D-optimal Design Optimization of Solvent Mixture for Flavonoid Extraction from Phalaenopsis Leaves with Antioxidant Activity

Aims: This study aimed to optimize the extraction of flavonoids and antioxidants from Phalaenopsis leaves by using solvent mixtures.

Method: The total flavonoid content (TFC) and antioxidant activity were evaluated using the colorimetric method and ferric-reducing antioxidant power (FRAP), respectively. Maceration extracts from fresh leaves were used for the analysis. The study used the Design Expert 13.0 program to optimize the solvents (water, acetone, and methanol) and their combined ratio.

Result: The results showed that 100% acetone was the best solvent for both responses, with a desirability value of 0.884, TFC of 0.434 mg QE/g fresh weight (FW) and FRAP of 713.53 μmol TE/g FW. Screening of the most potent Phalaenopsis genotypes for obtaining the most active leaf extract showed that P. amboinensis and P. pantherina were the best genotypes for TFC (0.786-0.797 mg QE/g FW) and FRAP activity (862.25-891.48 μmol TE/g FW).

Conclusion: This study demonstrates an easy and useful way to obtain flavonoids and antioxidants from Phalaenopsis materials that can be used in the flower-based industry to make new functional ingredients.