Optimization of Extraction Condition for Alisol B and Alisol B Acetate in Alismatis Rhizoma using Response Surface Methodology

Alismatis Rhizoma is a perennial herb originating from the rhizomes of Alisma orientalis (Sam) Juzep and the same species which have been used to treat seborrheic dermatitis, eczema, polydipsia, and pedal edema. We aimed to determine the concentrations of the compounds alisol B and alisol B acetate present in a sample of the herb using high-performance liquid chromatography coupled with a photodiode array detector. We selected methanol as the optimal solvent considering the structures of alisol B and alisol B acetate. We estimated the proportion of alisol B and alisol B acetate in a standard extract to be 0.0434% and 0.2365% in methanol, respectively. To optimize extraction, we employed response surface methodology to determine the yields of alisol B and alisol B acetate, which mapped out a central composite design consisting of 15 experimental points. The extraction parameters were time, concentration, and sample weight. The predicted concentration of alisol B derivatives was estimated to be 0.2388% under the following conditions: 81 min of extraction time, 76% of methanol concentration, and 1.52g of sample weight.