Indian Journal of Chemistry Vol. 44B, August 2005, pp. 1966-1969 Note Two new flavonoids from Andrographis macrobotrys B Anil Kumar Reddy a , M Vijaya Bhaskar Reddy a , D Gunasekar* ,a , M Marthanda Murthy b , C Caux c & B Bodo c a Natural Products Division, Department of Chemistry, Sri Venkateswara University, Tirupati 517 502, India E-mail: duvvurusekarg@rediffmail.com b Indian Institute of Chemical Technology, Hyderabad 500 007, India c Laboratoire de Chimie des Substances Naturelles ESA 8041 CNRS, Museum National d′ Histoire Naturelle, 63 rue Buffon 75005 Paris, France Received 15 September 2004; accepted (revised) 2 February 2005 Two new flavonoids, 5,7,8,2′-tetramethoxyflavanone 1 and 2′- hydroxy-2,3,4′-trimethoxychalcone 3, together with three known flavones, 5-hydroxy-7-methoxyflavone 2, 5,2′,6′-trihydroxy-7- methoxyflavone 4 and 5,7,2′,6′-tetrahydroxyflavone 5 have been isolated from the whole plant of Andrographis macrobotrys. The structures of the new compounds 1 and 3 have been established using extensive 2D NMR and ESI-MS/MS studies. Keywords: tetramethoxyflavanone, trimethoxychalcone, methoxyflavone, Andrographis macrobotrys IPC: Int.Cl. 7 A 61 K 35/00 Andrographis macrobotrys Nees (Acanthaceae) is a pubescent herb found widely in Western Ghats, Anamalais, Pulneys and hills of Travancore, South India 1 . In continuation of our investigations on Andrographis species 2-12 , we examined the whole plant of A. macrobotrys and report herein the isolation and structure elucidation of two new flavonoids 1 and 3, besides three known flavones 2, 4 and 5. Results and Discussion Compound 1, isolated as a colourless solid, showed [M + H] + peak at m/z 345.1373 in the positive ESITOFMS corresponding to the molecular formula C 19 H 20 O 6 . This was corroborated by the 13 C NMR spectrum which showed 19 carbon resonances. The UV absorption maxima of 1 in MeOH at 262 and 316 (sh) nm and negative ferric chloride test suggested that compound 1 was a non-phenolic flavanone 13 . The 1 H NMR spectrum of 1 showed three characteristic signals for H-2, H-3 ax and H-3 eq at δ 5.76 (1H, dd, J = 12.5, 3.2 Hz), 2.92 (1H, dd, J = 16.7, 12.5 Hz) and 2.83 (1H, dd, J = 16.7, 3.2 Hz) respectively, indicating that 1 had a flavanone skeleton 14 . It also showed signals for four aromatic methoxyl groups at δ 3.79, 3.80, 3.90 and 3.92. The ESI-MS/MS fragmentation 15 of [M + H] + ion (m/z 345.1) yield a diagnostic RDA fragment ion at m/z 211.0 ( 1,3 A + ) indicating the presence of three methoxyl groups in ring-A. A sharp one-proton singlet at δ 6.11 correlating with the carbon at δ 89.2 in the HSQC spectrum was assigned to H-6 as it showed HMBC correlations with C-5 (δ 157.8), C-7 OMe 1 A O MeO 2 3 4 5 6 7 8 9 1' 2' 3' 4' 10 5' 6' MeO O OMe OH O MeO OMe OMe α β 1 2 3 4 5 6 1' 2' 3' 4' 5' 6' 3 O O OH O R 3 R 2 R 1 2 : R 1 = Me, R 2 = R 3 = H 4 : R 1 = Me, R 2 = R 3 = OH 5 : R 1 = H, R 2 = R 3 = OH