Micro-herbs: a valuable source of phytochemicals from aromatic and medicinal plants

In recent years, interest in medicinal and aromatic plants (MAPs) has grown, as they are key sources of traditional remedies and raw materials for many plant-based recipes products worldwide. Meanwhile, the consumption of edible sprouts and microgreens has grown substantially, driven by their appealing taste and high content in phytochemicals with potential health-promoting effects. An emerging research trend has combined these two subjects, dealing with sprouts and microgreens of MAPs, which have been found, or are supposed, to be extremely interesting from a nutraceutical point of view. However, existing studies predominantly focus on a limited number of commonly cultivated species. In contrast, many lesser-known MAPs remain underexplored and data on their sprouts and microgreens are occasional and fragmented. This review surveys the last 25-year literature on sprouts and microgreens of MAPs, here referred to under the term of micro-herbs, which is more intuitive to a broader audience. After describing sprouts and microgreens characteristics, as along with an overview on phytochemicals, their antioxidant properties and related health benefits, the review examines the available evidence on micro-herbs derived from either herbaceous and shrub/tree species, emphasizing their distinctive traits, and evaluating their potentialities and limits related to their use in human nutrition. Current gaps and perspectives for future research on this emerging subject are finally discussed. • Medicinal and aromatic plants (MAPs) are essential sources of plant-based recipes. • Micro-herbs (sprouts and microgreens of MAPs) possess high nutraceutical value. • Last 25-year literature on micro-herbs of herbaceous & arboreal species is examined. • The phytochemical content and the antioxidant activity of micro-herbs are reviewed. • The potentialities and limits of micro-herbs in human nutrition are discussed.