Potential of Colocasia leaves in human nutrition: Review on nutritional and phytochemical properties

Colocasia esculenta leaves possess vital nutritive and nonnutritive components in significant amounts, but are underutilized, and lesser explored. The chemical composition varies significantly depending upon climatic conditions and other agronomical factors of the location of cultivation and variety. Micronutrients, viz. iron (3.4-11.7 mg 100 g^-1 ), copper (0.29-0.8 mg 100 g^-1 ), magnesium (170-752 mg 100 g^-1 ), potassium (0.4-2.4 g 100 g^-1 ), and zinc (0.6-4.2 mg 100 g^-1 ) are present in high amounts. The ratio of sodium to potassium (1:40) in the leaves add specifically to the antihypertensive properties. Preclinical and clinical studies provide evidence of its antidiabetic, antihemorrhagic, neuropharmacological properties, and as a remedy for stomach and liver ailments. Assessment of phytochemical compounds like chlorogenic acid, anthraquinones, cinnamic acid derivatives, and other phenolics validates these biological properties. The major limiting factor of this plant is oxalate that can be suppressed through food processing strategies. Colocasia leaves are promising green leafy vegetables with nutritional and clinical potential. PRACTICAL APPLICATIONS: Colocasia leaves have demonstrated the ability of antidiabetic, antihypertensive, immunoprotective, neuroprotective, and anticarcinogenic activities. The detailed assessment of phytochemical compounds present in various extracts of the leaves shows the presence of active chemical compounds like anthraquinones, apigenin, catechins, cinnamic acid derivatives, vitexin, and isovitexin which are possibly responsible for the exhibited biological properties. Colocasia leaves are rich sources of micronutrients; however, the presence of oxalates can prohibit proper utilization of these nutrients. Various food processing strategies like soaking, cooking, and so on can significantly reduce the antinutritional content and make these nutrients available for utilization. Documentation of traditional uses and food products from Colocasia leaves show that these leaves have immense potential in the functional food product as well as drug development.