Cadinane-Type Sesquiterpenoids with Cytotoxic Activity from the Infected Stems of the Semi-mangrove Hibiscus tiliaceus

Abstract

Eight new cadinane sesquiterpenoids (1−8), along with two known compounds (9 and 10), were isolated from infected stems of the semi-mangrove plant, Hibiscus tiliaceus. The structures of compounds 1−8 were elucidated through the analysis of their 1D and 2D NMR and MS data, and their absolute configurations were determined by comparing their experimental and calculated ECD spectra and by single-crystal X-ray diffraction. The two confused known compounds (9 and 10) were resolved using single-crystal X-ray crystallography. Compounds 1−3 have novel norsesquiterpene carbon skeletons arising from a ring contraction rearrangement. All obtained isolates were evaluated against the HepG2 and Huh7 cell lines, and compounds 1b, 2b, 4, 6, and 8 showed cytotoxic activity toward both cell lines, with IC 50 values ranging from 3.5 to 6.8 μM.

Discovery of Cadinane-Type Sesquiterpenoids from the Infected Stems of Hibiscus tiliaceus as Potential Agrochemical Fungicides

“…Thus, we theorized that these substances may exhibit fungicidal effects, and the phytochemistry of infected H. tiliaceus was further analyzed. gossyvertin (11), 36 isohemigossypol (12), 37 inuloidin (13), 38 7-hydroxy-3,4-dihydrocadalin (14), 39 (lR,4R)-7-hydroxycalamenene (15), 40 7-hydroxy-1,2-dihydrocadalene ( 16), 41 7hydroxycadalenal (17), 42 mansonone C (18), 42 parvifloral A (19), 43 syriacusin A (20), 43 7-hydroxycadalene (21), 42 hibisceusin D (22), 34 thespesilactam (23), 44 and mansonone D (24), 42 were separated from the infected stems of the plant (Figure 1). Compounds 1−24 represented a class of cadinanetype sesquiterpenoids, including diverse planar structures, and showed remarkable antifungal activities.…”

“…30,31 The plant has been used as an ornamental tree and is traditionally used as a traditional medicine in China. 32,33 According to prior investigations, 34,35 infected stems of H. tiliaceus produce a large amount of defensive specialized metabolites sesquiterpenoids, which differ from naturally occurring products isolated from healthy H. tiliaceus trees. Thus, we theorized that these substances may exhibit fungicidal effects, and the phytochemistry of infected H. tiliaceus was further analyzed.…”

“…The semimangrove plant Hibiscus tiliaceus L. (Malvaceae) has a genetic relationship with cotton, which is widely grown in tropical and subtropical coastal ecosystems. , The plant has been used as an ornamental tree and is traditionally used as a traditional medicine in China. , According to prior investigations, , infected stems of H. tiliaceus produce a large amount of defensive specialized metabolites sesquiterpenoids, which differ from naturally occurring products isolated from healthy H.…”

Streptinone, a New Indanone Derivative from a Marine-Derived Streptomyces massiliensis, Inhibits Particulate Matter-Induced Inflammation

“…[14], and some plants [15,16]. Indanone derivatives are reported to have anti-proliferative [9], cytotoxic [17], anti-inflammatory [18,19], anti-acetylcholinesterase [19], anti-oxidant [19], neuroprotective [20], and anti-osteoporotic [21] activities. Herein, we describe the isolation, purification, and structure elucidation of the new indanone derivative (1) and its inhibitory activity against PM-induced inflammation in RAW 264.7 cells.…”

Brief overview of recently reported misassigned natural products and their in silico revisions enabled by DU8ML, a machine learning-augmented DFT computational NMR method

“…Eight new cadinene sesquiterpenoids, hibisceusins A–H, were isolated from infected stems of the semi-mangrove plant, Hibiscus tiliaceus . 7 Structures of five of them were determined by X-ray crystallographic analysis. Yet according to DU8ML, hibisceusin H ( 11 ), characterized only by solution NMR, required revision to its 6-epimer 12 .…”