The flavonoid Oroxylin A (6-methoxychrysin or 5,7-dihydroxy-6-methoxy-2-phenyl-4H-chromen-4-one, C16H12O5) and its regioisomers are of increasing interest for a variety of bioactive functions and their pharmaceutical formulation is of importance. Previous difficulties in the separation and misidentification of Oroxylin A from its regioisomers Wogonin (8-methoxychrysin or 5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one) and Negletein (5,6-dihydroxy-7-methoxyflavone or 5,6-dihydroxy-7-methoxy-2-phenyl-4H-chromen-4-one) render its full structural and powder X-ray characterization highly desirable. The low-temperature (100 K) crystal structures of Oroxylin A, Negletein and Wogonin sesquihydrate are reported for the first time. Wogonin crystallizes in two related but distinct hydrated forms. These have very similar powder diffractograms, indicating that such issues need to be addressed for its pharmaceutical formulation.
黄酮类化合物 Oroxylin A(6-甲氧基金丝桃素或 5,7-二羟基-6-甲氧基-2-苯基-4H-苯并吡喃-4-酮,C16H12O5)及其 Regioisomers 因具有多种生物活性功能而越来越受到关注,其药物配方也非常重要。以前在将 Oroxylin A 从其 Regioisomers Wogonin(8-甲氧基 Chrysin 或 5,7-二羟基-8-甲氧基-2-苯基-4H-苯并吡喃-4-酮)和 Negletein(5,6-二羟基-7-甲氧基黄酮或 5,6-二羟基-7-甲氧基-2-苯基-4H-苯并吡喃-4-酮)中分离和错误鉴别方面存在困难,因此非常需要对其进行全面的结构和粉末 X 射线表征。本研究首次报道了 Oroxylin A、Negletein 和 Wogonin sesquihydrate 的低温(100 K)晶体结构。Wogonin 以两种相关但不同的水合形式结晶。它们的粉末衍射图非常相似,这表明其药物制剂需要解决这些问题。