Antioxidant activities and free radical scavenging potential of Bauhinia microstachya (RADDI) MACBR. (Caesalpinaceae) extracts linked to their polyphenol content.

Aqueous and hydro-ethanolic extracts of Bauhinia microstachya leaves (AEBM and HEBM) were investigated for their phenolic content and phytochemical profile (by spectrophotometry and HPLC), and for their antioxidant activities and free radical scavenging potential in different in vitro systems (TRAP, TEAC, TBARS, nitric oxide, superoxide and hydroxyl radical). HEBM presented a 27.4% higher content of phenolics when compared to AEBM and a distinct phytochemical profile was observed. Our work suggests that both extracts have potent antioxidant activities and that their antioxidant capacity and efficiency vary according to the radical-generating system. In general, HEBM was more effective than AEBM in avoiding ROS-generating damage and in scavenging the various radicals formed. Nevertheless, when results were normalized to total phenolic content, a different profile of antioxidant activities and free radical scavenging potential was observed, particularly against oxidative lipid damage and superoxide radical. B. microstachya extracts may be considered an interesting source of natural antioxidants as well as other phenolic-rich plants.