Survey of botanical characteristics and preliminary analysis of chemical composition of Persicaria odorata (Lour.) Sojak leaves
Abstract
Persicaria odorata (Lour.) Sojak is an aromatic herb widely used as a culinary and medicinal plant in Southeast Asia; however, comprehensive pharmacognostic data supporting its accurate identification and quality control remain limited. This study aimed to establish a detailed botanical and preliminary phytochemical profile of P. odorata to support species authentication and future phytochemical investigations. Macromorphological examination revealed diagnostic characteristics of the genus Persicaria, including nodal rooting stems, narrowly lanceolate leaves, and conspicuous ciliate ocreae. A detailed description of reproductive structures was provided, contributing essential taxonomic information for reliable species identification and differentiation from closely related taxa. Microscopic analysis of transverse sections of roots, stems, leaves, and petioles revealed distinct anatomical features, such as a continuous secondary xylem ring and lignified sclerenchyma clusters in roots, a large central lacuna in the stem pith, dorsiventral leaf mesophyll with collateral vascular bundles, and abundant calcium oxalate druses in petioles. Epidermal studies demonstrated paracytic stomata and multicellular glandular trichomes, suggesting potential sites for secondary metabolite accumulation. Powder microscopy of different organs showed characteristic diagnostic elements, including rosette-shaped calcium oxalate crystals, diverse xylem vessel types, and epidermal fragments bearing stomata and trichomes. Preliminary phytochemical screening of leaf extracts and solvent fractions of increasing polarity indicated the presence of essential oils, flavonoids, polyphenols, tannins, saponins, alkaloids, coumarins, and anthraquinones, with phenolic compounds predominantly detected in the ethyl acetate and n-butanol fractions. Overall, this study provides a comprehensive pharmacognostic and preliminary phytochemical framework for P. odorata, supporting accurate identification, quality control, and further studies on bioactive compound isolation.