Possible Interaction: Gamma-Linolenic Acid and Paclitaxel

“An in vitro study has shown that gamolenic acid (oil from the seeds of evening primrose and borage) potentiates the cytotoxicity of paclitaxel and vinorelbime in human breast cancer cell lines (Menendez et al, 2002).”

“For comparison, the effects of other … paclitaxel chemosensitivity were examined: GLA was the … at enhancing paclitaxel cytotoxicity, followed by alpha-linolenic acid (ALA; 18:3n.3), eicosapentaenoic acid (EPA; 20:5n-3) and … (DHA; 22:6n-3), whereas linoleic acid (LA; 18:2n-6) did not increase paclitaxel toxicity.”

“Interaction assessment using the median-effect principle and the combination-index (CI) method … that exposure of MDA-MB-231 cells to an equimolar combination of concurrent GLA plus paclitaxel for 24 h resulted in a moderate synergism at all effect levels, consistent with the results of the isobologram analysis.”

“Isobole analysis at the isoeffect levels of 50 and 70% revealed that drug interaction was predominantly synergistic when GLA and paclitaxel were added concurrently for 24 h to the cell cultures.”

“When exposure to GLA (24 h) was followed sequentially by paclitaxel (24 h) only an additive effect was observed.”

“When these observations were extended to three additional breast carcinoma cell lines (SK-Br3, T47D and MCF-7), simultaneous exposure to GLA and paclitaxel also resulted in synergism.”