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Hibiscus syriacus belongs to the Malvaceae family, and is a plant with medicinal, edible, and greening values. MADS-box transcription factor is a large family of regulatory factors involved in a variety of biological processes in plants. Here, we performed a genome-wide characterization of MADS-box proteins in H. syriacus and investigated gene structure, phylogenetics, cis-acting elements, three-dimensional structure, gene expression, and protein interaction to identify candidate MADS-box genes that mediate petal developmental regulation in H. syriacus. A total of 163 candidate MADS-box genes were found and classified into type I (Mα, Mβ, and Mγ) and type II (MIKC and Mδ). Analysis of cis-acting elements in the promoter region showed that most elements were correlated to plant hormones. The analysis of nine HsMADS expressions of two different H. syriacus cultivars showed that they were differentially expressed between two type flowers. The analysis of protein interaction networks also indicated that MADS proteins played a crucial role in floral organ identification, inflorescence and fruit development, and flowering time. This research is the first to analyze the MADS-box family of H. syriacus and provides an important reference for further study of the biological functions of the MADS-box, especially in flower organ development. [ABSTRACT FROM AUTHOR]

The dynamic development of the food industry and the growing interest of consumers in innovative solutions that increase the comfort and quality of life push the industry towards seeking pioneering solutions in the field of food packaging. Intelligent and active packaging, which affects the quality and durability of food products and allows one to determine their freshness, is still a modern concept. The aim of our study was to obtain two types of films based on chitosan and starch with micellar nanostructures containing extracts from turmeric rhizomes and hibiscus flowers. The presence of spherical nanostructures was confirmed using a scanning electron microscope. The structural and optical properties of the obtained composites were characterised by Fourier-transform infrared (FTIR), UltraViolet-Visible (UV-VIS), and photoluminescence (PL) spectroscopy. Scanning electron microscopy (SEM) analysis confirmed the presence of spherical micellar structures with a size of about 800 nm in the obtained biocomposites. The presence of nano-/microstructures containing extracts affected the mechanical properties of the composites: it weakened the strength of the films and improved their elongation at break (EAB). Films with nano-/microparticles were characterised by a higher water content compared to the control sample and lower solubility, and they showed stronger hydrophilic properties. Preliminary storage tests showed that the obtained biocomposites are sensitive to changes occurring during the storage of products such as cheese or fish. In addition, it was found that the film with the addition of turmeric extract inhibited the growth of microorganisms during storage. The results suggest that the obtained bionanocomposites can be used as active and/or intelligent materials. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop and characterise bionanocomposites based on chitosan (CHIT) and alginate (ALG) in two series, which were subsequently functionalised with emulsions based on a combination of water, oil, ozonated oil and hibiscus flower extracts. The structure and morphology of the materials produced were characterised by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and ultraviolet and visible light (UV-Vis) absorption spectroscopy, along with a surface colour analysis and the determination of the mechanical and thermal properties of the resulting composites. Functionalisation did affect the analysed composite parameters. The FTIR spectra indicated that the polysaccharide matrix components were compatible. The SEM images also confirmed the presence of nano/microcapsules in the polysaccharide matrix. The obtained results indicate that the order of adding polysaccharides has a significant impact on the encapsulation capacity. The encapsulation resulted in the improved thermal stability of the composites. The emissions analysis showed that the composites containing nano/microcapsules are characterised by a higher emission intensity and are sensitive to acid or base changes. Significant differences in emission intensity were observed even at low concentrations of acids and bases. A drop in the mechanical properties was observed following functionalisation. The results of this study suggest that these bionanocomposites can be used as active and/or smart packaging materials. [ABSTRACT FROM AUTHOR]

NAC transcription factor is one of the largest plant gene families, participating in the regulation of plant biological and abiotic stresses. In this study, 182 NAC proteins (HhNACs) were identified based on genomic datasets of Hibiscus hamabo Sieb. et Zucc (H. hamabo). These proteins were divided into 19 subfamilies based on their phylogenetic relationship, motif pattern, and gene structure analysis. Expression analysis with RNA-seq revealed that most HhNACs were expressed in response to drought and salt stress. Research of quantitative real-time PCR analysis of nine selected HhNACs supported the transcriptome data's dependability and suggested that HhNAC54 was significantly upregulated under multiple abiotic stresses. Overexpression of HhNAC54 in Arabidopsis thaliana (A. thaliana) significantly increased its tolerance to salt. This study provides a basis for a comprehensive analysis of NAC transcription factor and insight into the abiotic stress response mechanism in H. hamabo. [ABSTRACT FROM AUTHOR]

The renal system is engaged in metabolic syndrome (MS) and metabolites of arachidonic acid (AA) participate in renal homeostasis and disruption of functionality. Hibiscus sabdariffa L (HSL) is used as a diuretic and could improve renal function. The aim of this study was to assess if treatment with HSL at 2% improves renal function in MS through the metabolites of AA. A total of 24 male Wistar rats were divided into four groups: Group 1, control (C); Group 2, MS with 30% sucrose in drinking water, Group 3, MS plus HSL infusion at 2% (MS+HSL); and Group 4, C+HSL. We evaluated the perfusion pressure changes (∆-PP), the activities of cyclooxygenases (COXs), the percentage of AA, the expressions of PLA 2 , COX2, COX1, 5-LOX, TAXS and CYP450, and the concentrations of prostaglandins in the kidney from rats with MS. There was a decrease in the ∆-PP, in the activities of COXs, and the expressions of COX2 and CYP450 ( p ≤ 0.03, respectively)as well asPGE 2 , TxB 2 , and LKB 4 ( p ≤ 0.01, respectively). However, the percentage of AA and expressions of PLA 2 and PGE1 ( p = 0.01, respectively) were increased in C and MS+HSL. The HSL treatment improved the function and anatomical structure of the kidneys in the MS rats, through antioxidant molecules, and inhibited the pathways that metabolize the AA including that of PLA 2 , COX2, 5-LOX, TAXS, and CYP450 while favoring the COX1 pathway. This improves the vascular resistance of renal arterioles.

TGF-β1, a key fibrotic cytokine, enhances both the expression and translocation of the activating transcriptional factor 4 (ATF4) and activates the serine/glycine biosynthesis pathway, which is crucial for augmenting collagen production. Targeting the TGF-β1-ATF4-serine/glycine biosynthesis pathway might offer a promising therapeutic approach for fibrotic diseases. In this study, we aimed to identify a proline-containing dipeptide in Hibiscus sabdariffa plant cells that modulates collagen synthesis. We induced Hibiscus sabdariffa plant cells and screened for a proline-containing dipeptide that can suppress TGF-β1-induced collagen synthesis in fibroblasts. Analyses were conducted using LC-MS/MS, RT-qPCR, Western blot analysis, and immunocytochemistry. We identified Gly-Pro (GP) from the extract of Hibiscus sabdariffa plant cells as a dipeptide capable of suppressing TGF-β1-induced collagen production. GP inhibited the phosphorylation of Smad2/3 and reduced the expression of ATF4, which is upregulated by TGF-β1. Notably, GP also decreased the expression of enzymes involved in the serine/glycine biosynthesis and glucose metabolism pathways, such as PHGDH, PSAT1, PSPH, SHMT2, and SLC2A1 . Our findings indicate that the peptide GP, derived from Hibiscus sabdariffa plant cells, exhibits potent anti-fibrotic effects, potentially through its regulation of the TGF-β1-ATF4-serine/glycine biosynthesis pathway.

Roselle ( Hibiscus sabdariffa L.) is a plant that has traditionally been used in various food and beverage products. Here, we investigated the potential of water extracts derived from Roselle leaves and callus cells for cosmetic and pharmaceutical purposes. We generated calluses from Roselle leaves and produced two different water extracts through heat extraction, which we named Hibiscus sabdariffa plant extract (HSPE) and Hibiscus sabdariffa callus extract (HSCE). HPLC analysis showed that the two extracts have different components, with nucleic acids and metabolites such as phenylalanine and tryptophan being the most common components in both extracts. In vitro assays demonstrated that HSCE has strong anti-melanogenic effects and functions for skin barrier and antioxidant activity. Transcriptome profiling of human skin cells treated with HSPE and HSCE showed significant differences, with HSPE having more effects on human skin cells. Up-regulated genes by HSPE function in angiogenesis, the oxidation-reduction process, and glycolysis, while up-regulated genes by HSCE encode ribosome proteins and IFI6, functioning in the healing of radiation-injured skin cells. Therefore, we suggest that the two extracts from Roselle should be applied differently for cosmetics and pharmaceutical purposes. Our findings demonstrate the potential of Roselle extracts as a natural source for skincare products.

Previous findings on the capacity of Hibiscus sabdariffa (HS) polyphenols to ameliorate metabolic disturbances justify the necessity of studies oriented to find the potential metabolites responsible for such an effect. The present study examined the intestinal epithelial membrane permeability of polyphenols present in a phenolic-enriched Hibiscus sabdariffa extract (PEHS), free and encapsulated, using the Caco-2 cell line. Additionally, selected polyphenols (quercetin, quercetin-3-glucoside, quercetin-3-glucuronide, and N-feruloyltyramine) were also studied in the same absorption model. The powerful analytical platform used ultra-high-performance liquid chromatography coupled with ultra-high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-ESI-UHR-Qq- TOF-MS), and enabled the characterization of seven new compounds in PEHS. In the permeation study, only a few compounds were able to cross the cell monolayer and the permeability was lower when the extract was in an encapsulated form. Pure compounds showed a moderate absorption in all cases. Nevertheless, these preliminary results may need further research to understand the complete absorption mechanism of Hibiscus polyphenols. [ABSTRACT FROM AUTHOR]

Roselle ( Hibiscus sabdariffa L.) is an annual herbaceous plant of the genus Hibiscus in family Malvaceae. Roselle calyxes are rich in anthocyanins, which play important roles in human health. However, limited information is available on anthocyanin biosynthesis in the roselle calyx. In this study, transcriptomic and metabolomic analyses were performed to identify the key genes involved in anthocyanin biosynthesis in the roselle calyx. Three roselle cultivars with different calyx colors, including FZ-72 (red calyx, R), Baitao K (green calyx, G), and MG5 (stripped calyx, S), were used for metabolomic analyses with UPLC-Q-TOF/MS and RNA-seq. Forty-one compounds were quantified, including six flavonoids and 35 anthocyanins. The calyx of FZ-72 (red calyx) had the highest contents of anthocyanin derivatives such as delphinidin-3-O-sambubioside (955.11 μg/g) and cyanidin-3-O-sambubioside (531.37 μg/g), which were responsible for calyx color, followed by those in MG5 (stripped calyx) (851.97 and 330.06 μg/g, respectively). Baitao K (green calyx) had the lowest levels of these compounds. Furthermore, RNA-seq analysis revealed 114,415 differentially expressed genes (DEGs) in the calyxes at 30 days after flowering (DAF) for the corresponding cultivars FZ-72 (R), Baitao K (G), and MG5(S). The gene expression levels in the calyxes of the three cultivars were compared at different flowering stages, revealing 11,555, 11,949, and 7177 DEGs in R vs. G, R vs. S, and G vs. S, respectively. Phenylpropanoid and flavonoid biosynthesis pathways were found to be enriched. In the flavonoid pathway, 29, 28, and 27 genes were identified in G vs. R, G vs. S, and S vs. R, respectively. In the anthocyanin synthesis pathway, two, two, and one differential genes were identified in the three combinations; these differential genes belonged to the UFGT gene family. After joint analysis of the anthocyanin content in roselle calyxes, nine key genes belonging to the CHS , CHI , UFGT , FLS , ANR , DFR , CCoAOMT , SAT , and HST gene families were identified as strongly related to anthocyanin synthesis. These nine genes were verified using qRT-PCR, and the results were consistent with the transcriptome data. Overall, this study presents the first report on anthocyanin biosynthesis in roselle, laying a foundation for breeding roselle cultivars with high anthocyanin content.

This work studies the effects of water deficit and heat, as well as the involvement of chlororespiration and the ferredoxin-mediated cyclic pathway, on the tolerance of photosynthesis to high light intensity in Hibiscus rosa-sinensis plants. Drought and heat resulted in the down--regulation of photosynthetic linear electron transport in the leaves, although only a slight decrease in variable fluorescence (Fv)/maximal fluorescence (Fm) was observed, indicating that the chloroplast was protected by mechanisms that dissipate excess excitation energy to prevent damage to the photosynthetic apparatus. The incubation of leaves from unstressed plants under high light intensity resulted in an increase of the activity of electron donation by nicotinamide adenine dinucleotide phosphate (NADPH) and ferredoxin to plastoquinone, but no increase was observed in plants exposed to water deficit, suggesting that cyclic electron transport was stimulated by high light only in control plants. In contrast, the activities of the chlororespiration enzymes (NADH dehydrogenase (NDH) complex and plastid terminal oxidase (PTOX)) increased after incubation under high light intensity in leaves of the water deficit plants, but not in control plants, suggesting that chlororespiration was stimulated in stressed plants. The results indicate that the relative importance of chlororespiration and the cyclic electron pathway in the tolerance of photosynthesis to high illumination differs under stress conditions. When plants were not subjected to stress, the contribution of chlororespiration to photosynthetic electron flow regulation was not relevant, and another pathway, such as the ferredoxin-mediated cyclic pathway, was more important. However, when plants were subjected to water deficit and heat, chlororespiration was probably essential. [ABSTRACT FROM AUTHOR]

Hibiscus hamabo Sieb. et Zucc is an important semi-mangrove plant with great morphological features and strong salt resistance. In this study, by combining single molecule real time and next-generation sequencing technologies, we explored the transcriptomic changes in the roots of salt stressed H. hamabo. A total of 94,562 unigenes were obtained by clustering the same isoforms using the PacBio RSII platform, and 2269 differentially expressed genes were obtained under salt stress using the Illumina platform. There were 519 differentially expressed genes co-expressed at each treatment time point under salt stress, and these genes were found to be enriched in ion signal transduction and plant hormone signal transduction. We used Arabidopsis thaliana (L.) Heynh. transformation to confirm the function of the HhWRKY79 gene and discovered that overexpression enhanced salt tolerance. The full-length transcripts generated in this study provide a full characterization of the transcriptome of H. hamabo and may be useful in mining new salt stress-related genes specific to this species, while facilitating the understanding of the salt tolerance mechanisms. [ABSTRACT FROM AUTHOR]

The basic helix-loop-helix (bHLH) family of transcription factors is one of the most significant and biggest in plants. It is involved in the regulation of both growth and development, as well as stress response. Numerous members of the bHLH family have been found and characterized in woody plants in recent years. However, no systematic study of the bHLH gene family has been published for Hibiscus hamabo Sieb. et Zucc. In this research, we identified 162 bHLH proteins (HhbHLHs) from the genomic and transcriptomic datasets of H. hamabo, which were phylogenetically divided into 19 subfamilies. According to a gene structural study, the number of exon-introns in HhbHLHs varied between zero and seventeen. MEME research revealed that the majority of HhbHLH proteins contained three conserved motifs, 1, 4, and 5. The examination of promoter cis-elements revealed that the majority of HhbHLH genes had several cis-elements involved in plant growth and development and abiotic stress responses. In addition, the overexpression of HhbHLH2 increased salt and drought stress tolerance in Arabidopsis. [ABSTRACT FROM AUTHOR]