A new macrocyclic diterpenoid from Anisomeles indica

Area of Science:

• Natural Product Chemistry
• Immunology
• Pharmacology

Background:

• Anisomeles indica (L.) O. Kuntze (Labiatae) is a plant used in traditional medicine.
• The chemical constituents and biological activities of Anisomeles indica are of interest for potential therapeutic applications.

Purpose of the Study:

• To isolate and characterize new and known compounds from the aerial parts of Anisomeles indica.
• To evaluate the immunomodulatory effects of the isolated compounds, specifically their ability to inhibit Interleukin-2 (IL-2) secretion.

Main Methods:

• Extraction of dried aerial parts of Anisomeles indica using methanol.
• Isolation and purification of compounds using chromatographic techniques.
• Structure elucidation of the new compound using spectral evidence (e.g., NMR, MS).
• In vitro assessment of IL-2 secretion inhibition in human peripheral blood T cells stimulated with phorbol myristate acetate and anti-CD28 monoclonal antibody.

Main Results:

• A new macrocyclic diterpenoid, 4β,5β-dihydroxyovatodiolide (1), was identified.
• Twenty-two known compounds (2-23) were also isolated.
• Phenylethanoids, specifically acteoside (5) and isoacteoside (6), demonstrated significant inhibition of IL-2 secretion.
• The inhibition was observed in T cells stimulated via co-crosslinking of the T cell receptor/CD3 complex and CD28.

Conclusions:

• Anisomeles indica is a source of diverse chemical compounds, including novel diterpenoids.
• Certain phenylethanoids isolated from Anisomeles indica possess immunomodulatory properties by inhibiting T cell activation, as evidenced by reduced IL-2 secretion.
• These findings suggest potential therapeutic applications for Anisomeles indica constituents in managing immune-related conditions.