Three new clerodane diterpenes from Polyalthia longifolia var. pendula

Area of Science:

• Natural Product Chemistry
• Pharmacology

Background:

• Polyalthia longifolia var. pendula (Annonaceae) is a plant source of bioactive compounds.
• Diterpenes are a class of natural products with diverse biological activities.

Purpose of the Study:

• To isolate and characterize new clerodane diterpenes from *Polyalthia longifolia* var. pendula.
• To evaluate the anti-inflammatory potential of isolated compounds by assessing their nitric oxide (NO) inhibitory effects.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation of new compounds via spectroscopic analysis (e.g., NMR, MS).
• In vitro anti-inflammatory assay using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages to measure NO production.

Main Results:

• Three new clerodane diterpenes (1-3) and five known compounds (4-8) were isolated and structurally identified.
• Compounds 6 (16-hydroxycleroda-3,13-dien-15,16-olide) and 7 (16-oxocleroda-3,13-dien-15-oic acid) exhibited significant NO inhibitory activity.
• Inhibition rates of 81.1% and 86.3% for compounds 6 and 7, respectively, were observed at a concentration of 10 µg/mL.

Conclusions:

• The study successfully identified novel clerodane diterpenes from *Polyalthia longifolia* var. pendula.
• Specific clerodane diterpenes, namely 16-hydroxycleroda-3,13-dien-15,16-olide and 16-oxocleroda-3,13-dien-15-oic acid, show promising anti-inflammatory properties.
• These findings suggest potential therapeutic applications for these compounds in managing inflammatory conditions.