New Acylated Phenolic Glycosides with ROS-Scavenging Activity from Psidium guajava Leaves

Bacteroides uniformis ameliorates pro-inflammatory diet-exacerbated colitis by targeting endoplasmic reticulum stress-mediated ferroptosis

INTRODUCTION

A pro-inflammatory diet is positively associated with the risk and progression of inflammatory bowel diseases (IBD). Recently, ferroptosis has been observed in patients with different dietary patterns-associated intestinal inflammation, while the mechanisms underlying the effects of a pro-inflammatory diet and whether it mediates ferroptosis are unknown.

OBJECTIVES

This study aims to elucidate the mechanisms underlying pro-inflammatory diet-mediated colitis and explore potential intervention strategies.

METHODS

Mice were fed a dietary inflammatory index-based pro-inflammatory diet for 12 weeks. Subsequently, colitis was chemically induced using 2.5 % dextran sulfate sodium. The body weight, pathological score, immune response and mucosal barrier function were evaluated to assess intestinal inflammation. Intestine tissue transcriptomics, fecal microbiome analysis and serum metabolomics were applied to identify diet-microbe-host interactions. Additionally, the dietary inflammatory index (DII) scores and intestinal specimens of 32 patients with Crohn's disease were evaluated. The biological functions of Bacteroides uniformis were observed in vitro and in vivo.

RESULTS

Pro-inflammatory diet induces low-grade intestinal inflammation in mice and exacerbates colitis by activating glutathione peroxidase 4-associated ferroptosis in the endoplasmic reticulum stress-mediated pathway. These effects are reversed by ferrostatin-1 treatment. Additionally, the pro-inflammatory diet triggers colitis by modulating the gut microbiota and metabolites. Notably, supplementation with B. uniformis improves the pro-inflammatory diet-aggravated colitis by inhibiting endoplasmic reticulum stress-mediated ferroptosis. Moreover, B. uniformis is non-enterotoxigenic and non-enteroinvasive in co-cultures with intestinal epithelial cells.

CONCLUSIONS

Pro-inflammatory diet drives colitis by targeting endoplasmic reticulum stress-mediated ferroptosis, possibly in a gut microbiota-dependent manner. Pro-inflammatory diet restriction and microbial-based therapies may be effective strategies for preventing and treating IBD.

Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

Optimization of Enzyme-Assisted Extraction of Rosemary Essential Oil Using Response Surface Methodology and Its Antioxidant Activity by Activating Nrf2 Signaling Pathway

Rosemary essential oil (REO) is widely recognized as a food flavoring and traditional herb and possesses potential antioxidant activity. However, its low yield rate and unclarified antioxidant mechanism warrant further investigation. In this study, an enzyme pretreatment-assisted extraction method with Box-Behnken design (BBD) and response surface methodology (RSM) models was employed to optimize the main factors of REO, and its antioxidant molecular mechanism under oxidative stress was elucidated in hydrogen peroxide-induced human lung carcinoma (A549) cells. The optimized yield (4.10%) of REO was recorded with the following optimum conditions: enzyme amount 1.60%, enzyme digestion pH 5.0, enzyme digestion temperature 46.50 °C, and enzyme digestion time 1.7 h. Meanwhile, 1.8-cineole (53.48%) and β-pinene (20.23%) exhibited radical scavenging activity higher than that of BHA and BHT. At the cellular level, REO (12.5-50 µg/mL) increased the levels of cell viability, CAT, SOD, and GSH significantly while reducing the contents of ROS, MDA, and GSSG, when compared to H2O2 exposure. Mechanically, REO relieved oxidative stress via activating the Nrf2 signaling pathway and enhancing the protein expression of Nrf2, NQO-1, and HO-1, which was further verified by molecular docking between the main component 1.8-cineole and the Kelch domain of KEAP1. Therefore, REO could be considered as a potent natural antioxidant with a potential strategy in the food and pharmaceutical industries.

Discovery, Preliminary Structure-Activity Relationship, and Evaluation of Oleanane-Type Saponins from Pulsatilla chinensis for the Treatment of Ulcerative Colitis

To discover ulcerative colitis (UC) treatment agents, 28 oleanane-type triterpenoid saponins (1-28) including three new saponins, pulsatillosides P-R (1-3), were isolated from Pulsatilla chinensis. The isolated saponins could observably ameliorate UC by improving the intestinal epithelial cell barrier and intestinal flora in vivo. The structure-activity relationship indicated that the oligosaccharide chain at C-28 was essential for their anti-UC activities; the methyl group at the C-23 site of triterpene saponins showed important effects on anti-UC efficacy; the chain length of oligosaccharides at position C-28 had little effect on their anti-UC activities. In vivo investigation of representative saponins 1 and 13 further confirmed that 23-methyl-3,28-bisdesmosidic oleanane-type saponins inhibited the TNFα-NFκB-MLCK axis to improve the intestinal epithelial cell barrier of the colon in UC mice. These findings revealed the potential of 23-methyl-3,28-bisdesmosidic oleanane-type saponins from P. chinensis as promising candidates for the treatment of UC.

NO Release Inhibitory Activity of Flavonoids from Aesculus Wilsonii Seeds through MAPK (P38), NF-κB, and STAT3 Cross-Talk Signaling Pathways

The flavonoid constituents of Aesculus wilsonii, a source of the Chinese medicinal drug Suo Luo Zi, and their in vitro anti-inflammatory effects were investigated. Fifteen flavonoids, including aeswilflavonosides IA-IC (1:  - 3: ) and aeswilflavonosides IIA-IIE (4:  - 8: ), along with seven known derivatives were isolated from a seed extract. Their structures were elucidated by extensive spectroscopic methods, acid and alkaline hydrolysis, and calculated electronic circular dichroism spectra. Among them, compounds 3: and 7: possess a 5-[2-(carboxymethyl)-5-oxocyclopent-yl]pent-3-enylate or oleuropeoylate substituent, respectively, which are rarely reported in flavonoids. Compounds 2, 3, 7: , and 12:  - 15: were found to inhibit lipopolysaccharide-induced nitric oxide production in RAW 264.7 cell lines. In a mechanistic assay, the flavonoid glycosides 2, 3: , and 7: reduced the expressions of interleukin-6 and tumor necrosis factor-alpha induced by lipopolysaccharide. Further investigations suggest that 2: and 3: downregulated the protein expression of tumor necrosis factor-alpha and interleukin-6 by inhibiting the phosphorylation of p38. Compound 7: was found to reduce the production of inducible nitric oxide synthase, and the secretion of tumor necrosis factor-alpha and interleukin-6 through inhibiting nuclear factor kappa-light-chain-enhancer of activated B signaling pathway. Compounds 2, 3: , and 7: possessed moderate inhibitory activity on the expression of signal transducer and activator of transcription-3. Taken together, the data indicate that the flavonoid glycosides of A. wilsonii seeds exhibit nitric oxide release inhibitory activity through mitogen-activated protein kinase (p38), nuclear factor kappa-light-chain-enhancer of activated B, and signal transducer and activator of transcription-3 cross-talk signaling pathways.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

Psidium guajava L. An Incalculable but Underexplored Food Crop: Its Phytochemistry, Ethnopharmacology, and Industrial Applications

Psidium guajava L. (guava) is a small tree known for its fruit flavor that is cultivated almost around the globe in tropical areas. Its fruit is amazingly rich in antioxidants, vitamin C, potassium, and dietary fiber. In different parts of the world, this plant holds a special place with respect to fruit and nutritional items. Pharmacological research has shown that this plant has more potential than just a fruit source; it also has beneficial effects against a variety of chronic diseases due to its rich nutritional and phytochemical profile. The primary goal of this document is to provide an updated overview of Psidium guajava L. and its bioactive secondary metabolites, as well as their availability for further study, with a focus on the health benefits and potential industrial applications. There have been several studies conducted on Psidium guajava L. in relation to its use in the pharmaceutical industry. However, its clinical efficacy and applications are still debatable. Therefore, in this review a detailed study with respect to phytochemistry of the plant through modern instruments such as GC and LC-MS has been discussed. The biological activities of secondary metabolites isolated from this plant have been extensively discussed. In order to perform long-term clinical trials to learn more about their effectiveness as drugs and applications for various health benefits, a structure activity relationship has been established. Based on the literature, it is concluded that this plant has a wide variety of biopharmaceutical applications. As a whole, this article calls for long-term clinical trials to obtain a greater understanding of how it can be used to treat different diseases.

Extract of Jasminum grandiflorum L. alleviates CCl4-induced liver injury by decreasing inflammation, oxidative stress and hepatic CYP2E1 expression in mice

Jasminum grandiflorum L. (JG) is a medicinal plant containing many bioactive ingredients. Herein, we analyzed the effects of four different extracts and two compounds of JG on acute liver injury caused by carbon tetrachloride (CCl₄) and underlying molecular mechanisms. 7 weeks old C57BL/6 male mice were used to establish a liver injury model by injecting with 1% CCl₄, 10 mL/kg ip. Four different extracts and two compounds of JG were given to mice by gavage for 3 days. Clinical and histological chemistry assays were performed to assess liver injury. Moreover, hepatic oxidative stress and inflammation related markers were determined by immunohistochemistry and western blotting. As a result, JG extracts and two functional components showed different degree of protect effects against CCl₄-induced liver injury by the decrease of elevated serum transaminases and liver index, and the attenuation of histopathological changes in mice, among which JG extracted with petroleum ether (PET) had the most significant effect. In addition, PET remarkably alleviated hepatic oxidative stress and inflammation. Further studies revealed that PET significantly inhibited the TNF-α expression, signal pathway expression, NF-κB p65 and inflammatory factors IL-1β and IL-6 expression in CCl₄-induced liver injury mice. Nevertheless, hydroxytyrosol (HT) alleviated liver injury by reducing oxidative stress. Apart from PET extract, other extracts of JG can inhibit cytochrome CYP2E1 expression to protect liver tissue. These findings suggest that the extracts and its components of JG possesses the potential protective effects against CCl₄-induced liver injury in mice by exerting antioxidative stress and anti-inflammation.

The crude guava polysaccharides ameliorate high-fat diet-induced obesity in mice via reshaping gut microbiota

Guava is a popular fruit consumed worldwide with beneficial effects in regulation of glucose and lipid metabolism. Although polysaccharides are a major phytochemical component of guava, to date, the alleviative effects of polysaccharides from the guava fruit against diet-induced obesity remain unclear. The relationship between the anti-obesity effects of guava polysaccharide (GP) and gut microbiota is unknown. In current study, seven-week-old C57BL/6 mice were fed high-fat diet (HFD) supplemented with GP (100 mg/kg) by oral gavage for 11 weeks. GP supplementation alleviated HFD-induced body weight gain and visceral obesity, and reduced serum cholesterol, triglyceride, and LDL-C levels. In addition, GP ameliorated insulin resistance and prevented hepatic lipid accumulation and meta-inflammation in both liver and adipose tissues in obese mice. Remarkably, GP treatment restored the Firmicutes/Bacteroidetes ratio, induced growth of beneficial bacteria including Clostridium XlVa, Parvibacter, and Enterorhabdus, and decreased in inflammation-related bacteria Mucispirillum in mice fecal samples, accompanied with enhanced production of colonic short chain fatty acids especially butyric acid. However, the metabolic benefits of GP diminished in antibiotics-treated HFD-fed mice. Overall, GP improved metabolic profiles in HFD-induced obese mice via the mediation of gut microbiota-dependent pathways. GP might be developed and utilized as prebiotics in nutraceutical and food industry.

New Monoterpene Acid and Gallic Acid Glucose Esters with Anti-Inflammatory Activity from Blue Gum (Eucalyptus globulus) Leaves

Blue gum (Eucalyptus globulus) is a widely used botanical in the cosmeceutical and food industries. Although blue gum leaves are known for abundant essential oils, their nonvolatile phytochemical constituents and bioactivities remain unclear. Herein, a phytochemical investigation of blue gum leaves led to the identification of eight new monoterpene acid and gallic acid glucose esters (1-4 and 14-17; glubosides A-H, respectively) and 12 known analogues (5-13 and 18-20). Their structures were determined based on extensive spectroscopic data analysis, chemical degradation, and chiral separation. Oleuropeic acid conjugated glucose esters (1-13, 15, 16, 18, and 20) are reported as epimeric mixtures. Compounds 7, 12, 14, 19, and 20 (at 30 μM) inhibited nitrite release in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compounds 7 and 14 (at 3-30 μM) also down-regulated proinflammatory biomarkers, including cytokines (TNF-α, IL-6, and IL-1β), protein expression (iNOS and COX-2), and transcription factor nuclear translocation (NF-κB) in LPS-stimulated RAW264.7 cells. This work highlights the anti-inflammatory potential of phytochemicals from blue gum leaves, which supports their further development as cosmeceutical and/or nutraceutical products.

Dietary polyphenol oleuropein and its metabolite hydroxytyrosol are moderate skin permeable elastase and collagenase inhibitors with synergistic cellular antioxidant effects in human skin fibroblasts

Oleuropein (OLE) and hydroxytyrosol (HT) are dietary polyphenols with skin beneficial effects but their effects on skin-ageing-related enzymes are not clear. Herein, we evaluated their inhibitory effects on elastase and collagenase. OLE and HT (62.5-1 000 μM) showed moderate anti-elastase and anti-collagenase effects (5.1-26.3%, 5.8-12.2% and 12.6-31.0%, 11.6-31.9% inhibition, respectively). Combinations of OLE and HT (1:1 ratio) exerted synergistic inhibitory effects on elastase, which were supported by their combination index (CI), kinetic assay and computational docking. Moreover, HT (100 μM) reduced hydrogen peroxide (H₂O₂)-induced cytotoxicity and reactive oxygen species (ROS) in human dermal fibroblast cells by 21.8 and 15.2%, respectively. In addition, combinations of OLE and HT (6.25/6.25-100/100 μM) exerted synergistic cytoprotective effects by reducing ROS levels by 7.6-37.3% with CIs of 0.17-0.44, respectively. The findings from this study support the cosmeceutical activities of OLE and HT but further research is warranted to evaluate their anti-skin-ageing effects using in vivo models.

Gastroprotective effects of extract of Jasminum grandiflorum L. flower in HCl/EtOH-induced gastric mucosal ulceration mice

Jasminum grandiflorum L. is a medicinal plant used to treat hepatitis and gastritis, but the mechanisms underlying its protective effects against gastrointestinal mucosal damage remain to be elucidated. In this study, we analyzed the effects of four different extracts and two compounds from the flower of J. grandiflorum in a mouse model of HCl/EtOH-induced gastric ulcer. The flower extracts alleviated gastric mucosal ulceration by increasing PGE2 production and the activity of antioxidant enzymes, along with the suppression of reactive oxygen species (ROS) generation, lipid peroxidation, apoptosis-related proteins, pro-inflammatory cytokines and nitric oxide (NO) production.

Guava (Psidium guajava L.): a glorious plant with cancer preventive and therapeutic potential

Guava (Psidium guajava L.) tree (Myrtaceae family) bears fruit rich in vitamins, fiber, and other nutrients. While native to Latin America, guava is grown in many tropical and subtropical regions across the globe where it has long been used in traditional medicine to treat a myriad of ailments. Guava has been shown to exhibit a number of biological and pharmacological activities, such as antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, antidiabetic, and anticancer properties. Several parts of the plant, including the leaves, fruits, seeds, peels, pulp, bark, and oil, produce phytochemicals with medicinal properties. Emerging research has found that guava bioactive phytochemicals exert antitumorigenic effects against various human malignancies through multiple mechanisms. While there are numerous individual studies that document the anticancer effects of guava constituents, an up-to-date, comprehensive, and critical review of available research data has not been performed. Therefore, the purpose of this review is to present a complete analysis of the cancer preventive and anticancer therapeutic potential of guava-derived products and guava constituents, with a focus on the cellular and molecular mechanisms of action. The bioavailability, pharmacokinetics, and toxicity of guava as well as limitations, challenges, and future directions of research have also been discussed.

Chemical Characterization and Hepatoprotective Effects of a Standardized Triterpenoid-Enriched Guava Leaf Extract

Nutraceutical/pharmaceutical agents capable of maintaining redox and inflammation homeostasis are considered as candidates for the prevention and/or treatment of liver diseases. Psidium guajava (commonly known as guava) leaf is a commercially available functional food that has been reported to possess hepatoprotective property. However, the hepatoprotective constituents in guava leaf are not known. In the current study, a standardized triterpenoid-enriched extract of guava leaves (TGL) was developed. A new ursolic acid derivative, namely 2α,3β,6β,23,30-pentahydroxyurs-11,13(18)-dien-28,20β-olide (1), and 23 known triterpenoids were isolated and identified from TGL. The hepatoprotective effects of TGL were evaluated through a model using acetaminophen (APAP)-exposed C57BL/6 male mice. Pretreatment of TGL (75 and 150 mg/kg) restored the mice hepatic architecture, improved the serum ALT and AST levels, and reduced the hepatic ROS and MDA contents. Further molecular mechanistic study revealed that TGL modulated Nrf2 and MAPK signaling pathways to alleviate APAP-induced oxidative and inflammatory stress in liver. In addition, the new compound 1 from TGL showed protective effects against APAP-induced cytotoxicity via activation of the Nrf2 pathway in HepG2 cells. Overall, this is the first report on the hepatoprotective effects of a standardized triterpenoid-enriched extract of guava leaves, which supports its potential nutraceutical application in liver disease management.

Hitting the sweet spot: A systematic review of the bioactivity and health benefits of phenolic glycosides from medicinally used plants

Phenolic acid and flavonoid glycosides form a varied class of naturally occurring compounds, characterised by high polarity-resulting from the glycone moiety-and the presence of multiple phenol functionalities, which often leads to strong antioxidant activity. Phenolic glycosides, and in particular flavonoid glycosides, may possess strong bioactive properties with broad spectrum activity. This systematic literature review provides a detailed overview of 28 studies examining the biological activity of phenolic and flavonoid glycosides from plant sources, highlighting the potential of these compounds as therapeutic agents. The activity of glycosides depends upon the biological activity type, identity of the aglycone and the identity and specific location of the glycone moiety. From studies reporting the activity of both glycosides and their respective aglycones, phenolic glycosides appear to generally be a storage/reserve pool of precursors of more bioactive compounds. The glycosylated compounds are likely to be more bioavailable compared to their aglycone forms, due to the presence of the sugar moieties. Hydrolysis of the glycoside in the in vivo environment would release the free aglycone, potentiating their biological activity. However, further high-quality studies are needed to firmly establish the clinical efficacy of glycosides from many of the plant species studied.

Allelopathic Effects of Castanea henryi Aqueous Extracts on the Growth and Physiology of Brassica pekinensis and Zea mays

The present study investigated the allelopathic effects of aqueous extracts of Castanea henryi litter on the growth and physiological responses of Brassica pekinensis and Zea mays. Treatment with high concentrations of leaf extract (0.05 g/ml for B. pekinensis and 0.10 g/ml for Z. mays) significantly increased malonaldehyde content and reduced seed germination, seedling growth, chlorophyll content, and the activity levels of antioxidant enzymes. These effects generally increased with increasing extract concentration. However, in Z. mays, low extract concentrations actually promoted seed germination, shoot growth, chlorophyll content, and antioxidant enzyme activity. The allelopathic effects of the various C. henryi extracts decreased as follows: leaf extract > twig extract > shell extract. Eleven potential allelochemicals including rutin, quercetin, luteolin, procyanidin A2, kaempferol, allantoin, propionic acid, salicylic acid, jasmonic acid, methylmalonic acid, and gentisic acid were identified in the leaves of C. henryi which were linked to the strongest allelopathic effects. These findings suggest that the allelopathic effects of C. henryi differ depending on receptor plant species, and that leaves are the most allelopathic litter in C. henryi.

Guavinoside B from Psidium guajava alleviates acetaminophen-induced liver injury via regulating the Nrf2 and JNK signaling pathways

GUB, a main phenolic compound present in guava fruits, could alleviate APAP-induced liver injury in vitro and in vivo by activating the Nrf2 signaling pathway and inhibiting the JNK signaling pathway.