85EFFECT OF SEASON ON YIELD OF AN ISOLATED COMPOUND (AC- 1) FROM AGERATUM CONYZOIDES L. LEAVES RESPONSIBLE FOR IN VITRO ANTI THIAMINE EFFECTA compound (AC-1) was isolated from Ageratum conyzoides L. leaves. The compound had in vitro anti thiamine effect. Effect of season on yield of the isolated compound was studied. Results showed that leaves of A. conyzoides L. for the months of September and October yielded maximum amount of the compounddr_pkmitra@rediffmail.comResearch512015Ageratum conyzoides L. leaves,In vitro anti thiamine effectMrinmoy Guria,Prasenjit Mitra,Tanaya Ghosh,Ravindernath Salhan,Takhelmayum Amumacha Singh,Amit Chakrabarti,Prasanta Kumar Mitra Department 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.