Plants are a valuable source of specialized metabolites that provide a plethora of therapeutic applications. They are natural defenses that plants use to adapt and respond to their changing environment. Decoding their biosynthetic pathways and understanding how specialized plant metabolites (SPMs) respond to biotic or abiotic stress will provide vital knowledge for plant biology research and its application for the future sustainable production of many SPMs of interest. Here, we focus on the proteomic approaches and strategies that help with the study of plant-specialized metabolism, including the: (i) discovery of key enzymes and the clarification of their biosynthetic pathways; (ii) study of the interconnection of both primary (providers of carbon and energy for SPM production) and specialized (secondary) metabolism; (iii) study of plant responses to biotic and abiotic stress; (iv) study of the regulatory mechanisms that direct their biosynthetic pathways. Proteomics, as exemplified in this review by the many studies performed to date, is a powerful tool that forms part of omics-driven research. The proteomes analysis provides an additional unique level of information, which is absent from any other omics studies. Thus, an integrative analysis, considered versus a single omics analysis, moves us more closely toward a closer interpretation of real cellular processes. Finally, this work highlights advanced proteomic technologies with immediate applications in the field.

Grapevine stilbenes are a family of polyphenols which derive from trans-resveratrol having antifungal and antimicrobial properties, thus being considered as phytoalexins. In addition to their diverse bioactive properties in animal models, they highlight a strong potential in human health maintenance and promotion. Due to this relevance, highly-specific qualitative and quantitative methods of analysis are necessary to accurately analyze stilbenes in different matrices derived from grapevine. Here, we developed a rapid, sensitive, and specific analysis method using ultra-high-performance liquid chromatography coupled to triple-quadrupole mass spectrometry (UHPLC-QqQ) in MRM mode to detect and quantify five grapevine stilbenes, trans-resveratrol, trans-piceid, trans-piceatannol, trans-pterostilbene, and trans-ε-viniferin, whose interest in relation to human health is continuously growing. The method was optimized to minimize in-source fragmentation of piceid and to avoid co-elution of cis-piceid and trans-resveratrol, as both are detected with resveratrol transitions. The applicability of the developed method of stilbene analysis was tested successfully in different complex matrices including cellular extracts of Vitis vinifera cell cultures, reaction media of biotransformation assays, and red wine.

Much attention has been paid to the potential biological activities of prenylated flavonoids (PFs) in various plant families over the last decade. They have enormous potential for biological activities, such as anti-cancer, anti-diabetic, antimicrobial, anti-inflammatory, anti-Alzheimer’s, and neuroprotective activities. Medicinal chemists have recently shown a strong interest in PFs, as they are critical to the development of new medicines. PFs have been rapidly prepared by isolation and semi- or full synthesis, demonstrating their significant utility in medicinal chemistry research. This study encompasses the research progress on PFs in the last decade, including their pharmacological activities in the Fabaceae family. This information demonstrates the bioactive potential of PF compounds and their role in the control and treatment of various human health problems.

Prenylated flavonoids (PFs) are natural flavonoids with a prenylated side chain attached to the flavonoid skeleton. They have great potential for biological activities such as anti-diabetic, anti-cancer, antimicrobial, antioxidant, anti-inflammatory, enzyme inhibition, and anti-Alzheimer’s effects. Medicinal chemists have recently paid increasing attention to PFs, which have become vital for developing new therapeutic agents. PFs have quickly developed through isolation and semi- or full synthesis, proving their high value in medicinal chemistry research. This review comprehensively summarizes the research progress of PFs, including natural PFs from the Moraceae family and their pharmacological activities. This information provides a basis for the selective design and optimization of multifunctional PF derivatives to treat multifactorial diseases.

Mulberry ( Morus alba L.) is considered a millenary medicinal plant and a food source for silkworms. Different M. alba extracts offer a variety of biological and pharmacological properties that are in part attributed to stilbenoids, a small group of phenylpropanoids that include resveratrol and oxyresveratrol. These are naturally present in non-renewable parts of mulberry trees, impeding their efficient extraction. As a way to bypass this spatiotemporal restriction, we generated cell suspensions from mulberry twigs and demonstrated that the combined use of methyl jasmonate and methyl- or hydroxypropyl-β-cyclodextrins elicited a high production of resveratrol and oxyresveratrol, both intra and extracellularly. To identify oxyresveratrol-producing enzymes (unknown to date), we first improved the structural and functional annotation of the mulberry genome by integrating short and long-read sequencing data. We further combined this data with transcriptome, metabolite and proteome time-series evidence to identify a complete set of elicited phenylpropanoid- and stilbenoid-related genes. These included 22 stilbene synthase ( STS ) genes and a group of six p -coumaroyl-CoA 2’-hydroxylases (C2’Hs) that were highly co-expressed with resveratrol and oxyresveratrol accumulation. We transiently transformed Nicotiana benthamiana plants and grapevine ( Vitis vinifera L.) cell suspensions to functionally validate the role of C2’Hs as the first committed step of oxyresveratrol synthesis, providing an alternative substrate for STSs by hydroxylating p -coumaroyl-coA into 2’4’-dihydroxycinnamoyl-CoA. We offer tools for genomic and transcriptomic exploration in the context of jasmonate elicitation aiding in the characterization of novel stilbenoid-modifying and regulatory genes in the Morus genus.