Chemical Structure-Activity of Cnidium Rhizome-Derived Phthalides for the Competence Inhibition of Proliferation in Primary Cultures of Mouse Aorta Smooth Muscle Cells

Inhibitory effects of cnidium rhizome-derived phthalides on competence and progression phases of fetal bovine serum (10%)-induced proliferation were compared in primary cultures of mouse aorta smooth muscle cells (SMC). Their potencies for the competence inhibition were in the order of senkyunolide L ((Z)-6-hydroxy-7-chloro-6,7-dihydroligustilide) > senkyunolide H ((Z)-6,7-dihydroxy-6,7-dihydroligustilide) > senkyunolide J ((3S)-(E)-6,7-dihydroxy-3,6,7,8-tetrahydroligustilide) > senkyunolide I ((E)-6,7-dihydroxy-6,7-dihydroligustilide) > ligustilide = senkyunolide A ((3S)-3,8-dihydroligustilide) > butylidenephthalide. The order of their potencies for the progression inhibition was parallel with that for the competence inhibition. Senkyunolide L is considered to have been formed during the extraction of cnidium. These results demonstrate that the (Z)-6,7-dihydroxy isomer of the dihydroligustilide derivatives is essential for the anti-competent effect on proliferation of the SMC in primary culture. Senkyunolide H in cnidium rhizome may be a prototype for a new anti-atherosclerotic drug.