Medicinal-plant authentication is increasingly challenged by substitution, undeclared admixture, processing-related signal loss, compositional variability, and deliberate manipulation of routine quality-control markers. DNA-based, chromatographic, spectroscopic, and chemometric approaches are often discussed as competing solutions, although they measure different properties and do not support identical identity claims. A systematic review of peer-reviewed Q1 journal literature published from 2017 to 2023 was conducted using botanical-authentication, adulteration, DNA, chromatography, spectroscopy, mass-spectrometry, fingerprinting, and chemometric search concepts. Eligible studies and substantive methodological reviews were required to support a defined authentication claim, analytical limitation, validation issue, or boundary condition. Evidence was extracted by material state, identity endpoint, analytical modality, comparator, validation design, and uncertainty source, then synthesized narratively because outcome definitions and performance metrics were heterogeneous. Thirty-four articles were retained from a verified candidate pool of 50. DNA methods principally supported taxonomic presence or identity, whereas chromatographic, NMR, mass-spectrometric, and vibrational methods supported chemical-profile or constituent evidence. Chemometrics enabled discrimination within defined reference spaces but introduced dependence on preprocessing, class definition, and validation. Processing, incomplete reference libraries, unseen adulterants, and deliberate marker manipulation repeatedly constrained transferability. No single analytical family provides context-independent botanical authentication. This review proposes that method suitability should be interpreted through alignment among the claimed identity attribute, matrix state, adulteration mechanism, surviving analytical signal, authenticated comparator, and validation design. Orthogonal evidence is particularly informative when these layers can decouple.
