Studies on the Constituents from the Aerial Part of Baccharis dracunculifolia DC
Yoshimi NAGATANI, Tsutomu WARASHINA, Tadataka NORO
Chemical and pharmaceutical bulletin
Baccharis dracunculifolia DC. is indigenous throughout the southeast parts of Latin America and is used by local people in traditional medicine. 1) Phytochemical investigation of the essential oil has been reported, 1) but investigation of its glycosides has not been reported. Thus, we have started a study of its constituents in the course of our research on the phytochemicals of Brazilian plants. This paper describes the isolation and structural determination of ten new compounds, named
... ulifosides A-J, along with 16 known ones (1, 2) 2, 3) 3, 4) 4, 5) 5, 5) 6, 5) 7, 6,7) 8, 6) 9, 8, 9) 10, 10) 11, 11) 12, 12) 13, 13) 14, 14) 15, 15) 16, 16) ). The MeOH extract from the dried aerial part of B. dracunculifolia DC. was suspended in water. The suspension was then extracted with diethyl ether and partitioned into an ether-soluble fraction and a water-soluble fraction. The water-soluble fraction was passed through a Mitsubishi Diaion HP-20 column and the adsorbed material was subsequently eluted with 50% MeOH in water, 70% MeOH in water and MeOH. The 50% MeOH eluate from the Diaion HP-20 column was concentrated and the residue rechromatographed on a silica gel column and by semi-preparative HPLC to give compounds (1-26). Dracunculifoside A (17) was suggested to have the molecular formula, C 28 H 40 O 11 , based on a high resolution (HR)-FAB-MS [positive HR-FAB-MS ion at m/z 553.2638 [MϩH] ϩ , 575.2489 [MϩNa] ϩ ]. The 1 H-NMR spectrum showed AMX type-aromatic proton signals [d 7.06 (1H, d, Jϭ2.0 Hz), 6.95 (1H, dd, Jϭ8.0, 2.0 Hz), 6.79 (1H, d, Jϭ 8.0 Hz)] which had correlations in the 1 H-1 H correlation spectroscopy (COSY) spectrum, two trans-olefinic proton signals [d 7.57 (1H, d, Jϭ16.0 Hz), 6.31 (H, d, Jϭ16.0 Hz)], and one anomeric proton signal [d 4.38 (1H, d, Jϭ8.0 Hz)]. On the other hand, the 13 C-NMR spectrum exhibited one carbonyl carbon signal (d 169.2), two sp 2 carbon signals (d 147.1, 115.0), aromatic carbon signals (d 149.6, 146.8, 127.1, 123.0, 116.6, 115.2), and six carbon signals due to the sugar moiety (d 102.9, 78.2, 75.4, 75.3, 71.6, 64.7) together with the signals due to the aglycone moiety. Thus, compound 17 was considered to consist of an aglycone, one monosaccharide and an (E)-caffeoyl group. Since 13 carbon signals and four methyl proton signals [d 1.30 (3H, d, Jϭ6.5 Hz), 0.93 (3H, s), 0.88 (3H, s), 0.77 (3H, d, Jϭ6.5 Hz)] were assigned to the aglycone moiety in the 13 C-and 1 H-NMR spectra, the aglycone of 17 was deduce to be an ionone derivative. Mild alkaline hydrolysis of compound 17 afforded alan-Ten new glycosides, named dracunculifosides A-J, were isolated along with sixteen known glycosides from the aerial part of Baccharis dracunculifolia DC. (Compositae). The structures of these glycosides were determined on the basis of spectral and chemical evidence. These new glycosides consisted of b b-D-glucopyranose or b b-D-apiofuranosyl-(1→ → 6)-b b-D-glucopyranose, and most possess an (E)-caffeoyl group.