[Antioxidant activity of seed shell extract and its therapeutic effects on oral ulcer in rats].

OBJECTIVE

To investigate the therapeutic effect of seed shell extract on oral ulcer in rats and its underlying mechanism.

METHODS

The contents of polyphenols and flavonoids in seed shells were determined by Folin-phenol assay and aluminum nitrate colorimetry, respectively. DPPH·, ABTS·, ·OH and·O scavenging experiments were performed to evaluate the antioxidant activities of seed shell extract . In a rat model of oral ulcer induced by burning with glacial acetic acid, the therapeutic effect of seed shell extract was assessed by detecting changes in serum levels of oxidative factors by enzyme-linked immunosorbent assay (ELISA) and observing pathological changes of the ulcerous mucosa using HE staining; the therapeutic mechanism of the extract was explored by detecting the expression levels of Keap1, Nrf2, Nes-Nrf2 and HO-1 proteins in ulcerous mucosa using Western blotting.

RESULTS

The ethyl acetate extract of seed shells contained 306.74±1.04 mg/g polyphenols and 23.43±0.61 mg/g flavonoids and had IC values for scavenging DPPH· and ABTS· free radicals of 3.42 ± 0.97 μg/mL and 3.32 ± 0.90 μg/mL, respectively. In the rat models, the ethyl acetate extract significantly ameliorated oral mucosal ulcer, increased serum CAT level, and decreased serum MDA level. The protein expression levels of Nes-Nrf2 and HO-1 were increased and Keap1 protein expression was lowered significantly in the ulcerous mucosa of the rats after treatment with the extract (<0.05 or 0.01).

CONCLUSION

The therapeutic effect of seed shell extract on oral ulcers in rats is mediated probably by activation of the Keap1/Nrf2/HO-1 signaling pathway.