Chemical Constituents of Plumbago indica roots and reactions of plumbagin: Part II

From Plumbago indica a new quinone derivative-plumbagic acid lactone, two navonol methyl ethers-azaleatin (5-0methylquercetin ), ayanin (3,7,4', tri -O-methylquercetin), two aliphatics-palmitic acid, myricyl palmitate and one naphthoquinone-plumbagin have been isolated. The major constituent plumbagin has been subjected to Schmidt reaction , all yli c brominat ion, oxymercuration and demercurati on and Thiele-Winter addition. All the natural and reaction products have bcen c haracte ri zed by spectroscopic studies. The roots of Plumbago indica Linn (syn. P. rosea L.) of family Plumbaginac.:eae, a shrub di stributed in different parts of India is useful in folk medicine'. The isolation of several naphthoquinonoids and their derivatives, and flavonoids have been reported 2 . 3 . Our continued search for its chemical constituents has resulted in the isolation of plumbagin, palmitic acid and myricyl palmitate from the petrol extract and plumbagic ac id lactone 1, ayanin 7 and azaleatin 8 from the ethyl acetate extract of its roots. This is the first report of isol ation of palmitic acid, myricyl palmitate, azaleatin and ayanin from P. indica. Isolation of ayanin 7 from Alnus spp, Apuleia leiocarpa, Betula spp, Cheilanthes spp, Ostrya spp, Physalis angulata and Salvia glutinosa, and azaleatin 8 from Plumbago scandens and P. zeylanica as glycosides have been reported 2 .4 . The isolation of plumbagin has been reported earl ier 5 . The major constituent plumbagin (5-hydroxy-2-methyl-a­ naphthoquinone) has been reported to possess significant antitumor, antibacterial, antifungal and insecticidal activities 6 . 8 . In order to study the bioacti vities of the reaction products, we carried out Schmidt reaction with sodium azide, allylic bromination with NBS, oxymercuration with mercury (II) acetate and demercuration with NaBH4 and Thiele-Winter addition with AC20. Herein, we report the isolation and characterization of both natural and reaction products on the basis of spectroscopic data.