Anthocyanidins are a class of flavonoid compounds found in many fruits and vegetables, particularly those with red, blue, or purple pigmentation (such as berries, grapes, and red cabbage). Their use in supporting or treating gingivitis is primarily based on their well-documented antioxidant and anti-inflammatory properties. Several in vitro and animal studies have demonstrated that anthocyanidins and their glycoside forms (anthocyanins) can inhibit the production of pro-inflammatory cytokines, reduce oxidative stress, and modulate pathways involved in the inflammatory response associated with periodontal diseases, including gingivitis.

A small number of human clinical studies have investigated the effects of anthocyanin-rich extracts (e.g., from cranberries, blackcurrants, or blueberries) on oral health. These studies suggest that such extracts may reduce plaque accumulation, decrease gum bleeding, and improve markers of gingival inflammation, possibly due to their ability to inhibit the growth of pathogenic oral bacteria and interfere with bacterial adhesion to tooth surfaces. However, most of this evidence is preliminary and often based on small sample sizes or short intervention periods. There is not yet robust, large-scale clinical trial data to fully validate the efficacy of isolated anthocyanidins for gingivitis treatment.

In summary, there is scientific rationale and some early supportive evidence for the use of anthocyanidins to help manage gingivitis, but the body of evidence remains limited. Therefore, the strength of the evidence currently rates as modest.