Brassinosteroids in Rice Bran and Polished Rice

미강과 백미의 Brassinosteroid 활성물질

To investigate the presence of brassinosteroids in rice bran and pㅐlished rice, they were extracted with MeOH. The extracts were purified through sequential procedure of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 column chromatography and charcoal adsorption chromatography. The activity of brassinosteroids was monitored by the rice inclination test and its presence was confirmed in each purification step. The purified active components were further separated by TLC and HPLC. Brassinosteroids in active fractions of rice bran were identified as castasterone and teasterone by HPLC. We acknowledge that our work is probably the first report of brassinosteroids in mature seeds of rice The more amount of brassinosteroids was confirmed in rice bran than polished rice. The contents of castasterone and teasterone which were identified in rice bran were 0.15 ng/g and 0.37 ng/g, respectively.

벼(Oryza sativa L.)의 가식부인 쌀의 brassinosteroid 활성물질의 존재를 구명하기 위하여 벼를 도정하여 미강과 백미를 얻고 이들을 각각 MeOH로 추출하여 얻어진 추출물을 rice inclination test의 생물검정법으로 검정한 결과 활성이 인정되었다. 각각의 추출물을 생물검정법을 지표로 용매분획, silica gel adsorption chromatography, Sephadex LH-20 column chromatography, charcoal adsorption chromatography 등의 수법으로 brassinosteroid 활성물질을 정제하고, silica gel adsorption chromatography, TLC 등에 의해 활성본체를 분리하고 각 활성획분을 HPLC에 의해 활성본체 구명을 시도한 결과 미강의 활성획분에서는 castasterone과 teasterone이 동정되었다. 완숙된 쌀에서 brassinosteroid 활성물질의 확인 및 동정은 본 연구가 최초로 생각되며, brassinosteroid 활성물질은 주로 미강에 존재하였으며, 그 함량은 g중량당 castasterone이 0.15 ng 이고 teasterone은 0.37 ng 수준이었다.