Persicaria maculosa S. F. Gray 1821 – Comparative analysis of herb and root extracts: Chemical composition and antioxidant activity

Abstract

Persicaria maculosa (Polygonaceae, lady's thumb) is an annual herb distributed around the northern temperate regions. Extracts of its aerial parts exhibit a number of pharmacological activities (hemostatic, anti-inflammatory, bactericidal, analgesic, and diuretic) [1], which is probably due to a number of phenolic compounds present in this species. There has been no report on chemical composition of underground parts of this plant. Our goal was to compare the chemical composition and biological activity (DPPH radical scavenging activity and protective effect on lipid peroxidation [2]) of ethanolic extracts prepared from the herb and roots of P. maculosa. Plant material was collected from two localities in Serbia. Chemical composition of the prepared extracts was determined by quantitative LC-MS-MS analysis [3]. Based on our results (shown in table), there is a great difference in chemical composition, particularly in flavonoid content, between the aerial and underground parts of this plant, although there is a significant amount of gallic and quinic acids in both aerial parts and root extracts. Aerial parts extracts (unlike the root ones) are rich in quercetin and its derivatives: quercetin-3-O-Glc, hyperoside, quercitrin, rutin, which is in accordance with the previous reports [4]. Also, apigenin aglycone and chlorogenic acid are present in high amounts in the aerial part of this plant, which has never been reported before. Root extracts contain only flavan-3-ols in similar amounts to those in herb extracts. There is no significant difference in DPPH scavenging activity between the herb and root extracts (results shown in table). Therefore, it can be assumed that the high content of gallic acid in both extracts has an important role in the antioxidant activity. On the other hand, herb extracts exhibit significantly higher LP inhibiting ability thus indicating that a high amount of flavonoids in herb extracts is responsible for protective effect against LP.