Nutraceutical Potential of Oilseeds and By-Products (Cakes) of Three Underutilized Malvaceae Trees Grown in Sudan

The nutraceutical potential of seed oils and cakes of Adansonia digitata, Grewia tenax, and Thespesia garckeana was evaluated by determining their chemical profile and examining their antioxidant and enzyme inhibitory properties. Oils of G. tenax and T. garckeana were rich in polyunsaturated fatty acids. The cake methanolic extract of T. garckeana revealed the highest antiradical (44.67 mg trolox equivalent (TE)/g extract) and metal chelating (26.38 mg EDTA equivalent/g extract) properties, while the oil of G. tenax displayed the highest Cu⁺⁺ (180.62 mg TE/g extract) and Fe⁺⁺⁺ (82.07 mg TE/g extract) reducing capacity. Pelargonidin and rutin were the dominant antioxidant compounds. The oil of A. digitata displayed the highest anti-acetylcholinesterase (2.44 mg galantamine equivalent (GALAE)/g extract) and butyrylcholinesterase (2.10 mg GALAE/g extract) activity, while its cake exhibited the best α-glucosidase inhibitory activity (1.46 acarbose equivalent (ACAE)/g extract). The cake of T. garckeana exerted the highest α-amylase inhibitory effect (0.71 mmol ACAE/g extract). The highest anti-tyrosinase activity (10.88 mg kojic acid equivalent/g extract) was recorded from the cake of G. tenax. These results indicated that these seeds could be a rich source of antioxidants that target diseases associated with oxidative stress, like diabetes and certain neurological disorders.