BIOACTIVE SECONDARY METABOLITES FROM MEDICINAL AND AROMATIC PLANTS UNDER STRESS: ELICITATION AND DEVELOPMENT OF COSMETIC AND THERAPEUTIC INGREDIENTS

Abstract

Medicinal and aromatic plants respond to stress conditions, including water deficit, salinity, ultraviolet radiation, extreme temperatures, metals, and biotic agents, by reprogramming their specialized metabolism and accumulating bioactive secondary metabolites, such as phenolic compounds, flavonoids, terpenoids, and alkaloids. This adaptive response, known as elicitation, represents a promising strategy for the production of natural ingredients with applications in the cosmetic and pharmaceutical industries. This narrative review systematizes 52 original articles published between 2020 and 2026, selected exclusively from experimental studies with their own methodology, addressing: (i) the metabolic and molecular bases of plant responses to stress; (ii) the effect of different abiotic stresses on metabolite accumulation; (iii) elicitation by phytohormones, polysaccharides, and biotic agents, including in vitro cultures and transformed roots; (iv) the application of metabolomics, transcriptomics, and predictive modeling in the characterization of these compounds; and (v) evidence of the safety and efficacy of extracts and essential oils obtained from stressed plants in photoprotection, antioxidant, antimicrobial, and anti-inflammatory activities, wound healing, and skin lightening. Moderate and controlled stress can substantially increase the content of phenolics and flavonoids and favorably modify the composition of essential oils, increasing the bioactivity of extracts; however, stress intensity and duration are critical factors, as severe stress reduces biomass and may compromise overall yield. Methodological gaps, protocol standardization, field-scale validation, and advanced-phase clinical trials still limit the translation of these findings into commercial products.