MEDICINAL PLANTS’ STRESS FACTORS: EFFECTS ON METABOLITES AND NOVEL PERSPECTIVES FOR TOLERANCE

Abstract

Medicinal plants are rich in secondary metabolites representing different chemical classes and synthesized by various biochemical pathways. However, these compounds are susceptible to potential herbal predators and to environmental influences. Several factors induce different biotic and abiotic stresses (drought, cold, salinity, heat) that lead to fluctuations in the biogenesis and accumulation of secondary metabolites by which plants react to overcome the threatening stress conditions. This contribution aims to give an overview of the various medicinal plant defense mechanisms against imminent threats and their impact on secondary metabolites profiles in the most effective medicinal plant species such as the levels of vincristine in Catharanthus roseus which is affected by salinity and drought stress, sage (Salvia officinalis) that showed fluctuations in terpenes level under drought stress and mineral contents in the soil and Papaver somniferum that exhibited a decrease in alkaloids content under cold stress. From a wider perspective, the aim of this study is to present novel tools and strategies used for the preservation of some plant species from extinction by minimizing as much as possible the risk of exogenous influences on phytochemicals levels and on plant bio genome and manipulating the stress factors to ensure plants quality and safety. It also aims to raise awareness about the consumption of herbal medicines without respecting the herbal monographs information about the safe dose, the interactions with drugs, and the side effects, in addition to the necessity of performing toxicity studies by pharmaceutical industries, especially on herbal medicines raised under various stress factors because of the risk of SMs (secondary metabolites) accumulation in these plants at a critical level that may be toxic to consumers.