Pressurized Hot Water Extraction of Okra Seeds Reveals Antioxidant, Antidiabetic and Vasoprotective Activities

Genomic assembly, characterization, and quantification of DICER-like gene family in Okra plants under dehydration conditions

Background

Okra is a plant farmed for its pods, leaves, and stems all of which are edible. It is famous for its ability to tolerate long desiccation periods. It belongs to the Malvaceae family and is a sister species to hibiscus, cotton, and cacao plants.

Methods

In the current study, okra plants were used as a model to sequence, assemble, and analyze the evolutionary and functional characteristics of the Dicer-like protein gene family (DCL) based on DNAseq and qPCR techniques.

Results

Four Dicer-like (DCL) single-copy genes of the okra plant Abelmoschus esculentus (L.) Moench (AeDCL) were successfully assembled. The lengths of the AeDCL copies were 8,494, 5,214, 4,731, and 9,329 bp. The detected exons in these samples ranged from a single exon in AeDCL3 to 24 exons in AeDCL4. AeDCLs had five functional domains of two DEAD-like helicase superfamilies, N and C; one Dicer domain; one ribonuclease III domain (a and b); and one double-stranded RNA-binding domain. The PAZ domain was completely annotated only for AeDCL1 and AeDCL3. All AeDCLs were up-regulated under drought conditions, with leaves showing more extensive fold changes than roots. The study focused on a comprehensive genome-wide identification and analysis of the DCL gene family in naturally drought-tolerant okra plants, an orphan crop that can be used as a model for further genomic and transcriptomic studies on drought-tolerance mechanisms in plants.

Time-dependent specific molecular signatures of inflammation and remodelling are associated with trimethylamine-N-oxide (TMAO)-induced endothelial cell dysfunction

Endothelial dysfunction is a critical initiating factor contributing to cardiovascular diseases, involving the gut microbiome-derived metabolite trimethylamine N-oxide (TMAO). This study aims to clarify the time-dependent molecular pathways by which TMAO mediates endothelial dysfunction through transcriptomics and metabolomics analyses in human microvascular endothelial cells (HMEC-1). Cell viability and reactive oxygen species (ROS) generation were also evaluated. TMAO treatment for either 24H or 48H induces reduced cell viability and enhanced oxidative stress. Interestingly, the molecular signatures were distinct between the two time-points. Specifically, few Gene Ontology biological processes (BPs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were modulated after a short (24H) compared to a long (48H) treatment. However, the KEGG signalling pathways namely "tumour necrosis factor (TNF)" and "cytokine-cytokine receptor interaction" were downregulated at 24H but activated at 48H. In addition, at 48H, BPs linked to inflammatory phenotypes were activated (confirming KEGG results), while BPs linked to extracellular matrix (ECM) structural organisation, endothelial cell proliferation, and collagen metabolism were repressed. Lastly, metabolic profiling showed that arachidonic acid, prostaglandins, and palmitic acid were enriched at 48H. This study demonstrates that TMAO induces distinct time-dependent molecular signatures involving inflammation and remodelling pathways, while pathways such as oxidative stress are also modulated, but in a non-time-dependent manner.

Pressurized Hot Water Extraction of Mangosteen Pericarp and Its Associated Molecular Signatures in Endothelial Cells

The mangosteen (Garcinia mangostana L.) pericarp is known to be rich in potent bioactive phytochemical compounds such as xanthones, which possess pharmacologically important antioxidant activity and beneficial cardiometabolic properties. Mangosteen pericarp is typically classified as unavoidable food waste and discarded, despite being rich in bioactive phytochemical compounds that therefore present an exciting opportunity for valorization. Thus, this study aims to extract phytochemical compounds from mangosteen pericarp using pressurized hot water extraction (PHWE) and determine its biological effects in endothelial cells using RNA sequencing. Liquid chromatography with MS/MS (LC/MSMS) and UV detection (LC/UV) was subsequently used to identify three key phytochemical compounds extracted from the mangosteen pericarp: α-Mangostin, γ-Mangostin, and Gartanin. Within the tested range of extraction temperatures by PHWE, our results demonstrated that an extraction temperature of 120 °C yielded the highest concentrations of α-Mangostin, γ-Mangostin, and Gartanin with a concomitant improvement in antioxidant capacity compared to other extraction temperatures. Using global transcriptomic profiling and bioinformatic analysis, the treatment of endothelial cells with mangosteen pericarp extracts (120 °C PHWE) for 48 h caused 408 genes to be differentially expressed. Furthermore, our results demonstrated that key biological processes related to "steroid biosynthesis and metabolism", likely involving the activation of the AMPK signaling pathway, were upregulated by mangosteen pericarp extract treatment. In conclusion, our study suggests a green extraction method to valorize phytochemical compounds from mangosteen pericarp as a natural product with potential beneficial effects on cardiometabolic health.

Recent advances in the combination of organic solvent-free extraction, chemical standardization, antioxidant assay, and cell culture metabolomics for functional food and its by-product

Functional foods and their by-products contain a wide range of bioactive components with an array of health benefits and were proposed to improve public health, well-being, and others. To achieve a circular economy, the processing and extraction of flavonoids, phenolic compounds, and others from functional food and agri-food wastes will require the use of environmentally friendly, sustainable, and a low-cost solution. Extraction methods that can eliminate the use of organic solvents, suitable for use in the laboratory and production of extracts will be covered. This will include subcritical water extraction (SBE), pressurized hot water extraction (PHWE), supercritical fluid extraction (SFE), and others. Based on the selected analytical methods, the determination of the marker or bioactive compounds and chemical fingerprints will provide the control measures to identify the batch-to-batch variation of the composition of the functional food products obtained. The combination of chemical standardization with antioxidant assay, such as DPPH and ABTS+ will provide further information on the quality of the extracts. Lastly, to ascertain the biological and physiological relevance of the antioxidant properties of the target sample, treatment of the antioxidant compounds or extracts was carried out using cellular models, and validated using other experimental endpoints, such as metabolomics.

Urine Metabolites and Bioactive Compounds from Functional Food: Applications of Liquid Chromatography Mass Spectrometry

Bioactive compounds in functional foods, medicinal plants and others are considered attractive value-added molecules based on their wide range of bioactivity. It is clear that an important role is occupied by polyphenol, phenolic compounds and others. Urine is an effective biofluid to evaluate and monitor alterations in homeostasis and other processes related to metabolism. The current review provides a detailed description of the formation of urine in human body, various aspects relevant to sampling and analysis of urinary metabolites before presenting recent developments leveraging on metabolite profiling of urine. For the profiling of small molecules in urine, advancement of liquid chromatography mass tandem spectrometry (LC/MS/MS), establishment of standardized chemical fragmentation libraries, computational resources, data-analysis approaches with pattern recognition tools have made it an attractive option. The profiling of urinary metabolites gives an overview of the biomarkers associated with the diet and evaluates its biological effects. Metabolic pathways such as glycolysis, tricarboxylic acid cycle, amino acid metabolism, energy metabolism, purine metabolism and others can be evaluated. Finally, a combination of metabolite profiling with chemical standardization and bioassay in functional food and medicinal plants will likely lead to the identification of new biomarkers and novel biochemical insights.

Relaxin elicits renoprotective actions accompanied by increasing bile acid levels in streptozotocin-induced diabetic mice

BACKGROUND

The peptide hormone relaxin has potent anti-fibrotic and anti-inflammatory properties in various organs, including the kidneys. However, the protective effects of relaxin in the context of diabetic kidney complications remain controversial. Here, we aimed to evaluate the effects of relaxin treatment on key markers of kidney fibrosis, oxidative stress, and inflammation and their subsequent impact on bile acid metabolism in the streptozotocin-induced diabetes mouse model.

METHODS AND RESULTS

Male mice were randomly allocated to placebo-treated control, placebo-treated diabetes or relaxin-treated diabetes groups (0.5 mg/kg/d, final 2 weeks of diabetes). After 12 weeks of diabetes or sham, the kidney cortex was harvested for metabolomic and gene expression analyses. Diabetic mice exhibited significant hyperglycaemia and increased circulating levels of creatine, hypoxanthine and trimethylamine N-oxide in the plasma. This was accompanied by increased expression of key markers of oxidative stress (Txnip), inflammation (Ccl2 and Il6) and fibrosis (Col1a1, Mmp2 and Fn1) in the diabetic kidney cortex. Relaxin treatment for the final 2 weeks of diabetes significantly reduced these key markers of renal fibrosis, inflammation, and oxidative stress in diabetic mice. Furthermore, relaxin treatment significantly increased the levels of bile acid metabolites, deoxycholic acid and sodium glycodeoxycholic acid, which may in part contribute to the renoprotective action of relaxin in diabetes.

CONCLUSION

In summary, this study shows the therapeutic potential of relaxin and that it may be used as an adjunctive treatment for diabetic kidney complications.

Gut-Derived Metabolite, Trimethylamine-N-oxide (TMAO) in Cardio-Metabolic Diseases: Detection, Mechanism, and Potential Therapeutics

Trimethylamine N-oxide (TMAO) is a biologically active gut microbiome-derived dietary metabolite. Recent studies have shown that high circulating plasma TMAO levels are closely associated with diseases such as atherosclerosis and hypertension, and metabolic disorders such as diabetes and hyperlipidemia, contributing to endothelial dysfunction. There is a growing interest to understand the mechanisms underlying TMAO-induced endothelial dysfunction in cardio-metabolic diseases. Endothelial dysfunction mediated by TMAO is mainly driven by inflammation and oxidative stress, which includes: (1) activation of foam cells; (2) upregulation of cytokines and adhesion molecules; (3) increased production of reactive oxygen species (ROS); (4) platelet hyperreactivity; and (5) reduced vascular tone. In this review, we summarize the potential roles of TMAO in inducing endothelial dysfunction and the mechanisms leading to the pathogenesis and progression of associated disease conditions. We also discuss the potential therapeutic strategies for the treatment of TMAO-induced endothelial dysfunction in cardio-metabolic diseases.

Phenolic Compounds from New Natural Sources-Plant Genotype and Ontogenetic Variation

Phenolic compounds (PCs) are widespread secondary metabolites with potent biological activity. Their sources are mainly plants from cultivated and natural states, providing valuable protective and health-promoting extracts. The wide biological activity of PCs (antioxidant, anti-inflammatory, antimicrobial, antiatherosclerotic, antidiabetic, antiallergic, prebiotic, antimutagenic) means that new sources of PCs are constantly being sought, as exemplified by extracting these compounds from tissue culture or agricultural by-products. Plant phenols show marked qualitative and quantitative variation not only at different genetic levels (between and within species and clones) but also between different physiological and developmental stages. Assessing genetic and seasonal variations in phenolic content and activity allows for selecting the best time to harvest the plant. Learning about the causes of PCs' variability and putting this knowledge into practice can significantly increase PCs' yields and extract the most valuable compounds. The health-promoting properties resulting from consuming products rich in plant PCs are undeniable, so it is worth promoting high-phenolic products as a regular diet. This paper presents an overview of different sources of PCs for use as potential therapeutic alternatives. Additionally, factors of variation in the phenolic complex at the genome and ontogeny levels, relevant in practical terms and as a basis for further scientific research, are presented.

Antioxidant and antidiabetic activities of a polyphenol rich extract obtained from Abelmoschus esculentus (okra) seeds using optimized conditions in microwave-assisted extraction (MAE)

Functional foods have gained popularity in recent decades. They are exploited for their bioactive compounds like polyphenols, which are highly demanded in cosmetic, pharmaceutical and nutraceutical industries. However, extractive techniques and conditions used up to recently are almost obsolete and must be optimized for higher efficiency. The current study aimed to evaluate the antidiabetic potential of an optimized extract of Abelmoschus esculentus (okra) seeds. The optimal conditions for extracting polyphenolic compounds from okra seeds were determined using Microwave Assisted Extraction (MAE). A Face Center Composite Design (FCCD) was used for optimization. Solvent/dry matter ratio, wavelength and time were considered while the response studied was the polyphenolic content. The extract obtained at optimal conditions was characterized using Thin Layer Chromatography (TLC) and Fourier Transform Infra-Red (FTIR) spectroscopy, then tested for its antioxidant, alpha amylase inhibitory and antidiabetic activities. Response Surface Methodology (RSM) permitted the determination of the optimal conditions for phenols extraction as: microwave power 330 W, with a solvent ratio of 97.04/1 mL/g for 9.5 min of extraction time. The optimized extract showed a phenolic content up to 86.37 ± 1.13 mg GAE/g containing quercetin and catechin as revealed by the TLC. Functional groups characteristic of polyphenols were identified on FTIR spectra, and the extract exhibited good in vitro antioxidant capacities with DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging capacity and FRAP (Ferric Reducing Antioxidant Power Assay). An IC50 of 3.99 ± 0.15 μg/mL was obtained with the DPPH scavenging test. Alpha amylase inhibitory assay revealed that the optimized okra extract behaved as a non-competitive inhibitor of porcine pancreatic amylase with an IC50 of 484.17 ± 2.33 μg/mL. Antidiabetic activity of the extract was observed in streptozotocin-induced diabetic males Wistar rats, as shown by the fasting blood glucose levels, food intake, changes in body weight and serum lipid profile among others.

Utilizing Nutritional and Polyphenolic Compounds in Underutilized Plant Seeds for Health Application

Plants represent a significant part of the human diet. Humans have utilized every part of plants for survival, and seeds are no exception. Seeds offer high protein, unsaturated fats, fibre, essential vitamins, and minerals for various food applications. They are also a promising reservoir of bioactive compounds, where various phytochemicals, such as polyphenolic compounds, capable of maintaining and improving well-being, are present in abundant quantities. Plants from Malvaceae and Cannabaceae families are known for their fibre-rich stems that benefit humankind by serving numerous purposes. For many centuries they have been exploited extensively for various commercial and industrial uses. Their seeds, which are often regarded as a by-product of fibre processing, have been scientifically discovered to have an essential role in combating hypercholesterolemia, diabetes, cancer, and oxidative stress. Maximizing the use of these agricultural wastes can be a promising approach to creating a more sustainable world, in accordance with the concept of Sustainable Development Goals (SDGs).

Schisandra chinensis (Turcz.) Baill. essential oil exhibits antidepressant-like effects and against brain oxidative stress through Nrf2/HO-1 pathway activation

The present study aimed to evaluate the antidepressant-like effect of essential oils from Schisandra chinensis (Turcz.) Baill. (SEO) and its possible mechanisms of SEO. The behavioral despair mouse model in vivo and H2O2-induced PC12 cells model in vitro were employed. And the potential effective components were identified by the spectrum-effect relationships analysis. SEO significantly decreased the immobility time in the forced swimming test and tail suspension test, which indicated a promising antidepressant-like effect of SEO in depressed mice. The decreased levels of SOD, GSH, and CAT, and increased levels of MDA were significantly reversed by SEO treatment, which showed good antioxidant activities both in vitro and in vivo. Besides, SEO significantly promoted the nuclear translocation of Nrf2 and the expression of HO-1 in depressed mice and H2O2-induced PC12 cells. The histopathological examination results showed a potential neuronal protective effect of SEO in the hippocampus and cortex. Furthermore, the upregulation of PI3K/AKT/GSK3β signaling was observed after SEO treatment in the H2O2-induced PC12 cells. Additionally, based on the spectrum-effect relationship analysis, 9 peaks were identified as positively correlated with the antioxidant activity of SEO. These results suggested that SEO promoted Nrf2/HO-1 pathway to improve the oxidative stress status and exerted the antidepressant-like effects.

Green Extraction of Orange Peel Waste Reduces TNFα-Induced Vascular Inflammation and Endothelial Dysfunction

Orange peel waste (OPW) is known to contain an abundant amount of polyphenols compounds such as flavonoids, well-reported for their antioxidant and anti-inflammatory properties. While OPW is generally regarded as a food waste, the opportunity to extract bioactive compounds from these “wastes” arises due to their abundance, allowing the investigation of their potential effects on endothelial cells. Hence, this study aims to use a green extraction method and pressurized hot water extraction (PHWE) to extract bioactive compounds from OPW. Liquid chromatography with UV detection (LC/UV) and liquid chromatography mass spectrometry (LC/MS) were subsequently used to identify the bioactive compounds present. Through the optimization of the extraction temperature for PHWE, our results demonstrated that extraction temperatures of 60 °C and 80 °C yield distinct bioactive compounds and resulted in better antioxidant capacity compared to other extraction temperatures or organic solvent extraction. Despite having similar antioxidant capacity, their effects on endothelial cells were distinct. Specifically, treatment of endothelial cells with 60 °C OPW extracts inhibited TNFα-induced vascular inflammation and endothelial dysfunction in vitro, suggesting that OPW possess vasoprotective effects likely mediated by anti-inflammatory effects.

Valorization of avocado seeds with antioxidant capacity using pressurized hot water extraction

The pulp of avocado (Persea Americana) is widely consumed as the primary food source, while the seed is often discarded as food waste. Increased consumption of avocado would inevitably results in production of waste by-products such as avocado seeds, hence the ability to extract phytochemicals from such waste, and upcycling to potential nutraceutical products is of great interest. The overall aim of this study is to explore avocado seeds as potential functional food through the combined use of a green extraction method, chemical standardization and pattern recognition tools, and biological characterization assays. Specifically, this study utilized an organic solvent-free extraction method, pressurized hot water extraction (PHWE) to extract phytochemicals from avocado seeds and liquid chromatography mass spectrometry (LCMS) was used to identify the phytochemicals present in the avocado seeds. Our results demonstrated that avocado seed extracts have antioxidant activity and inhibited oxidative stress-induced metabolomics changes in endothelial cells, suggesting that avocado seed extracts have vasoprotective actions.

Immunomodulatory effects of Abelmoschus esculentus water extract through MAPK and NF-κB signaling in RAW 264.7 cells

During the current COVID-19 pandemic, the world is facing a new, highly contagious virus that suppresses innate immunity as one of its early virulence mechanisms. Therefore, finding new methods to enhance innate immunity is a promising strategy to attenuate the effects of this major global health problem. With the aim of characterizing bioactive ingredients as immune-enhancing agents, this study focuses on Abelmoschus esculentus (okra), which has several previously demonstrated bioactivities. Firstly, we investigated the immune-stimulatory effects of okra leaf ethanol extract (OLE) and okra leaf water extract (OLW) on nitric oxide (NO) production in macrophages. OLE significantly decreased nitrite accumulation in LPS-stimulated RAW 264.7 cells, indicating that it potentially inhibited NO production in a concentration-dependent manner. In contrast, OLW significantly enhanced the production of prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NO in a dose-dependent manner. OLW also increased the expression levels of NO synthase (iNOS) and cyclooxygenase (COX)-2, potentially explaining the OLW-induced increase in NO and PGE₂ production. In addition, OLW stimulated the phosphorylation of mitogen-activated protein kinases (MAPKs; ERK, p38, and JNK) as well as the activation and subsequent nuclear translocation of nuclear factor κB (NF-κB). This indicated that OLW activates macrophages to secrete PGE₂, TNF-α, IL-1β, and NO, inducing iNOS and COX-2 expression via activation of the NF-κB and MAPK signaling pathways. In conclusion, our results demonstrate that OLW can effectively promote the activation of macrophages, suggesting that OLW may possess potent immunomodulatory effects and should be explored as a potential health-promoting materials to boost the immune system.