The Antiviral Activity of Sandalwood Oil on Human Papillomavirus Type 16 Using a Disc-Based Carrier Assay

Essential oils derived from plants have gained increasing interest in recent years for their potential antimicrobial, antiviral, and disinfectant properties. However, data specifically examining the virucidal efficacy of essential oils against human papillomavirus (HPV), a major human pathogen, remains very limited. In this study, we compared the chemical composition of sandalwood essential oils derived from five different species (Santalum album, S. austrocaledonicum, S. insulare, S. paniculatum, and S. spicatum). We further investigated the ability of S. album sandalwood oil, the species highest in α- and β-santalol content, to inactivate infectious HPV type 16 virions dried onto glass carriers at contact times of 5 and 30 min. HPV-16 is a high-risk HPV type frequently associated with cervical and other cancers. A RT-qPCR assay based on E1^E4 spliced transcript detection was used to measure viral infectivity levels post-treatment. S. album oil exhibited moderate but incomplete virucidal activity, achieving a mean 2.59 log reduction (99.7% inactivation) of HPV-16 after a 30 min contact time. In contrast, the shorter 5 min contact time resulted in negligible reductions in viral infectivity compared to untreated controls. These data suggest that while S. album oil has the ability to inactivate HPV, it requires relatively long contact times to achieve significant reduction.