Exhaustive solvent extraction and LC-MS-based phytochemicals profiling of Tapinanthus quequensis with network pharmacology-based evaluation of pharmacological relevance

Abstract

Mistletoes, the most successful group of parasitic flowering plants in the order Santalales, have long been used in traditional medicine as versatile remedies. Despite their ethnobotanical importance, many species remain scientifically understudied. Investigations conducted on the limited number of species studied to date have revealed notable bioactive properties, highlighting their medicinal potential and warranting further exploration. Therefore, exhaustive chemical profiling is essential to characterize unknown species and elucidate their potential pharmacological relevance comprehensively. In this study, the taxonomic identity of Tapinanthus quequensis was first confirmed through DNA barcoding followed by chemical profiling of the plant samples extracted in six different solvents through liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-qTOF-MS) and molecular networking. The study revealed diverse classes of metabolites such as tannins, glycerophospholipids, and glycosylglycerols as the major constituents of this plant, with a prevalent presence of gallic acid-containing compounds serving as key chemo-taxonomic markers of this species. The solvent type significantly influenced both the relative abundance and diversity of gallic acid-containing metabolites, suggesting that structural modifications had an influence on the extraction efficiency of these compounds. Using the m/z highlight function of GNPS2 molecular networking, we identified product ions that can be used to confirm the presence of gallic acid in each molecule rapidly. In this process, we introduced new terminology ‘identifier’ and ‘qualifier’ ions, to further strengthen the metabolite identification capabilities of molecular networking. Its pharmacological relevance was explored through different antioxidant assays and a network pharmacology approach. Polar solvent extracts exhibited enhanced antioxidant activities than non-polar solvents. Most importantly, using Pearson bivariate modelling, metabolites that contributed towards the antioxidative properties observed herein were also highlighted. Network pharmacology showed that gallic acid-containing compounds modulated multiple targets involved in inflammatory pathways, suggesting their potential anti-inflammatory effects. Therefore, the findings of this study highlight that T. quequensis contains a remarkably diverse class of metabolites with significant ethnopharmacological relevance; however, optimized extraction strategies are essential to fully harness their therapeutic potential. Notably, extracts from this plant may aid in managing inflammatory complications associated with various medical conditions. Further exploration of the chemistry of this plant could provide innovative avenues for developing new smart drugs, particularly those incorporating gallic acid through the chemical diversification strategies observed in this study.