Evaluation of clinical, histological, TNF-α, and collagen expressions on oral ulcer in rats after treatment with Areca catechu L. nut and Dendranthema grandiflora oral gel [version 7; peer review: 2 approved, 2 not approved]

Background A. catechu (Areca catechu Linn.; A. catechu) is the seed of the fruit of the oriental palm that is commonly used among Southeast Asian communities. Dendrathema grandiflora (chrysanthemum; D. grandiflora) is a flowering plant originating from East Asia and dominantly grows in China. Both of these plants have strong antioxidant activities. To investigate the mechanism of their wound healing activities, we prepared A. catechu and D. grandiflora polyethylene oral gel and performed several in vivo assays using Sprague–Dawley rats. Methods Sprague–Dawley rats were divided into six groups: Negative control group (rats with base gel treatment), positive control group (rats treated with triamcinolone acetonide), F1 (20% A. catechu:80% D. grandiflora), F2 (50% A. catechu:50% D. grandiflora), F3 (80% A. catechu:20% D. grandiflora), and normal group. Traumatic ulcers were performed on the buccal mucosa of all experimental animals that received topical oral gel and triamcinolone acetonide twice a day for seven days. The clinical and histological characteristics were analyzed and scored. Results During the six days, the ulcerated area receded linearly over time and was completely cicatrized in F2, F3, and positive control group (Dependent t-test, p<0.05). There were significant increases in body weight in F2 and positive control groups. There were no significant differences between groups in histology examination (Kruskal Wallis test, p<0.05). The moderate score of TNF-α levels was seen in F2 and positive control groups (ANOVA/Tukey test, p<0.05). In the collagenase assay, high concentration of A. catechu (F3) induced the abundant of collagen during the ulcer healing process. Conclusions The combination of A. catechu and D. grandiflora extract in the oral gel can optimize the healing of traumatic oral ulcers in Sprague-Dawley rats through the increase of TNF-α and collagen deposition.