Metabolic profiling of different parts of Physalis alkekengi L. var. franchetii (Mast.) Makino based on UPLC-Q-Orbitrap-HRMS coupled with bioactivity assays

Abstract

Physalis alkekengi L.var. franchetii (Mast.) Makino (PAF) is an important edible and medicinal plant resource in China. Historically, phytochemical studies have primarily examined the calyx and fruit due to their long-standing use in traditional Chinese medicine for their ability to clear heat and detoxify. Metabolites and bioactivities of other parts such as the leaves, stems and roots, are rarely studied. The study involved conducting metabolic profiling of five plant parts of PAF using UPLC-Q-Orbitrap-HRMS analysis, in conjunction with two bioactivity assays. A total of 95 compounds were identified, including physalins, flavonoids, sucrose esters, phenylpropanoids, nitrogenous compounds and fatty acids. Notably, 14 aliphatic sucrose esters, which are potentially novel compounds, were initially identified. Furthermore, one new aliphatic sucrose ester was purified and its structure was elucidated by 1D and 2D NMR analysis. The hierarchical clustering analysis and principal component analysis showed the close clustering of the root and stem, suggesting similarities in their chemical composition, whereas the leaf, calyx and fruit clustered more distantly. Orthogonal partial least-squares discriminant analysis results showed that 41 compounds potentially serve as marker compounds for distinguishing among plant parts. Variations in activity were observed among the plant parts during the comparative evaluation with biological assays. The calyx, leaf and fruit extracts showed stronger antibacterial and anti-inflammatory activities than the stem and root extracts, and 19 potential biomarkers were identified by S-plot analysis for the observed activities, including chlorogenic acid, luteolin, cynaroside, physalin A, physalin F, physalin J, apigetrin, quercetin-3β-D-glucoside and five ASEs, which likely explain the observed potent bioactivity.