Effect of Fruit Maturation Stage on the Chemical Composition and Antioxidant and Cytotoxic Activities of <scp> <i>Piper nigrum</i> </scp> Essential Oil

ABSTRACT The genus Piper (Piperaceae) is one of the most diverse groups of tropical plants, with its species extensively used in traditional medicine and the pharmaceutical industry. Among them, Piper nigrum L. (black pepper) is distinguished by its economic relevance and biotechnological potential, owing to the presence of alkaloids, oleoresins, and essential oils (EOs) rich in bioactive monoterpenes and sesquiterpenes. The composition of these metabolites varies according to physiological and environmental conditions, particularly at the stage of fruit maturation, which modulates the chemical profile and bioactivity of the EOs. In this study, we investigated the influence of different stages of fruit maturation on the chemical composition and biological properties of P. nigrum EOs. The oils were extracted by hydrodistillation from black (sun‐dried), red (ripe), yellow (mid‐ripening), and green (unripe) P. nigrum fruits. The volatile composition of the EOs was determined by GC–MS, while antioxidant and cytotoxic activities were evaluated using the DPPH• and ABTS• + radical scavenging assays and the MTT assay, respectively. A total of 115 volatile constituents were identified, predominantly oxygenated monoterpenes and sesquiterpenes, which exhibited marked qualitative and quantitative variations among the fruit maturation stages. The EO obtained from ripe fruits displayed the highest antioxidant and cytotoxic activities, which correlated with the enrichment in limonene, β‐pinene and α‐bisabolol. In contrast, the green stage showed greater chemical diversity but lower bioactivity. These findings demonstrate that fruit ripening triggers enzymatic and oxidative transformations that directly modulate the composition and functionality of P. nigrum EOs. The integration of chemical and biological analyses provides new insights into the metabolic dynamics of P. nigrum and supports the optimization of harvest timing to maximise the pharmacological and industrial value of the species. This study advances our understanding of the relationship between fruit maturation, phytochemistry and the bioactivity of tropical aromatic species, reinforcing P. nigrum as a model for biotechnological research in natural product chemistry.