One-pot enantioselective synthesis of (S)-spirobrassinin and non-natural (S)-methylspirobrassinin from amino acids using a turnip enzyme

Mechanistic Perspective on C-N and C-S Bond Construction Catalyzed by Cytochrome P450 Enzymes

Cytochrome P450 enzymes catalyze a large number of oxidative transformations that are responsible for natural product synthesis. Recent studies have revealed their unique ability to catalyze the formation of C-N and C-S bonds, broadening their biosynthetic applications. However, the enzymatic mechanisms behind these reactions are still unclear. This review focuses on theoretical insights into the mechanisms of P450-catalyzed C-N and C-S bond formation. The key roles of the conformational dynamics of substrate radicals, influenced by the enzyme environment, in modulating selectivity and reactivity are highlighted. Understanding these reaction mechanisms offers valuable guidance for P450 enzyme engineering and the design of biosynthetic applications.

Isolation and Identification of Herbicidal Active Compounds from Brassica oleracea L. and Exploration of the Binding Sites of Brassicanate A Sulfoxide

Brassica oleracea L. has strong allelopathic effects on weeds. However, the allelochemicals with herbicidal activity in B. oleracea L. are still unknown. In this study, we evaluated the activity of allelochemicals isolated from Brassica oleracea L. based on the germination and growth of model plant Lactuca sativa Linn., grass weed Panicum miliaceum, and broadleaf weed Chenopodium album. Additionally, we employed molecular docking to predict the binding of brassicanate A sulfoxide to herbicide targets. The results of this study showed that eight compounds with herbicidal activity were isolated from B. oleracea L., and the predicted results indicated that brassicanate A sulfoxide was stably bound to dihydroxyacid dehydratase, hydroxymethylpyruvate dioxygenase, acetolactate synthase, PYL family proteins and transport inhibitor response 1. This research provides compound sources and a theoretical foundation for the development of natural herbicides.

2-Oxindole and related heterocycles: synthetic methodologies for their natural products and related derivatives

Natural goods, medications, and pharmaceutically active substances all contain substituted oxindoles. Generally, the C-3 stereocenter of the substituents of oxindoles and their absolute arrangement have a substantial impact on the bioactivity of these substances. In this case, the desire for contemporary probe and drug-discovery programs for the synthesis of chiral compounds using desirable scaffolds with high structural diversity further drives research in this field. Also, the new synthetic techniques are generally simple to apply for the synthesis of other similar scaffolds. Herein, we review the distinct approaches for the synthesis of diverse useful oxindole scaffolds. Specifically, the research findings on the naturally existing 2-oxindole core and a variety of synthetic compounds having a 2-oxindole core are discussed. We present an overview of the construction of oxindole-based synthetic and natural products. In addition, the chemical reactivity of 2-oxindole and its related derivatives in the presence of chiral and achiral catalysts are thoroughly discussed. The data compiled herein provides broad information related to the bioactive product design, development, and applications of 2-oxindoles and the reported techniques will be helpful for the investigation of novel reactions in the future.

Antiproliferative Activities of Diterpenes from Leaves of Isodon trichocarpus against Cancer Stem Cells

Two new diterpenes named trichoterpene I (1) and trichoterpene II (2) were isolated from the extract from the leaves of Isodon trichocarpus together with 19 known diterpenes. Their chemical structures were elucidated on the basis of chemical and physicochemical properties. Among them, oridonin (3), effusanin A (4), and lasiokaurin (9) with the α,β-unsaturated carbonyl moiety showed antiproliferative activities against breast cancer MDA-MB-231 and human astrocytoma U-251 MG cells [i.e., non-cancer stem cells (non-CSCs)] and their cancer stem cells (CSCs) isolated by sphere formation. In particular, compound 4 (IC₅₀ = 0.51 µM) showed a higher antiproliferative activity against MDA-MB-231 CSCs than against MDA-MB-231 non-CSCs. The antiproliferative activity toward CSCs of compound 4 was equal to adriamycin (positive control, IC₅₀ = 0.60 µM).

Chemical Structures of Phenylbutanoids From Rhizomes of Zingiber cassumunar

Zingiber cassumunar is widely distributed in Asia, and its rhizomes are used for asthma treatment in traditional medicine and as a spice. Five new phenylbutanoids, cassumunols I–M (1-5), were isolated from Z cassumunar rhizomes collected in Thailand, and their structures were characterized on the basis of physiochemical and chemical evidence.