Subulatin, an Antioxidic Caffeic Acid Derivative Isolated from the In Vitro Cultured Liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta
2002
TAZAKI, Hiroyuki | ITO, Mayumi | MIYOSHI, Masako | KAWABATA, Jun | FUKUSHI, Eri | FUJITA, Takashi | MOTOURI, Mutsumi | FURUKI, Tatsuo | NABETA, Kensuke
The new caffeic acid derivative, subulatin (1), was isolated from in vitro cultured liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta. The structure of 1 involved two caffeic acids, D-glucose, and 2-carboxy-6-(1,2-dihydroxy-ethyl)-4,5-dihydroxy-5,6-dihydro-4H-pyran. The connectivity of those and the absolute stereochemistry of 1 were elucidated on the basis of spectroscopic evidence. The antioxidative activity of 1 was comparable to that of α-tocopherol. (2′R)-Phaselic acid (2a) and (−)-9,2″-epiphylloyl-L-malic acid (4) were also isolated from J. subulata and L. heterophylla, respectively. A chiral HPLC analysis of the p-bromobenzoyl-malic acids derived from 2a showed that 2a from J. subulata was unusual (+)-trans-caffeoyl-D-malic acid.
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