Abstract:

Through single factor experiment and L9(34) orthogonal test, the extraction process of volatile oil from flower of S. miltiorrhiza. by steam distillation was optimized and the effects of different extraction solutions, soaking time, extracting time, and solidtoliquid ratio on the yield of the volatile oil from the flower of S. miltiorrhiza. were investigated. The antioxidant capacity of volatile oil from S. miltiorrhiza flower was evaluated by DPPH method, and the free radical scavenging capacities of volatile oils from different extraction solutions  were compared. The results showed that the primary factors affecting the yield of volatile oil from S. miltiorrhiza flower were distillation time, followed by solidliquid ratio and soaking time. The optimum extraction conditions were as follows: saturated sodium chloride solution, soaking 6 hours, extracting 8 hours, solidtosolvent ratio 1∶18(g/mL). Under this condition, the extraction rate of volatile oil from flower of S. miltiorrhiza was 0.0935%. The DPPH assays showed that volatile oil from flower of S. miltiorrhiza has significant antioxidant capacity. In a certain concentration range, antioxidant capacity was positively correlated with the concentration of volatile oil from flower of S. miltiorrhiza. In the DPPH assays, the IC50 values of volatile oil extracted by four kinds of extraction solution (distilled water, saturated sodium chloride solution, aqueous sulfuric acid of pH=1, saturated sodium chloride and aqueous sulfuric acid of pH=1) were 1.07, 1.03, 1.45 and 1.40 mg/mL, respectively. The results showed that the optimized extraction process of volatile oil from flower of S. miltiorrhiza was stable and practicable.

Key words: volatile oil, extraction process, antioxidant activity, flower of S. miltiorrhiza, DPPH