Antioxidant supplements from natural ingredients can be an alternative to counteract the effects of free radicals. None of the products use a combination of Chrysanthemum indicum and Centella asiatica extracts formulated as antioxidant supplements, particularly in syrup form. To date, sugar has been commonly used as a syrup base. However, honey can also be used as a base for syrups as a sugar substitute, but it has antioxidant activity. This study evaluated the antioxidant activity of honey-based herbal syrup with varying concentrations of Xanthan Gum and Propylene Glycol. This study aims is to asses two Indonesian honeys' antioxidant capacity against Manuka honey as standard. Ceiba honey was selected as the base for herbal syrup due to its superior antioxidant activity. Subsequently, the antioxidant activity of the three active compounds used in the formula was assessed using DPPH, yielding a result of 272.82 ± 5.167 μg/ml, which falls into the weak category. The antioxidant activity of the honey-based syrup remained unaffected by the addition of propylene glycol and xanthan gum. The honey-based syrup was also subjected to a physical analysis, where pourability, density, and viscosity decreased as the composition of xanthan gum decreased compared to propylene glycol. Meanwhile, higher xanthan gum content increased water activity and a darker appearance. The simplex lattice design (SLD) method identified an optimal formulation containing 0.099% xanthan gum and 10.401% propylene glycol. Freeze-thaw stability testing confirmed the honey-based syrup maintained stable physical properties.
