Phytochemical study and antioxidant capacity of three fractions from the stem of Caesalpinia bahamensis Lam

Context: Caesalpinia bahamensis Lam. is a medicinal plant used by the Cuban population to treat renal and hepatic diseases. However, this species lacks scientific studies that support its biological applications. Aims: To evaluate the chemical composition and the antioxidant capacity of fractions obtained from the stem of Caesalpinia bahamensis Lam. Methods: A continuous extraction of the stem was made by maceration using a battery of solvents of increasing polarity: chloroform, ethyl acetate and methanol. All fractions were analyzed by TLC and phytochemical screening. The compounds of the chloroform fraction were identified by GC/MS, while the ethyl acetate and methanol fractions were characterized by UV-Vis spectroscopy. The antioxidant capacity was evaluated by the DPPH and FRAP assays. Results: Ten compounds were identified by GC/MS of the chloroform fraction, associated with fatty acids, terpenoids and phytosterols. The major compounds of this fraction were octacosanol, monopalmitin and palmitic acid. The presence of flavonoids in the ethyl acetate and methanol fractions was demonstrated by phytochemical screening, TLC and UV spectroscopy. The three fractions showed antioxidant capacity in the DPPH assay, with the methanol fraction (IC50=11.1 µg/mL) being the most active. The ethyl acetate fraction (equivalent to 100.7 µmol ascorbic acid) and the methanol fraction (equivalent to 37.3 µmol ascorbic acid) showed antioxidant capacity in the FRAP assay at concentrations of 125 µg/mL and 1000 µg/mL, respectively. Conclusions: The fractions evaluated showed antioxidant capacity in the DPPH and FRAP assays, possibly associated with the presence of phenols and flavonoids.