Antibacterial evaluation of guava leaves extract and its effect on reactive oxygen species formed by calcium hydroxide and chlorhexidine mixture

BACKGROUND: Reactive oxygen species (ROS) are formed when mixing calcium hydroxide (CH) with chlorhexidine (CHX). AIM: To analyze the antibacterial efficacy of aqueous (AGL) and ethanolic (EGL) extracts of Psidium guajava leaves against root canal bacteria such as Streptococcus mutans, Staphylococcus aureus, Lactobacillus acidophilus and Enterococcus faecalis, to evaluate the antioxidant potential of the extracts and its ability to counteract the ROS. MATERIALS AND METHODS: Three different concentrations (10%, 25%, and 35%) of AGL and EGL were prepared. The antibacterial efficacy was analyzed using the Kirby-Bauer disc diffusion method. The different concentrations of both AGL and EGL were evaluated for their antioxidant property using ultraviolet spectrometer. Further, the ability of these extracts on neutralizing the ROS formation was analyzed using mass spectrometer. RESULTS: CH and CHX mixture exhibited maximum antibacterial activity followed by the same mixture with 35% EGL. EGL showed greater antioxidant activity than AGL extract at all concentrations. CONCLUSIONS: The addition of natural antioxidants like guava leaves extract decreases ROS formed by CH and CHX mixture.