Extraction of saponin from Gleditsia sinensis Lam and applications on natural shampoo

Synthetic shampoos that include several chemical components are available in the market. However, the safety and impact of chemical additives are under discussion, because their long-term use may result in hair dryness, scalp irritation, and hair loss. To develop a formulated shampoo as an alternative to synthetic shampoos, this study focused on fabricating a completely natural shampoo comprising Gleditsia sinensis Lam extract (GSW) and Sapindus mukurossi extract (SMW), Gleditsia polysaccharides (SP), cod skin collagen peptide (CSCP), and an essential oil. The influence of the interaction between GSW and SMW, SP, and CSCP components on the foaming performance was investigated using the Ross–Miles method, and the antioxidant activity was analyzed using free radical scavenging. The formulated shampoos were prepared using low-energy emulsification, and their surface tensions were determined using the Wilhelmy plate method. The antibacterial and antifungal activities of the shampoos were revealed by determining the minimum inhibitory and bactericidal concentrations. An interaction assay showed that GSW and SMW exhibited synergistic effects on foaming performance, and SP showed an improved foam stability of GSW. In addition, the antioxidant properties of the mixture (GSW and CSCP) exhibited cooperation. Finally, the optimal formulation of shampoo was GSW (20 wt%) and SMW (20 wt%), CSCP (0.5 wt%), and SP (2 wt%). The shampoo exhibited good foaming performance and decontamination and strong antioxidant, antibacterial, and antifungal activities.