QSAR Studies of Triterpenoid Saponin Analogues for Nematicidal Activity

Abstract

2-D QSAR of triterpenoid saponin analogues with nematicidal activity performed by using three methods: Multiple Linear Regression (MLR), Partial Least Square (PLS) and Principle Component Regression (PCR). The overall degree of prediction of descriptor was found to be around 100% in all three models: MLR, PLS PCR. But, result of Multiple Linear Regression (MLR) analysis showed significant predictive power and reliability as compared to other two methods. The correlation coefficient r2-0.8684 indicates 86.84% correlation between activities and molecular descriptors of training set compound. Cross validated regression coefficient q2-0.82071 meaning that the prediction accuracy of QSAR is 82.07%. slogP descriptor having 100% positive correlation with the activity. This descriptor signifies log of the octanol/water partition coefficient (including implicit hydrogens). This property is an atomic contribution model that calculates logP from the given structure; i.e., the correct protonation state. Carboxyl group at position C-28 of aglycone is most responsible for nematicidal activity.