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Phenylpropanoids, the largest class of natural products including flavonoids, anthocyanins, monolignols and tannins perform multiple functions ranging from photosynthesis, nutrient uptake, regulating growth, cell division, maintenance of redox homeostasis and biotic and abiotic stress responses. Being sedentary life forms, plants possess several regulatory modules that increase their performance in varying environments by facilitating activation of several signaling cascades upon perception of developmental and stress signals. Of the various regulatory modules, those involving MYB transcription factors are one of the extensive groups involved in regulating the phenylpropanoid metabolic enzymes in addition to other genes. R2R3 MYB transcription factors are a class of plant-specific transcription factors that regulate the expression of structural genes involved in anthocyanin, flavonoid and monolignol biosynthesis which are indispensable to several developmental pathways and stress responses. The aim of this review is to present the regulation of the phenylpropanoid pathway by MYB transcription factors via Phospholipase D/phosphatidic acid signaling, downstream activation of the structural genes, leading to developmental and/or stress responses. Specific MYB transcription factors inducing or repressing specific structural genes of anthocyanin, flavonoid and lignin biosynthetic pathways are discussed. Further the roles of MYB in activating biotic and abiotic stress responses are delineated. While several articles have reported the role of MYB’s in stress responses, they are restricted to two or three specific MYB factors. This review is a consolidation of the diverse roles of different MYB transcription factors involved both in induction and repression of anthocyanin, flavonoid, and lignin biosynthesis.

Although bioproduction of Paclitaxel by endophytic fungi is highly considered as an alternative promising source, but its yield is usually very low in comparison with other taxoids. Different strategies i.e., chemical and physical elicitations have been developed in order to overcome the shortage of Paclitaxel production. Paclitaxel biosynthesis is started with terpenoid pathway followed by phenylpropanoid metabolism where a benzoylphenylisoserine moiety is attached to C13 of baccatin III skeleton. This point which is catalyzed by the function of PAM seems to be a bottleneck that limits the rate of Paclitaxel production. Whether phenylpropanoids pathway regulates the taxanes biosynthesis in Cryptosporiopsis tarraconensis endophytic fungus elicited with benzoic acid (BA) was hypothesized in the present paper. The involvement of certain signal molecules and key enzymes of terpenoid and phenylpropanoid metabolism were investigated. According to the results, application of BA promoted a signaling pathway which was started with increase of H2O2 and ABA and continued by increase of NO and MJ, and finally resulted in increase of both phenylpropanoids and taxanes. However, again the rate of Paclitaxel production was lower than other taxoids, and the latter was much lower than phenolics. Therefore, supplying benzoic acid provided the precursor for the common taxan ring production. It is unlikely that Paclitaxel production is merely controlled by side chain production stage. It is more likely that in C. tarraconensis endophytic fungus, similar to Taxus sp., the competition between phenylpropanoid and taxoid pathways for substrate ended in favor of the former. The interaction network which was constructed based on DSPC algorithm confirmed that most compounds with close proximity have shared metabolic pathway relationships. Therefore, it is unlikely that the feeding with a given precursor directly result in increase of a desired metabolite which is composed of different merits.

See also the Commentary on this article by McGrath, 226 : 1225–1227 .

Three undescribed phenylpropanoid derivatives, including two new bibenzyl constituents (1–2), one new stilbene constituent (3), together with five known compounds stilbostemin F (4), dihydropinosylvin (5), 2-(4-hydroxyphenyl)ethyl benzoate (6), 1-(4-hydroxybenzoyl)ethanone (7), and 4-hydroxy-3-prenylbenzoic acid (8), were isolated from the tuber of Asparagus cochinchinensis. The structures of 1–8 were elucidated according to UV, IR, HRMS, 1D and 2D-NMR methods together with the published literature. All of the isolated compounds were assessed for anti-inflammatory activity by acting on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells in vitro. The results showed that compounds 2 and 5 were found to inhibit the production of nitric oxide (NO) with the IC[sub.50] value of 21.7 and 35.8 µM, respectively. In addition, further studies found that compound 2 demonstrated concentration-dependent suppression of the protein expression of iNOS and exerted anti-inflammatory activity via the NF-κB signalling pathway. The present data suggest that phenylpropanoid derivatives from the tuber of A. cochinchinensis might be used as a potential source of natural anti-inflammatory agents.

Secondary metabolites, such as phenols and salicylic, play a crucial role in the regulation of development and tolerance mechanisms against a wide range of stresses. During adverse conditions such as biotic and abiotic stresses, plants induce the biosynthesis of phenolic compounds to provide tolerance. Phenolics are secondary aromatic metabolites synthesized through the shikimate/phenylpropanoid pathway or polyketide acetate/malonate pathway, which produce monomeric and polymeric phenolics. Phenolic compounds in plants not only take part in preventing stresses but also in regulating physiological activities. These compounds significantly regulate both below- and above-ground defense mechanisms. Plants synthesize thousands of phenolic compounds throughout their evolution to survive in changing environments. Environmental factors, such as high light, cold, drought, heavy metals, etc., increase the accumulation of phenolics to neutralize any toxic effects. This review focuses on the biosynthesis of phenolic compounds and their updated studies against abiotic stresses.

Phenolic compounds or polyphenols are among the most common compounds of secondary metabolism in plants. Their biosynthesis is characteristic of all plant cells and is carried out with the participation of the shikimate and acetate-malonate pathways. In this case, polyphenols of various structures are formed, such as phenylpropanoids, flavonoids, and various oligomeric and polymeric compounds of phenolic nature. Their number already exceeds 10,000. The diversity of phenolics affects their biological activity and functional role. Most of their representatives are characterized by interaction with reactive oxygen species, which manifests itself not only in plants but also in the human body, where they enter through food chains. Having a high biological activity, phenolic compounds are successfully used as medicines and nutritional supplements for the health of the population. The accumulation and biosynthesis of polyphenols in plants depend on many factors, including physiological–biochemical, molecular–genetic, and environmental factors. In the review, we present the latest literature data on the structure of various classes of phenolic compounds, their antioxidant activity, and their biosynthesis, including their molecular genetic aspects (genes and transfactors). Since plants grow with significant environmental changes on the planet, their response to the action of abiotic factors (light, UV radiation, temperature, and heavy metals) at the level of accumulation and composition of these secondary metabolites, as well as their metabolic regulation, is considered. Information is given about plant polyphenols as important and necessary components of functional nutrition and pharmaceutically valuable substances for the health of the population. Proposals on promising areas of research and development in the field of plant polyphenols are presented.

Background: Bcl-2 family proteins regulate apoptosis, and their overexpression is linked to cancer progression and therapy resistance. Targeting Bcl-2 with novel inhibitors is a promising approach for anticancer drug development. Methods: Pharmacophore modeling was performed using a training set of 5 diverse Bcl-2 inhibitors with IC_50 values ranging from 0.00012 to 3.37µM. Ten pharmacophore models were generated and validated using receiver operating characteristic (ROC) curves, enrichment factor (EF), and Güner-Henry (GH) scoring with a test set containing 24 active compounds and 1309 decoys. Model 8 demonstrated the best performance (AUC = 0.83, EF_1% = 3.66, GH score = 0.58) and was used for virtual screening of 220 eugenol derivatives. Docking studies were conducted using AutoDock against Bcl-2 crystal structure (PDB ID: 4LXD), and in silico ADMET analysis assessed pharmacokinetic and toxicity profiles. Results: Model 8 effectively distinguished active Bcl-2 inhibitors with good sensitivity and selectivity. Virtual screening identified 24 eugenol derivatives with high pharmacophore fit scores (>45), among which compounds 57, 57', 71 and 91 exhibited favorable docking binding energies ranging from -5.11 to -7.35kcal/mol compare with ABT-263 with value -9.82kcal/mol, overlapping well with the binding site of known inhibitor navitoclax. In silico ADMET profiling predicted good solubility, partition coefficients, and low toxicity risks, supporting their drug-likeness. Conclusion: The integrated pharmacophore and docking approach successfully identified promising eugenol derivative candidates as potential Bcl-2 inhibitors. These compounds demonstrate favorable binding affinity and pharmacokinetic properties, meriting further experimental validation and development as anticancer agents. Future work should include molecular dynamics simulations and in vitro bioactivity assays to confirm and optimize these leads.

Background Foxtail millet [ Setaria italica (L.) P. Beauv.] is an excellent crop known for its superior level of drought tolerance across the world. Especially, less water is needed during its germination period than the other cereal crops. However, the knowledge of the mechanisms underlying the abiotic stress effects on seed germination of foxtail millet is largely unknown. Results The water uptake pattern of foxtail millet seeds was ploted during germination period, according to which the germination time course of millet was separated into three phases. We sequenced the transcriptome of foxtail millet seeds, which were treated by PEG during different germination phases after sowing. The transcriptional studies revealed that more DEGs were identified during the further increase in water uptake period (phase III) than during the rapid initial uptake period (phase I) and the plateau period (phase II) under PEG stress. The pathway analysis of DEGs showed that the highly enriched categories were related to phenylpropanoid biosynthesis, plant hormone signal transduction and phenylalanine metabolism during phase III. The 20 phenylpropanoids-related genes of germinating foxtail millet were found to be down-regulated during the further increase in water uptake period under PEG stress. Further expression analysis identified 4 genes of phenylalanine ammonia-lyase, 4-coumarate-CoA ligase 3, cinnamoyl-CoA reductase 1, cationic peroxidase SPC4 in phenylpropanoids-related pathway, which played important roles in foxtail millet in response to PEG stress during different germination periods. The studies of metabolites in phenylpropanoid biosynthesis pathway revealed that higher amount of cinnamic acid was accumulated in germinating seeds under PEG stress, while the contents of p-coumaric acid, caffeic acid, ferulic acid and sinapic acid were decreased. And the effects of five phenolic compounds on germination and growth of foxtail millet showed that 1 mM concentration of cinnamic acid inhibited shoot and root growth, especially root development. Ferulic acid, caffeic acid, sinapic acid and p-coumaric acid could increase the root length and root/sprout in lower concentration. Conclusions These findings suggest that key genes and metabolites of foxtail millet related with phenylpropanoids pathway may play prominent roles in the regulation of resistance to drought during germination. Foxtail millet can probably avoid drought by regulating the levels of endogenous allelochemicals.

The extensive and sometimes unregulated use of synthetic chemicals, such as drugs, preservatives, and pesticides, is posing big threats to global health, the environment, and food security. This has stimulated the research of new strategies to deal with bacterial infections in animals and humans and to eradicate pests. Plant extracts, particularly essential oils, have recently emerged as valid alternatives to synthetic drugs, due to their properties which include antibacterial, antifungal, anti-inflammatory, antioxidant, and insecticidal activity. This review discusses the current research on the use of electrospinning to encapsulate essential oils into polymeric nanofibres and achieve controlled release of these bioactive compounds, while protecting them from degradation. The works here analysed demonstrate that the electrospinning process is an effective strategy to preserve the properties of essential oils and create bioactive membranes for biomedical, pharmaceutical, and food packaging applications.

Powdery mildew is one of the most destructive diseases and the major cause to the production losses of cucurbit worldwide. A number of strategies have been developed and applied to discover suitable and safer methods to manage the occurrence of powdery mildew disease in pumpkins ( Cucurbita pepo L.), but information is limited in screening tolerant germplasms and exploring their mechanisms in preventing the disease occurrence at physiological, biochemical, and molecular levels. Therefore, we investigated the responses of two commercial pumpkin cultivars to Podosphaera xanthii infection. Compared with mock-inoculated seedlings, few small and sparse powdery areas were observed on the leaves of the Sixing F 1 cultivar on the 13 th day after inoculation with P. xanthii , whereas a large number of diseased powdery areas and a layer of white powdery mildew were observed on the surface of Jin 12 F 1 leaves. The inoculation duration (7, 9, 11, and 13 days) significantly and continuously increased the disease incidence and index of pumpkin seedlings. The contents of H 2 O 2 , MDA, lignin, and total phenolics in the leaves of Sixing F 1 and Jin 12 F 1 cultivars were markedly increased after inoculation with P. xanthii . However, the Sixing F 1 cultivar exhibited much less reactive oxygen species (ROS) accumulation, a lower rate of lipid peroxidation, and a higher level of lignin and total phenolics contents after inoculation than the Jin 12 F 1 cultivar. Compared with untreated control pumpkin seedlings, significantly higher activities and gene expressions of the phenylpropanoids pathway enzymes (PAL and PPO), ROS scavenging defense enzymes (SOD, CAT, POD, and APX), and other salicylic acid (SA) signaling pathway marker genes were observed in the leaves of both cultivars after P. xanthii inoculation at different inoculation time points. These enhancements were significantly higher in Sixing F 1 than Jin 12 F 1 . Our results indicate that the Sixing F 1 cultivar exhibited a much stronger ability in resistance to P. xanthii infection than the Jin 12 F 1 cultivar. Our results suggest that one possible mechanism of C. pepo cultivars to prevent the pathogen P. xanthii infection is by activating and enhancing the activity and gene expression of the phenylpropanoids pathway to synthesize phenolic substances and lignin, ROS scavenging defense enzymes to eliminate the harmful effects of ROS, and signaling pathway marker gene expression to improve plant disease resistance.