Ethanol Extract from Astilbe Chinensis Inflorescence Suppresses Inflammation in Macrophages and Growth of Key Oral Pathogenic Bacteria

Abstract

Dysregulation of infection-derived inflammatory responses has been one of the crucial pathological causes of oral diseases. Even though the organic extracts of Astilbe chinensis have been frequently reported to have anti-inflammatory activity, the study on the extract of A. chinensis inflorescence has yet to be reported. Here, we evaluated the anti-inflammatory efficacy of A. chinensis collected from a variety of regions and seasons and successfully demonstrated that GA-13-6, an ethanol extract of A. chinensis inflorescence collected in a flowering season, inhibited the production of inflammatory mediators and proinflammatory cytokines, such as nitric oxide (NO), tumor necrosis factor (TNF), and interleukin-6 (IL-6) and suppressed the expression of cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) both in mRNA and protein levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Importantly, we for the first time confirmed that GA-13-6 efficiently inhibited the growth of Porphyromonas gingivalis, Streptococcus sanguinis, and Streptococcus mutans, showing that GA-13-6 possesses antibacterial activity against these pivotal oral pathogens. Thus, GA-13-6 is a potential active ingredient not only for the treatment or prevention of periodontal and dental diseases but many other inflammation-related diseases.