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Keywords:
arthropod; ¡NOS; Kronopolites svenhedini (Verhoeff); non-peptide small molecules
Abstract
Six new compounds, including a tetralone 1. two xanthones 2 and 3. a flavan derivative 4. and two nor-diterpenoids 7 and 8. accompanied by two known flavan derivatives 5 and 6 and a known olefine acid (9) were isolated from whole bodies of Kronopolites svenhedini (Verhoeff). The structures of the new compounds were determined by ID and 2D nuclear magnetic resonance (NMR) and other spectroscopic methods, as well as computational methods. Selected compounds were evaluated for their biological properties against a mouse pancreatic cancer cell line and inhibitory effects on iNOS and COX-2 in RAW264.7 cells.
Introduction
The millipede (class Diplopoda) is a pervasive arthropod in nature, functioning as a decomposer in forest ecosystems [1]. Most current research on millipedes centers around biological sciences and environmental sciences, such as community changes [2-4]. Limited studies on millipede chemical composition and biological activity have revealed the presence of antimicrobial peptides [5], defensive alkaloids [6], and defensive long chain alcohol acetates [7]. Historically, in China, numerous records documented the utilization of animals like arthropods for medicinal purposes. Millipedes hereby represent a traditional Chinese medicine (TCM) with anti-inflammatory, analgesic, stomach-soothing, and fatigue-relieving effects [8]. K. svenhedini (Diplopoda. Strongylosomidae) is a millipede species first described by Verhoeff in 1934 [9]. Based on literature [10], we know that K. svenhedini is the animal source of the TCM millipedes. In our studies of arthropods over the years. we have found that non-peptide small molecules play a significant role in chemical structures and biological activities filló].
In examining the chemical constituents of the millipede K. svenhedini. the focus was directed toward non-peptide small molecules. leading to the isolation of six new and three known compounds (Figure 1) from its extract. These structures were determined by ID and 2D NMR spectra and the experimental and calculated electronic circular dichroism (ECD) spectra. The six new compounds have been named kronopoone A (1). kronopoiols A (2) and B (3). 5-O-methyldaphnegiralin Ci (4). and kronoponoids A (7) and B (8). Biological activity experiments were conducted with the isolated compounds, revealing that compounds 3-5 exhibited the expression of iNOS in a dose-dependent manner.
Results and Discussion
Structural identification
Compound 1. a yellow gum. possesses the molecular formula...