옥수수수염에 함유된 Flavonoids의 분리 및 동정

Abstract

This study was carried out to isolate and characterize the flavonoids present in corn silks. Maysin content in the unpollinated corn silks (Kwangpyeongok) showed its highest level at 3 days after silking, and decreased thereafter, while the content of open pollinated silks were consistently decreased after silking. This result indicates that the maysin content is considerably affected by the pollination of corn silk. Unpollinated corn silks were collected with excising, and ethanol employed to extract flavonoids at common temperature for 9 days. After extraction, chlorophyll, lipids etc. were removed with methylene chloride, then submitted to flash column cartridge (150 × 40 mm i.d.) packed with a preparative RP-C18 bulk packing material (125 A, 55-105 μm), and monitored at 352 nm. Four fractions, fraction-I, -II, -III, and -IV, were isolated from ethanolic extract of corn silks. Absorption spectrum of fraction I showed its maximum intensity (λmax) at 327 nm and 239 nm, fraction-II showed its maximum intensity at 339 nm and 274 nm, fraction-III showed its maximum intensity at 345 nm and 277 nm, and fraction-IV showed its maximum intensity at 352 nm, 270 nm, 257 nm, respectively. On the baisis of ESI micro-TOF analysis, fraction-I was identified as chlorogenic acid (m/z 355, 3-(3,4-dihydroxycinnamoyl) quinic acid, C16H18O9), fraction-II identified as a mixture of chlorogenic acid and luteolin 3'-methyl ether 7-glucuronosyl-(1→2)-glucuronide (m/z 653, C28H28O18), fraction-III identified as a mixture of chlorogenic acid luteolin 7-O-neohesperidoside (m/z 595, C27H30O15), and luteolin 3'-methyl ether 7-glucuronosyl-(1→2)-glucuronide, and fraction-IV identified as maysin (m/z 577, 2''-O-α-L-rhamnosyl-6-C-(6-deoxy-xylohexose- 4-ulosyl)luteolin, C27H28O14), respectively. From the ethanolic extract of corn silks, fraction-I was obtained about 35 mg/100 g F.W., fraction-II was about 48 mg/100 g F.W., fraction-III was about 46 mg/100 g F.W., and fraction-IV was about 138 mg/100 g F.W., respectively.