Comparative antisickling and antioxidant activities of Pseudobombax ellipticum cultivars in relation to their...

Pseudobombax ellipticum is native to South America and is cultivated worldwide mostly for its medicinal benefits. The plant is used traditionally in respiratory disorders such as dry cough, in the treatment of fever and stomach pain, and as an antimicrobial and analgesic. The antisickling and antioxidant effects of the flowers of P. ellipticum (Kunth) Dugand (red) and P. ellipticum cultivar alba (white) were compared using an in vitro assay in 2% sodium metabisulfite sickling induction model, DPPH, and metal chelation assays. Both red and white flowers exhibited antioxidant and antisickling activities. In DPPH assay, lower IC₅₀ (34.89 ± 0.98 and 53.28 ± 1.14 μg mL^-1) in red and white flowers respectively were detected relative to Trolox as a positive control (56.82 ± 0.87 μg mL^-1). Comparable metal chelation activity (81.4 and 77.8 μM EDTA equivalent/mg) was detected in red and white flowers of both cultivars respectively. The average readings of the "reversal of sickling test "revealed a decrease in sickling percent from 49% to 15% in red flowers and to 18% in white flowers. Also, polymerization inhibition rate was increased from 0.34 to 1 and to 0.92 in red and white flowers respectively. Total phenolics, flavonoids and anthocyanins were quantified in red and white flowers as (163.9, 43.13 mg gallic acid equivalent/g extract), (71.92, 34.5 mg rutin equivalent/g extract) and (127.0, 85.9 mg pelargonidine-3-mono glucoside equivalent/kg extract), respectively. Liquid chromatography mass spectrometry (LC-MS) analysis was further employed for detection and identification of anthocyanins in flower extracts. Eight new anthocyanins were identified for the first time in genus Pseudobombax. These results reveal the potential role for both red and white flower extracts as possible antisickling agents in sickle cell anemia management.