Gynura bicolor DC. (Okinawa spinach): A comprehensive review on nutritional constituents, phytochemical compounds, utilization, health benefits, and toxicological evaluation

•Gynura bicolor is a perennial plant and native to China, Taiwan, Thailand, and Myanmar.•G. bicolor pigment showed potential use as a natural food colorant.•G. bicolor can be used as a functional food and source of therapeutic pharmaceuticals.•G. bicolor extracts exhibit antioxidant activities and anti-hyperglycemic effects.