3,3',4',5,5',7,8-Heptamethoxyflavone (hibiscetin heptamethyl ether) has been isolated from the leaves of Murraya exotica L.Plant material. Murraya exotica L. (Rutaceae) collected at Thenmala Forest, Kerala, in October 1965.Previous work. Chemical.1-4Leaves. Extracted with MeOH and the crude extract (12 g) chromatographed on (120 g) silica gel (0.05-0.2 mm).Compound isolated. Elution with CHCl3-2 % MeOH gave pale yellow needles recrystallized from CH2Cl2-EtOH (130 mg), m.p. 190°, R_f 0·7 (TLC on Si gel; CHCl3:3%) MeOH). Analyses for C22H24O9 (M+ at m/e 432). A red colour in Shinoda test and the u.v. spectrum λ_max EtOH 209, 252, 266 (infl.), 274, 310 (infl.) and 348 nm; log ε , 4.73, 4.19, 4.25, 4.27, 4.16 and 4.22 are characteristic of a flavonoid compound. In the NMR spectrum (solvent, CDCl1), signals at 7.578 (2H, singlet), 6.458 (1H, singlet) and 4.08 (21H, multiplet) indicated it to be a heptamethoxyflavone. The singlets at 7.75δ and 6.45δ should be attributed to the 2',6'-protons of ring B1 and the 6-proton of ring A.5 This data suggested 3.3'.4'.5.5'.7.8-heptamethoxyflavone as the probable structure. Methylation of 5,7,-8trihydroxy-3,3',4',5'-tetramethoxyflavone (m.p. 255 °) with dimethyl sulphate gave the completely methylated flavone (heptamethyl ether of hibiscetin), m.p. 190°, identical with natural compound (mxd. m.p., i.r., TLC).