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研究知母宁的 酮结构是否有利于提高其清除自由基活性并探讨知母宁酚羟基活性的顺序．方法：用半经验量子化学方法ＡＭＩ计算出知母宁不同状态的△ＨＯＦ值（母体化合物与其自由基生成热之差）和电子自旋密度分布，以△ＨＯＦ值作为衡量知母宁清除自由基活性的理论指标，观察结构因素对△ＨＯＦ值的影响．结果：计算得出不同酚羟基的△ＨＯＦ值为 Ｏ５－Ｈ６： １３９．０９ ｋＪ·ｍｏｌ－１； Ｏ４ －Ｈ５： １４１．４６ ｋＪ· ｍｏｌ－１； Ｏ２－Ｈ２： １８５．１４ ｋＪ·ｍｏｌ－１； Ｏ１－Ｈ１： １９５．７１ ｋＪ·ｍｏｌ－１，同时得到自由基的自旋密度分布．结论：知母宁的 酮结构使Ｃ环对Ｂ环有较强的钝化作用，降低了Ｂ环酚羟基清除自由基的活性．知母宁酚羟基活性的顺序为Ｏ５－Ｈ６＞Ｏ４－Ｈ５＞Ｏ２－Ｈ２＞Ｏｌ－Ｈｌ。
It is investigated whether the ketone structure of Zhimining is beneficial to increase its scavenging activity of free radicals and to explore the order of phenolic hydroxyphenol activity. METHODS: The semi-empirical quantum chemistry method AMI was used to calculate the △HOF value (the difference between the parent compound and its free radical generation heat) and the electron spin density distribution for different states of senin, and the △HOF value was used as a measure of the scavenging free radicals of mannin. The theoretical indicators of activity, observed the influence of structural factors on the △ HOF value. Results: The ΔHOF values of different phenolic hydroxyl groups were calculated as O5-H6: 139.09 kJ·mol-1; O4 -H5: 141.46 kJ·mol-1; O2-H2: 185.14 kJ·mol- 1; O1-H1: 195.71 kJ·mol-1, at the same time, the spin density distribution of free radicals. Conclusion: The ketone structure of Zhimining makes the C ring have a strong passivation effect on the B ring, and reduces the activity of the phenolic hydroxyl radical scavenging free radicals of the B ring. The order of the hydroxyphenol activity of the Zhininuzhi is O5-H6>O4-H5>O2-H2>Ol-Hl.