Gastroprotective Effects of Paeonia Extract Mixture HT074 against Experimental Gastric Ulcers in Rats

Abstract

Background: Paeonia extract mixture HT074 is a standardized multiherbal mixture comprising extracts from Inula britannica flowers and Paeonia lactiflora roots, which are used to treat digestive disorders in traditional Korean medicine. This study was focused on elucidating the underlying mechanisms of the gastroprotective effects of HT074 in different gastric ulcer models.

Methods: Gastric lesions were induced in rats by an HCl/EtOH solution, water immersion-restraint stress (WIRS), and indomethacin. Gastric secretions were studied in pylorus-ligated rats, while mucus secretions were assessed by measuring alcian blue-binding capacity of mucus in the rat model of HCl/EtOH-induced gastric ulcer. Additionally, the involvement of nitric oxide (NO) and sulfhydryl compounds in HT074-mediated mucosal protection was elucidated using their inhibitors, i.e., N ^G -nitro- _L-arginine methyl ester hydrochloride (L-NAME) and N-ethylmaleimide (NEM), respectively. Furthermore, the effects on indomethacin-induced cell death and prostaglandin E₂ (PGE₂) levels were assessed in AGS cells.

Results: Oral administration of HT074 significantly decreased gastric lesions induced by HCl/EtOH, WIRS, and indomethacin. Furthermore, it significantly decreased the volume, acidity, and total acidity of gastric juice in pylorus-ligated rats and increased the alcian blue-stained gastric mucus in HCl/EtOH-induced gastric ulcer in rats. Pretreatment with NEM abolished the gastroprotective effects of HT074, while L-NAME did not. In AGS cells, HT074 significantly reduced indomethacin-induced cell death and increased the PGE₂ levels.

Conclusions: These findings suggest that HT074 has gastroprotective effects against various ulcerogens, including HCl/EtOH, immersion stress, and NSAIDs. These effects are attributed to the inhibition of gastric secretions and preservation of the gastric mucosal barrier by increased mucus production, which is partially mediated through endogenous sulfhydryl compounds and PGE₂. Based on these findings, we propose that HT074 may be a promising therapeutic agent for gastritis and gastric ulcer.

Figure 1

High-performance liquid chromatograms for standardization of HT074, Paeonia extract mixture. Arrows in (a) and (b) show the peaks of 1-O-acetylbritannilactone and paeoniflorin, respectively.

Figure 2

(a) Protective effects of HT074 on HCl/EtOH-induced gastric mucosal lesions in rats. (A–E) Representative stomach images from each group. Rats were pretreated orally with distilled water ((A), control), omeprazole 20 mg/kg (B), HT074 30 mg/kg (C), HT074 100 mg/kg (D), or HT074 300 mg/kg (E) 30 min before oral administration of HCl/EtOH. (b) Quantification of the gastric lesion area. Values are expressed as mean ± SEM. n=6 per group. ∗∗ p < 0.01 and ∗∗∗ p < 0.001 vs. control by ANOVA with Dunnett's post hoc test. OMP: omeprazole.

Figure 3

(a) Protective effects of HT074 on the water immersion-restraint stress-induced gastric mucosal lesions in rats. (A–E) Representative stomach images from each group. Rats were pretreated orally with distilled water ((A), control), omeprazole 20 mg/kg (B), HT074 30 mg/kg (C), HT074 100 mg/kg (D), or HT074 300 mg/kg (E) 1 h before exposure to water immersion-restraint stress. (b) Quantification of gastric lesion area. Values are expressed as mean ± SEM. n=6 per group. ∗ p < 0.05 vs. control by ANOVA with Dunnett's post hoc test. OMP: omeprazole.

Figure 4

(a) Protective effects of HT074 on indomethacin-induced gastric lesion area in rats. (A–E) Representative stomach images from each group. Rats were pretreated orally with distilled water ((A), control), omeprazole 20 mg/kg (B), HT074 30 mg/kg (C), HT074 100 mg/kg (D), or HT074 300 mg/kg (E) 30 min before oral administration of indomethacin. (b) Quantification of gastric lesion area. Values are expressed as mean ± SEM. n=5-6 per group. ^∗∗ p < 0.01, ^∗∗∗ p < 0.001 vs. control by ANOVA with Dunnett's post hoc test. OMP: omeprazole.

Figure 5

Effects of HT074 on gastric wall mucus in HCl/EtOH-ulcerated rats. Rats were pretreated orally with distilled water (control), omeprazole 20 mg/kg, or HT074 (30, 100, or 300 mg/kg) 30 min before oral administration of HCl/EtOH. The gastric wall mucus was quantitatively estimated using alcian blue dye binding. Values are expressed as mean ± SEM. n=6 per group. ^∗ p < 0.05 and ^∗∗ p < 0.01 vs. control by ANOVA with Dunnett's post hoc test. OMP: omeprazole.

Figure 6

Effects of HT074 on HCl/EtOH-induced gastric lesions in L-NAME (a) and NEM (b) pretreated rats. Rats were pretreated intraperitoneally with saline or L-NAME or NEM and were then orally administered distilled water (control), carbenoxolone 100 mg/kg or HT074 300 mg/kg 30 min before oral administration of HCl/EtOH. Values are expressed as mean ± SEM. n=6-9 per group. ^∗∗ p < 0.01 and ^∗∗∗ p < 0.001 vs. control; ^# p < 0.05 vs. control + L-NAME by ANOVA with Dunnett's post hoc test. CAR: carbenoxolone.

Figure 7

Effects of HT074 on indomethacin-induced apoptosis in AGS cells. (a) AGS cells were treated with HT074 for 24 h. (b) Cells were pretreated with either HT074 in serum-free medium or vehicle (serum-free medium) for 24 h and then incubated with indomethacin (800 μg/mL) for 3 h. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Values are expressed as mean ± SEM. ^### p <0.001, ^∗ p < 0.05, and ^∗∗∗ p < 0.001 by ANOVA with Dunnett's post hoc test.

Figure 8

Effects of HT074 on PGE ₂ concentration in AGS cells. Cells were treated with either HT074 or vehicle (serum-free medium) for 1 h. Values are expressed as mean ± SEM. ^∗∗∗ p < 0.001 by ANOVA with Dunnett's post hoc test.