In‐vitro cytotoxicity of various Siphonochilus aethiopicus (Schweinf.) B.L. Burtt extracts in combination with selected tableting excipients

Objectives To investigate the cytotoxic potential of S. aethiopicus extracts in combination with chitosan and Pharmacel®101, on two cell lines. Methods Extracts were chemically characterised utilising UPLC‐Q‐TOF/MS, followed by determination of cell viability and membrane integrity. Key findings Ethanol (EtOH) and diethyl ether (DiEt) extracts contained significant quantities of all chosen biomarker molecules; however, only two were scarcely quantifiable in aqueous extracts. Aqueous extracts did not induce any cytotoxic effects, whereas EtOH and DiEt extracts caused concentration‐dependent decreases in cell viability and membrane integrity loss in both cell lines. Ensuing exposure to EtOH extracts at 50, 100 and 150 μg/ml, HepG2 cells were considered 15.5%, 12.5% and 32.8% apoptotic, whereas DiEt extracts caused 4.5%, 13.5% and 33.9% apoptotic cells. Exposure to EtOH and DiEt extracts at 50 μg/ml ensued in 20.2% and 21.3% apoptosis in Caco‐2 cells; 100 μg/ml induced apoptosis in 19.9% and 10.3% of Caco‐2 cells; whereas exposure to 150 μg/ml EtOH extracts caused 12.6% apoptosis compared to 11.7% induced by the DiEt extract. Conclusions None of the excipients caused any significantly altered cellular effects, indicating little chance for physicochemical interactions. Aqueous extracts did not possess any cytotoxic properties. However, it is clear that organic extracts caused apoptotic and necrotic cell death.