Hypoglycemic Constituents Isolated from Trapa natans L. Pericarps

Area of Science:

• Phytochemistry
• Molecular Biology
• Metabolic Research

Background:

• Trapa natans L. (water chestnut) is a plant with edible fruits.
• Its pericarps contain various chemical compounds, including tannins, lignans, and flavonoids.
• Understanding the bioactivity of these compounds is crucial for potential therapeutic applications.

Purpose of the Study:

• To isolate and identify compounds from Trapa natans pericarps.
• To investigate the effects of these isolated compounds on glucose uptake in C2C12 myotubes.
• To elucidate the molecular mechanisms underlying the observed glucose uptake enhancement.

Main Methods:

• Isolation and structural elucidation of compounds using chemical and spectral methods.
• Assessment of glucose uptake activity in C2C12 myotubes.
• Analysis of protein expression (GLUT4) and phosphorylation (AMPK, AKT) via Western blotting.
• Pharmacological inhibition of AMPK and PI3K pathways.

Main Results:

• Twenty-four compounds were isolated, including new tannins, neolignans, and norlignans.
• Several compounds, particularly hydrolyzable tannins (1-8), lignin (13), flavonoid (16), norlignan (17), and phenolic compounds (18, 20, 21, 24), enhanced glucose uptake.
• Compounds 4 and 5 significantly increased GLUT4 protein expression and promoted the phosphorylation of AMPK and AKT.
• Involvement of AMPK and PI3K pathways was confirmed through inhibitor studies.
• Compounds 4 and 5 increased GLUT4 protein levels in plasma membranes.

Conclusions:

• Trapa natans pericarps are a rich source of bioactive compounds with potential anti-diabetic properties.
• Compounds 4 and 5 demonstrate significant potential for improving glucose metabolism by enhancing glucose uptake via the AMPK/PI3K/GLUT4 pathway.
• Further research into these compounds could lead to novel therapeutic strategies for managing glucose homeostasis.