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Saussurea lappa (Costus root; Chinese name: Yun Mu Xiang; Asteraceae) is a famous traditional Chinese medicine and also an important spice since ancient times, and is now in common use in China and Japan. Its roots can be used for the treatment of abdominal distension, indigestion, nausea, abdominal pain, etc. The main chemical and bioactive constituents of this plant are several types of sesquiterpenoids 1-6) including two sulfonated eudesmanes. 7) Further to search for biologically active compounds, we have reinvestigated the chemical constituents of this plant. This paper reports the isolation and structure elucidation of two new guaiane sesquiterpene lactones with a sulfonic acid group named sulfocostunolide A (1) and sulfocostunolide B (2) ). The 13 C-NMR spectrum (CD 3 OD) exhibited 15 carbon signals including two sets of terminal double bonds at d 153.8 (s), 108.9 (t); 151.8 (s), 111.8 (t), a g-lactone carbonyl resonance at d 179.9 (s) and an oxygenbearing methine carbon at d 88.0 (d), suggestive of a skeleton of sesquiterpene lactone containing three rings. The NMR spectra were similar to those of dehydrocostus lactone (3), 1,4) isolated as the major sesquiterpene of this medicinal plant. Nevertheless, there were several significant differences as follows: a) the resonances of terminal double bond within lactone ring in 3 were absent and replaced by a set of signals at "d C 45.2 (d); d H 2.82 (ddd, Jϭ11.4, 5.5, 5.1 Hz)" and "d C 51.1 (t); d H 3.11 (dd, Jϭ14.6, 5.5 Hz), 3.35 (dd, Jϭ14.6, 5.1 Hz)"; b) the g-lactone carbonyl resonance was also evidently shifted downfield to the saturated zone at d 179.9 (s), which indicated that the terminal double bond was hydrogenated then substituted by a sulfonic acid group.Further validation was made by careful analysis of the HMBC spectrum (Fig. 2), in which the following significant correlations were observed: from H-11 to C-8, C-12; from H-13 to C-7, C-12. The correlation peaks in the ROESY spectrum (Fig. 3) between H-11 and H-8b, H-11 and H-6b, and H-6b and H-8b were clearly detectable, indicative of a orientation of the sulfomethyl group at C-11. Therefore the structure of 1 was elucidated as 13-sulfo-4(15),10(14)-guaiadien-12,6-olide, as shown in Fig. 1, named sulfocostunolide A.Compound 2 was also obtained as viscid solid, possessing the same molecule formula C 15 H 20 O 5 S as sulfocostunolide A (1) based on the negative-ion HR-ESI-MS. The IR and NMR (Table 1) spectra were considerably in accordance with those of 1, and their TLC behaviors (see Experimental) were very close but discriminable, suggesting a structurally wondrous similarity for both substances. Unexpectedly, analysis of the HMBC spectrum led to the same planar structure as sulfocostunolide A. Therefore the structure difference consequentially arose from the stereochemistry. The significant correlations in the ROESY experiment (Fig. 3): H-13 and H-8b, H-13 and H-6b, and H-6b and H-8b were observed, indicative of b orientation of the sulfomethyl group. Consequently, the structure of 2 was determin...

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Terpenes U 0200 Sulfonated Guaianolides from Saussurea lappa. -[i.e.ulfocostunolide A (Ia) and B (Ib)]. -(WANG, F.; XIE, Z.-H.; GAO, Y.; XU, Y.; CHENG, X.-L.; LIU*, J.-K.; Chem.