Chemical composition and antibacterial activity of <i>Pogostemon cablin</i> Benth., <i>Piper betle</i> L., and <i>Syzygium aromaticum</i> L. leaves essential oils as bioadditives in solid bath soap

Essential oils have been recognized as effective bioadditives in soaps. This study was performed to isolate essential oils from patchouli (<i>Pogostemon cablin</i> Benth.), green betel (<i>Piper betle</i> L.), and clove (<i>Syzygium aromaticum</i> L.) leaves, identify their chemical components (using the GC-MS method), and test their antibacterial activity against <i>Staphylococcus aureus</i> ATCC 25923, primarily to find out the most optimum formula for good quality solid soaps with the most effective antibacterial activity. Quality test was done by considering parameters: transparency, water content, pH, foam stability, and saponification number. The research found that patchouli, green betel, and clove leaves essential oils contain 19, 30, and 9 compounds, respectively, with the main components being patchouli alcohol (37.47%), β-caryophyllene (13.13%), and eugenol (79.42%), each type of essential oil gave different color and scent, and all variants of soap had good quality. Against <i>S. aureus</i> ATCC 25923, the base soap’s antibacterial activity had a zone of inhibition of 9.67 mm, thus categorized as moderate. Soaps with the addition of patchouli, green betel, and clove leaves essential oils, each 3%, were confirmed having the highest level of antibacterial activities, with zones of inhibition of 15.20 mm, 13.52 mm, and 15.85 mm, respectively (strong). Based on these findings, the addition of patchouli, green betel, and clove leaves essential oils can be recommended for good quality antibacterial solid bath soaps.