Two neolignans from Perilla frutescens and Their inhibition of nitric oxide synthase and tumor necrosis factor-α expression in murine macrophage cell line RAW 264.7

Two neolignans were isolated from leaves of Perilla frutescens (Labiatae) as inhibitors of nitric oxide syntheses (IC50 5.9 μM and 53.5 μM, respectively) and tumor necrosis factor-α in lipopolysaccharide-activated RAW 264.7 cells. Their structures were identified as 1β,2α,3β,4α-1,2-dimethyl-3,4-bis-(2,4,5-trimethoxyphenyl)-cyclobutane (magnosalin), and 1α,2β,3β,4α-1,2-dimethyl-3,4-bis-(2,4,5-trimethoxyphenyl)-cyclobutane (andamanicin), and their activities were confirmed as resulted from the suppressed expression of inducible nitric oxide synthase enzyme and from the secretion of tumor necrosis factor-α from activated macrophages.