Nutmeg Seed Essential Oil Hand Cream: Formulation and In Vitro Antibacterial Activity Against Staphylococcus aureus

The skin of the palms is easily exposed to chemicals and microorganisms, making it prone to dryness, irritation, and infection, including Staphylococcus aureus. Excessive use of alcohol based hand sanitizers may worsen skin dryness, so an alternative hand cream with antibacterial properties is needed. This study aimed to formulate nutmeg seed essential oil into a hand cream, evaluate its physicochemical characteristics, and assess its in vitro antibacterial activity against S. aureus. This experimental study used essential oil concentrations of 5.0% (F1), 7.5% (F2), and 10.0% (F3); a formulation without oil (F0) was the negative control. Evaluations included organoleptic characteristics, homogeneity, emulsion type, pH, viscosity, spreadability, adhesiveness, freeze-thaw cycling, and hedonic tests. Antibacterial activity was evaluated by agar well diffusion (three technical replicates from one formulation batch) and analyzed using One-Way ANOVA and Tukey HSD. All formulations were homogeneous, semisolid oil-in-water (O/W) emulsions without phase separation after three freeze-thaw cycles. The pH values (6.56–7.64) did not meet the recommended skin pH range of 4.5–6.5, whereas viscosity (17,333.33–34,000.00 cPs), spreadability (6.25–6.90 cm), and adhesiveness met the reference requirements. Mean inhibition zones increased with oil concentration: 4.33 mm (F1, weak), 10.00 mm (F2, moderate), and 10.83 mm (F3, strong), versus 12.00 mm for the positive control (gentamicin 0.1% cream). ANOVA showed a significant difference among groups (F = 35.679; p < 0.001); F2 and F3 did not differ significantly from each other (p = 0.954) or from the positive control (p = 0.498 and 0.864). Nutmeg seed essential oil can be formulated into a hand cream that was physically stable under the freeze-thaw conditions tested and showed in vitro antibacterial activity; F2 (7.5%) was the most efficient concentration. These findings are preliminary: one bacterial strain and one batch were used, and irritation, moisturizing efficacy, and long-term stability were not evaluated.