Figure 1.
Chemical structures of cinnamaldehyde and methyl syringate.
Figure 2.
Effects of cinnamaldehyde (CALD) and methyl syringate (MS) on cumulative food intake.
Vehicle (1.5% methyl cellulose), CALD, or MS were administered orally to ICR mice at a dose of 10 mg/kg after fasting in the presence or absence of the TRPA1 antagonists RR and HC-030031. Mice were allowed free access to normal food and water immediately after treatment. Changes in cumulative food intake were monitored for 28 h. Data represent means ± SEM (n = 4); *p<0.05 compared with the vehicle group by Dunnett's test.
Figure 3.
Effect of cinnamaldehyde (CALD) and methyl syringate (MS) on food remaining in the stomach.
Vehicle (1.5% methyl cellulose), CALD, or MS were administered orally to ICR mice at a dose of 10 mg/kg after fasting in the presence or absence of the TRPA1 antagonists, ruthenium red (RR) and HC-030031. After 28 h, mice were sacrificed and the stomach contents of each were weighed. Columns and vertical bars represent means ± SEM (n = 4); *p<0.05 compared with the vehicle control.
Figure 4.
Effects of cinnamaldehyde (CALD) and methyl syringate (MS) on gastric emptying.
Phenol red was administered 5 min after treatment with vehicle (1.5% methyl cellulose), CALD (0.1–80 mg/kg) and MS (0.1–10 mg/kg). Gastric emptying was evaluated by measuring the quantity of phenol red retained in the stomach 15 min after administration. Columns and vertical bars represent means ± SEM (n = 4); *p<0.05 compared with the vehicle control.
Figure 5.
Inhibitory effect of ruthenium red (RR) or HC-030031 on gastric emptying in mice treated with cinnamaldehyde (CALD) or methyl syringate (MS).
Phenol red was administered 5 min after treatment with vehicle (1.5% methyl cellulose), CALD, or MS at a dose of 10 mg/kg in the presence or absence of RR (A) and HC-030031 (B). Gastric emptying was evaluated measuring the quantity of phenol red retained in the stomach after 15 min. Columns and vertical bars represent the means ± SEM (n = 4); *p<0.05 compared with the vehicle control.
Figure 6.
Effects of cinnamaldehyde (CALD) or methyl syringate (MS) on plasma PYY and glucagon-like peptide (GLP-1) levels.
Vehicle (1.5% methyl cellulose), CALD, or MS were administered orally to ICR mice at a dose of 10 mg/kg after fasting in the presence or absence of the TRPA1 antagonists RR and HC-030031. Plasma PYY (A) or GLP-1 levels (B) upon CALD and MS treatment alone or with the addition of RR and HC-030031 (C) were evaluated at 0 min and 15 min and relative values calculated. Columns and vertical bars represent means ± SEM (n = 4); *p<0.05 compared with the vehicle control.