all the four homoisoflavonoids was determined by superoxide (NBT) and DPPH free radical scavenging methods. The synthetic analog 7,8-dihydroxy-3-[(3,4-dihydroxyphenyl)methylene]chroman-4-one displayed excellent activity in both methods.