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Isodonoids A-L: Ent-kauranoid diterpenoid-flavanone conjugates from Isodon rubescens
Can-Can Wang1, Meng-Yu Bao1, Hui-Ying Li1
1State Key Laboratory of Mechanism and Quality of Chinese Medicine & Faculty of Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, 999078, China.
Phytochemistry
|May 7, 2026
Summary
Twelve new diterpenoid-flavanone conjugates, isodonoids A–L, were discovered in Isodon rubescens. Some compounds showed significant anticancer activity, with two promoting apoptosis in cancer cells.
Area of Science:
- Natural Product Chemistry
- Phytochemistry
- Organic Chemistry
Background:
- Isodon rubescens is a plant known for its medicinal properties.
- Diterpenoid-flavanone conjugates represent a novel class of natural products.
- Previous research has identified various compounds from Isodon species, but not this specific conjugate type.
Purpose of the Study:
- To isolate and characterize novel ent-kauranoid diterpenoid-flavanone conjugates from Isodon rubescens.
- To investigate the cytotoxic and apoptotic effects of these newly discovered compounds.
Main Methods:
- Isolation of compounds using chromatographic techniques.
- Structure elucidation via High-Resolution Electrospray Ionization Mass Spectrometry (HRESIMS) and Nuclear Magnetic Resonance (NMR) spectroscopy.
- Absolute configuration determination using DP4+ analyses and Electronic Circular Dichroism (ECD) calculations.
- Cytotoxicity assays against various human cancer cell lines (MDA-MB-231, HepG2, H1299, A375).
- Apoptosis assays in MDA-MB-231 cells.
Main Results:
- Twelve new ent-kauranoid diterpenoid-flavanone conjugates, named isodonoids A–L (1–12), were isolated.
- Compounds 1–4 feature a unique diterpenoid-flavanone skeleton with a direct C-C bond.
- Compounds 5–12 possess an unreported diterpenoid-flavanone structure with an oxygen bridge.
- Compounds 5, 11, 12, and 14 demonstrated significant cytotoxicity against tested cancer cell lines (IC50 values 5.0–14.9 μM).
- Compounds 11 and 12 induced apoptosis in MDA-MB-231 cells in a dose-dependent manner.
Conclusions:
- This study reports the first discovery of diterpenoid-flavanone conjugates in the plant kingdom.
- The novel compounds isodonoids A–L possess unique structural features.
- Several isolated compounds exhibit promising anticancer potential, warranting further investigation.
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