DESIGN, DEVELOPMENT AND ANTIBACTERIAL EVALUATION OF A POLYHERBAL SOAP INCORPORATING CALENDULA OFFICINALIS, DAUCUS CAROTA AND CITRUS SINENSIS PEEL EXTRACTS

Abstract

Plant-based ingredients are increasingly being investigated for incorporation into topical formulations because they provide a diverse range of naturally occurring phytoconstituents. A combination of botanicals with complementary phytochemical profiles may provide additional functional properties in personal-care preparations. The present study aimed to develop a polyherbal soap incorporating extracts of Calendula officinalis, Daucus carota and Citrus sinensis peel and to evaluate its physicochemical properties and antibacterial activity. The selected plant materials were shade-dried, powdered and extracted separately using 70% ethanol by maceration. Preliminary phytochemical screening was performed to identify major classes of secondary metabolites. The extracts were incorporated into a soap base prepared by saponification using coconut oil, olive oil, almond oil and potassium hydroxide. The prepared formulation was evaluated for color, odor, appearance, pH, foaming behavior, foam retention, moisture content and preliminary skin irritation. Antibacterial activity was investigated against Staphylococcus aureus ATCC 12598, Escherichia coli ATCC 25922 and Staphylococcus epidermidis ATCC 25175. Minimum inhibitory concentration (MIC) was also determined using Medimix soap as reference standard. The finished soap showed a smooth, solid and opaque appearance with a yellowish-brown color and pleasant odour. Its pH was 7.96, foam retention was approximately 10 min and moisture content were 13%. No visible irritation was observed during the preliminary irritation assessment. At the highest tested concentration, inhibition zones of 30, 28 and 42 mm were obtained against S. aureus, E. coli and S. epidermidis, respectively. The corresponding MIC values were 485.082, 550.216 and 600.096 µg/mL The findings support further investigation of this plant combination as a potential botanical cleansing formulation.