Optimization of the Extraction Process of Triterpenoids from the Seeds of Syzygium jambos L. Alston by Response Surface Methodology and Its Antioxidant Activity

In this study the single factor experiments were employed to determine the effects of various factors on extraction rate of triterpenoids in the seeds of S. jambos L. Alston using the yields as indicator. Then Box-Behnken design and response surface methodology were employed to optimize the extraction process using the Design-Expert 12 software. Moreover, the antioxidant activity of triterpenoids in the seeds of S. jambos L. Alston was evaluated by determining the scavenging capacity of DPPH and ABTS free radical. The results showed that the optimal conditions were as follows: Methanol concentration 44.30%, solid-liquid ratio 1:47.18 g/mL, extraction time was 101.07 min (adjusted to 101 min in the experiment). Under these conditions, the deviation between the experimental extraction yield value (12.11 mg/g) and the predicted value (12.28 mg/g) of triterpenoids in the seeds of S. jambos L. Alston was only 1.26% (<5%), and the error was small. The IC₅₀ values of scavenging rates on DPPH and ABTS free radicals were 24.93 and 12.16 μg/mL, respectively. The antioxidant activity showed a certain dose effect relationship with the sample concentration. The results indicated that this optimization test was effective and feasible, and the extracted S. jambos L. Alston triterpenoids had good antioxidant activity in vitro. The present study provides supplement information for the potential use of the seeds of S. jambos L. Alston in food and medicine ingredients.