Effects of Etlingera elatior flower extract on cyclooxygenase-2 expression in the gingival epithelium in a diabetic periodontitis rat model

This research was aimed at investigating the effects of 70% ethanolic Etlingera elatior flower extract on cyclooxygenase-2 (COX-2) expression in the gingival epithelium in rats with diabetic periodontitis. Diabetes and periodontitis were induced in 32 male Rattus norvegicus individuals weighing 200-300 g each. Streptozotocin dissolved in 1 mL citrate buffer was injected intraperitoneally to elicit hyperglycemia. Three days after diabetes induction, the rats' fasting blood glucose levels were measured with a GCU EasyTouch® glucometer. Diabetes was confirmed by fasting blood glucose levels exceeding 200 mg/dL. After diagnosis of diabetic periodontitis, a daily injection of 70% ethanolic E. elatior extract (n = 16) and saline (n = 16) was intraperitoneally administered for 7 days. Immunohistochemistry was used to detect COX-2 expression in the gingival epithelium on days 1, 3, 5, and 7 after injection, and the number of positively colored cells was expressed as a percentage. Brownish cytoplasm in the gingival epithelium was considered to indicate positive COX-2 expression, which extended from the basal layer to the corneum. The percentage of immunopositive cells was analyzed with two-way ANOVA followed by post-hoc LSD analysis at a 95% significance level. Injection of 70% ethanolic extract of E. elatior flower, compared with saline, resulted in greater COX-2 expression on days 1-5. On day 7, however, the E. elatior group exhibited substantially lower COX-2 expression than the saline group (p < 0.05). In diabetic periodontitis, 70% ethanolic E. elatior extract was found to be a useful active component for host modulation therapy. The 70% ethanolic extract of E. elatior flower modulated COX-2 expression in the gingival epithelium in rats with diabetic periodontitis.