Profiling of phenolic compounds in desiccation-tolerant and non-desiccation-tolerant Linderniaceae

Introduction Craterostigma plantagineumandLindernia brevidensare resurrection plants, so these plants can tolerate desiccation of their vegetative tissues. Different components and mechanisms contribute to desiccation tolerance and secondary plant metabolites, like phenolic compounds, may play a role during these processes. Objectives Secondary plant metabolites of the two resurrection plants,C. plantagineumandL. brevidensas well as the closely related desiccation sensitive species,L. subracemosa, were investigated regarding the polyphenol profile. Material and methods Secondary plant compounds were extracted with acidified methanol and analysed with ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry (UHPLC-ESI-MS). Phenolic compounds were identified by comparing of ultraviolet (UV) and MSn-spectra with published data. All compounds were quantified as verbascoside equivalents by external calibration at the compound specific wavelength. Results In total, eight compounds that belong to the subclass of phenylethanoid glycosides and one flavone, luteolin hexoside pentoside, were identified. Two of these compounds exhibited a fragmentation pattern, which is closely related to phenylethanoid glycosides. The predominantly synthesised phenylethanoid in all of the three plant species and in every stage of hydration was verbascoside. The total content of phenolic compounds during the three stages of hydration, untreated, desiccated, and rehydrated revealed differences especially betweenC. plantagineumandL. brevidensas the latter one lost almost all phenolic compounds during rehydration. Conclusion The amount of verbascoside correlates with the degree of desiccation tolerance and verbascoside might play a role in the protective system in acting as an antioxidant.

Automated summary

The study aimed to investigate the secondary plant metabolites of resurrection plants and a desiccation sensitive species. Results showed the presence of eight phenylethanoid glycosides and one flavone compound in the plants, with verbascoside being the predominantly synthesized phenylethanoid in all three plant species. The amount of verbascoside correlated with the degree of desiccation tolerance, suggesting a potential role as an antioxidant in the protective system.