Justicia lignans: Part 4 † -Two new arylnaphthalide lignans from J usticia neesii Ramamoorthy

The genus Justicia (N.O. Acanthaceae) comprises about 300 species world over and nearly 50 species occur in Indial.2. About 20 species have been chemically investigated and the lignans isolated from them are the common secondary metabolites. In continuation of our study on Justicia species of Tirumala Hill Tracts 3 - 5 , we have now investigated J. neesii Ramamoorthy (syn. J. micrantha Wall. ex Cl.), which remains hitherto unexamined and occurs in plains and ghats, on moist loose soil and in the shade along the outskirts of wet deciduous forests in South­ west India. The results of the investigation are reported herein. The ethanolic extract of the whole plants of J. neesii was impregnated on silica gel and extracted repeatedly with pet. ether (60-80°), ethyl acetate and methanol. The combined extractives from pet. ether and ethyl acetate solubles were chromatographed over silica gel to get six pure compounds (A-F). Compounds n, C, D and E were identified as helioxanthin 4 6 . 7 , taiwanin C 8 8 • 9 , retrohelioxanthin 9 1O - t2 and justicidin A 10 13 - t6 respectively. Compounds A and F are new metabolites and are described below. Compound A was obtained as yellow coloured crystals from ethyl acetate-pet. ether, mp 190-192°C. Its molecular formula was deduced as C22Ht607 (mlz 392, M+). The IH NMR spectral data (el Table I) of compound A showed strong resemblence to those of helioxanthin 4, with six aromatic protons constituting two AB doublets (8 7.67, IH, d, J=8.7 Hz and 7.31,