Biological impact of harmaline ricinine and their

Authors: Muhammad RizwanulHaq Qiong Bo Hu Mei Ying Hu Qing Shen Lin Wan Li Zhang

Publish Date: 2009/05/09

Volume: 82, Issue: 4, Pages: 327-

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Abstract

The history of botanical pesticides reveals that their study did mainly focus on the determination of acute median lethal dose or concentration In the current situation it is the dire need to understand the sublethal effects of the botanical extracts along with the traditional studies of lethal concentrations in order to comprehensively investigate the future role of the botanical extracts as pesticides This study reveals the effects of traditionally used medicinal plant extracts harmaline H and ricinine R either individually or in combination with Bacillus thuringiensis Bt on the acute toxicity and sublethal effects on the nutrition and enzyme system of Spodoptera exigua Harmaline and ricinine caused reduction in the growth of neonate larvae up to 9312 and 8431 The EC50 values of harmaline against fourth and fifth instars were 024 and 027 mg/ml but these values remained 049 and 054 mg/ml against fourth and fifth instars after being treated with ricinine The combination of harmaline and ricinine with Bt resulted in the increased efficiency of these chemicals as the mortality percentages significantly increased up to 96 and 8782 in significantly less exposure time in case of H + Bt and R + Bt respectively as compared to individual treatments The nutritional analysis revealed the increased toxicity of harmaline and ricinine in combination with Bt but H + Bt2 showed the higher efficiency with minimal relative consumption rate 250 mg/mg/day relative growth rate 116 mg/mg/day and efficiency of conversion of ingested food 2966 of control respectively Changes in antioxidant enzymes such as superoxide dismutase SOD and catalases CAT were noticed to some extent over different exposure times at all the treatments The highest SOD +3729 and CAT +2927 activity was observed at the 6th day of treatment with H + R + Bt2 The study clearly shows the significantly increased efficiency of harmaline and ricinine in combination with Bt against S exigua This phenomenon can be helpful in order to develop better control strategies against different notorious pestsWe gratefully acknowledge the role of National Science Foundation of People’s Republic of China for funding this work under the grant no 30671387 The authors also thank the support from Foundation for the Author of National Excellent Doctoral Dissertation of P R China FANEDD NO 2004061

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