In the treatment of cancer, it is intended to increase the anticancer effect and decrease cytotoxicity using various plant-derived phenolic compounds with chemotherapeutic drugs. Pycnogenol® (PYC), a phenolic compound, has been the subject of many studies. Since the mechanisms of the interactions of PYC with cisplatin need to be clarified, we aimed to determine the effects of PYC on cisplatin cytotoxicity in human cervix cancer cells (HeLa) and to evaluate the genotoxicity of PYC. The cytotoxicity of cisplatin and PYC was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HeLa cells for 24 h and 48 h. The effect of PYC against oxidative DNA damage was evaluated using the comet assay. The IC50 values of cisplatin were 22.4 μM and 12.3 μM for 24 h and 48 h, respectively. The IC50 values of PYC were 261 μM and 213 μM for 24 h and 48 h, respectively. For 24 h exposure, PYC significantly reduced the IC50 value of cisplatin at the selected concentrations (15.6-500 μM). For 48 h exposure, PYC did not change the cytotoxicity of cisplatin at concentrations between 15.6 and 125 μM, but significantly reduced it at concentrations of 250 μM and 500 μM. PYC alone did not induce DNA damage at concentrations of 10 μM or 25 μM; however, it significantly induced DNA damage at higher concentrations (50-100 μM). It also significantly reduced H2O2-induced DNA damage at all concentrations studied (10-100 μM). Our results suggest that PYC may increase the cisplatin cytotoxicity in HeLa cells at nongenotoxic doses. The results might contribute to the anticancer effect of cisplatin with PYC in cervical carcinoma, but in order to confirm this result further in vitro studies with cancer cell lines and in vivo studies are needed.

Objective: Lung cancer is the most common cause of morbidity and mortality. Platinum-based chemotherapy, which is the primary line of treatment, offers limited benefit due to drug resistance and side effects. Berberine (BBR), which is characterised by its potent and safe anticancer activity, represents a promising combination option in chemotherapy. To overcome the limitations in lung cancer chemotherapy, we investigated whether BBR and cisplatin (CIS) exert synergistic effects on non-small cell lung cancer cell line (A549) based on cytotoxicity and apoptotic response markers. Methods: The potential cytotoxic effects of the combination treatment were evaluated using the MTT and Chou-Talalay methods. Elisa assays were also performed to measure the levels of the pro-apoptotic protein Bax and the effector protein caspase (Cas)-3. Results: The results showed that BBR alone reduced A549 cell viability in a dose-dependent manner and synergized with CIS (CI =0.34±0.05 at IC50 concentrations). Elisa results showed that the combined treatment (both at IC50 concentrations) modulated apoptotic signalling pathways in A549 cells. Bax and Cas3 protein levels were dramatically enhanced in A549 cells treated with CIS +BBR compared to control (0.5% DMSO) (p < 0.001). Conclusion: Our results suggest that BBR can synergistically enhance the therapeutic effect of CIS in A549 cells. The potential therapeutic efficacy of BBR as part of a combination in current chemotherapy should be supported by in-depth research and clinical studies on the molecular mechanisms associated with cancer.