The potential use of Origanum majorana L. as a source of bioavailable phenolic compounds, specifically rosmarinic acid (RA), has been evaluated. Phenolic bioavailability was tested using an in vitro digestion process followed by a Caco-2 cellular model of intestinal absorption. The high-performance liquid chromatography-photodiode array detector-tandem mass spectrometry (HPLC-PAD-MS/MS) analysis showed the main components in the extract were 6-hydroxyluteolin-7-O-glucoside and rosmarinic acid, followed by luteolin-O-glucoside. After digestion process, the amount of total phenolic compounds (TPC) only decreased slightly, although a remarkable reduction in RA (near 50%) was detected. Bioavailable fraction contained 7.37 ± 1.39 mg/L digested extract of RA with small quantities of lithospermic acid and diosmin and presented an important antioxidant activity (0.89 ± 0.09 mmol Trolox/L digested extract). Besides, this bioavailable fraction produced a significant inhibition in TNF-α, IL-1β, and IL-6 secretion, using a human THP-1 macrophages model. Therefore, RA content in the basolateral compartment could play an important role in the antioxidant and anti-inflammatory activities found.