고추의 매운 성분 Capsaicin혼합체(capsaicin과 dihydrocapsaicin의 혼정)를 Aspergillus niger의 배양액 중에 첨가하면 Capsaicin은 매운 맛이 없어지고 극성이 강한 phenol성 물질로 전환된다. 이 전환된 물질을 확인하기 위하여 한국산 고추에서 분리한 Capsaicin 혼정 1g를 발효시킨후 배양액을 추출하고 silicic acid column chromatography를 행하여 360 mg의 유상 물질을 분리하였다. 이 물질중에는 vanillylamide 부분이 있다는것을 Capsaicin 표준폼의 UV 흡수 spectrum과 비교하여 확인하였다. 또한 이 물질과 표준 Capsaicin의 NMR signal를 비교하면 Capsaicin중의 직쇄(side chain) 말단에 있는 isopropyl부분의 methylproton($ au$9.5)의 일부가 사라지고 대신 hydroxymethyl기의 두 methylene proton($ au$ 6.5)이 새로 나타났다. 이 유상 물질은 acetate로 만들어 결정화 시키고 다시 NMR, IR, GC로 분석하였다. 이러한 결과를 종합하여 Capsaicin 혼합체의 A. niger에 의한 미생물학적 대사 물질은 $omega$-hydroxy화합물인 trans-8-hydroxymethyl-N-vanillyl-6-nonenamide와 8-hydroxymethyl-N-vanillylnonanamide인 것을 증명하였다.
When a capsaicin mixture (capsaicin and dihydrocapsaicin) was exposed to Aspergillus niger, it was transformed to more polar phenolic compounds. In order to characterize the main transformed compound, one gram of capsaicin mixture was fermented and the culture broth was extracted. After silicic acid column chromatography, 360mg of of oily product was isolated. The presence of vanillyl amide moiety in the product was confirmed by comparison of the pattern of UV absorption spectrum with of authentic capsaicin. When NMR signals of the product were compared with capsaicin, a new signal ($ au$6.5) corresponding to the two methylene protons of hydroxymethyl group appeared at the expense of methyl protons of terminal isopropyl group of capsaicin ($ au$9.5). The oily product was derivatized to its acetate. The acetate was also analyzed by NMR, IR, and GC. It was proved that the transformation product of capsaicin mixture was a mixture of two compounds; trans-8-hydroxymethyl-N-vanillyl-6-nonenamide and 8-hydroxymethyl-N-vanillylnonanamide.
