Henna is a plant that has been used traditionally for coloring nail, skin, and hair, and as medicinal plant. The supercritical fluid technology offers a considerable promise as extraction media due to its advantages over other conventional extraction techniques. The extraction of volatile components from flowers of henna was studied using supercritical carbon dioxide at temperatures and pressures ranging from 35 to 55°C and 80 to 120 bar, respectively. A maximum extraction yield of 31 % from 2g of henna flowers was obtained at 45 °C and 120 bar. The composition of the extracts was investigated by gas chromatography technique. Furthermore, the extracts were tested for their antibacterial and antioxidant activities. No inhibition zone was observed in the antibacterial study; however, the extracts obtained at most of the extraction conditions exhibited antioxidant activity.
A mathematical model of the extraction curve based on mass transfer principles was developed at all extraction conditions. Powell optimization method was used to obtain the model parameters by adjusting to experimental results. The calculated extraction yields were in good agreement with experimental results
