This thesis explored the nutritional composition and antioxidant potential of Hippophae rhamnoides spp. Mongolica, a sea buckthorn species native to Mongolia. The study sought to assess whether the particular sample of Mongolian sea buckthorn has qualities that justify its inclusion in health-promoting diets and nutraceutical applications, given the increasing interest in natural antioxidants and functional foods. Investigated through both biological tests and chemical analysis. Drosophila melanogaster (fruit flies) were used in sugar manipulation experiments to simulate metabolic stress conditions. The sea buckthorn supplementation improved developmental outcomes in the flies with high sugar diets, implying protective antioxidative or metabolic effects. Furthermore, a functional food product was developed using the sea buckthorn samples.