METHODS: The N. oleracea fractions were obtained using solid phase extraction (SPE). A metabolomics approach that coupled the use of proton nuclear magnetic resonance (1H NMR) with multivariate data analysis (MVDA) was applied to distinguish the metabolite variations among the N. oleracea fractions, as well as to assess the correlation between metabolite variation and the studied bioactivities (DPPH free radical scavenging and α-glucosidase inhibitory activities). The bioactive fractions were then subjected to ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis to profile and identify the potential bioactive constituents.
RESULTS: The principal component analysis (PCA) discriminated EF and MF from the other fractions with the higher distributions of phenolics. Partial least squares (PLS) analysis revealed a strong correlation between the phenolics and the studied bioactivities in the EF and the MF. The UHPLC-MS/MS profiling of EF and MF had tentatively identified the phenolics present. Together with some non-phenolic metabolites, a total of 37 metabolites were tentatively assigned.
CONCLUSIONS: The findings of this work supported that N. oleracea is a rich source of phenolics that can be potential antioxidants and α-glucosidase inhibitors for the management of diabetes. To our knowledge, this study is the first report on the metabolite-bioactivity correlation and UHPLC-MS/MS analysis of N. oleracea fractions.
AIMS: To provide an up-to-date, authoritative review with respect to the traditional uses, chemical composition, in vitro and in vivo pharmacological properties, and toxicological estimations accomplished either utilizing the crude extracts or, wherever applicable, the bioactive compounds isolated from B. glabra. Besides, a critical evaluation of the published literature has been undertaken with regards to the current biochemical and toxicological data.
MATERIALS AND METHODS: Key databases per se, Ovid, Pubmed, Science Direct, Scopus, and Google scholar amongst others were probed for a systematic search using keywords to retrieve relevant publications on this plant. A total of 52 articles were included for the review depending on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
RESULTS: The studies conducted on either crude extracts, solvent fractions or isolated pure compounds from B. glabra had reported a varied range of biological effects comprising antibacterial, antifungal, antidiabetic, cytotoxic, analgesic, antipyretic, anti-inflammatory, and antioxidant activities. Phytochemical analysis of different parts of B. glabra unveiled 105 phytochemicals, belonging to phenolic, flavonoid, betacyanin, terpenoid, glycoside and essential oils classes of secondary metabolites.
CONCLUSION: Most of the pharmacological activities of crude extracts from this plant have been reported. A very few studies have reported the isolation of compounds responsible for observed biological potential of this plant. Moreover, the toxicity studies of this plant still need to be explored comprehensively to ensure its safety parameters. Additional investigations are recommended to transmute the ethnopharmacological claims of this plant species in folklore medicines into scientific rationale-based information.