A comprehensive review of natural dye yielding plant diversity in India

The interest in natural dyes from plants has resurfaced on a global platform due to their non-toxic, biodegradable, and eco-friendly characteristics. India has a vast repository of natural dye plants, which include over 390 species from 89 families of dicots, 10 families of monocots, 3 families of gymnosperms, and 1 family of lichens. In spite of this vast wealth of natural dye plants, the literature on natural dyes from plants is scattered, limited, or focused on a few species or plants used for specific purposes or in a few geographic locations. The present review provides the first-ever exhaustive and contemporary taxonomic account of natural dye plants from India that simultaneously addresses all major plant groups, like angiosperms (dicots and monocots), gymnosperms, and lichens. This review provides the latest information on natural dye plants, which is the widest and most inclusive account of natural dye plants from the Indian subcontinent. In addition to taxonomic details on natural dye plants from India, the present review also addresses the major classes of natural dyes like anthraquinones, flavonoids, tannins, carotenoids, and betalains that impart color to natural dyes, along with their biochemical characteristics. Plant families such as Fabaceae, Euphorbiaceae, Asteraceae, Combretaceae, and Apocynaceae are also identified as major contributors of dye resources, among which Fabaceae is found to be one of the major contributors of plant dyes. In addition to this, another unique feature of this review is its integration of ethnobotanical information, traditional/tribal dyeing practices, regional patterns of utilization, and the increasing scope of industrial applications of plant dyes. This unique integration of information helps in understanding plant dyes from various dimensions. India is blessed with immense floral resources, but despite this, various problems are associated with plant dyes, including scientific standardization, optimized methods of extraction, sustainable harvesting, and conservation of plant dyes. The present study is a unique compilation of scattered literature that has been critically analyzed to identify gaps in existing research, emphasizing the need for conservation of plant dyes, and outlining future research directions that would help in the development of plant dyes for modern industrial applications.