Evaluation of nutritional composition of Citrullus lanatus Linn. (watermelon) seed and biochemical assessment of the seed oil in rats.

The present study investigated the nutritional composition of watermelon seeds and the effect of extracted oil on the biochemical parameters in rats after 28 days of oral administration. The watermelon seeds showed considerable proximate values but with less moisture, crude fiber, ash, and phytochemical components. The maximal dose of 50 ml/kg of watermelon seed oil (WMSO) showed no sign of toxicity in rats. WMSO significantly decreased serum cholesterol, triglyceride, LDL, ALT, and MDA but enhanced the level of HDL, VLDL, SOD, and CAT without compromising the liver integrity. For glucose tolerance, a positive oral glucose-lowering was observed. The fatty acid analysis showed the presence of three major fatty acids; 9,12-octadecadienoic acid (52.32%), n-hexadecenoic acid (21.23%), and oleic acid (10.11%) with good oxidative stability and fatty acid ratio. The outcome of this study suggests that the seeds and oil from watermelon could have a beneficial effect on man. PRACTICAL APPLICATIONS: Plant-based oils have gained significant interest globally as a source of food, cosmetics, and compounds with therapeutic potential against certain human diseases. The watermelon seed oil is a rich source of oleic acid, linoleic, and palmitic acid. These prominent biologically active fatty acid components have contributed to the robust biochemical effects observed in this study. Based on the data obtained in this work on the nutritional analysis of the watermelon seed and potent antioxidative capacity, improved liver biomarkers, good oxidative stability, and the fatty acid ratio of WMSO, we proposed that consumption of the seed and its oil could offer a cheap and affordable nutraceutical for human benefits. However, we recommend further studies on the biological activity and safety aspect of watermelon seed oil for its long-term usage.