Two novel alkaloids with a unique fused hexacyclic skeleton from Daphniphyllum subverticillatum.

Two novel major alkaloids, deoxycalyciphylline B (1) and deoxyisocalyciphylline B (2) with a unique fused hexacyclic skeleton, together with a quite recently reported alkaloid calyciphylline B (3), were isolated from the stem of Daphniphyllum subverticillatum. Their structures were established by spectral methods and chemical evidence, especially 2D NMR techniques. The structure of 1 was further confirmed by a single-crystal X-ray diffraction determination.

Antifungal diterpenoids of Pseudolarix kaempferi, and their structure-activity relationship study.

The in vitro antifungal activities of 19 structurally diversified analogues of pseudolaric acids tested against the major pathogenic fungus Candida albicans has led to the establishment of a very clear structure-activity relationship of pseudolaric acids derivatives. Pseudolaric acid A was first found to be a potent antifungal component comparable with pseudolaric acid B. Among the tested 19 diterpenoids, pseudolaric acids A2 (1), B2 (3), B3 (4) and methyl pseudolarate A2 (2) are new isolates of the root bark of Pseudolarix kaempferi, and their structures were elucidated mainly by 2D-NMR techniques and chemical methods.

New glycosphingolipids from the fungus Catathelasma ventricosa.

Three new glycosphingolipids with a cis-Delta(17)-fatty acyl moiety, namely, catacerebrosides A-C (1-3), along with two known glycosphingolipids, cerebrosides B and D, six known ergostane-type sterols, and tyrosamine were isolated from the fungus Catathelasma ventricosa. The structures of 1-3 were elucidated on the basis of spectroscopic analysis and chemical methods.

Biologically active phenols from Saussurea medusa.

Sixteen phenolic compounds were isolated from the polar fraction of Saussurea medusa and were structurally elucidated by chemical evidences and spectral methods. These compounds include two new lignan glucosides, namely medusasides A (1) and B (2), and fourteen known phenolic compounds (3-16). One major compound, apigenin 7-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside] (6) showed remarkable activity to attenuate the scopolamine induced memory deficit of mice.

Songorine, a diterpenoid alkaloid of the genus Aconitum, is a novel GABA(A) receptor antagonist in rat brain.

Songorine, a diterpenoid alkaloid isolated from the genus Aconitum, was recently found to enhance the excitatory synaptic transmission in rat hippocampus. The mechanism underlying the effects was examined in the present study. The alkaloid at 0.

Five new diterpenoids from Pseudolarix kaempferi.

Five new diterpenoids, pseudolaric acids F (1), G (2), and H (3), 2',3'-dihydroxy-1'-propoxypseudolarate B (4), and 6'-O-acetylpseudolaric acid B O-beta-D-glucopyranoside (5), along with nine known diterpenoids, pseudolaric acids A, B, and C(1), deacetylpseudolaric acid C(2), deacetylpseudolaric acid A, methyl pseudolarate A, methyl pseudolarate B, pseudolaric acid A-O-beta-D-glucopyranoside, and pseudolaric acid B-O-beta-D-glucopyranoside, were isolated from the root bark of Pseudolarix kaempferi. Their structures and stereochemistry were elucidated mainly by spectral data, especially 2D NMR techniques.

Triterpene saponins from Craniotome furcata.

Three saponins, craniosaponin A (1) and buddlejasaponins Ia (2) and I (3) were isolated from the n-butanol soluble fraction of Craniotome furcata for the first time. Among them, craniosaponin A (1) was identified to be a new compound. The structure of craniosaponin A was assigned mainly by spectral methods.