In vitro Pharmacological Properties and Phenolic Contents of Stem Barks Extracts of Piliostigma reticulatum (DC) HOCHST and Piliostigma thonningii (SCHUM) MILNE-REDH. (Caesalpiniaceae)

Abstract

Aims: This study aimed to investigate the cytotoxic, antioxidant and lipoxygenase inhibition activities of extracts from stem barks of Piliostigma reticulatum and Piliostigma thonningii. Methodology: Methanol extract and decoction from stem barks of P. reticulatum and P. thonningii were evaluated for their lipoxygenase inhibitor effect and antioxidant properties using 2, 2’-azino-bis (acid 3-ethylbenzothiazoline-6-sulfonique (ABTS) and lipid peroxidation. Cytotoxic effect on leukemia cell lines (K562) was evaluated by trypan blue assay. Total phenolic, tannins and flavonoids contents in the extracts were determined with standard methods. Results: P. thonningii and P. reticulatum methanol extracts inhibited lipoxygenase activity with IC50 values of 7.80 ± 0.57 and 12.86 ± 1.47 µg/mL respectively. With ABTS scavenging method,     P. thonningii methanol extract showed the strongest activity with IC50 value of 3.96 ± 0.03 µg/mL, followed by P. reticulatum methanol extract (IC50 = 4.90 ± 0.07 µg/mL). Both decoctions from these plants had scavenged ABTS+ radical. Methanol extracts from P. thonningii and P. reticulatum exhibited significant activity against lipid peroxidation and K562 cells viability. Phytochemical analysis showed the presence of phenolic compounds including tannins and flavonoids in methanolic extracts and decoctions from P. reticulatum and P. thonningii. Conclusion: The extracts from Piliostigma reticulatum and Piliostigma thonningii stem barks exhibited lipoxygenase inhibitor, antioxidant and cytotoxic effects.