S mitis

Authentic P. elliottii (batch number 21811-09) and P. tropicalis (batch number 20511-09) resin samples were obtained from the Brazilian Association of Resinators (ARESB), located in the city of Avaré – SP, Brazil. DHA was isolated from the P. elliottii resin and was obtained by the method previously described by Leandro et al. (2014) (link) (Supplementary Figures S1, S2).
The following bacteria from the American Type Culture Collection (ATCC) collection were used to conduct the antibacterial assays: S. mutans (ATCC 25175), S. mitis (ATCC 49456), S. sanguinis (ATCC 10556), S. sobrinus (ATCC 33478), S. salivarius (ATCC 25975), Lactobacillus casei (ATCC 11578), and Enterococcus faecalis (ATCC 4082). These microorganisms were maintained in a freezer at −80°C in 20% glycerol solution in the Laboratory of Applied Microbiology Research (LaPeMA) – University of Franca (Unifran).

Standard strains were used for evaluating species specificity of the PCR amplifications and as controls in the bile solubility test. These strains were S. oralis ATCC 35037, S. parasanguinis ATCC 15912, S. gordonii ATCC 33399, S. mitis ATCC 49456, S. constellatus ATCC 27823, S. mutans ATCC 25175, S. sanguinis ATCC 10556, S. intermedius ATCC 27335, S. sobrinus ATCC 33478, S. anginosus ATCC 33397, S. vestibularis ATCC 49124, S. salivarius ATCC 25975, S. cristatus ATCC 51100, S. infantis ATCC 700779, S. pseudopneumoniae ATCC BAA-960, and S. pneumoniae ATCC 10813.

OSCC cell lines CAL27, SCC4 and SCC25 were acquired from the American Tissue Culture Collection (ATCC), certified as mycoplasma-free and STR-authenticated. The cell lines were grown in 5% CO₂ at 37°C in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 2.5 mM L-glutamine (CAL27) or a 1:1 mixture of DMEM and Ham’s F12 medium containing 2.5 mM L-glutamine, 400 ng/ml hydrocortisone and 10% FBS (SCC4 and SCC25).
Bacterial strains S. mitis ATCC 49456, N. flavescens ATCC 13120 and P. gingivalis ATCC 33277 were obtained from ATCC whereas H. parainfluenzae NCTC 10665 was obtained from Public Health England. P. gingivalis was included as a pathogenic control given existing evidence on its carcinogencity [2 ,3 (link)]. Brain Heart Infusion (BHI) supplemented with 0.5% hemin, 0.1% Vitamin K and 1% Isovitalex was used as a culture medium for all bacteria. The health-associated strains were grown at 37°C in 5% CO₂; P. gingivalis was grown at 37°C in anaerobic conditions (10% hydrogen, 10% CO₂, and 80% nitrogen).

The following strains commonly present in the oral microbiome (Aas et al., 2005 (link); Maddi and Scannapieco, 2013 (link); Loozen et al., 2014 (link)) were obtained from the American Type Culture Collection (ATCC): A. actinomycetemcomitans (ATCC 43718), F. nucleatum (ATCC 10953), P. gingivalis (ATCC 33277), P. intermedia (ATCC 25611), S. mutans (ATCC 25175), S. sobrinus (ATCC 33478), T. forsythia (ATCC 43037), Actinomyces naeslundii (ATCC 51655), Capnocytophaga sputigena (ATCC 33612), Streptococcus gordonii (ATCC 49818), Actinomyces viscosus (ATCC 15987), and S. mitis (ATCC 49456). Veillonella parvula was obtained from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (DSM 2007); S. sanguinis was acquired from the BCCM/LMG Bacteria Collection (LMG 14657). S. salivarius strain TOVE-R (Tanzer et al., 1985 (link)) was utilized. Bacterial strains were classified as either commensal (indigenous), potentially health-associated or disease-associated, as indicated in Table 1.