From the n-hexane fraction of the fruits of Vitex agnus-castus, two labdane-type diterpenes, vitetrifolin B and C, were isolated by means of multiple chromatographic separations, together with the previously identified rotundifuran, vitexilactone and the sesquiterpene spathulenol. From the EtOAc fraction, eupatorin was identified for the first time, besides the known casticin, penduletin, vitexin and orientin. The n-hexane, EtOAc and MeOH-H(2)O fractions of the MeOH extract of Agni-casti fructus were subjected to in vitro antioxidant assays. The EtOAc extract displayed a significant concentration-dependent effect when tested by 1,1-diphenyl-2-picrylhydrasyl (DPPH) free radical assay (IC(50) = 68 microg/mL) and against the autooxidation of a standard rat brain homogenate (IC(50) = 14 microg/mL). The MeOH-H(2)O fraction was less active with 3643 microg/mL (DPPH test) and IC(50) = 125 microg/mL (rat brain homogenate), while the n-hexane phase proved to be inactive. The main flavonoid constituents of the EtOAc extract, casticin, vitexin and orientin were assayed for antioxidant activity and found that only casticin possesses a marked lipid peroxidation inhibitory effect (IC(50) = 0.049 mm) compared with that of the positive control ascorbic acid (IC(50) = 0.703 mm).

A conceptionally new 3D molecular descriptor type and methodology are deduced by simple statistical thermodynamic reasoning, based on the free energy change encountered during a transformation of a conformational ensemble of the ligand to an active conformation. The performance of the descriptor was first tested on 37 endomorphin analogues with mu-opiate activity. The method resulted in predictive 3D-QSAR models, and the active conformation was also predicted. Generally, the methodology can be combined with the traditional 3D-QSAR techniques in a 3+3D-QSAR manner. This feature was tested on a series of 38 PGF2alphaprostaglandin analogues with antinidatory activity; the extent to which the molecular flexibility explains the variation in the biological activity was estimated and the active conformation was predicted. The novel descriptors in combination with the grid-based SOMFA descriptors resulted in 3+3D-QSAR models with good levels of predictivity leading to the approach of separation of the effect of the molecular interaction field of the active conformation and the effect of the conformational free energy loss.

Keywords: Amino acids / Heterocycles / Diastereoselectivity / Structure elucidation By means of total regio-and diastereoselective functionalizations of cis-and trans-2-amino-4-cyclohexenecarboxylic acid derivatives 1, 9, 12 and 16, isomers of 2-amino-4-hydroxycyclohexanecarboxylic acid 8 and 11, and 2-amino-5-hydroxycyclohexanecarboxylic acid 15 and 19 were prepared in good yields, via 1,3-oxazine or γ-lactone intermediates. The enantiomers of 8 and 15 were also prepared by the same