Catha edulis (khat) Induces Apoptosis in Madin-Darby Bovine Kidney Cell Line

BACKGROUND: Khat (Catha edulis) is a controversial plant having a euphoretic effect, at the same time part of culture in many countries such as Africa and Arabian Peninsula. The presence of amphetamine-like substance, cathinone and cathine make this plant banned in many countries. Many neurological and other system related studies have been carried out in this plant, but the lack of toxicity studies are there especially the mechanism. OBJECTIVE: In this study, Madin-Darby Bovine Kidney cell line was used as an in vitro model to study the cell death mechanism. Crude extract of fresh Khat plant leaves were prepared and exposed to cells. MATERIALS AND METHODS: Trypan blue assay, phase-contrast microscopy, fluorescent microscopy, clonogenic assay, annexin-V assay, and hematoxylin and eosin (H and E) staining were employed to check the objectives. RESULTS: Reductions in cellular viability were observed at concentrations above 1.25 mg/ml while using Trypan blue assay. The results of the clonogenic assay had shown that the untreated control with the highest number of colonies (100% survival) and the 0.1562 concentration could not prevent the colony formation significantly. The high concentrations reduced the colony formation at concentration dependent manner 27.4% and 24.9%, for 0.625 mg/ml and 1.25 mg/ml concentrations, respectively. The acridine orange/ethidium bromide experiment had observed the cells were intact with round nucleus while the apoptosis features such as blebbing and nuclear chromatin condensation were clearly observed in treatment. The shrinkage of cells was clearly observed in H and E staining. CONCLUSION: In addition, annexin-V binding confirmed the presence of apoptosis significantly on Khat treatment. SUMMARY: Khat (Catha edulis) is a controversial plant having euphoretic effect. Reductions in cellular viability were observed at concentrations above 1.25 mg/ml while using Trypan blue assay. The high concentrations of khat extract had reduced the colony formation at concentration dependent manner. The acridine orange/ethidium bromide experiment had observed the apoptosis features such as blebbing and nuclear chromatin in treatment. Annexin-V binding confirmed the presence of apoptosis significantly on Khat treatment. Abbreviation used: PS: Phosphatidylserine (PS); MDBK: Madin-Darby Bovine Kidney; DMEM: Dulbecco's modified Eagle's medium; PI: propidium iodide; EB: ethidium bromide; PBS: Phosphate Buffer saline; FITC: fluorescein isothiocyante; TUNEL: Terminal deoxynucleotidyl transferase dUTP nick end labeling.