Bioactive composition and medicinal properties of Walnut kernels

The purpose of this review is to evaluate the biological compounds present in walnut kernels and also to assess potential human health benefits. Walnuts are one of the most important tree nuts, belonging to the Juglandaceae family. They are cultivated worldwide, primarily in temperate regions. Throughout history, walnut kernels have been utilized to treat various disorders such as diarrhea, diabetes mellitus, thyroid issues, cancer, anorexia, and infectious diseases, in addition to their dietary benefits. Presently, advanced techniques like UHPLC-MS/MS, HPLC-DAD chromatography, and GC–MS are employed to identify key compounds in walnuts. These include phenolic compounds, phenolic acids, tannins and related compounds, flavonoids, phytosterols, fatty acids, triglycerides, tocopherols, vitamins, and carotenoids. The review also demonstrates that walnut kernels possess numerous medicinal properties, including antioxidants, cardiovascular effects, anti-cancer effects, antidiabetic effects, hepatoprotective effects, and antimicrobial effects. The current review also gives details on plant origin, distribution, classification, cultivation, and consumption as food. The review also described the recent medicinal plant profile, identification, and screening of the active ingredients of walnut's kernels. Researchers around the world are taking an interest in the clinical evaluation of walnut's active ingredients. The current review also gives details of the most recent conducted clinical studies. Mostly the reviews of walnuts are focused on walnut cultivars and/or specific types of compounds, although our current review is mostly focused on the active ingredients of walnut kernels and their specified biological role. In conclusion, different varieties of walnuts are abundant in significant bioactive compounds that possess important medicinal properties.