サンシシ抽出物のTLC分析中に観察される青色呈色物質の同定－生薬化学実習における学修効果向上を目指した基礎研究結果の応用－

抄録

’Sanshishi (SS)’ is the dried fruit of Gardenia jasminoides Ellis and is an important herbal medicine in Kampo. Geniposide, an iridoid glycoside, which is the active component of Kampo, is an important compound not only in pharmacy but also in industry as a raw material for blue pigment. A simple and rapid procedure was developed for the isolation of geniposide by the treatment of water extracts of SS with an absorbent, DIAION^® HP-20 followed by silica gel column chromatography (SGCC). In the TLC analysis of samples during the SGCC purification, a characteristic blue spot was observed near the geniposide on the TLC plate by spraying dilute sulfuric acid followed by heating. This compound was isolated, and NMR analysis elucidated its structure as gardenoside, whose additional hydroxyl group was suggested to provide the property of acid-induced blue pigmentation. The findings were applied to the chemical laboratory practice (LP) of pharmacognosy for pharmaceutical students, and the students with and without the structural information about blue pigmentation on TLC plate were assessed. Analysis of student reports indicated an increase in the number of students describing mechanistic consideration on pigmentation, leading to the improved overall quality of LP results in the group with the structural information. This study serves as a model case to show that the application of new findings from basic research to student LP is useful in improving the learning effectiveness in pharmaceutical education.