SummaryWe investigated the protective effects of a phytochemical carotenoid-rich extract obtained from Crocus sativus L., commonly known as saffron, against ovarian damage induced by cyclophosphamide (CPM). Mice received saffron extract (SE; 300 mg/kg) by oral administration for 15 days, followed by CPM treatment (100 mg/kg; SE+CPM group). The number of primordial and antral follicles decreased in CPM-mice when compared with control (p<0.001), whereas saffron administration prior to CPM partially prevented this loss. Protein expression of FOXO3a, a regulator of primordial follicle dormancy and adaptive response to oxidative stress, decreased in CPM-mice (p<0.05), whereas it was similar to control in the SE+CPM group (p=0.419). Levels of AGEs (Advanced-Glycation End-products), markers of oxidative stress and aging, were higher in CPM when compared to both control (p<0.05) and SE+CPM (p<0.05). Staining level for DNA double strand breaks increased in CPM ovaries (p<0.05), while it was similar to control in SE+CPM (p=0.194). These results provide evidence that oral administration of phytochemical carotenoids may counteract chemo-induced primordial follicle loss and oxidative damage. This approach may represent a pharmacological intervention to reduce the toxicity of alkylating agents so expanding options for fertility preservation in cancer patients.KEY WORDS:cyclophosphamide (CPM), premature ovarian failure (POF), saffron extract, oxidative stress, FOXO3a.