The leaves of Morus alba (LMA) are crucial traditional Chinese medicine (TCM) of clearing heat. In ancient Chinese materia medica and the current Pharmacopoeia of the People's Republic of China, LMA are recorded to be harvested after frost for medicinal purpose. However, the reason and mechanism of this traditional usage have been still unknown so far. In this work, it was confirmed firstly that the antipyretic effect of LMA after frost was better than that of before frost significantly on feverish rats. Subsequently, the chemical profiles of LMA before and after frost were characterized by fingerprint, respectively. Then, the endemic peaks after frost and positive differential peaks were screened as the research object of spectrum-effect correlation by orthogonal signal correction partial least square discrimination (OPLS). Finally, a multivariable and continuous-index spectrum-effect correlation model coupled with OPLS was established. As a result, the antipyretic components of postfrost LMA were screened and identified as citric acid derivative and tryptophan which may be the synergistic material basis. The study can provide a scientific foundation for the enhancement of effects in the postfrost LMA. Moreover, the strategy of this research could provide a valuable reference for revealing the material basis of synergetic or antagonistic effects among other complex drug systems.

中文翻译：

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基于多变量和连续指数光谱效应相关性的桑白霜后解热成分的筛选与鉴定。

桑叶（LMA）的叶子是清热的重要中药（TCM）。在古老的中药和现行的中华人民共和国药典中，记录到LMA是在霜冻后收获的，用于药用。但是，到目前为止，仍不清楚这种传统用法的原因和机制。在这项工作中，首先证实了LMA对发烧的大鼠的解冻作用优于霜冻之前。随后，分别通过指纹对LMA霜冻前后的化学特征进行表征。然后，通过正交信号校正偏最小二乘鉴别（OPLS），筛选出霜冻后的流行峰和正微分峰，作为频谱效应相关的研究对象。最后，建立了带有OPLS的多变量连续指数频谱效应相关模型。结果，筛选了霜冻后LMA的解热成分，并将其鉴定为柠檬酸衍生物和色氨酸，这可能是协同的物质基础。该研究可为增强霜冻后LMA的效应提供科学依据。此外，本研究策略可为揭示其他复杂药物系统之间协同或拮抗作用的物质基础提供有价值的参考。该研究可为霜冻后LMA效应的增强提供科学依据。而且，该研究策略可为揭示其他复杂药物系统之间协同或拮抗作用的物质基础提供有价值的参考。该研究可为增强霜冻后LMA的效应提供科学依据。而且，该研究策略可为揭示其他复杂药物系统之间协同或拮抗作用的物质基础提供有价值的参考。