Six Algerian plants: Phenolic profile, antioxidant, antimicrobial activities associated with different simulated gastrointestinal digestion phases and antiproliferative properties

Mediterranean countries, including Algeria, have medicinal plants used in folk medicine, such as Artemisia campestris L., Artemisia herba-alba Asso, Juniperus phoenicea L., Juniperus oxycedrus L., Mentha pulegium L., and Lavandula angustifolia Mill. It is noteworthy that the bioaccessibility of their polyphenolic ingredients have not been critically evaluated before. The bioactive properties of the aqueous extracts of Artemisia campestris L., Artemisia herba-alba Asso, Juniperus phoenicea L., Juniperus oxycedrus L., Mentha pulegium L., and Lavandula angustifolia Mill. were investigated. They were subjected to a simulated gastrointestinal digestion to evaluate the antioxidant, antimicrobial activities and total polyphenol contents. Their antiproliferative activities against three human cancer cell lines (MCF-7, T47D, and Caco-2) were also performed using the aqueous extracts. The phenolic profile was also studied by reversed-phase high-performance liquid chromatography coupled to ultraviolet spectrometry detector (RP-HPLC-UV). The results indicated that bioaccessibility of total phenolic compounds after the post-gastric, intestinal, and colon phases was in the ranges of 4.34–11.57 %, 0–0.55 %, and 3.92–9.24 %, respectively when compared with their aqueous extracts. Intestinal and colon phase samples collected from intestinal digestion of six plant extracts did not have any antioxidant activity. Juniperus spp. extracts had the highest antiproliferative activity compared to the results obtained from other tested species. The high antioxidant and cytotoxic activities of Juniperus samples may be attributed to the higher levels of total phenols, as well as the catechins, rutin and caffeic acid, whilst M. pulegium extract with the lowest phenolic content and lower amounts of these metabolites, having p-coumaric acid as a predominant phenolic compound, was shown to be less effective as an antioxidant and anticancer agent.