Phytochemical characterization of pumpkin seed with antiparasitic action

The indiscriminate use of antibiotics, vermifuges and antifungals by individuals has been causing resistance in some parasites and microorganisms. Pumpkin seeds have been used in traditional medicine because they have action against human parasites. In the agroindustry, these seeds are discarded as by-products, although they present bioactive compounds such as tocopherol, fatty acids (omega oils), carotenoids and amino acids, which make them a promising approach to use as an alternative to treat helminth infections, as well as to be used in human feeding to improve the immune system. Thus, the objective of the present study was to determine the chemical composition of Cucurbita maxima seeds and to evaluate in tests in vitro the potential of their extract against Strongyloides venezuelensis larvae. Aqueous extracts of pumpkin seeds were prepared, and the chemical composition of the seeds was characterized by AOAC methods. Oil stability was measured by rancimat. Tocopherol and carotenoids were quantified by high-performance liquid chromatography (HPLC), while antioxidant capacity has been determined by spectrophotometer methods. The antiparasitic action against larvae of S. venezuelensis was evaluated in vitro, where the extract was added into assay tubes varying in volume from 0 to 400 μL, containing S. venezuelensis larvae (1500), in which they were incubated at 25°C for 48 h. Samples were withdrawn every 12 h, centrifuged and the larvae were suspended in aqueous solution and counted by microscopic method. Ivermectin and water have been used as positive and negative controls, respectively. Chemical analysis (HPLC) of the seeds revealed a predominant presence of tocopherol. The seed extract showed antioxidant activity, probably due to bioactive substances, mainly tocopherol and fatty acids. After 12 h, volume greater than 200 μL (33.3 mg mL^‑1) eliminated 92% of the larvae. Increasing the incubation period up to 48 h, low concentrations of extract (<10 mg mL^‑1) were sufficient to eliminate more than 90% of the larvae, while ivermectin killed 90% and in the water control sample, around 80% of the larvae remained alive. This is the first study to evaluate the potential of C. maxima seed extract to eliminate S. venezuelensis larvae in tests in vitro. Our results suggest that the low dose of pumpkin seeds’ extract has anthelmintic properties to eliminate infective larva of Strongyloides venezuelensis, being a promising alternative as a medicinal plant and phytotherapeutic product for the elimination of helminths.