Reduction of oral pathogens and oxidative damage in the CAL 27 cell line by Rosmarinus officinalis L. and Taraxacum officinale Web. extracts

Abstract

Ethnopharmacological relevance: Dandelion (Taraxacum officinale Web.) and rosemary (Rosmarinus officinalis L.) are treasured botanicals with a long usage history in traditional herbal practices worldwide. Dandelion was used to treat kidney, spleen, and liver disease, as well as cardiovascular disease, diabetes, and bacterial infections, whereas rosemary was used to treat pain, spasms, and to improve blood circulation.

Aim of the study: The aim of this study was to determine the influence of rosemary and dandelion leaves aqueous extracts on the human tongue epithelial carcinoma cell line (CAL 27) at the level of interaction between oral microbiota and tongue epithelial cells, genomic damage, and H₂O₂ - induced oxidative damage protection.

Materials and methods: The polyphenolic composition of the extracts was determined by spectrophotometric and HPLC analyses. After extract treatment, cytotoxic impact and ROS generation in CAL 27 cells were measured using the MTT assay and the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay, respectively. Microdilutions were applied to investigate the antimicrobial and adhesive properties against representatives of the oral microbiota. The single-cell gel electrophoresis (comet assay) and cytokinesis-blocked micronucleus cytome assay (CBMN cyt) were used to detect induced genomic damages.

Results: Both extracts increased the adhesion of the lactic acid bacteria L. plantarum but decreased the adhesion of the bacterial pathogens S. enterica serovar Typhimurium LT21 and E. coli K-12 MG1655 adhesion onto CAL 27 cells. 1 h treatment with 5x concentrated dandelion extract and 1x, 2.5x, and 5x of rosemary extract caused an increase in comet tail intensity. CBMN cyt results demonstrated a significant increase in micronucleus formation even at concentrations several times lower than the usual bioactive compound concentrations found in a cup of beverage, with higher concentrations also inducing cell apoptosis and necrosis. Rosemary extract showed a protective effect against H₂O₂ - induced oxidative damage by decreasing the apoptotic cell number, probably preventing mutations leading to tumor aggressiveness, invasion, and metastasis.

Conclusions: Both tested extracts demonstrated their usefulness in maintaining good oral bacteria balance and their protective capability as powerful antitumor agents by causing a protective apoptotic effect in tumor cell line already at the dosage of an average daily cup.

Keywords: Adhesion; Dandelion (Taraxacum officinale Web.); Human tongue squamous carcinoma cell line CAL 27; Oral microbiota; Oxidative DNA damage; Rosemary (Rosmarinus officinalis L.).