Lead compounds for anti-inflammatory drugs isolated from the plants of the traditional oriental medicine in Korea

Effects of compounds isolated from medicinal plants in Korea on prostaglandin E₂ (PGE₂) production in rat peritoneal macrophages were examined, and mechanism of action of the active constituents was analyzed. The active constituents were as follows; tectorigenin and tectoridin isolated from the rhizomes of Belamcanda chinensis, platycodin D isolated from the roots of Platycodon grandiflorum, imperatorin isolated from the roots of Angelica dahurica, and hyperin isolated from the roots of Acanthopanax chiisanensis. These compounds inhibit the induction of cyclooxygenase-2 (COX-2), thus inhibiting PGE₂ production. The chemically synthesized chalcone derivative, 2′-hydroxy-4′-methoxychalcone, also inhibits PGE₂ production by suppressing COX-2 induction. In contrast, taiwanin C isolated from the roots of Acanthopanax chiisanensis inhibited PGE₂ production by direct inhibition of COX-1 and COX-2.