The Spectrum of Pharmacological Actions of Syringetin and Its Natural Derivatives-A Summary Review

Unraveling the hydroxylation and methylation mechanism in polymethoxylated flavones biosynthesis in Dracocephalum moldavica

Dracocephalum moldavica, which belongs to the Lamiaceae family, is an important medicinal plant rich in polymethoxylated flavones (PMFs). PMFs have multi-methoxy groups on the central flavone skeleton. Hydroxylation and methylation are important modifications in the biosynthesis of PMFs, but the corresponding mechanism and related enzymes have not yet been elucidated in D. moldavica. In this study, we analyzed the transcriptome database of D. moldavica and identified three flavonoid hydroxylases (DmFH1/2/3) and four flavonoid O-methyltransferases (DmOMT1/2/3/4) related to the biosynthesis of PMFs. DmFH1 was characterized as a novel F6/8/3'H and has broad substrate specificity for flavones and flavanones. It catalyzes the formation of 7-methylscutellarein and isoscutellarein, which are the key intermediates in PMF biosynthesis. DmOMT4 and DmOMT1 sequentially catalyze the two-step methylation of scutellarein to generate circimaritin, while DmOMT3 has high specificity for 4'-OH of flavonoids. Notably, it catalyzes the conversion of circimaritin into salvigenin, which is an important polymethoxylated flavone. In addition, through heterologous expression of DmFH1 and DmOMT1 in Nicotiana benthamiana, diversified polyhydroxylated and polymethylated metabolites, including 7-methylscutellarein and circimaritin were achieved. Our work uncovers the key hydroxylation and the complex metabolic network of methylation processes in the biosynthesis of PMFs in D. moldavica, and the screened candidate genes can be exploited in synthetic biology research on PMFs.

Sludge-derived biostimulants promote glycosylation of tricin and luteolin in the flavone and flavonol biosynthesis to enhance anti-inflammatory activities of rice

Alkaline thermal hydrolysis of sewage sludge produces nutrients and biostimulants that enhance plant growth, attracting considerable interest in agriculture. However, the metabolic differences and regulatory mechanisms of sewage sludge-derived biostimulants (SS-BS) on the phenotypic traits, nutritional quality, and safety indicators of harvested crops remain unclear. This study investigates the impact of SS-BS on rice quality on an agricultural production scale. The research reveals that rice treated with SS-BS complies with safety standards comparable to premium rice. SS-BS significantly enhances nutrient enrichment in the endosperm, increasing protein, vitamin B1, dietary fiber, and vitamin E content by 7%, 7.2%, 23.2%, and 42.2%, respectively. Furthermore SS-BS upregulates the FG2 gene,leading to increased Nictoflorin content and activation of the gene expression of UGT73C6 and CYP75A, which catalyze O-glycosylation and promot glycosyl transfer. By inhibiting the synthesis of Trifolin, Scolymoside, and Swertiajaponin, SS-BS favors the synthesis of glycosylated derivatives of Tricin and Luteolin, which exhibit higher anti-inflammatory activity. Additionally, two novel genes, novel.2100 and novel.1300, and an uncharacterized gene, LOC9269295, are closely associated with the production of anti-inflammatory and antioxidant compounds. This study provides new evidence for SS-BS application and insights into their regulatory mechanisms affecting crop quality, contributing to the development of functional foods and sustainable agriculture.

Exploring the phytochemicals, antioxidant properties, and hepatoprotective potential of Moricandia sinaica leaves against paracetamol-induced toxicity: Biological evaluations and in Silico insights

Thirteen components were identified in the methanol extract of Moricandia sinaica leaves (MSLE) through analysis utilizing HPLC-ESI-MS/MS., including flavonoids, anthocyanins, phenolic acids, and fatty acids. The methanol extract of M. sinaica leaves contained total phenolics and flavonoids (59.37 ± 2.19 mg GAE/g and 38.94 ± 2.72 mg QE/g), respectively. Furthermore, it revealed in vitro antioxidant properties as determined by the DPPH and FRAP assays, with respective IC50 values of 10.22 ± 0.64 and 20.89 ± 1.25 μg/mL. The extract exhibited a notable hepatoprotective effect in rats who experienced paracetamol-induced hepatotoxicity. When a dose of 250 mg/kg was given, there was a 52% reduction in alanine transaminase and a 30% reduction in aspartate transaminase compared to the group with the disease. Furthermore, it demonstrated a 3.4-fold, 2.2-fold, and 2.6-fold increase in superoxide dismutase, non-protein sulfhydryl, and glutathione peroxidase, respectively. In addition, it demonstrated a 68% decrease in lipid peroxide levels compared to the group with paracetamol-induced condition. The verification was conducted using a histological study, which identified improved liver histology with a small number of distended hepatocytes. Moreover, in silico studies focused on the enzymes NADPH oxidase, butyrylcholinesterase, and tyrosinase as the targets for the major compounds. In conclusion, MSLE showed promising hepatoprotective and antioxidant activities due to its richness in antioxidant metabolites.

Vaccine-based therapeutic interventions in lung cancer management: A recent perspective

The incidence of lung cancer continues to grow globally, contributing to an ever-increasing load on healthcare systems. Emerging evidence has indicated lowered efficacy of conventional treatment strategies, such as chemotherapy, surgical interventions and radiotherapy, prompting the need for exploring alternative interventions. A growing focus on immunotherapy and the development of personalized medicine has paved the way for vaccine-based delivery in lung cancer. With various prominent targets such as CD8+T cells and PD-L1, immune-targeted, anti-cancer vaccines have been evaluated in both, pre-clinical and clinical settings, to improve therapeutic outcomes. However, there are a number of challenges that must be addressed, including the scalability of such delivery systems, heterogeneity of lung cancers, and long-term safety as well as efficacy. In addition to this, natural compounds, in combination with immunotherapy, have gained considerable research interest in recent times. This makes it necessary to explore their role in synergism with immune-targeted agents. The authors of this review aim to offer an overview of recent advances in our understanding of lung cancer pathogenesis, detection and management strategies, and the emergence of immunotherapy with a special focus on vaccine delivery. This finding is supported with evidence from testing in non-human and human models, showcasing promising results. Prospects for phytotherapy have also been discussed, in order to combat some pitfalls and limitations. Finally, the future perspectives of vaccine usage in lung cancer management have also been discussed, to offer a holistic perspective to readers, and to prompt further research in the domain.

Phytochemical Analysis, Acetylcholinesterase Inhibition, Antidiabetic and Antioxidant Activities of Atriplex halimus L. (Amaranthaceae Juss.)

Mediterranean saltbush Atriplex halimus L. (Amaranthaceae) from different bioclimatic arid zones (ten wild populations) were studied. Phenols contents, flavonoids, flavonols, tannins and anthocyanins were determined and then tested for their antioxidants, antidiabetic and anti-acetylcholinesterase (AChE) activities. Levels of total polyphenols including flavonoids and flavonols, tannins and anthocyanins were high and varied significantly among analyzed populations. Nine phenolic acids and four flavonoids were identified for the first time in the methanolic fraction and quantified by liquid high-performance chromatography system HPLC (DAD). All extracts showed a substantial antioxidant activity, as assessed by DPPH assay (1,1-diphenyl-2-picrylhydrazyl free radical) (IC50DPPH=147.3for population of Seliena), Ferric Reducing Antioxidant Power (FRAP; IC50FRAP=3.2 for populations of Sousse and Kairouan), and Chelation Fer test (IC50FerCh=1.5 μg/mL for populations of El-hamma and Mednine). Atriplex halimus possessed a high inhibitory effect against α-amylase activity (up to 2.6 mg ACE/gE), a moderate activity for α-glucosidase (up to 91.0 mg ACE/gE) and AChE (up to 147.2 μg/mL) compared to standard. The analyzed populations were isolated and subdivided into three distinct groups, without any bioclimatic structuration. Enzymatic activities seem to be associated with the presence, in plant extracts, of other classes of compounds then phenols such as terpenes, sterols, saponins, coumarins and carotenoids.

Antimicrobial Potential of Different Isolates of Chaetomium globosum Combined with Liquid Chromatography Tandem Mass Spectrometry Chemical Profiling

The antimicrobial resistance of pathogenic microorganisms against commercial drugs has become a major problem worldwide. This study is the first of its kind to be carried out in Egypt to produce antimicrobial pharmaceuticals from isolated native taxa of the fungal Chaetomium, followed by a chemical investigation of the existing bioactive metabolites. Here, of the 155 clinical specimens in total, 100 pathogenic microbial isolates were found to be multi-drug resistant (MDR) bacteria. The Chaetomium isolates were recovered from different soil samples, and wild host plants collected from Egypt showed strong inhibitory activity against MDR isolates. Chaetomium isolates displayed broad-spectrum antimicrobial activity against C. albicans, Gram-positive, and Gram-negative bacteria, with inhibition zones of 11.3 to 25.6 mm, 10.4 to 26.0 mm, and 10.5 to 26.5 mm, respectively. As a consecutive result, the minimum inhibitory concentration (MIC) values of Chaetomium isolates ranged from 3.9 to 62.5 µg/mL. Liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) analysis was performed for selected Chaetomium isolates with the most promising antimicrobial potential against MDR bacteria. The LC-MS/MS analysis of Chaetomium species isolated from cultivated soil at Assuit Governate, Upper Egypt (3), and the host plant Zygophyllum album grown in Wadi El-Arbaein, Saint Katherine, South Sinai (5), revealed the presence of alkaloids as the predominant bioactive metabolites. Most detected bioactive metabolites previously displayed antimicrobial activity, confirming the antibacterial potential of selected isolates. Therefore, the Chaetomium isolates recovered from harsh habitats in Egypt are rich sources of antimicrobial metabolites, which will be a possible solution to the multi-drug resistant bacteria tragedy.

A Review on Natural Antioxidants for Their Role in the Treatment of Parkinson's Disease

The neurodegenerative condition known as Parkinson's disease (PD) is brought on by the depletion of dopaminergic neurons in the basal ganglia, which is the brain region that controls body movement. PD occurs due to many factors, from which one of the acknowledged effects of oxidative stress is pathogenic pathways that play a role in the development of Parkinson's disease. Antioxidants, including flavonoids, vitamins E and C, and polyphenolic substances, help to reduce the oxidative stress brought on by free radicals. Consequently, this lowers the risk of neurodegenerative disorders in the long term. Although there is currently no cure for neurodegenerative illnesses, these conditions can be controlled. The treatment of this disease lessens its symptoms, which helps to preserve the patient's quality of life. Therefore, the use of naturally occurring antioxidants, such as polyphenols, which may be obtained through food or nutritional supplements and have a variety of positive effects, has emerged as an appealing alternative management strategy. This article will examine the extent of knowledge about antioxidants in the treatment of neurodegenerative illnesses, as well as future directions for research. Additionally, an evaluation of the value of antioxidants as neuroprotective agents will be provided.

Syringetin Promotes Melanogenesis in B16F10 Cells

Syringetin, an active compound present in red grapes, jambolan fruits, Lysimachia congestiflora, and Vaccinium ashei, is a dimethyl myricetin derivative which contains free hydroxyl groups at the C-2' and C-4' positions in ring B. Recent studies have revealed that syringetin possesses multiple pharmacological properties, such as antitumor, hepatoprotective, antidiabetic, antioxidative, and cytoprotective activities. To date, there has been no attempt to test the action of syringetin on melanogenesis. In addition, the molecular mechanism for the melanogenic effects of syringetin remains largely unknown. In this study, we investigated the effect of syringetin on melanogenesis in a murine melanoma cell line from a C57BL/6J mouse, B16F10. Our results showed that syringetin markedly stimulated melanin production and tyrosinase activity in a concentration-dependent manner in B16F10 cells. We also found that syringetin increased MITF, tyrosinase, TRP-1, and TRP-2 protein expression. Moreover, syringetin inhibited ERK and PI3K/Akt phosphorylation by stimulating p38, JNK, PKA phosphorylation levels, subsequently stimulating MITF and TRP upregulation, resulting in the activation of melanin synthesis. Furthermore, we observed that syringetin activated phosphorylation of GSK3β and β-catenin and reduced the protein level of β-catenin, suggesting that syringetin stimulates melanogenesis through the GSK3β/β-catenin signal pathway. Finally, a primary skin irritation test was conducted on the upper backs of 31 healthy volunteers to determine the irritation or sensitization potential of syringetin for topical application. The results of the test indicated that syringetin did not cause any adverse effects on the skin. Taken together, our findings indicated that syringetin may be an effective pigmentation stimulator for use in cosmetics and in the medical treatment of hypopigmentation disorders.