Capparis spinosa: A rich source of phenolic compounds - A comprehensive review of its phytochemistry, health benefits, and biotechnological applications

Caper (Capparis spinosa) is a plant of significant socio-economic importance in the Mediterranean region which is traditionally used to fight various metabolic diseases. It has indeed long been recognized for its medicinal properties, notably attributed to its rich nutritional content and potent antioxidant activity due to phenolic compounds and other secondary metabolites. However, the commercial production of relevant secondary metabolites requires innovative approaches improving the biosynthesis of these metabolites to fulfill the industrial demand and mitigate the overexploitation of natural resources. For this end, different techniques such as cell suspension culture, hairy roots culture, biotic and abiotic elicitors supply as well as genetic engineering could be used to enhance the production of caper-derived secondary metabolites. In addition, omics tools including genomics, transcriptomics, metabolomics and proteomics can help to elucidate the biosynthetic pathway and altering the production of targeted metabolites. While this review first highlights the phytochemistry, ethno-pharmacological uses, and biological activities of caper, it also discusses the significance of in vitro culture systems, omics tools and metabolic engineering approaches to improve the production of caper-derived bioactive compounds.