Metabolite Profiling and Bioactivities of Leaves, Stems, and Flowers of Rumex usambarensis (Dammer) Dammer, a Traditional African Medicinal Plant

The comprehensive identification of secondary metabolites represents a fundamental step for the assessment of bioactivities and pharmacological properties of traditional herbal drugs. Rumex usambarensis (Dammer) Dammer has been described as a multipurpose remedy in different African traditional pharmacopoeias, but its phytochemical profile has not been properly investigated. Herein we report a high throughput metabolomic screening, based on ultra-high performance liquid chromatography-travelling wave ion mobility spectrometry quadrupole time-of-flight (UHPLC-TWINS-QTOF), which was performed for the first time on different R. usambarensis plant parts. By applying high-resolution mass spectrometry-based metabolomics and chemometric analysis, a complete discrimination of different aerial parts was obtained, with the annotation of 153 significant metabolites in leaves, stems, and flowers, suggesting an easy authentication and discrimination route. Phytochemical data were correlated to antimicrobial and antioxidant properties. Flavonoids, benzopyranes, chromones, and xanthones derivatives, along with a richer phytocomplex, might be responsible for the stronger bioactivities obtained from flowers.

Automated summary

We conducted a high throughput metabolomic screening using UHPLC-TWINS-QTOF on different parts of R. usambarensis. Through the use of high-resolution mass spectrometry-based metabolomics and chemometric analysis, we were able to distinguish between different aerial parts and identify 153 significant metabolites in leaves, stems, and flowers. The results suggest that flavonoids, benzopyranes, chromones, and xanthones derivatives, along with a richer phytocomplex, may be responsible for the stronger bioactivities obtained from flowers.