Structural Characterization, In Vitro Antidiabetic Activity, and Molecular Docking Studies of Isolated Compounds From...

Area of Science:

• Phytochemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Allamanda cathartica is a shrub with traditional medicinal uses.
• The plant contains bioactive secondary metabolites with diverse chemical classes.
• Previous research highlights its ornamental and medicinal value.

Purpose of the Study:

• To conduct a phytochemical investigation of Allamanda cathartica leaves.
• To isolate and characterize secondary metabolites.
• To evaluate the in vitro inhibitory activity of isolated compounds against alpha-amylase and alpha-glucosidase.

Main Methods:

• Phytochemical analysis of A. cathartica leaves.
• Isolation and characterization of five compounds (ACL 1-5) using NMR and HRMS.
• In vitro screening for alpha-amylase and alpha-glucosidase inhibitory activity.
• Molecular docking studies for in silico validation.

Main Results:

• Five secondary metabolites were isolated: beta-sitosterol, beta-sitosterol glucoside, ursolic acid, plumieride (ACL-4), and pinitol (ACL-5).
• Plumieride (ACL-4) and pinitol (ACL-5) demonstrated significant inhibitory activity against alpha-amylase and alpha-glucosidase.
• IC50 values for alpha-amylase inhibition ranged from 522.95 to 662.67 µg/mL, with plumieride being most potent.
• IC50 values for alpha-glucosidase inhibition ranged from 576.82 to 691.12 µg/mL, with plumieride showing the strongest activity.

Conclusions:

• The isolated compounds, particularly plumieride (ACL-4) and pinitol (ACL-5), exhibit strong antidiabetic potential.
• Plumieride demonstrated a slightly more potent antidiabetic effect than pinitol based on in vitro and docking studies.
• These findings support the traditional use of Allamanda cathartica and suggest its potential as a source for novel antidiabetic agents.