Comprehensive evaluation of physico-chemical, antioxidant, and antimicrobial properties in commercial soaps: A study...

Soap is essentially used for various purposes. Therefore, it is important to determine the physico-chemical, antioxidant, and antimicrobial properties of soaps to evaluate their quality. The present research work focuses on 22 commercial soaps which include bar soaps (SN 1-SN 19) and liquid hand washes (SN 20-SN 22). The values of different parameters for commercial soaps are observed which are between 3.84-83.75 % for moisture content, 6.83-25.16 cm for foam height, 7.01-10.17 for pH, 62.47-91.39 % for total fatty matter, 0.20-1.17 % for total alkali content, zone of inhibition, 17.33-29.27 mm/100 % conc., antioxidant activity, 357.41-777.15 μg/mL. It is observed that all of the soaps have a foam height, and pH within the permitted limit (FH-above 1.5 cm, pH 7-10). All bar soap has a total fatty matter and a total alkali content within the accepted value. Moreover, 8 soaps show antimicrobial properties against Staphylococcus aureus, which were further tested for rapid efficacy and antioxidant properties. A survey report of 22 commercial branded soaps was done on 50 people in Bangladesh to get feedback from customers. Combining all the parameters, SN 3 has good results among bar soaps with mild moisturizing and cleansing properties (MC-8.30 ± 0.035 %, FH-22.33 ± 0.29 cm), is safe for the skin (pH-9.83 ± 0.02, TAC-0.99 ± 0.03), has good TFM values (72.89 %), has proficient bacteria growth-inhibiting properties (ZI-18.67 ± 0.29 mm/100 % conc.) and has the ability to remove free radicals (357.41 ± 2.07 μg/mL). Besides, SN-21 among liquid hand wash soaps possesses overall excellence as it moisturizes skin well (MC-83.75 ± 0.05 %), is almost safe for skin (pH-7.73 ± 0.02, TAC-0.98 ± 0.01 %), has TFM (11.35 %), has good cleansing capacity (FH-22.66 ± 0.58 cm) and bacteria growth inhibiting activity (29.27 ± 0.25 mm/100 % conc.), destroys selected bacteria (MIC - 1.2 × 10⁷ CFU at 1 min and 5.5 × 10⁷ CFU at 10 seconds), and wash away free radicals from skin (420.64 ± 3.62 μg/mL).