METHODS: Different parts of the plants were subjected to sequential extraction method. Cytotoxicity of the extracts was determined by dimethylthiazol-2-yl)- 2,5diphenyl tetrazolium bromide (MTT) assay on 2 human cancer (colon and breast) and normal (endothelial and colon fibroblast) cells. Anti-angiogenic potential was tested using ex vivo rat aortic ring assay. DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was conducted to screen the antioxidant capabilities of the extracts. Finally, total phenolic and flavonoid contents were estimated in the extracts using colorimetric assays.
RESULTS: The results indicated that out of 6 plants tested, 4 plants (Nicotiana glauca, Tephrosia apollinea, Combretum hartmannianum and Tamarix nilotica) exhibited remarkable anti-angiogenic activity by inhibiting the sprouting of microvessels more than 60%. However, the most potent antiangiogenic effect was recorded by ethanol extract of T. apollinea (94.62%). In addition, the plants exhibited significant antiproliferative effects against human breast (MCF-7) and colon (HCT 116) cancer cells while being non-cytotoxic to the tested normal cells. The IC50 values determined for C. hartmannianum, N. gluaca and T. apollinea against MCF-7 cells were 8.48, 10.78 and 29.36 μg/ml, respectively. Whereas, the IC50 values estimated for N. gluaca, T. apollinea and C. hartmannianum against HCT 116 cells were 5.4, 20.2 and 27.2 μg/ml, respectively. These results were more or less equal to the standard reference drugs, tamoxifen (IC50 = 6.67 μg/ml) and 5-fluorouracil (IC50 = 3.9 μg/ml) tested against MCF-7 and HCT 116, respectively. Extracts of C. hartmannianum bark and N. glauca leaves demonstrated potent antioxidant effect with IC50s range from 9.4-22.4 and 13.4-30 μg/ml, respectively. Extracts of N. glauca leaves and T apollinea aerial parts demonstrated high amount of flavonoids range from 57.6-88.1 and 10.7-78 mg quercetin equivalent/g, respectively.
CONCLUSIONS: These results are in good agreement with the ethnobotanical uses of the plants (N. glauca, T. apollinea, C. hartmannianum and T. nilotica) to cure the oxidative stress and paraneoplastic symptoms caused by the cancer. These findings endorse further investigations on these plants to determine the active principles and their mode of action.
Methods: In this study, wtHALT-1 (wild type) and its Y110A mutated binding domain counterpart (mHALT-1) were produced and evaluated for their cytotoxic and apoptotic effects on various cancer cell lines. A total of seven different tumour and non-tumour cell lines including HeLa, HepG2, SW-620, MCF-7, CCD841CoN, NHDF and HCT116 were used. Immunofluorescence assays were used to observe membrane binding and localization changes between both HALT-1 recombinant proteins based on 6xHis-tag detection.
Result: Based on MTT data, mHALT-1 demonstrated a significant reduction of 82% ± 12.21% in cytotoxic activity across all cell lines after the membrane recognition domain had been mutated in comparison to the wtHALT-1. Annexin V FITC/PI assay data also indicated that HeLa, HepG2 and MCF-7 demonstrated an apoptosis-mediated cell death after being treated with wtHALT-1. Additionally, a notable difference between wtHALT-1 and mHALT-1 binding affinity was clearly observed where emission of green fluorescence along the cell membrane was observed only in wtHALT-1 treated cells.
Discussion: These results suggest that mHALT-1 (Y110A) can be potentially developed as a toxin-moiety candidate for the development of future immunotoxins against various human cell-based diseases.