The Combination of Untargeted Metabolomics and Machine Learning Predicts the Biosynthesis of Phenolic Compounds in Bryophyllum Medicinal Plants (Genus Kalanchoe).

Pascual García-Pérez,Eva Lozano-Milo,Pedro P. Gallego,Mariana Landin,Begoña Miras-Moreno,Leilei Zhang,Luigi Lucini

doi:10.3390/plants10112430

Pascual García-Pérez, Eva Lozano-Milo + Show 5 more

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https://doi.org/10.3390/plants10112430

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Abstract

Phenolic compounds constitute an important family of natural bioactive compounds responsible for the medicinal properties attributed to Bryophyllum plants (genus Kalanchoe, Crassulaceae), but their production by these medicinal plants has not been characterized to date. In this work, a combinatorial approach including plant tissue culture, untargeted metabolomics, and machine learning is proposed to unravel the critical factors behind the biosynthesis of phenolic compounds in these species. The untargeted metabolomics revealed 485 annotated compounds that were produced by three Bryophyllum species cultured in vitro in a genotype and organ-dependent manner. Neurofuzzy logic (NFL) predictive models assessed the significant influence of genotypes and organs and identified the key nutrients from culture media formulations involved in phenolic compound biosynthesis. Sulfate played a critical role in tyrosol and lignan biosynthesis, copper in phenolic acid biosynthesis, calcium in stilbene biosynthesis, and magnesium in flavanol biosynthesis. Flavonol and anthocyanin biosynthesis was not significantly affected by mineral components. As a result, a predictive biosynthetic model for all the Bryophyllum genotypes was proposed. The combination of untargeted metabolomics with machine learning provided a robust approach to achieve the phytochemical characterization of the previously unexplored species belonging to the Bryophyllum subgenus, facilitating their biotechnological exploitation as a promising source of bioactive compounds.

Highlights

IntroductionBryophyllum spp. medicinal properties are a consequence of the production of phenolic compounds as recently established [4,5,6]
The phenolic profiling of Bryophyllum plants was determined by using ultra-highpressure liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer (UHPLC-QTOF/MS), considering three species—i.e., Bryophyllum daigremontianum (BD), Bryophyllum × houghtonii (BH), and Bryophyllum tubiflorum (BT), two organ parts—i.e., aerial parts and roots, and seven culture media formulations—i.e., full-strength medium (MS), half-strength medium (1/2MS), quarter-strength medium (1/4MS), and eighth-strength medium (1/8MS) of both macronutrients (M) and micronutrients (μ)
Due to the high plasticity that flavonols and anthocyanins exhibit on plant physiology depending on mineral nutrition [7], our results suggested that the biosynthesis of these phenolic compounds could be stimulated by other mineral compositions different from those performed in this work for Bryophyllum spp. cultured in vitro

Summary

Introduction

Bryophyllum spp. medicinal properties are a consequence of the production of phenolic compounds as recently established [4,5,6]. Different extracts from Bryophyllum have been reported to exhibit valuable health-promoting properties because of the high contents of phenolic compounds, as determined through different in vitro assays. The anticancer activity of Bryophyllum was determined towards a wide panel of cancer cell lines, such as MCF-7 breast adenocarcinoma, NCI-H460 non-small cell lung carcinoma, HeLa cervical carcinoma, and HepG2 hepatocellular carcinoma cell lines [6]. Due to the aforementioned health properties associated with Bryophyllum extracts, novel strategies should be proposed to ensure the large-scale production of phenolic compounds from these underexplored medicinal plants

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