Abstract Free radicals are highly reactive unstable molecules, which can be synthesized in different ways, considered harmful and threatening to humans; these chemical species have free traffic throughout the human body, interacting with biological molecules and human body organ tissues. The interaction between free radicals and biological molecules is the main factor for disease development or pre-existing disease symptoms aggravation. Antioxidants are chemical compounds able to donate electric charge to stabilize molecules such as free radicals. Recent studies have proved the benefits of antioxidants intake in health improvement. In this way, the search for natural sources of antioxidants has become an ascending trend. In this field, the microbial sources are considered poorly explored compared to the numerous amount of other compounds obtained from them, especially from Actinobacteria. The searched literature about Actinobacteria highlights an important capacity of producing natural antioxidants; however, there is a lack of in vivo studies of these isolated compounds. In this review, we gathered information that supports our point of view that Actinobacteria is a truly renewable and superficially explored source of natural antioxidants. Furthermore, our purpose is also to point this limitation and stimulate more researches in this area.

Abstract: Currently, the research of new natural compounds with biological potential demonstrates great ethnopharmacological importance. In this study, we evaluated the biological properties promoted by saline extract from Malpighia emarginata DC leaves, whose objective is to evaluate the antioxidant, antimicrobial and cytotoxicity potential. Phytochemical characterization was performed by UPLC-MS chromatography to identify the chemical compounds. For the antioxidant potential, DPPH, ATT and FRAP methods were used. The antibacterial and antifungal tests were performed evaluating the MIC50, MIC90, CMB and CMF parameters. Moreover, antibiofilm action was evaluated. Cytotoxicity and proliferation were performed using splenocytes from Balb/c mice and were evaluated by cytometry. We found a list of phenolic compounds among other bioactive compounds in the M. emarginata saline extract. In addition, higher antioxidant profile and antifungal activity against different strains of Candida spp. was promoted by the saline extract. Splenocytes showed greater cell viability (more than 90%) and showed higher proliferate index in 24 and 48 hours of incubation with the extract. Saline extract from Malpighia emarginata DC has potential action like antioxidant and antifungal agent without promote animal cell damage.