The Role of Plant Oils in Combating Streptococcal Infections: Mechanisms, Efficacy, and Therapeutic Potential

Streptococcal infections, caused by species such as Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus mutans, represent a major global health concern, particularly in the face of rising antimicrobial resistance (AMR). Conventional treatments-including vaccines and antibiotics-are increasingly compromised by factors such as genetic variability, biofilm formation, and drug resistance mechanisms. In this context, plant-derived oils emerge as promising alternatives due to their broad-spectrum antimicrobial activity and complex phytochemical profiles that hinder resistance development.This review consolidates current findings on the antimicrobial efficacy of plant oils against streptococcal pathogens, emphasizing their mechanisms of action-disruption of bacterial membranes, inhibition of biofilm formation, and interference with quorum sensing. Essential oils from Thymus vulgaris, Origanum vulgare, Cinnamomum verum, and Eucalyptus spp. exhibit notable activity. The review further highlights the phytochemical composition of these oils, including terpenes, aldehydes, and phenolics, and their synergistic effects, both internally and with conventional antibiotics. Applications in topical formulations, oral hygiene products, and advanced delivery systems such as nanoemulsions are explored, alongside cytotoxicity, allergenicity, and environmental sustainability considerations. Despite their potential, plant oils face challenges such as variability in chemical composition and limited clinical validation. Future directions call for standardization, advanced delivery methods, expanded toxicological studies, and sustainable production practices. Overall, this review explores plant oils as natural, effective, and sustainable alternatives to combat streptococcal infections, particularly in the era of escalating antibiotic resistance.