Discriminating Luvunga scandens (Roxb.) Wight from Paramignya trimera : Insights from DNA barcoding with ITS1 as a potential core marker

Abstract Luvunga scandens (Roxb.) Wight, is a valuable medicinal plant traditionally used in the treatment of ailments such as cirrhosis and ascites. However, its morphological similarity to other species, particularly Paramignya trimera , has led to frequent misidentification in usage, highlighting the urgent need for a reliable and precise identification method. While conventional approaches based on morphology remain useful, DNA barcoding has emerged as a rapid and accurate tool for species discrimination in medicinal plants. In this study, we analyzed genetic distances and constructed phylogenetic trees using three DNA barcode regions including ITS1, ITS, and rbc L from leaf samples of L. scandens , P. trimera , and their close relative Triphasia trifolia . Our findings demonstrate that the ITS1 marker provides high resolution in distinguishing L. scandens from closely related species. The rbcL region, although highly conserved, revealed a strong interspecific divergence between L. scandens and P. trimera , confirming its utility at higher taxonomic levels. By contrast, the ITS region offered greater resolution but was complicated by high intraspecific variation. Taken together, our results suggest that the combined use of ITS1 represents a robust and practical DNA barcoding strategy for accurate identification of L. scandens and related taxa in Rutaceae, with significant implications for conservation and medicinal plant determination.