Bioactive Composition, Antioxidant, and α-Glucosidase Inhibition of Edible Areca catechu Waste Seed

In view of the problem that edible Areca catechu seeds treated as waste and cannot be massively used after processing, in this study, the waste seeds after edible Areca catechu processing (PAS) are used. 75% ethanol extract of PAS (processed seed extraction, PSE) was extracted assisted by ultrasonic with a 75% ethanol solution as the extraction solvent. The contents of total polyphenols, total flavonoids and proanthocyanidins in the PSE were determined. Three methods (radical scavenging activities and Fe³⁺ reduction) were used to evaluate the antioxidant activity of PSE. Then the inhibitory of PSE on the activity of α-glucosidase was studied. The result showed that PSE was rich in polyphenols and flavonoid. The total contents of polyphenols, flavonoids and proanthocyanidins were (127.29±5.16) milligram gallic acid, (421.84±13.82) milligram rutin, and (87.83±6.60) milligram epicatechin in per gram of PSE, respectively. PSE contains 44 flavonoids were detected in PSE, in which the relative content of catechins was up to 77.27%. The IC₅₀ for scavenging DPPH free radical and ABTS⁺ free radical of PSE were (310.10±0.62) and (150.10±11.57) μg/mL, respectively. In addition, PSE had significant inhibitory effect on α-glucosidase, and its ability to inhibit α-glucosidase (IC₅₀=(90.10±1.89) μg/mL) was significantly stronger (P<0.05) than acabosose as a positive control (IC₅₀=(453.60±4.02) μg/mL). Therefore, it is necessary to recycle the PAS.