ReviewCoix: Chemical composition and health effects

•Chemical composition and claimed health effects of coix are summarised.•Relationships between in vitro and in vivo studies are discussed.•Coix is compared with other common cereals.•Suggestions on how to better understand coix are provided.

BackgroundCoix (Coix lachryma-jobi L.), commonly known as adlay or Job's tears, is a minor cereal and an important food item in some parts of Asia. It has also been used in the traditional Chinese medicine for relieving various ailments. Lack of systematic information on the composition and health effects greatly hinders the development of coix as a sustainable crop.Scope and approachThis review summarises the chemical composition and health effects of coix. Various parts of coix seeds including bran, hull, and testa are studied. Research on the health effects of coix includes both in vitro and in vivo studies. The relationships between the bioactivities from the in vitro and the in vivo studies are discussed. The claimed health effects and chemical constituents of coix are compared with other common cereals.Key findings and conclusionsCoix seeds contain a range of bioactive components including polysaccharides, proteins, lipids, polyphenols, phytosterols, carotenoids, spiroenone and lactams. The chemical constituents of coix contribute to a range of medical and nutritional benefits. These claimed health benefits include anti-oxidation, anti-cancer, anti-inflammation, anti-allergy, enhancing immunological activity, regulating endocrine functions, anti-obesity, anti-diabetes, gastroprotection, hypolipidemia, and modulating gut microbiota. The bioactivity of coix depends on the varieties as well as the sample preparation methods such as the solvent type. Coix seed is rich in starch and has similar processing properties of other cereals for food formulation. Coix can be further developed as a healthy grain for human consumption.