Bioactive ent-kaurane diterpenoids from Isodon serra

Area of Science:

• Natural Products Chemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Isodon serra is a traditional medicinal plant containing bioactive diterpenoids.
• Kaurane diterpenoids are known for diverse biological activities, including anticancer and anti-inflammatory properties.

Purpose of the Study:

• To isolate and characterize new 7,20-epoxy-ent-kaurane diterpenoids from Isodon serra.
• To evaluate the cytotoxic and anti-inflammatory activities of these isolated compounds.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation through extensive spectroscopic analysis (NMR, MS) and X-ray crystallography.
• Cytotoxicity assays against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480).
• Nitric oxide (NO) production inhibition assay in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

Main Results:

• Nine new 7,20-epoxy-ent-kaurane diterpenoids were identified, along with seven known compounds.
• Serrin F, rabdocoestin B, and 1α,11β-dihydroxy-1α,11β-acetonide-7α,20-epoxy-ent-kaur-16-en-15-one displayed significant cytotoxicity (IC50 0.7–4.6 μM) against all tested cancer cell lines.
• Serrin F also potently inhibited NO production.
• Several other compounds, including 14β-hydroxyrabdocoestin A, serrins H and I, enanderianin N, and megathyrin B, showed inhibitory effects on NO production without significant cytotoxicity.

Conclusions:

• The study successfully isolated and characterized novel kaurane diterpenoids from Isodon serra.
• Serrin F exhibits promising dual activity, showing potent cytotoxicity and anti-inflammatory effects.
• These findings suggest that Isodon serra diterpenoids are valuable leads for developing new anticancer and anti-inflammatory agents.