New Bioactive Macrocyclic Diterpenoids from Euphorbia helioscopia

Area of Science:

• Natural Product Chemistry
• Chemical Ecology
• Pharmacology

Background:

• Euphorbia helioscopia is a plant known to produce diverse secondary metabolites.
• Macrocyclic diterpenoids are a class of compounds with various biological activities.
• Insect herbivores pose a significant threat to plant survival and agricultural productivity.

Purpose of the Study:

• To isolate and characterize new macrocyclic diterpenoids from Euphorbia helioscopia.
• To evaluate the antifeedant activity of these compounds against the insect Helicoverpa armigera.
• To assess the cytotoxic effects of the isolated compounds on selected human tumor cell lines.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation of new compounds via spectroscopic methods (NMR, MS).
• Bioassays for antifeedant activity (e.g., leaf-disk assay) and cytotoxicity (e.g., MTT assay).

Main Results:

• Three new macrocyclic diterpenoids, euphoscopoids A-C (1-3), were identified, including two jatrophanes and one lathyrane.
• All isolated compounds demonstrated significant antifeedant activity against Helicoverpa armigera, with EC50 values between 2.05 and 4.34 μg/cm².
• Compound 2 exhibited moderate cytotoxicity against NCI-H1975, HepG2, and MCF-2 cell lines, while compounds 1 and 3 were inactive at 80 μm.

Conclusions:

• Macrocyclic diterpenoids in Euphorbia helioscopia play a role in plant defense against insect herbivores.
• The identified compounds, particularly euphoscopoids, show potential as natural insect antifeedants.
• Compound 2 warrants further investigation for its potential anticancer properties.