A metabolomic platform to identify and quantify polyphenols in coffee and related species using liquid chromatography mass spectrometry

Abstract

IntroductionProducts of plant secondary metabolism, such as phenolic compounds, flavonoids, alkaloids, and hormones, play an important role in plant growth, development, stress resistance. The plant family Rubiaceae is extremely diverse and abundant in Central America and contains several economically important genera, e.g. Coffea and other medicinal plants. These are known for the production of bioactive polyphenols (e.g. caffeine and quinine), which have had major impacts on human society. The overall goal of this study was to develop a high-throughput workflow to identify and quantify plant polyphenols.MethodsFirst, a method was optimized to extract over 40 families of phytochemicals. Then, a high-throughput metabolomic platform has been developed to identify and quantify 184 polyphenols in 15 min.ResultsThe current metabolomics study of secondary metabolites was conducted on leaves from one commercial coffee variety and two wild species that also belong to the Rubiaceae family. Global profiling was performed using liquid chromatography high-resolution time-of-flight mass spectrometry. Features whose abundance was significantly different between coffee species were discriminated using statistical analysis and annotated using spectral databases. The identified features were validated by commercially available standards using our newly developed liquid chromatography tandem mass spectrometry method.DiscussionCaffeine, trigonelline and theobromine were highly abundant in coffee leaves, as expected. Interestingly, wild Rubiaceae leaves had a higher diversity of phytochemicals in comparison to commercial coffee: defense-related molecules, such as phenylpropanoids (e.g., cinnamic acid), the terpenoid gibberellic acid, and the monolignol sinapaldehyde were found more abundantly in wild Rubiaceae leaves.

Single-cell and spatial RNA sequencing reveal the spatiotemporal trajectories of fruit senescence

“…In order to further elucidate the changes in flavonoids and other metabolites in different components during the senescence process, mass spectrometry was employed to detect the metabolite levels in H. undatus at four storage time points. A data-independent acquisition (DIA) method, sequential window acquisition of all theoretical fragment-ion spectra (SWATH), was utilized for data analysis 20 , 21 . Using this method, the instrument deterministically fragmented all precursor ions within the predefined m/z range in a systematic and unbiased fashion.…”

Exploring biodiversity dynamics and taxonomy of Rubiaceae fungal endophytes in tropical regions

“…However, the hydrophobic nature of the cuticle causes aerial depositions to be washed off during rainfalls, leading to self-cleaning surfaces (87). Despite leaves being rich in bioactive compounds with antifungal properties such as phenolics, alkaloids and terpenes (101,102), endophytes thrive in these environments due to high moisture content and nutrient availability. In this study, differences in foliar endophyte richness due to leaf developmental stage (young vs. mature) was not consistent across various diversity indices (Table 2).…”

Untargeted HR-MS Profiling and Discrimination of Coffea arabica L. Leaves under Different Postharvest Production Processes

“…It may allow, also in the absence of analytical standards, us to annotate plant metabolites by taking advantage of the large online repositories and database available for plant metabolomics, such as PlantCyc . The application of HR-MS-based techniques has recently allowed a more thorough description of the wide variety of secondary metabolites occurring in coffee leaves, along with the simultaneous detection of entire molecular families. − However, few papers have investigated the potential effect of such techniques on the postharvest processing of coffee leaves and the phytochemical modifications involved . This approach allows the untargeted comparison of large analytical data in several herbal plants and spices, leading to not only the discrimination of plants with distinct geographical origin but also the classification of different styles of postharvest management. − …”