Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Americanin B inhibits pyroptosis in lipopolysaccharide-induced septic encephalopathy mice through targeting NLRP3 protein

BACKGROUND

Sepsis is considered as a severe illness due to its high mortality. Sepsis can cause septic encephalopathy, thus leading to brain injury, behavioral and cognitive dysfunction. Pyroptosis is a type of regulated cell death (RCD) and takes a crucial part in occurrence and development of sepsis. Americanin B (AMEB) is a lignan compounds, which is extracted from Vernicia fordii. In our previous study, AMEB could inhibit microglial activation in inflammatory cell model. However, the function of AMEB in septic encephalopathy mice is uncertain. It would be worthwhile to ascertain the role and mechanism of AMEB in sepsis.

PURPOSE

Current study designs to certify the relationship between pyroptosis and septic encephalopathy, and investigate whether AMEB can restrain NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome activation and restrict pyroptosis by targeting NLRP3 in septic mice model.

STUDY DESIGN

C57BL/6 mice were utilized to perform sepsis model in vivo experiments. BV-2 cell lines were used for in vitro experiments.

METHODS

In vivo sepsis model was established by lipopolysaccharide (LPS) intraperitoneal injection in male C57BL/6 J mice and in vitro model was exposed by LPS plus ATP in BV-2 cells. The survival rate was monitored on the corresponding days. NLRP3, apoptosis associated Speck-like protein (ASC), caspase-1, GasderminD (GSDMD), interleukin-1β (IL-1β) and interleukin-18 (IL-18) level were detected by western blotting and immunofluorescence analysis. Molecular docking, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) experiments, RNAi transfection and quantitative real-time PCR were applied to confirm the potential target of AMEB.

RESULTS

The results suggested that AMEB could rise survival percentage and lighten brain injury in LPS-induced sepsis mice. In addition, AMEB could inhibit pyroptosis and the activiation of NLRP3 inflammasome. The inhibiting function of AMEB on the activiation of NLRP3 inflammasome is weakened following si-NLRP3 transfection. Moreover, AMEB exerted anti-pyroptosis effect via targeting NLRP3 protein.

CONCLUSIONS

Our findings first indicate NLRP3 is an effective druggable target for septic encephalopathy related brain injury, and also provide a candidate-AMEB for the treatment of septic encephalopathy. These emerging findings on AMEB in models of sepsis suggest an innovative approach that may be beneficial in the prevention of septic encephalopathy.

1-Acetoxypinoresinol, a Lignan from Olives: Insight into Its Characterization, Identification, and Nutraceutical Properties

Extra virgin olive oil (EVOO) is a symbol of the Mediterranean diet, constituting its primary source of fat. The beneficial effect of EVOO is strictly related to the presence of fatty acids and polyphenols, bioactive compounds endowed with nutraceutical properties. Among EVOO polyphenols, lignans possess a steroid-like chemical structure and are part of the phytoestrogen family, which is renowned for its health properties. The natural lignans (+)-pinoresinol and 1-acetoxypinoresinol (1-AP) are commonly present in olives and in EVOO. Although (+)-pinoresinol is found in different edible plants, such as flaxseed, beans, whole-grain cereals, sesame seeds, and certain vegetables and fruit, 1-AP was exclusively identified in olives in 2000. So far, the scientific literature has extensively covered different aspects of (+)-pinoresinol, including its isolation and nutraceutical properties. In contrast, less is known about the olive lignan 1-AP. Therefore, this review aimed to comprehensively evaluate the more important aspects of 1-AP, collecting all the literature from 2016 to the present, exploring its distribution in different cultivars, analytical isolation and purification, and nutraceutical properties.

Magnolia biondii flower extract attenuates UVB-induced skin damage through high-mobility group box protein B1

OBJECTIVE

Magnolia biondii, a plant containing many magnolian-like compounds in its flowers or buds, exhibits anti-inflammatory and antiallergic effects; however, no study has addressed its effect on alleviating ultraviolet light (UV)-induced skin damage. We thus aimed at studying the effects of M. biondii flower extract (MB) on UVB-induced skin damage and determine the relationship between cell damage and damage-associated molecular patterns (DAMPs).

METHODS

Reconstructed epidermal models and foreskin samples were selected to detect cellular reactions after UVB irradiation and MB treatment. MTT, haematoxylin-eosin and immunofluorescence staining were used to examine total viability, sunburned cells and expression and migration of DAMPs at 16 or 48 h. Prostaglandin E2 (PGE-2) and interleukin 8 (IL-8) levels were measured using enzyme-linked immunosorbent assays. A clinical UVB-damaged test was carried out on human arms subjected to MB pre- or post-treatment. Human skin probes were used to measure erythema, melanin, ITA° and transepidermal water loss (TEWL), while skin photos were captured using the VISIA system.

RESULTS

MB is rich in lignans such as magnolin, pinoresinol dimethyl ether and fargesin, and shows weak UV absorption at 280-320 nm. Coculturing with MB for 16 or 48 h after UVB irradiation improved the tissue viability and structure of Skinovo-Epi, and reduced the expression and migration of high mobility group box protein B1 (HMGB1) as well as the expression of IL-8 and PGE-2. In the excised foreskin treated with MB after UVB irradiation, the generation of 8-hidroxy-2-deoxyguanosine and nuclear transfer of HMGB1 were reduced. When pre-treated with MB for 3 days, UVB-induced skin erythema and ITA° were significantly decreased. When post-treated with MB for 5 days, a decrease in skin erythema, melanin and TEWL values and an increase in skin ITA° were observed.

CONCLUSIONS

Treatment with MB attenuated UVB-induced skin damage, such as erythema, pigmentation and skin barrier function, by improving the tissue viability and structure and reducing sunburned cells and skin inflammation. This effect may be related to DNA damage, which causes the migration of HMGB1 from the nucleus to the outside of the cell to induce skin inflammation.

The exogenous application of naringenin and rosmarinic acid modulates functional traits in Lepidium sativum

BACKGROUND

Phenolic modulators have attracted attention for their potential in shaping functional traits in plants. This work investigated the impact of naringenin (Nar) and rosmarinic acid (RA) on the functional properties of Lepidium sativum leaves and roots.

RESULTS

Untargeted metabolomics identified a diverse phenolic profile, including flavonoids, phenolic acids, low molecular weight phenolics, lignans, and stilbenes. Cluster, analysis of variance multiblock orthogonal partial least squares (AMOPLS), and orthogonal projection to latent structures discriminant analysis (OPLS-DA) multivariate analyses confirmed tissue-specific modulation of bioactive compounds. The tissue was the hierarchically most influential factor, explaining 27% of observed variability, while the treatment and their interaction were statistically insignificant. Thereafter, various in vitro assays were employed to assess antioxidant capacity, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, cupric ion reducing antioxidant capacity (CUPRAC), and ferric ion reducing antioxidant power (FRAP), metal chelating ability, and phosphomolybdenum (PMD) assays. Extracts were also tested for inhibitory effects on cholinesterase, amylase, glucosidase, and tyrosinase enzymes. RA application positively impacted antioxidant and enzyme inhibitory activities, holding valuable implications in shaping the health-promoting properties of L. sativum.

CONCLUSION

The untargeted metabolomics analysis showed a significant tissue-dependent modulation of bioactive compounds, determining no synergistic effect between applying phenolic compounds in combination. Specifically, the sole application of RA increased anthocyanins and hydroxyphenyl propanoic acid content on leaves, which was strictly related to enhancing the biological activities. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Computational analysis followed by in vitro studies to explore cytokines (TNF-α, IL-6 and IL-1β) inhibition potential of the new natural molecule polonilignan

Targeting pro-inflammatory cytokines and their production is found to be of therapeutic benefit for the regulation of inflammation in various chronic autoimmune diseases. Our continued efforts to discover small molecular-weight pro-inflammatory cytokine inhibitors resulted in identifying a novel natural lignan molecule named polonilignan, isolated from the culture broth extract of an endophytic fungus Penicillium polonicum. An in silico study (molecular docking, ADME predictions, binding free energy calculation and molecular dynamics simulation) of the polonilignan over the pro-inflammatory cytokines proteins TNF-α, IL-6 and IL-1β was performed using Schrodinger LLC software to understand the binding interactions, drug-like properties, and stability of the ligand-protein complex. Further, in-vitro testing of inhibition of TNF-α, IL-6 and IL-1β by polonilignan was carried out using ELISA and RT-PCR on LPS-induced RAW 264.7 cell lines along with the testing of nitrite production effect (Griess assay) and cytotoxicity (MTT) analysis. Under the computational study, polonilignan revealed good docking scores, binding interactions, and stability under MDS and desirable in silico ADME results over the proteins TNF-α, IL-1β and IL-6. Poloniligan showed significant inhibition of IL-1β, IL-6 and TNF-α with IC50 values of 2.01 μM, 6.59 μM and 42.10 μM, respectively. Also, it reduced the translocation of the NF-κB subunit p65 to the nucleus (confocal microscopy). The mRNA expression levels of pro-inflammatory markers IL-1β, TNF-α and IL-6 levels were lowered significantly (p < .001) by the compound, and the diminution was higher with IL-1β. Further, the lignan was non-cytotoxic and effective in attenuating nitrite release (IC50 48.56 μM). Thus, polonilignan has been identified as a new pan-cytokine and NO inhibitor, it is recommended to optimise a method for the synthesis of this small molecular weight lignan and explore its pharmacokinetic characteristics, toxicity and therapeutic effect under various chronic inflammatory disease models.

Negative Association of Lignan and Phytosterol Intake with Stress Perception during the COVID-19 Pandemic-A Polish Study on Young Adults

BACKGROUND

There has been an increasing global prevalence of depression and other psychiatric diseases in recent years. Perceived stress has been proven to be associated with psychiatric and somatic symptoms. Some animal and human studies have suggested that consuming foods abundant in lignans and phytosterols may be associated with lower levels of stress, depression, and anxiety. Still, the evidence is not yet strong enough to draw firm conclusions. Thus, we investigated the association between dietary intake of these phytochemicals and the level of stress experienced by adult individuals.

METHODS

Diet was assessed using self-reported 7-day dietary records. The intakes of lignans and phytosterols were estimated using databases with their content in various food products. The Perceived Stress Scale (PSS) was implemented to measure the level of perceived stress. A logistic regression analysis was used to test for associations.

RESULTS

The odds of elevated PSS were negatively associated with dietary intake of total phytosterols, stigmasterol, and β-sitosterol, with evidence of a decreasing trend across tertiles of phytochemicals. The analysis for doubling the intake reinforced the aforementioned relationships and found protective effects against PSS for total lignans, pinoresinol, and campesterol.

CONCLUSIONS

Habitual inclusion of lignans and phytosterols in the diet may play a role in psychological health. To address the global outbreak of depression and other mental health issues triggered by stress, it is important to take a holistic approach. There is a need to develop effective strategies for prevention and treatment, among which certain dietary interventions such as consumption of products abundant in lignans and phytosterols may play a substantial role.

Pharmacological properties of Polygonatum and its active ingredients for the prevention and treatment of cardiovascular diseases

Despite continued advances in prevention and treatment strategies, cardiovascular diseases (CVDs) remain the leading cause of death worldwide, and more effective therapeutic methods are urgently needed. Polygonatum is a traditional Chinese herbal medicine with a variety of pharmacological applications and biological activities, such as antioxidant activity, anti-inflammation, antibacterial effect, immune-enhancing effect, glucose regulation, lipid-lowering and anti-atherosclerotic effects, treatment of diabetes and anticancer effect. There has also been more and more evidence to support the cardioprotective effect of Polygonatum in recent years. However, up to now, there has been a lack of comprehensive studies on the active ingredients and their pharmacotoxicological effects related to cardiovascular diseases. Therefore, the main active components of Polygonatum (including Polysaccharides, Flavonoids, Saponins) and their biological activities were firstly reviewed in this paper. Furthermore, we summarized the pharmacological effects of Polygonatum's active components in preventing and treating CVDs, and its relevant toxicological investigations. Finally, we emphasize the potential of Polygonatum in the prevention and treatment of CVDs.

Activity of Colocasia esculenta (Taro) Corms against Gastric Adenocarcinoma Cells: Chemical Study and Molecular Characterization

Colocasia esculenta (L.) Schott is a tuberous plant, also known as taro, employed as food worldwide for its renowned nutritional properties but also traditionally used in several countries for medical purposes. In this study, methanolic extracts were prepared from the corms and leaves of Colocasia, subsequently fractionated via molecular exclusion chromatography (RP-HPLC) and their anti-tumor activity assessed in an in vitro model of gastric adenocarcinoma (AGS cells). Vorm extract and isolated fractions II and III affected AGS cell vitality in a dose-dependent manner through the modulation of key proteins involved in cell proliferation, apoptosis, and cell cycle processes, such as caspase 3, cyclin A, cdk2, IkBα, and ERK. To identify bioactive molecules responsible for anti-tumoral activity fractions II and III were further purified via RP-HPLC and characterized via nuclear magnetic resonance (NMR) and electrospray mass spectrometry (ESI-MS) techniques. The procedure enabled the identification of ten compounds including lignans and neolignans, some isolated for the first time in taro, uncommon megastigmane derivatives, and a gallic acid derivative. However, none of the isolated constituents showed efficacy equivalent to that of the fractions and total extract. This suggests that the whole Colocasia phytocomplex has intriguing anti-tumor activity against gastric cancer.

One-Pot Biocatalytic Synthesis of rac-Syringaresinol from a Lignin-Derived Phenol

The drive for a circular bioeconomy has resulted in a great demand for renewable, biobased chemicals. We present a one-pot biocatalytic cascade reaction for the production of racemic syringaresinol, a lignan with applications as a nutraceutical and in polymer chemistry. The process consumes dihydrosinapyl alcohol, which can be produced renewably from the lignocellulosic material. To achieve this, a variant of eugenol oxidase was engineered for the oxidation of dihydrosinapyl alcohol into sinapyl alcohol with good conversion and chemoselectivity. The crystal structure of the engineered oxidase revealed the molecular basis of the influence of the mutations on the chemoselectivity of the oxidation of dihydrosinapyl alcohol. By using horseradish peroxidase, the subsequent oxidative dimerization of sinapyl alcohol into syringaresinol was achieved. Conditions for the one-pot, two-enzyme synthesis were optimized, and a high yield of syringaresinol was achieved by cascading the oxidase and peroxidase steps in a stepwise fashion. This study demonstrates the efficient production of syringaresinol from a compound that can be renewed by reductive catalytic fractionation of lignocellulose, providing a biocatalytic route for generating a valuable compound from lignin.

Recent updates on correlation between reactive oxygen species and synbiotics for effective management of ulcerative colitis

Ulcerative colitis (UC) is presently considered a multifactorial pathology, which may lead to persistent inflammatory action of the gastrointestinal tract (GIT) because of an improperly managed immunological reactivity to the intestinal microbiota found in the GIT. The immune response to common commensal microbes plays an essential role in intestinal inflammation related to UC synbiotics, and it is an important element in the optimal therapy of UC. Therefore, synbiotics, i.e., a mixture of prebiotics and probiotics, may help control the diseased state. Synbiotics alleviate the inflammation of the colon by lowering the reactive oxygen species (ROS) and improving the level of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD). Prebiotic supplementation is not a common practice at the moment, despite numerous research findings proving that the benefits of both probiotics and prebiotics encourage their continued existence and positioning in the GIT, with positive effects on human health by managing the inflammatory response. However, the fact that there have been fewer studies on the treatment of UC with different probiotics coupled with selected prebiotics, i.e., synbiotics, and the outcomes of these studies have been very favorable. This evidence-based study explores the possible role of ROS, SOD, and synbiotics in managing the UC. The proposed review also focuses on the role of alteration of gut microbiota, antioxidant defense in the gastrointestinal tract, and the management of UC. Thus, the current article emphasizes oxidative stress signaling in the GI tract, oxidative stress-based pathomechanisms in UC patients, and UC therapies inhibiting oxidative stress' effects.

Antiaging effects of dietary supplements and natural products

Aging is an inevitable process influenced by genetics, lifestyles, and environments. With the rapid social and economic development in recent decades, the proportion of the elderly has increased rapidly worldwide, and many aging-related diseases have shown an upward trend, including nervous system diseases, cardiovascular diseases, metabolic diseases, and cancer. The rising burden of aging-related diseases has become an urgent global health challenge and requires immediate attention and solutions. Natural products have been used for a long time to treat various human diseases. The primary cellular pathways that mediate the longevity-extending effects of natural products involve nutrient-sensing pathways. Among them, the sirtuin, AMP-activated protein kinase, mammalian target of rapamycin, p53, and insulin/insulin-like growth factor-1 signaling pathways are most widely studied. Several studies have reviewed the effects of individual natural compounds on aging and aging-related diseases along with the underlying mechanisms. Natural products from food sources, such as polyphenols, saponins, alkaloids, and polysaccharides, are classified as antiaging compounds that promote health and prolong life via various mechanisms. In this article, we have reviewed several recently identified natural products with potential antiaging properties and have highlighted their cellular and molecular mechanisms. The discovery and use of dietary supplements and natural products that can prevent and treat multiple aging-related diseases in humans will be beneficial. Thus, this review provides theoretical background for existing dietary supplements and natural products as potential antiaging agents.

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

It is more effective to maintain good health than to regain it after losing it. This work focuses on the biochemical defense mechanisms against free radicals and their role in building and maintaining antioxidant shields, aiming to show how to balance, as much as possible, the situations in which we are exposed to free radicals. To achieve this aim, foods, fruits, and marine algae with a high antioxidant content should constitute the basis of nutritional elements, since natural products are known to have significantly greater assimilation efficiency. This review also gives the perspective in which the use of antioxidants can extend the life of food products, by protecting them from damage caused by oxidation as well as their use as food additives.

Interplay between Lignans and Gut Microbiota: Nutritional, Functional and Methodological Aspects

Lignans are non-flavonoid polyphenols present in a wide range of foods frequently consumed in the Western world, such as seeds, vegetables and fruits, and beverages such as coffee, tea and wine. In particular, the human gut microbiota (GM) can convert dietary lignans into biologically active compounds, especially enterolignans (i.e., enterolactone and enterodiol), which play anti-inflammatory and anti-oxidant roles, act as estrogen receptor activators and modulate gene expression and/or enzyme activity. Interestingly, recent evidence documenting those dietary interventions involving foods enriched in lignans have shown beneficial and protective effects on various human pathologies, including colorectal and breast cancer and cardiovascular diseases. However, considering that more factors (e.g., diet, food transit time and intestinal redox state) can modulate the lignans bioactivation by GM, there are usually remarkable inter-individual differences in urine, fecal and blood concentrations of enterolignans; hence, precise and validated analytical methods, especially gas/liquid chromatography coupled to mass spectrometry, are needed for their accurate quantification. Therefore, this review aims to summarize the beneficial roles of enterolignans, their interaction with GM and the new methodological approaches developed for their evaluation in different biological samples, since they could be considered future promising nutraceuticals for the prevention of human chronic disorders.

Comprehensive Characterization of Chemical Composition and Antioxidant Activity of Lignan-Rich Coniferous Knotwood Extractives

A knotwood of coniferous trees containing large amounts of polyphenolic extractives is considered a promising industrial-scale source of lignans possessing antioxidant properties and other bioactivities. The present study is aimed at a detailed characterization of the chemical composition and antioxidant activity of lignan-rich extractives obtained from the knotwood of the Norway spruce, Scotch pine, Siberian fir, and Siberian larch growing in the European North of Russia as a region with a highly developed forest industry. To achieve this, a comprehensive approach based on a combination of two-dimensional NMR spectroscopy with high-performance liquid chromatography-high-resolution Orbitrap mass spectrometry, and the determination of antioxidant activity by the three complementary methods were proposed. The studied knotwood samples contained from 3.9 to 17% of extractive substances and were comparable to Trolox's antioxidant activity in the single-electron transfer processes and superoxide radical scavenging, which is associated with the predominance of polyphenolic compounds. The latter was represented by 12 tentatively identified monolignans and 27 oligolignans containing 3-5 phenylpropane units in their structure. The extracts were characterized by an identical set of lignans and differed only in the ratios of their individual compounds. Other components of the knotwood were flavonoids taxifolin, quercetin (Siberian larch), and three stilbenes (pinosylvin, its methyl ester, and pterostilbene), which were identified in the Scotch pine extractives. Sesquiterpene juvabione and its derivatives were found in extracts of Siberian larch knotwood.