OBJECTIVE: The present novel study aims to evaluate and make a comparison of antioxidant and antiproliferative activities of different extractions of C. cassia bark using seven solvents having different polarities. Solvents polarity gradients start with the solvent of lower polarity, n-hexane, and end with water as the highest polar solvent. Among the extracts, acetone extract contains the highest phenolic and flavonoid contents; therefore, it is assessed for the ability to protect DNA from damage.
METHODS: The extracts are evaluated for total phenolic, flavonoid contents and antioxidant activities, using FRAP, DPPH, superoxide, and hydroxyl and nitric oxide radicals scavenging assays. DNA damage protecting activity of the acetone extract is studied with the comet assay. Each of the extracts is studied for its antiproliferative effect against, MCF-7, MDA-MB-231(breast cancer), and HT29 (colon cancer), using MTT assay.
RESULTS: The acetone extract exhibited the highest FRAP value, phenolic and flavonoids contents when compared to the other extracts and could protect 45% mouse fibroblast cell line (3T3-L1) from DNA damage at 30 μg/ml. The lowest IC50 value in DPPH, superoxide, and hydroxyl radicals scavenging was noticed in the ethyl acetate extract. IC50 value obtained for the hexane extract was the lowest compared to the other extracts in scavenging nitric oxide radicals. The hexane extract showed the highest antiproliferative effect against cancer cells followed by the chloroform extract. The ethyl acetate extract inhibited the proliferation of only MCF-7 by IC50 of 100 μg/ml, while the other extracts exhibited no IC50 in all the cancer cells.
CONCLUSION: C. cassia showed promising antioxidant and anticancer activities with significant DNA damage protecting effect.
OBJECTIVE: Hence, this study aimed to determine the effects of bedak sejuk made from Oryza sativa ssp. indica (Indica) and Oryza sativa ssp. japonica (Japonica) on UVB-induced B164A5 melanoma cells, and also identify the antioxidant capacities of both types of bedak sejuk.
METHODS: The optimum dose of Indica and Japonica bedak sejuk to treat the cells was determined via the MTT assay. Then, the antioxidant capacities of both types of bedak sejuk were determined using the FRAP assay.
RESULTS: From the MTT assay, it was found that Indica and Japonica bedak sejuk showed no cytotoxic effects towards the cells. Hence, no IC50 can be obtained and two of the higher doses, 50 and 100 g/L were chosen for treatment. In the FRAP assay, Indica bedak sejuk at 50 and 100 g/L showed FRAP values of 0.003 ± 0.001 μg AA (ascorbic acid)/g of bedak sejuk and 0.004 ± 0.0003 μg AA/g of bedak sejuk. Whereas Japonica bedak sejuk at 50 g/L had the same FRAP value as Indica bedak sejuk at 100 g/L. As for Japonica bedak sejuk at 100 g/L, it showed the highest antioxidant capacity with the FRAP value of 0.01 ± 0.0007 μg AA/g of bedak sejuk which was statistically significant (p < 0.05) when compared to other tested concentrations.
CONCLUSION: In conclusion, Japonica bedak sejuk has a higher antioxidant capacity compared to Indica bedak sejuk despite both being not cytotoxic towards the cells. Regardless, further investigations need to be done before bedak sejuk could be developed as potential melanoma chemoprevention agents.
METHODS: We used a combination of proliferation and apoptosis assays to assess the effect of JB on AML cell lines and patient samples, with BH3 profiling being performed to identify early effects of the drug (4 h). Phosphokinase arrays were adopted to identify potential driver proteins in the cellular response to JB, the results of which were confirmed and extended using western blotting and inhibitor assays and measuring levels of reactive oxygen species.
RESULTS: AML cell growth was significantly impaired following JB exposure in a dose-dependent manner; potent colony inhibition of primary patient cells was also observed. An apoptotic mode of death was demonstrated using Annexin V and upregulation of apoptotic biomarkers (active caspase 3 and cleaved PARP). Using BH3 profiling, JB was shown to prime cells to apoptosis at an early time point (4 h) and phospho-kinase arrays demonstrated this to be associated with a strong upregulation and activation of both total and phosphorylated c-Jun (S63). The mechanism of c-Jun activation was probed and significant induction of reactive oxygen species (ROS) was demonstrated which resulted in an increase in the DNA damage response marker γH2AX. This was further verified by the loss of JB-induced C-Jun activation and maintenance of cell viability when using the ROS scavenger N-acetyl-L-cysteine (NAC).
CONCLUSIONS: This work provides the first evidence of cytotoxicity of JB against AML cells and identifies ROS-induced c-Jun activation as the major mechanism of action.