Biological Activities of Citrus hystrix Leaf Essential Oil: Extraction and Application in Health Care Products

Abstract This study investigated the extraction, biological activities, and potential applications of kaffir lime ( Citrus hystrix DC.) leaf essential oil in health care products. Steam distillation conducted with a 1:17 ratio of plant material to water produced an essential oil yield of 0.72 ± 0.06%. GC-MS analysis revealed citronellal (87.9%) as the dominant component, followed by citronellol (9.4%), linalool (1.2%), and several minor compounds. The essential oil exhibited strong anti-inflammatory activity, with an IC 50 of 1.75 µg/mL, outperforming dexamethasone. Antibacterial assays showed inhibitory effects against Gram-positive bacteria: Staphylococcus aureus (MIC = 13.76 mg/mL), Propionibacterium acnes (MIC = 3.44 mg/mL), and Streptococcus mutans (MIC = 6.88 mg/mL), while no activity was observed against Escherichia coli . No antifungal activity was found against Malassezia furfur . Based on these findings, the essential oil was formulated into soap for treating folliculitis and into an antibacterial spray for oral care. The results highlight the potential of kaffir lime essential oil as a natural, effective, and sustainable ingredient for personal care formulations.