Abstract:
Wolffia arrhiza L., also known locally as 'phaam' in Thailand, contains proteins, essential amino acids, unsaturated fatty acids, vitamins, minerals, carotenoids, phytosterols, and high levels of flavonoids. This study aimed to prepare extracts from Wolffia arrhiza L. using green extraction methods and to evaluate the protein content, phenolic compounds, and antioxidant activity of duckweed extracts for cosmetic applications. Wolffia arrhiza L. was extracted using cellulase-assisted extraction compared to a conventional method using 70% ethanol. Protein content, total phenolic content, flavonoid content, and antioxidant activities of the extracts were analyzed. The extract obtained using cellulase at a concentration of 5 units/mL yielded the highest protein content at 54.25 ± 0.74 mg BSA/g extract, which was significantly higher than the other extraction methods (p < 0.05). This indicates that cellulase-assisted extraction enhances protein yield. For antioxidant activity measured by the DPPH assay, the filtrate extract obtained using cellulase at 15 units/mL showed the highest antioxidant activity at 7.51 ± 0.04 mg TEAC/g extract, significantly higher than the other extracts (p < 0.05). In the FRAP assay, the crude phenolic extract using 70% ethanol and the filtrate extract using cellulase at 15 units/mL showed no statistically significant difference, with values of 56.97 ± 0.86 and 54.92 ± 2.48 mg TEAC/g extract, respectively. The crude phenolic extract obtained using 70% ethanol had the highest total phenolic content at 58.93 ± 1.03 mg GAE/g extract and the highest total flavonoid content at 323.73 ± 1.93 mg QE/g extract. Following that, the filtrate extract using cellulase at 15 units/mL had a total phenolic content of 45.56 ± 0.46 mg GAE/g extract and a total flavonoid content of 86.85 ± 0.16 mg QE/g extract.