Changes of Phenolic Profiles, Bioaccessibility, and Antioxidant Performance of Areca catechu L. Extracts During In Vitro Digestion

Areca nut (Areca catechu L.), an economically vital tropical fruit in China, generates substantial agricultural waste with untapped bioactive potential. This study provides new insights into the impacts of in vitro digestion on the phenolic components, bioactivity, and bioaccessibility of extracts from the areca nut fruit (ANF), husk (ANH), and seed (ANS) of areca nut. Remarkably, the ANS extract showed the highest total phenolic content (TPC, 497.99 ± 2.35 mg GAE/g extract DW) and total flavonoid content (TFC, 1341.08 ± 25.15 mg RE/g extract DW), significantly surpassing other samples both before and after in vitro digestion. Areca nut seed extract revealed the strongest antioxidant activity following intestinal digestion. The bioaccessibility of areca polyphenols increased after in vitro digestion, and flavonoids from the extract exhibited significantly higher bioaccessibility (62.23%–73.27%) compared to total phenols. The phenolic profile revealed that flavonoids accounted for the largest proportion, followed by phenolic acids. Importantly, the majority of the identified polyphenols (on average, 26 out of 33 per part) were significantly upregulated during gastrointestinal digestion. The results reveal that areca nuts, particularly the seeds, are a valuable source of bioactive compounds, highlighting their potential as bioactive ingredients for functional food or nutraceutical applications.