<div>Exposure of C6 and CHO-K1 cells to different concentrations of the antineoplastic drug paclitaxel resulted in a loss of cellular viability. The percentage of surviving cells fell significantly after 48 hours of treatment and IC50 values observed were between 0.5 to 0.75 and 0.25 to 0.75 &micro;g/ml in C6 and CHO-K1 cells, respectively. No significant cytotoxicity was observed after 24 hours of treatment and cells incubated at higher concentrations of paclitaxel showed increased survivability. Paclitaxel induced apoptosis by caspase 3/7 activation and caused accumulation of cells in the G2/M phase of the cell cycle. Upon fluorescent microscopy, both the cell lines lost the morphology, confluence and adherence at 24 hours but effects were much more pronounced at 48 hours of treatment. The in vitro data suggested that paclitaxel is highly effective when there is prolonged exposure of tumor to the drug rather than increasing the intratumoral or biophasic concentration of the drug.&nbsp;</div>

<div>In vitro Cytotoxicity, Apoptosis, Effects on Cell Cycle Kinetics and Schedule-Dependent Effects Induced by Paclitaxel on C6 and CHO-K1 Cell Lines</div>

Background: Ellagic acid, a phytochemical polyphenol found in fruits such as Fragaria, Vitis vinifera and Punica granatum, exhibits potent antioxidant and anticancer activities. Its therapeutic application is limited by poor solubility and low bioavailability. To overcome these limitations, a novel serum-based polymeric nanoparticle formulation was developed to enhance topical delivery and improve biological efficacy. 
&nbsp; 
Methods: The antioxidant activity of ellagic acid nanoformulation was evaluated using the DPPH assay, where serial dilutions were incubated with DPPH solution and absorbance was measured at 517 nm to calculate radical scavenging activity (RSA) and IC50&nbsp;values. Cytotoxicity was assessed in michigan cancer foundation-7 (MCF-7) breast cancer cells using the MTT assay, where cells were treated with the nanoformulation at concentrations of 20-100 &micro;mol/L for 48 hours and cell viability and IC50&nbsp; values were&nbsp;determined. 
&nbsp; 
Result: The ellagic acid nanoformulation exhibited concentration-dependent DPPH radical scavenging activity ranging from 24.28% to 54.63%, with an IC50&nbsp;of ~50 &micro;g/mL, compared to ascorbic acid (46.77-78.90%; IC50&nbsp;~12.5 &micro;g/mL). In cytotoxicity studies, the formulation inhibited MCF-7 cell proliferation from 14.09% at 20 &micro;mol/L to 92.49% at 100 &micro;mol/L, with an IC50&nbsp;of 54.88 &micro;mol/L, whereas paclitaxel (0.1 &micro;mol/L) produced 66.45% inhibition. These results confirm that the serum-based ellagic acid nanoformulation possesses significant antioxidant and anticancer potential, supporting its therapeutic applicability.

In vitro Cytotoxicity, Apoptosis, Effects on Cell Cycle Kinetics and Schedule-Dependent Effects Induced by Paclitaxel on C6 and CHO-K1 Cell Lines

Novel Serum-based Approach for Evaluating Phytochemical Polyphenol Ellagic Acid: Antioxidant and Cytotoxic Assessment by DPPH and MTT Assays