Chemical Constituents of Persicaria sagittata (L.) H.Gross: Antioxidant Activity and Chemotaxonomy Significance

Background: Persicaria sagittata (L.) H.Gross (Polygonaceae) has long been used in Indonesian traditional medicine to treat diarrhea, skin diseases, and internal problems. To date, the chemistry and biological activity of P. sagittata have not investigated, requiring more research. Objectives: This study aimed to investigate the chemical constituents of P. sagittata stems, evaluate their antioxidant activity, and discuss their chemotaxonomy values in genus Persicaria. Methods: Compounds isolated from the plant stems were identified using physicochemical and spectroscopic measurements (1D and 2D NMR) and by comparison with literature data. The antioxidant activity was evaluated based on the qualitative and quantitative DPPH assays. The chemotaxonomy value was assessed based on extensive studies of the phytochemically investigated Persicaria species. Results: We successfully isolated 10 compounds for the first time from P. sagittata, including arborinone (1), 25-hydroxycholest-5-en-3β-yl acetate (2), β-sitosterol (3), methyl-4-hydroxy cinnamate (4), protocatechuic acid (5), gallic acid (6), methyl gallate (7), quercetin (8), vanicoside A (9), and vanicoside B (10). Of these, compound 6 (IC50: 8.88 μM) exhibited the most significant antioxidant activity relative to ascorbic acid (IC50: 30.49 μM), followed by compounds 7, 9, 8, 5, and 10 (IC50: 15.37, 26.82, 29.18, 32.38, and 35.06 μM, respectively). Meanwhile, compounds 1 - 4 were inactive toward DPPH radicals (IC50 400 μM). The chemistry of P. sagittata showed a relatively similar profile to other species profiles, implying a close chemotaxonomy relationship of P. sagittata with other species of genus Persicaria. Compounds 2 and 4 were first reported in genus Persicaria, which may serve as chemical markers for P. sagittata. Conclusions: The chemical constituents of P. sagittata have potent antioxidant activities, in particular, phenolics, flavonoids, and sucrose esters. The presence of compounds 1 - 10 could enrich the chemotaxonomy value of P. sagittata in genus Persicaria.