Physical properties and antibacterial activity of herbal tinctures of calendula (Calendula officinalis L) and cashew tree (Anacardium occidentale L)

ABSTRACT

Objective: To evaluate in vitro the pH, Brix and antibacterial activity of herbal tinctures of calendula (Calendula officinalis L.) and cashew tree (Anacardium occidentale L.) against the following bacterial strains Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 10557), Streptococcus salivarius (ATCC 9758), Enterococcus faecalis (ATCC 29212) and Eikenella corrodens (ATCC 23834). Material and Method: The strains were reactivated in agar Brain Heart Infusion (BHI) and seeded in blood agar with BHI. Susceptibility tests were performed and the strains were incubated in microaerophilia (37 °C) for 48 h. Chlorhexidine at 0.12% was used as a positive control and distilled water as a negative control. Dilution of the tinctures was carried out from 11 (pure form) to 164 in alcohol 70%, which is found in their composition, in order to evaluate a possible influence of alcohol on the antibacterial activity of the tinctures. O Bx readings were made by refractometry using an Abbe refractometer and the pH was measured using a digital pH meter. Results: The calendula tincture had pH=5.43 and 18 °Brix and cashew tree tincture had pH=7.2 and 17 °Brix. The cashew tree tincture did not presentantibacterial activity against S. oralis, but it inhibited the growth of all other bacteria up to the 164 dilution. The calendula tincture presented antibacterial activity against S. oralis up to 116 dilution (6.5 mm halo diameter); against S. mutans and S. salivarius up to 132 dilution (7 and 7.5 mm halo diameter, respectively); and against E. faecalis and E. corrodens up to 164 dilution. Alcohol 70% did not show any antibacterial activity against the bacterial strains. Conclusion: The tinctures of calendula and cashew tree have soluble solids, have different pH values and present a significant antibacterial activity against several bacterial strains, except for the cashew tree tincture against S. oralis, which was ineffective...