Phenolics of Green Pea (Pisum sativum L.) Hulls, Their Plasma and Urinary Metabolites, Bioavailability, and in Vivo Antioxidant Activities in a Rat Model

Increased processing of pulses generates large volumes of hulls, which are known as an excellent source of phenolic antioxidants. However, the bioavailability and in vivo activity of these phenolics are rarely reported. This research was therefore carried out to study the absorption, metabolism, and in vivo antioxidant activities of green pea hull (GPH) phenolics using ultrahigh-pressure liquid chromatography with a linear ion trap-high-resolution Orbitrap mass spectrometry and an oxidative stress rat model. A total of 31 phenolics, including 4 phenolic acids, 24 flavonoids, and 3 other phenolics, were tentatively identified. Ten of these phenolics and 49 metabolites were found in the plasma and urine of rats, which helped to explain the favorable changes by GPH phenolics in key antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and glutathione) and indicators (total antioxidant capacity, malondialdehyde) in the plasma and different tissues of rats. This is the first comprehensive report on dry pea hull phenolics and their bioavailability, metabolic profiles, and mechanisms of in vivo antioxidant activities.