Potent cytotoxic lignans from Justicia procumbens and their effects on nitric oxide and tumor necrosis factor-alpha production in mouse macrophages. - Day,S.H.; Lin,Y.C.; Tsai,M.L.; Tsao,L.T.; Ko,H.H.; Chung,M.I.; Lee,J.C.; Wang,J.P.; Won,S.J.; Lin,C.N. (J Nat Prod, 2002)