Integrative Study of Dipsaci Radix and Phlomidis Radix: Nomenclature, Morphology, DNA-Based Authentication, and Comparative Effects on Osteoclastogenesis

<b>Background/Objectives</b>: Dipsaci Radix (<i>Dipsacus asper</i>) and Phlomidis Radix (<i>Phlomoides umbrosa</i>) are both traditional medicines used in Korea and China for various bone-associated diseases. However, the two are misused due to similarities in name and appearance. Additionally, <i>D. japonicus</i> root frequently contaminates Dipsaci Radix in Korean herbal markets. <b>Methods</b>: We examined morphological plant traits and performed a DNA barcoding analysis using ITS2 and <i>matK</i> sequences to differentiate between these three species. The effects of root extracts on bone resorption and osteoclast differentiation, measured as tartrate-resistant acid phosphatase (TRAP)-positive cell formation, were evaluated using mouse (5 weeks male ICR mice) bone marrow-derived macrophages. Cytotoxicity assays were conducted to assess extract safety. <b>Results</b>: <i>Phlomoides umbrosa</i> is easily distinguished by its verticillaster inflorescences and 2-labiate corollas. <i>Dipsacus asper</i> and <i>D. japonicus</i>, which share globose inflorescences, are distinguishable by flower color and leaf lobation. The ITS2 and <i>matK</i> sequences clearly differentiated the three species, with haplotype analysis supporting their genetic distinctiveness, enabling robust species discrimination. All three extracts decreased osteoclastic bone resorption and inhibited TRAP-positive cell formations in a dose-dependent manner. Only the <i>D. japonicus</i> extract demonstrated toxicity. <b>Conclusions</b>: This integrative study provides the current scientific names of the original species and proposes their use in the Korean Herbal Pharmacopoeia. Moreover, a reasonable molecular method for authenticating medicinal materials is suggested. <i>Dipsacus japonicus</i> shows promise as an additional origin species in the Korean Pharmacopoeia. However, processing methods that reduce toxicity must be discovered.