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Preliminary antioxidant activity analysis of Brazilian pepper tree (Schinus terebinthifolius) extracts via TLC, FRAP, and DPPH
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1  School of Science, Technology and Engineering Management, St. Thomas University, Miami Gardens, FL 33054, USA


Medicinal plants continue to attract increasing attention because of their potential benefits in the field of medicine and pharmacology. Recently, the study of antioxidant levels in plants has received a great deal of attention because it is widely believed that increased oxidative stress and free radical levels in the body lead to the progression of any diseases. In the present study, Schinus terebinthifolius (Brazilian Pepper Tree) extracts were evaluated for antioxidant activity using free radical scavenging activity, and ferric reducing power. The plant was collected in the organic garden at St. Thomas University and the extracts were prepared by maceration of three parts of the plants, the leaves, the berries, and the bark. The extracts were made using varying proportions of ethanol and hexane solvents. All the samples were analyzed using thin layer chromatography (TLC). Multiple extract samples were submitted to DPPH (2,2-diphenyl-1- picrylhydrazyl) assay to determine the free radical scavenging (FRS) capacity, and absorbance was read at 517 and 520 nm in a plate reader. A control sample was prepared containing the same volume of solvent and DPPH without any extract and reference ascorbic acid. Percent scavenging activity of the DPPH free radical is expressed as an ascorbic acid (AA) equivalent antioxidant capacity (mg AA/100g). A Ferric reducing anti-oxidant power assay (FRAP) was performed and absorbance was measured at 700 nm to quantify the total antioxidant activity. FRAP and DPPH assays indicated that the bark has significantly higher free radical scavenging ability than any other part of the plant. Ethanol was optimal for extracting and preserving the plant’s active compounds. Cytotoxicity assay on chemical extracts were tested on breast cancer cells, and methylthiazol tetrazolium (MTT) assays were used to quantify cytotoxicity. Preliminary data indicated the extracts were not cytotoxic at the concentrations tested.

Keywords: medicinal plants, antioxidant levels, chromatography, free radical scavenging, cytotoxicity