Structural Analysis and Identity Confirmation of Anthocyanins in Brassica oleracea Extracts by Direct Injection Ion Mobility-Mass Spectrometry.

Anthocyanins are a subclass of plant-derived flavonoids that demonstrate immense structural heterogeneity which is challenging to capture in complex extracts by traditional liquid chromatography-mass spectrometry (MS)-based approaches. Here, we investigate direct injection ion mobility-MS as a rapid analytical tool to characterize anthocyanin structural features in red cabbage (Brassica oleracea) extracts. Within a 1.5 min sample run time, we observe localization of structurally similar anthocyanins and their isobars into discrete drift time regions based upon their degree of chemical modifications. Furthermore, drift time-aligned fragmentation enables simultaneous collection of MS, MS/MS, and collisional cross-section data for individual anthocyanin species down to a low picomole scale to generate structural identifiers for rapid identity confirmation. We finally identify anthocyanins in three other Brassica oleracea extracts based on red cabbage anthocyanin identifiers to demonstrate our high-throughput approach. Direct injection ion mobility-MS therefore provides wholistic structural information on structurally similar, and even isobaric, anthocyanins in complex plant extracts, which can inform the nutritional value of a plant and bolster drug discovery pipelines.

Polyphenol characterisation and diverse bioactivities of native Australian lilly pilly (Syzygium paniculatum) extract.

Magenta lilly pilly (Syzygium paniculatum) is an Australian native tree that produces berry fruits that are rich in phytochemicals reportedly beneficial to human health. Here we explored the biological activities of polyphenol-enriched extracts from the magenta lilly pilly fruit, benchmarking it against traditional sources including purple sweet potato and blackberry. We show that the extracts exert potent antioxidant and neuroprotective properties as well as antimicrobial activity against Staphylococcus aureus. The phenolic composition of lilly pilly was investigated using liquid chromatography coupled to mass spectrometry (HPLC-DAD-MS), revealing anthocyanins to be the primary component in high abundance compared to traditional anthocyanin-containing plants. Three anthocyanins from lilly pilly, along with their glycosylation patterns and stability, were characterised. Altogether, our results demonstrate the potential to exploit magenta lilly pilly fruits as a high-yielding source of phenolics with beneficial biological properties of potential interest for multiple downstream applications.