Rhodomyrtus tomentosa-incorporated silicone inhibits planktonic growth and surface adhesion of Staphylococcus spp. and Candida albicans in simulated vaginal fluid

Menstrual cups are increasingly used for menstrual hygiene. However, their use may alter the vaginal microenvironment and increase susceptibility to opportunistic infections caused by Staphylococcus spp. and Candida albicans. The current study aimed to develop an antimicrobial menstrual cup by incorporating silicone with Rhodomyrtus tomentosa (RT) leaf extract, a medicinal plant recognized for its antimicrobial properties. RT-loaded silicone was fabricated using an internal mixer and compression molding at 160 °C for 3 min. Surface roughness and wettability remained unchanged after incorporation. RT-loaded silicone exhibited pronounced anti-planktonic growth and antimicrobial adhesion against single- and dual-species cultures of Staphylococcus aureus, Staphylococcus epidermidis, and C. albicans. The loaded silicone significantly inhibited bacterial growth as early as 1 h after incubation (p < 0.05), with a reduction of > 5 log CFU/mL of pathogens after 12 h. Similar inhibitory activity was observed in experiments conducted in simulated vaginal fluid. Scanning electron microscopy confirmed the strong antimicrobial properties of the RT-loaded material. No cytotoxic effects were detected on fibroblast cells. Importantly, the antimicrobial activity was retained after 12 boiling cycles, indicating good stability. These findings demonstrate the potential of RT-loaded silicone as a promising material for developing safer menstrual cups with enhanced antimicrobial protection.