Three kinds of new, natural xanthones, named athyriol (I), isoathyriol (II), and norathyriol (IV), were isolated from the acetone extract of fresh leaves of
Athyrium mesosorum MAKINO, together with mangiferin (V) and hydroquinone (III).
Norathyrial (IV) is obtained as pale yellowish brown needle crystals of m.p. above 320° and its molecular formula corresponded to C
13H
8O
6. It was identified with 1, 3, 6, 7-tetrahydroxyanthone from its physical properties and the result of methylation.
Athyriol (I) is obtained as pale yellowish brown needle crystals of m.p. 300° (decomp.), C
14H
10O
6. Isoathyriol forms pale yellow needle crystals of m.p. 325° (capillary), C
14H
10O
6. Both (I) and (II) had one methoxyl group, formed a triacetate by acetylation, and 1-hydroxy-3, 6, 7-trimethoxyxanthone by methylation. Therefore, they must be monomethyl derivatives of (IV), having a methoxyl group in 3-, 6-, or 7-position. (V) was identified with mangiferin from its physical properties and formation of norathyriol by the action of hydriodic acid.
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