Citrus Hystrix Oil Incorporated into Cosmetic Formulation: Physicochemical, Stability and Antimicrobial Properties

Abstract

This study explores the incorporation of Citrus hystrix oil (CHO) into cosmetic formulation as natural alternative to synthetic additives due to its antioxidant, antimicrobial and anti-inflammatory properties. The peel of Citrus hystrix fruit was extracted by using hydrodistillation method and the bioactive components were identified by GC-MS. The CHO was incorporated into cosmetic formulation at different amount (0.1, 0.2, 0.3 and 0.4%). FTIR analysis revealed the successful incorporation of CHO into the cosmetic formulation. The formulation containing 0.4% CHO exhibited the highest total phenolic content which was 163.63 mg GAE/mL, confirming its superior antioxidant potential. The cosmetic formulation incorporating CHO shows improved physicochemical properties. The shear stress trends demonstrate shear-thinning properties, confirming the desirability for cosmetic application. The increase of spreadability over time reflects that the formulation can easily spread which offers smooth coverage and fast absorption on skin. In addition, stability studies for 8 weeks show that the formulations containing CHO maintained the pH, weight and moisture content with minimal variation, suggesting enhanced stability. The antimicrobial activity against Escherichia coli shows the inhibition zone increased with the increasing of CHO, ranging from 6.0 mm to 15.7 mm, validating the efficacy of CHO. Overall, the findings of this study demonstrate that CHO enhances physicochemical, stability and antimicrobial activity of the cosmetic formulation, confirming its viability as a safer, effective and sustainable additive for natural skincare products.