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C18H16O8, monoclinic, P21/n (no. 14), a = 14.5762(6) Å, b = 6.6791(3) Å, c = 17.4240(7) Å, β = 103.5820(10)°, V = 1648.89(12) Å3, Z = 4, R gt(F) = 0.0436, wR ref(F 2) = 0.1218, T = 293(2) K.

Detailed analysis of its crystal structure revealed that the methoxyl groups located at C-3 and C-6 are turned out from the plane of chromone skeleton, which is in accordance with that of casticin, the methyl etherified derivative at 4'-OH of the title compound [[11], [13]]. The title compound (131.8 mg) was obtained from the E4 fraction I via i repeated silica gel column chromatography. The ethyl acetate fraction (0.219 kg) was then separated over silica gel column chromatography eluted with petroleum ether/ethyl acetate and dichloromethane/methanol in gradient, affording six fractions of E1-E6. [Extracted from the article]

Detailed analysis of its crystal structure revealed that the methoxyl groups located at C-3 and C-6 are turned out from the plane of chromone skeleton, which is in accordance with that of casticin, the methyl etherified derivative at 4'-OH of the title compound [[11], [13]]. The title compound (131.8 mg) was obtained from the E4 fraction I via i repeated silica gel column chromatography. The ethyl acetate fraction (0.219 kg) was then separated over silica gel column chromatography eluted with petroleum ether/ethyl acetate and dichloromethane/methanol in gradient, affording six fractions of E1-E6. [Extracted from the article]