Chemical profile by GC-MS and protective effect of Algerian cloves (Syzygium aromaticum) against Lactobacillus spp. and Streptococcus spp. isolated from dental caries

The oral cavity is home to a large and diversified microbial flora, which plays an important role in the genesis of multiple diseases, including tooth decay. Indeed, tooth decay is the most common ailment in the world, with almost everyone having experienced it at least once in their lifetime. Examining plants used in traditional medicine is one of the research approaches used to discover novel, potent antibacterial chemicals with a broad spectrum of action, as present antibacterials have significant drawbacks. This study aims to examine the chemical composition of Algerian clove Syzygium aromaticum using GC-MS and to evaluate the antibacterial activity of the methanol extract against bacteria isolated from dental caries caused by Streptococcus spp. and Lactobacillus spp. The results show a strong extraction yield of 29.7%, with high amounts of polyphenols and flavonoids calculated at 178.82 mg GAEQ/g and 24.13 mg QEQ/g. The principal chemical elements of S. aromaticum peel methanol extract were identified as eugenol (61.23%) and eugenol acetate (26.45%) based on mass spectrum data and retention times. The methanol extract has a significant antibacterial effect against tested strains, with MICs ranging from 111.37 to 445.5 mg/mL. Higher concentrations of polyphenols resulted in a significant increase in inhibition zone diameter against S1 (r2 = 0.94, p < 0.001), L3 (r2 = 0.94, p < 0.001), L5 (r2 = 0.93, p < 0.001), and L9 (r2 = 0.96, p < 0.001).