Abstract
Oxyresveratrol, a compound in the heartwood of Artocarpus lakoocha Roxb and other medicinal plants, has been shown to have various biological activities. However, these have not been studied in periodontal research. In this study, we investigated whether oxyresveratrol has antibacterial activity against the predominant perio-pathogenic bacteria Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Moreover, the anti-inflammatory properties of oxyresveratrol were studied in LPS-stimulated human periodontal ligament (hPDL) cells. The antibacterial activity of oxyresveratrol on P. gingivalis and A. actinomycetemcomitans was initially evaluated using a disc diffusion test. The anti-bacterial strength of oxyresveratrol was then assessed in vitro by determining the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC). Furthermore, the effects of oxyresveratrol on the LPS-induced production of inflammatory mediators were measured in hPDL cells. The levels of cytokine mRNA and protein expression were determined using reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed that oxyresveratrol exhibited antibacterial activities against P. gingivalis with MIC and MBC values of 0.07 mg/mL and 0.16 mg/mL, respectively. The MIC and MBC values against A. actinomycetemcomitans were 0.08 mg/mL and 0.16 mg/mL, respectively. When examining inflammatory stimulation, LPS treatment strongly induced the expression of pro-inflammatory cytokines in hPDL cells. However, pre-treatment with oxyresveratrol significantly inhibited the expression of IL-6 and IL-8 at both the mRNA and protein levels. The IL-1β mRNA level was suppressed by oxyresveratrol, but the level of secreted IL-1β protein was not detectable using ELISA. The results of the present study indicate that oxyresveratrol is a potential candidate for use as an anti-periodontitis agent because of its anti-bacterial activity against the main oral pathogens related to periodontal disease and its anti-inflammatory activity in LPS-stimulated hPDL cells.