Physicochemical and Antibacterial Properties of Myristica fragrans and Syzygium aromaticum Methanolic Extract Soap Formulations

Abstract

The rapid emergence of antimicrobial resistance and the preference of consumers for natural products are driving the exploration of herbal skin care products, including soaps. This study aimed to determine the physicochemical and antibacterial properties of herbal soaps formulated from single and combined methanolic extracts of Myristica fragrans and Syzygium aromaticum. The methanolic extracts of Myristica fragrans (Mf), Syzygium aromaticum (Sa), and a combination (MfSa) were used in the formulation of soaps. Antibacterial activities, minimum inhibitory concentrations, minimum bactericidal concentrations, moisture content (MC), total fatty matter (TFM), iodine value (IV), pH, free caustic alkali (FCA), total alkali content (TAC), and foaming capacity (FC) of the formulae were determined. The MC of the formulations ranged from 22.0% to 39.13%, TFM from 35.3% to 52.2%, IV from 0.57 gI2/100 g to 10.40 gI2/100 g, pH from 10.35 to 10.54, TAC from 5.81 to 6.06, FCA from 0.0406% to 0.03391%, and FC from 20 cm to 15 cm for the extract formulations. The antibacterial activity of Sa (12.0 ± 3.5 mm) against Staphylococcus aureus ATCC 29213 was the greatest, and it had the lowest MIC (2.5 × 10−2 mg/mL), lowest MBC (6.25 × 10−3 mg/mL), and highest activity indices. The MC, TFM, and FC of MfSa were significantly greater than the corresponding values for the non-extract formula. In conclusion, the Sa extract formula was the most potent in terms of antibacterial activity against S. aureus.