Two new diterpenoids from Leonotis leonurus R. Br

Area of Science:

• Natural Products Chemistry
• Pharmacology

Background:

• Leonotis leonurus, commonly known as Lion's Tail, is a plant traditionally used in herbal medicine.
• Diterpenoids are a class of naturally occurring compounds with diverse biological activities.

Purpose of the Study:

• To isolate and characterize chemical constituents from the aerial parts of Leonotis leonurus.
• To evaluate the isolated compounds for estrogen sulfotransferase inhibitory activity.

Main Methods:

• Phytochemical investigation involving extraction and isolation techniques.
• Structure elucidation using comprehensive spectroscopic analyses (e.g., NMR, MS).
• In vitro assay to determine estrogen sulfotransferase inhibitory activity.

Main Results:

• Two novel diterpenoids, 14α-hydroxy-9α,13α-epoxylabd-5(6)-en-7-on-16,15-olide and 13ξ-hydroxylabd-5(6),8(9)-dien-7-on-16,15-olide, were identified.
• Six known diterpenoids were also isolated and characterized.
• Several isolated compounds demonstrated weak to moderate inhibition of estrogen sulfotransferase.

Conclusions:

• The chemical investigation of Leonotis leonurus yielded new diterpenoid structures.
• The identified compounds possess potential estrogen sulfotransferase inhibitory properties, warranting further investigation for therapeutic development.