Background: Oleanolic Acid (OA) is a ubiquitous product of triterpenoid compounds. Due to its inexpensive availability, unique bioactivities, pharmacological effects and non-toxic properties, OA has attracted tremendous interest in the field of drug design and synthesis. Furthermore, many OA derivatives have been developed for ameliorating the poor water solubility and bioavailability.

Objective: Over the past few decades, various modifications of the OA framework structure have led to the observation of enhancement in bioactivity. Herein, we focused on the synthesis and medicinal performance of OA derivatives modified on A-ring. Moreover, we clarified the relationship between structures and activities of OA derivatives with different functional groups in A-ring. The future application of OA in the field of drug design and development also was discussed and inferred.

Conclusion: This review concluded the novel achievements that could add paramount information to the further study of OA-based drugs.

中文翻译：

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植物来源的齐墩果酸：A环修饰衍生物的合成及药理性质

背景：齐墩果酸（OA）是三萜类化合物的普遍产物。由于其廉价的可获得性，独特的生物活性，药理作用和无毒特性，OA在药物设计和合成领域引起了极大的兴趣。此外，已经开发了许多OA衍生物以改善差的水溶性和生物利用度。

目的：在过去的几十年中，OA框架结构的各种修改已导致观察到生物活性的增强。在这里，我们专注于在A环上修饰的OA衍生物的合成和药物性能。此外，我们阐明了A环中具有不同官能团的OA衍生物的结构与活性之间的关系。还讨论并推断了OA在药物设计和开发领域的未来应用。

结论：这篇综述总结了可以为基于OA的药物的进一步研究增加最重要信息的新成就。