79IN VITRO ANTI THIAMINE EFFECT OF AGERATUM CONYZOIDES L. LEAVES: EFFECT OF SEASONIn vitro anti thiamine effect of Ageratum conyzoides L. leaves was studied. Results showed that 1 g of powdered leaves of A. conyzoides L. inactivated 26.5 mg of thiamine hydrochloride. Effect of season on in vitro anti thiamine effect of A. conyzoides L. leaves was also studied. It was found out that leaves of A. conyzoides L. of the period September – October had maximum anti thiamine effect. dr_pkmitra@rediffmail.comResearch512015Ageratum conyzoides L,Anti thiamine effect,Seasonal variationMrinmoy Guria,Prasenjit Mitra,Tanaya Ghosh,Ravindernath Salhan,Takhelmayum Amumacha Singh,Amit Chakrabarti ,Prasanta Kumar MitraDepartment of Biochemistry, North Bengal Medical College, Sushrutanagar 734012. Dist. Darjeeling, West Bengal, India,Biochem Academy, Saktigarh, Siliguri 734005, West Bengal, India,Biochem Academy, Saktigarh, Siliguri 734005, West Bengal, India,Sikkim Manipal University, Sikkim Manipal Institute of Medical Sciences, Tadong, Gangtok 737102, Sikkim, India,Sikkim Manipal University, Sikkim Manipal Institute of Medical Sciences, Tadong, Gangtok 737102, Sikkim, India,Sikkim Manipal University, Sikkim Manipal Institute of Medical Sciences, Tadong, Gangtok 737102, Sikkim, India,Department of Biochemistry, North Bengal Medical College, Sushrutanagar 734012. Dist. Darjeeling, West Bengal, India