Guo-Jun Xu

Dibenzocyclo-octadiene lignans from Kadsura heteroclita

Abstract From the stems of Kadsura heteroclita , new dibenzocyclo-octadiene lignans, named heteroclitins A-E, were isolated together with the known compounds, kadsurin and interiorin. Their structures were determined by spectroscopic means.

β-Carboline alkaloids from hypodematium squamuloso-pilosum

Abstract A new β -carboline alkaloid, 1-acetyl-8-hydroxy- β -carboline, was isolated from the fern, Hypodematium squamuloso-pilosum , along with a known compound, 1-acetyl- β -carboline. Their structures were elucidated from spectral evidence. This is the first report of this type of alkaloid being found in ferns.

Steroidal glycosides from the subterranean parts of Liriope spicata var. prolifera

In a continuation of phytochemical studies on the underground organs of Liriope spicata var. prolifera, four new steroidal glycosides, lirioproliosides A-D, along with two known compounds, 25(S)-ruscogenin 1-O-[alpha-L-rhamnopyranosyl(1-->2)[beta-D-xylopyranosyl (1-->3)]-beta-D-fucopyranoside and ophiopogonin A, were identified. The structures of lirioproliosides A-D were established by a combination of spectroscopic and chemical methods as 25(S)-ruscogenin 1-O-[alpha-L-rhamnopyranosyl(1-->2)][beta-D-xylopyranosyl (1-->3)]-beta-D-fucopyranoside-3-O-alpha-L-rhamnopyranoside, 25(S)-ruscogenin 1-O-[3-O-acetyl-alpha-L-rhamnopyranosyl(1-->2)]-beta-D-fucopyranoside, 25(S)-ruscogenin (1-O-[2-O-acetyl-alpha-L-rhamnopyranosyl (1-->2)]-beta-D-fucopyranoside and ruscogenin (1-O-[2-O-acetyl-alpha-L-rhamnopyranosyl(1-->2)]-beta-D-fucopyranoside, respectively. Among these steroidal glycosides, ophiopogonin A and lirioprolioside B, and lirioproliosides C and D, were isolated as epimeric pairs.

A steroidal alkaloid from Fritillaria ebeiensis

Abstract A unique steroidal alkaloid with a 5β-hydroxyl group, ebeietinone, was isolated from the bulbs of Fritillaria ebeiensis var. purpurea . Its structure was determined by means of MS, 1 H NMR and 13 C NMR and confirmed by X-ray crystallography.

A steroidal alkaloid from Veratrum oblongum

Abstract A new alkaloid, named oblonginine, has been isolated from the roots of Veratrum oblongum , along with five known alkaloids. It was determined to be (22 R ,25 S )-22,26-epiminocholest-5-en-3β-ol [(22 R )-22, N -dihydroverazine] on the basis of spectroscopic evidence and was shown to be identical with a compound obtained by solanidine degradation.

Sesquiterpene lactones from Ixeris sonchifolia

Abstract The whole plant of Ixeris sonchifolia afforded two new guaianolide sesquiterpene lactones named 8-desoxyartelin [3-hydroxy-1(10),3-guaiadiene-12,6-olide-2-one] and ixerin Z [1(10),3,11(13)-guaiatriene-12,6-olide-2-one-3- O -glucopyranoside], along with the known compound 9α-hydroxyzaluzalin C, whose structure and stereochemistry wee determined by spectroscopic methods.

Two new sesquiterpene glucosides from Ixseris plants

Abstract The whole plant of Ixeris denticulata f. pinnatipartita and I. sonchifofia respectively afforded a new guaianolide sesquiterpene lactone glucoside named ixerin X, 8(,15-dihydroxy-1(10), 3,11(13)-guaiatriene-12,6-olide-15-O-β-D-glucopyranoside ( 1 ), ixerin Z, 1(10),3,11(13)-guaiatriene-12,6-olide-2-one-3-O- β -D-glucopyranoside ( 2 ), whose structure and stereo-chemistry were determined by spectroscopic methods. 1 inhibited the growth of human breast cancer MCF7 & MDA468 cell lines.

Reassignment of the stereochemistry of oblonginine

Abstract The stereochemistry of the steroidal alkaloid oblonginine from Veratrum oblongum (Chinese name Changgenglilu), previously reported to possess the structure (22R,25S)-22,26-epiminocholest-5-en-3β-ol, was re-examined using X-ray crystallography and high resolution NMR spectroscopy and reassigned with regard to C-22 and C-25. Therefore, oblonginine has the structure (22S,25R)-22,26-epiminocholest-5-en-3β-ol.