The present study constructs a model of three-dimensional quantitative structure and bioactivity of anti-HIV for a Chinese traditional medicine-Schizandrins, by implementing a new 3D-QSAR technique: comparative molecular similarity indices analysis (CoMSIA). Here four models are built based on different form of biphenyl and two aligned methods. The results of PLS analyses indicate that a good 3D- QSAR model can be obtained if biphenyl prefers S form and all the compounds are aligned according to the atoms in biphenyl group. After field expressions in terms of similarity indices in CoMSIA instead of the conventionally used Lennard-Jones and Coulomb-type potentials in CoMFA, the cross-validated q~2 and predictive ability are significantly improved. The CoMSIA coefficient contour plots identify several key features that the torsion angel of two benzene planes is a critical factor for the activity and the substituent at cyclooctadiene is also related to the activity, which are very valuable for designing and optimizing new active structures.

Key words: SCHISANDRA CHINENSIS, LIGNIN, DIPHENYL P, CYCLOOCTADIENE, QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP