440 0009-3130/14/5003-0440  2014 Springer Science+Business Media New York Chemistry of Natural Compounds, Vol. 50, No. 3, July, 2014 [Russian original No. 3, May–June, 2014] CARAGISIDE D, A NEW ISOFLAVONE GLUCOSIDE FROM Caragana conferta Shagufta Perveen, 1* Areej Mohammad Al-Taweel, 1 Afsar Khan, 2 Ghada Ahmed Fawzy, 1,3 and Abdul Malik 4 Caragiside D (1), a new isoflavone glucoside, has been isolated from the n-BuOH soluble subfraction of the MeOH soluble extract of the whole plant of Caragana conferta along with one known isoflavone glucoside, caragiside A (2), and two lignan glucosides, pinoresinol 4-O-glucoside (3) and syringaresinol 4-O-glucoside (4). The structures of these compounds were elucidated through spectroscopic techniques including MS and 2D NMR. The purity of compound 1 was confirmed by HPLC. Keywords: Caragana conferta, caragiside D, isoflavone glucoside. The genus Caragana comprises over 80 species, of which 10 species have so far been identified in Pakistan [1]. Some of these species are used for the treatment of fever, hypertension, irregular menstruation, and fatigue [2, 3]. Caragana conferta Benth. ex Bake (Fabaceae) is a shrub that grows in Asia, Africa, and Southeast Europe. In Pakistan it is mainly found in the Gilgit and Kashmir Valleys [1]. The whole plant is used as folk medicine in China and Korea for the treatment of neuralgia, rheumatism, arthritis, and hypertension [4]. Literature survey revealed that many compounds have so far been reported from this species [5–10]. The ethnopharmacological and chemotaxanomic importance of this species prompted us to carry out further studies on C. conferta. Isolation studies on the n-BuOH-soluble subfraction resulted in one new isoflavone glucoside, named caragiside D (1), along with one known isoflavone glucoside named caragiside A (2) [5] and two lignan glucosides, pinoresinol 4-O-glucoside (3) [11] and syringaresinol 4- O-glucoside ( 4) [12]. The MeOH extract of the aerial parts of C. conferta was divided into subfractions soluble in n-hexane, CHCl 3 , EtOAc, and n-BuOH. A part of the n-BuOH soluble subfraction was subjected to a series of column chromatographic techniques to afford compounds 1–4. Their structures were established through spectroscopic techniques. Caragiside D (1) was obtained as a yellow gummy solid, [] 25 D +29 (c 0.20 in CH 3 OH). It gave a violet coloration with FeCl 3 for a phenol. The negative mode electron spray ionization mass spectrum (ESI-MS) gave a quasi-molecular [M – H] – peak at m/z 461, while the HR-FAB-MS showed the [M – H] – peak at m/z 461.1014, corresponding to the molecular formula C 22 H 22 O 11. The negative mode FAB-MS further shows a peak at m/z 299 resulting from the loss of a hexose moiety. The 1 H NMR spectrum (Table 1) exhibited two singlets at  8.26 (1H, s, H-5) and 7.29 (1H, s, H-8), which were consistent with a 6,7-dioxygenated A ring of isoflavone. The protons of the 1,3,4-trisubstituted ring B were observed at 7.92 (1H, d, J = 1.8 Hz, H-2), 7.23 (1H, d, J = 8.2 Hz, H-5), and 7.51 (1H, dd, J = 8.2, 1.8 Hz, H-6). The 1 H NMR spectrum gave the downfield singlet of an olefinic proton at  8.21. The signal of the methoxyl group appeared at 3.79 (3H, s). It also gave the signal for an anomeric proton at 4.89 (1H, d, J = 7.6 Hz, H-1), suggesting the -configuration of the hexose unit. Further signals of the hexose moiety were observed between 3.47 and 3.97. Acid hydrolysis of 1 provided the sugar, which could be identified as D-glucose through co-TLC and the sign of its optical rotation. On the basis of these resonances, 1 was deduced to be an isoflavone glucoside. 1) Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, P. O. Box 2457, Riyadh 11451, Saudi Arabia, e-mail: shagufta792000@yahoo.com, shakhan@ksu.edu.sa; 2) Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad-22060, Pakistan; 3) Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, 11562, Cairo, Egypt; 4) International Center for Chemical and Biological Sciences, H.E.J. Research Institute of Chemistry, University of Karachi, 75270, Karachi, Pakistan. Published in Khimiya Prirodnykh Soedinenii, No. 3, May–June, 2014, pp. 380–382. Original article submitted January 1, 2013.