Semisynthesis and Pesticidal Activities of Novel Cholesterol Ester Derivatives Containing Cinnamic Acid-like Fragments

Due to the extensive use of agrochemicals resulting in the emergence of pesticide resistance and ecological environment problems, the research and development of new alternatives for crop protection is highly desirable. In order to discover potent natural product-based insecticide candidates, a series of new cholesterol ester derivatives containing cinnamic acid-like fragments at the C-7 position were synthesized. Some derivatives showed potent pesticidal activities. Against Mythimna separata Walker, compounds 2a, Id, Ig, and IIg showed 2.1-2.4-fold growth-inhibitory activity of the precursor cholesterol. Against Plutella xylostella Linnaeus, compounds Ig, IIf, and IIi exhibited 1.9-2.1-fold insecticidal activity of cholesterol. These results will pave the way for the future synthesis of cholesterol-based derivatives as agrochemicals.

Review of lignans from 2019 to 2021: Newly reported compounds, diverse activities, structure-activity relationships and clinical applications

Lignans, with various biological activities, such as antitumor, antioxidant, antibacterial, and antiviral activities, are widely distributed in nature and mainly exist in the xylem of plants. In this paper, we summarized the structures and bioactivities of lignans reported in recent years (2019-2021) from five parts, including (1) a summary and classification of newly reported compounds; (2) the pharmacological activities of lignans; (3) molecular resources and activity distribution; (4) the structure-activity relationships; and (5) the clinical application of lignans. This review covers all undescribed compounds that were reported within the covered period of time and all bioactivity data about previously isolated lignans. The distribution of lignans in different plants and families is visualized, which improves the efficiency of searching for specific molecules. The diverse activities of different types of lignans provide an important reference for the rapid screening of these compounds. Discussion about the structure-activity relationships of lignans provides a direction for the structural modification of skeleton molecules. Combined with the clinical application of such molecules, this work will provide a valuable reference for pharmaceutical chemists.