Natural product derivatives are chemical compounds that retain a defined structural relationship to a naturally occurring metabolite while differing from the parent compound through chemical, enzymatic, or biosynthetically directed modification. Within natural-product bioactivity and synthesis, this category principally includes semisynthetic derivatives obtained by transformation of an isolated natural product, as well as analogues derived by modifying its biosynthetic pathway or enzymatic processing ^[1][2]. The parent natural product provides a recognizable molecular scaffold, whereas modifications may affect functional groups, oxidation state, stereochemical features, glycosylation pattern, substituents, or side chains ^[1][3].

The term is based on origin and structural lineage rather than on a specific metabolite class, biological source, or biological activity. Accordingly, derivatives can arise from alkaloid, terpenoid, polyketide, peptide, or other natural-product frameworks ^[2][4]. Natural product derivatives are distinguished from unmodified natural products, which are biosynthesized and isolated in their native molecular form, and from wholly synthetic compounds lacking a demonstrable scaffold-level relationship to a natural metabolite ^[1][3]. A derivative may preserve, remove, replace, or elaborate structural features of its parent compound, provided that its natural-product-derived core or direct biosynthetic relationship remains identifiable ^[2][4].