Trimer procyanidin oligomers contribute to the protective effects of cinnamon extracts on pancreatic β-cells in vitro.

Abstract

AIM:

Cinnamon extracts rich in procyanidin oligomers have shown to improve pancreatic β-cell function in diabetic db/db mice. The aim of this study was to identify the active compounds in extracts from two species of cinnamon responsible for the pancreatic β-cell protection in vitro.

METHODS:

Cinnamon extracts were prepared from Cinnamomum tamala (CT-E) and Cinnamomum cassia (CC-E). Six compounds procyanidin B2 (cpd1), (-)-epicatechin (cpd2), cinnamtannin B1 (cpd3), procyanidin C1 (cpd4), parameritannin A1 (cpd5) and cinnamtannin D1 (cpd6) were isolated from the extracts. INS-1 pancreatic β-cells were exposed to palmitic acid (PA) or H2O2 to induce lipotoxicity and oxidative stress. Cell viability and apoptosis as well as ROS levels were assessed. Glucose-stimulated insulin secretion was examined in PA-treated β-cells and murine islets.

RESULTS:

CT-E, CC-E as well as the compounds, except cpd5, did not cause cytotoxicity in the β-cells up to the maximum dosage using in this experiment. CT-E and CC-E (12.5-50 μg/mL) dose-dependently increased cell viability in both PA- and H2O2-treated β-cells, and decreased ROS accumulation in H2O2-treated β-cells. CT-E caused more prominent β-cell protection than CC-E. Furthermore, CT-E (25 and 50 μg/mL) dose-dependently increased glucose-stimulated insulin secretion in PA-treated β-cells and murine islets, but CC-E had little effect. Among the 6 compounds, trimer procyanidins cpd3, cpd4 and cpd6 (12.5-50 μmol/L) dose-dependently increased the cell viability and decreased ROS accumulation in H2O2-treated β-cells. The trimer procyanidins also increased glucose-stimulated insulin secretion in PA-treated β-cells.

CONCLUSION:

Trimer procyanidins in the cinnamon extracts contribute to the pancreatic β-cell protection, thus to the anti-diabetic activity.

• Authors: Peng Sun, Ting Wang, Lu Chen, Bang-Wei Yu, Qi Jia, Kai-Xian Chen, Hui-Min Fan, Yi-Ming Li, He-Yao Wang
• Journal: Acta pharmacologica Sinica (Acta Pharmacol Sin) Vol. 37 Issue 8 Pg. 1083-90 (Aug 2016) ISSN: 1745-7254 [Electronic] United States
• PMID: 27238208 (Publication Type: Journal Article)

Chemical References

• Insulin
• Plant Extracts
• Proanthocyanidins
• Reactive Oxygen Species
• Palmitic Acid
• Hydrogen Peroxide

Topics

• Animals
• Apoptosis (drug effects)
• Cell Survival (drug effects)
• Cells, Cultured
• Cinnamomum zeylanicum (chemistry)
• Dose-Response Relationship, Drug
• Hydrogen Peroxide
• Insulin (metabolism)
• Insulin Secretion
• Insulin-Secreting Cells (cytology, drug effects, metabolism)
• Islets of Langerhans (metabolism)
• Molecular Structure
• Oxidative Stress (drug effects)
• Palmitic Acid
• Plant Extracts (chemistry)
• Proanthocyanidins (isolation & purification, pharmacology)
• Rats
• Reactive Oxygen Species (metabolism)