Statistical analysis Statistical analysis was performed using GraphPad Prism software 5. 0. Students t test was used to analyze the data. selleck Values of p 0. 05 or less were considered statistically significant. Results Induction of apoptosis by fungal taxol and baccatin III in Jurkat cells Interference of the mitotic spindle apparatus by microtubule stabilizing drugs would be expected to have an effect on the cell cycle distribution. To determine whether taxol and its precursor would have any such ef fect, JR4 Jurkat cells were treated for 48 h with 0. 1 uM fungal taxol and 3. 5 uM baccatin III, subjected to PI stain ing and the DNA content of the cells measured by flow cytometry. Flow cytometry analysis showed that while un treated and vehicle treated Jurkat cells were pre dominantly in the G1 phase of the cell cycle, significant changes were observed with fungal taxol and baccatin III treated cells.

Upon treatment, the percentage of G1 and G2/M cells decreased and the percentage of sub G1 cells increased considerably, suggesting initiation of apoptosis process in the cells. Induction of apoptosis by taxol and baccatin III in cells We observed a clear dose and time dependent induc tion of apoptosis by taxol and baccatin III in cells. The maximal increase in the frequency of apoptotic cells was observed after 48 h of incubation with 0. 1 uM fungal taxol, while the maximal induction of apoptosis by fungal baccatin III was obtained in 48 h at a concentration of 5 uM. Later the effect of induction of apoptosis by fungal taxol and baccatin III was analyzed in adherent cell lines.

HepG2, HeLa, Ovcar3 and T47D cells treated with fungal taxol and baccatin III showed results similar to that obtained with the Jurkat cells. Time and concentration dependent effect of fungal taxol and baccatin III on apoptosis induction in the four different adherent cell lines was observed, though the IC50 concentrations differed. IC50 values of apoptosis were calculated from all the five different cell lines that were in duced by fungal taxol and baccatin III. Both the compounds were active in all the cancer cell lines we tested, with IC50 ranging from 0. 005 to 0. 2 uM for fungal taxol and 2 5 uM for fungal baccatin III. These results indicate that both fungal taxol and baccatin III have potent apop tosis inducing activity.

Fungal taxol and baccatin III induced reduction of mitochondrial membrane potential in JR4 Jurkat cells Disturbance AV-951 in the mitochondrial membrane potential is an early event in the process of apoptosis and can be studied using the cationic carbocyanine dye JC 1 as a fluorescent marker for assessing the loss in mitochon drial membrane potential. The distinctive feature of JC 1 is its potential sensitive emission color shift resulting in a decrease of the red/green fluorescence intensity ratio in response to mitochondrial depolarization.