Enzyme inhibitory constituents from Duranta repens

Area of Science:

• Phytochemistry
• Natural Product Chemistry
• Pharmacology

Background:

• Duranta repens is a plant species known for its diverse chemical constituents.
• Flavonoids and acetophenone derivatives are classes of natural products with significant biological activities.
• Investigating the chemical composition of medicinal plants can lead to the discovery of novel bioactive compounds.

Purpose of the Study:

• To isolate and characterize new isoprenylated flavonoids and acetophenone derivatives from Duranta repens.
• To evaluate the biological activities of the isolated compounds, specifically their inhibitory effects on prolyl endopeptidase and thrombin.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation employing various spectroscopic methods, including 1H- and 13C-NMR, IR, UV, MS, and 2D-NMR experiments.
• In vitro assays to assess inhibitory activity against prolyl endopeptidase and thrombin.

Main Results:

• Three new compounds were isolated: isoprenylated flavonoids 5,7-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-3,6,4'-trimethoxyflavone (1) and 3,7-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-5,6,4'-trimethoxyflavone (2), and an isoprenylated acetophenone derivative (3).
• Eight known compounds were also identified, with compounds 6-8 being isolated from Duranta repens for the first time.
• Compounds 1-5 exhibited inhibitory activity against prolyl endopeptidase.
• Compounds 4 and 5 also showed activity against thrombin.

Conclusions:

• The study successfully identified novel isoprenylated flavonoids and acetophenone derivatives from Duranta repens.
• The isolated compounds, particularly 1-5, demonstrate potential as inhibitors of prolyl endopeptidase.
• Compounds 4 and 5 show promise as inhibitors of thrombin, suggesting potential therapeutic applications in relevant diseases.