Abstract

ABSTRACTLiquorice root extract (Glycyrrhiza glabra L.) contains glabridin, an isoflavane as inhibitors of tyrosinase. This enzyme is responsible in melanin synthesis. The aim of this research was to determine the tyrosinase inhibition activity of liquorice root extract and to formulate into a cream with a variety of emulsifier agent glyceryl monostearate. Liquorice root was macerated using ethanol 96%, invitro tyrosinase inhibition assay was conducted using kojic acid as positive control in 96-well plate. The physical quality parameters of the cream were also evaluated. The results showed that liquorice root extract inhibits tyrosinase with the IC50 126.75 µg/mL. Creams containing 1.01% liquorice root extract were yellowish white, aromatics odour, soft texture, homogen and no segregation in O/W emulsion type. It also showed plastic thixotropic rheological property, viscosity of (2800±0.00) – (4000±0.00) Ps, spreadability of (3029.72±0.81) – (3531.79±6.15)mm2, droplet size of (60.00±0.00) – (65.12±0.01)μm, pH of (4.55±0.03)–(4.63±0.04) and inhibited tyrosinase 10.14 - 19.30%. It can be concluded that the formula with 0.1% of glyceryl monostearate was the best formula that conforms physical quality test and potentially to be developed as a skin whitening cream.