Nanoparticle-assisted elicitation of therapeutically important secondary metabolites in plants
Govind Vyavahare, Ravishankar R. Patil, Jin Hee Park
Abstract
Plants are the major reservoir of bioactive compounds such as flavonoids, phenolics, proanthocyanidins, alkaloids, terpenoids, saponins, glycosides, essential oils, carotenoids, and natural dyes, some of which demonstrate bioactive properties. Bioactive compounds play a vital role in the food, fragrance, cosmetic, textile, and pharmaceutical sectors. Globally, the demand for plants as a whole and plant-based biomolecules is increasing to treat human diseases effectively. However, conventional production methods are time-consuming and fail to meet market demand. Recently, researchers have been exploring the potential of nanoparticles (NPs) as novel elicitors for increasing the levels of industrially important bioactive compounds in plants. Nanoparticles can be categorized into metallic, metal-oxide, non-metallic, bimetallic, and nanocomposites. Nanoparticles trigger the synthesis of reactive oxygen species (ROS), resulting in the upregulation of secondary metabolism to enhance bioactive compound synthesis. This review systematically discusses recent advancements in NPs assisted elicitation of bioactive plant metabolites in both in vitro and in vivo systems. The role of NPs in enhancing the production of secondary metabolites (SMs) has been comprehensively examined across various culture conditions. Several NPs, including silver, gold, zinc, cobalt, nickel, cerium, and aluminum, have shown promise as effective elicitors for boosting SM levels. However, some studies have reported phytotoxic effects, negatively affecting plant growth and SM accumulation. Accordingly, this review also highlights the potential adverse effects of NPs on plant systems and discusses the challenges associated with scaling up this technology. Overall, NPs present a novel and promising strategy for enhancing SM production in plants for industrial, pharmaceutical, and other applications.