Abstract:
This study aimed to identify suitable solvents for extracting Rhinacanthus nasutus leaves with antifungal activity, evaluate the antioxidant activity of the extracts, and develop stable hair care product formulations. R. nasutus leaf extracts were prepared by maceration using ethyl acetate and 95% ethanol as solvents. The results showed that the 95% ethanol extract yielded a higher percentage (8.23% ± 0.81) compared to the ethyl acetate extract (4.24% ± 0.45). LCMS analysis confirmed the presence of flavonoids, steroids, triterpenoids, anthraquinones, lignans, coumarins, benzenoids compounds, and naphthoquinone, consistent with literature reports. For antioxidant activity, the DPPH radical scavenging assay revealed that the 95% ethanol extract exhibited superior antioxidant activity with an IC50 value of 0.25 ± 0.01 mg/ml, whereas the ethyl acetate extract had an IC50 of 0.41 ± 0.07 mg/ml. Evaluation of antifungal activity against Malassezia furfur using the broth microdilution method showed that both ethyl acetate and 95% ethanol extracts had an identical Minimum Inhibitory Concentration (MIC) of 62.5 mg/ml, with ketoconazole serving as a standard control at 0.004 mg/ml. When a 95% ethanol extract of Rhinacanthus nasutus was combined with zinc pyrithione, the minimum inhibitory concentration (MIC) was found to be 8.3 mg/ml, which was identical to that of zinc pyrithione alone. This suggests that the R. nasutus extract does not diminish with the antimicrobial activity of zinc pyrithione. Subsequently, the 95% ethanol R. nasutus extract combined with zinc pyrithione was incorporated into shampoo and hair tonic formulations. Both formulations were subjected to a 6-cycle heating-cooling stability test. The results demonstrated that both the shampoo and hair tonic maintained stable physical characteristics and pH values, without significant changes. The color difference was within an acceptable range. However, the shampoo exhibited a slight increase in viscosity compared to its initial formulation. In conclusion, R. nasutus leaf extract shows promising potential for development into hair care products, possessing notable antioxidant and Malassezia furfur inhibitory properties in combination with zinc pyrithione, along with good physical stability.