Two new prenylflavonoids from Morus alba.

Two new prenylflavonoids, morusalbols A and B (1 and 2), were isolated from the branches and leaves of Morus alba, together with three known compounds, kuwanon C (3), morusin (4), morusinol (5). The structures of these two prenylflavonoids were elucidated by extensive analyzes of the spectroscopic data.

Two new xanthones from Swertia angustifolia.

Two new xanthones, angustins A and B (1 and 2), were isolated from the aerial parts of Swertia angustifolia together with six known compounds (3-8). The structures of these two xanthones were elucidated by extensive analysis of the spectroscopic data. In addition, compounds 3 and 6-8 were isolated from this plant for the first time.

Structure elucidation and theoretical investigation of key steps in the biogenetic pathway of schisanartane nortriterpenoids by using DFT methods.

Rubrifloradilactone C (4), a novel bioactive nortriterpenoid, along with four other nortriterpenoids (1-3, 5) were isolated from Schisandra rubriflora. The structure of 4 was determined by extensive NMR spectral analysis, computational evidence by using the GIAO method at the B3LYP/6-311++G(2d,p)//B3LYP/6-31G(d) levels, and X-ray analysis. DFT at the B3LYP/6-311+G(d,p) level was selected to clarify the key mechanistic steps in the formation of 1 and 4 through transition-state (TS) investigations. The effect of enzymes on the TS barriers was considered by using the polarized continuum model. Other possible products based on the new mechanism were predicted.

Vibralactone: a lipase inhibitor with an unusual fused beta-lactone produced by cultures of the basidiomycete Boreostereum vibrans.

The structure and absolute configuration of vibralactone (1) from the cultures of the Basidiomycete Boreostereum vibrans were established by spectroscopic methods and computational methods. Vibralactone, an unusual fused beta-lactone-type metabolite, was found to inhibit pancreatic lipase with an IC50 of 0.4 microg/mL. [structure: see text]

Isolation and structure elucidation of kadlongilactones C-F from Kadsura longipedunculata by NMR spectroscopy and DFT computational methods.

Four new triterpenoids, kadlongilactones C-F (2-5), containing a consecutive hexacyclic [7,7,5,6,6,6] ring system, were isolated from the leaves and stems of Kadsura longipedunculata. In comparison with the NMR data of kadlongilactones A (1) and D (3), a significant phenomena was discovered that ring D of 3 inverted from a half-chair in 1 to a half-boat conformation when the HO-16 group changed from alpha- to beta-orientation. The structures of 2-5 were established on the basis of detailed spectroscopic analysis, and DFT computational methods were applied in the structural validation of compounds 3 and 5. Compounds 1-4 showed significant cytotoxicity against A549, HT-29, and K562 cell lines with IC50 values of 0.49-3.61 microM in vitro.