FREE RADICAL SCAVENGING AND NOS ACTIVATION PROPERTIES OF WATER SOLUBLE CRUDE POLYSACCHARIDE FROM PLEUROTUS OSTREATUS

The aim of this study was to investigate the antioxidant activity using different in vitro assays and nitric oxide synthase activation property of crude water soluble polysaccharide from P. ostreatus. The polysaccharide was isolated by hot water extraction and physico-chemical investigation revealed that it contained high amount of carbohydrate (mostly β-glucan) and low amount of protein and phenolic compounds. EC50 values for scavenging of hydroxyl radical and superoxide radical as well as chelating ability of ferrous ion were 665, 390 and 370 µg/ml respectively. The polysaccharide also showed potential nitric oxide synthase activation properties. This mushroom might be a good source of bioactive compounds

Water Soluble Antioxidative Crude Polysaccharide From Russula senecis Elicits TLR Modulated NF-κB Signaling Pathway and Pro-inflammatory Response in Murine Macrophages

Russula senecis has recently been reported as a new addition to macrofungal flora of West Bengal. Besides, it also emerged as a seasonal health promoting nutrient to local ethnic people and enlisted for the first time as tribal food in our previous publication. In this context, the present work was designed to establish such usefulness scientifically and to meet the aim, crude polysaccharide, Rusenan, was prepared using conventional heated water reflux. Initially, the polymers were characterized to determine chemical composition and for that spectrophotometry along with Fourier-transform infrared spectroscopy (FT-IR), high-performance thin-layer chromatography (HPTLC), and gas chromatography-mass spectrometry (GC-MS) were performed. Analysis indicated that Rusenan was consisted mainly of carbohydrate conjugated with trace amount of protein. Furthermore, glucose was detected as the major monosaccharide (mainly in β-type glycosidic linkage) while other monomers were presented in the order of galactose > mannose > xylose > rhamnose. Conversely, antioxidant potential was determined following eight in vitro systems where the fraction evidenced strong superoxide, hydroxyl, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity, high affinity to Fe2+ as well as instant ability to donate electron with EC50 values ranging from 80 to 3885 μg/ml concentration. In addition, effect on murine macrophages was also investigated where the polysaccharide treatment increased cell proliferation, phagocytic activity, filopodia or lamellipodia formation, nitric oxide (NO) production and reactive oxygen species (ROS) synthesis. Thereafter, through reverse transcriptase polymerase chain reaction (RT-PCR) analysis, significant increase in the expression of Toll like receptor (TLR)-4, TLR-2 and nuclear factor kappa B (NF-κB) was observed; as a result alleviated level of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α, IκB-α, and interferon (IFN)-γ were also noticed explaining definite immune-stimulatory activity of the fraction. Thus, overall finding suggests that R. senecis can be considered as a functional food and may be used in preparation of dietary supplement to enhance general health

Understanding immune-modulatory efficacy in vitro

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGBoosting or suppressing our immune system represents an attractive adjunct in the treatment of infections including SARS-CoV-2, cancer, AIDS, malnutrition, age related problems and some inflammatory disorders. Thus, there has been a growing interest in exploring and developing novel drugs, natural or synthetic, that can manipulate our defence mechanism. Many of such studies, reported till date, have been designed to explore effect of the therapeutic on function of macrophages, being a key component in innate immune system. Indeed, RAW264.7, J774A.1, THP-1 and U937 cell lines act as ideal model systems for preliminary investigation and selection of dose for in vivo studies. Several bioassays have been standardized so far where many techniques require high throughput instruments, cost effective reagents and technical assistance that may hinder many scholars to perform a method demanding compilation of available protocols. In this review, we have taken an attempt for the first time to congregate commonly used in vitro immune-modulating techniques explaining their principles. The study detected that among about 40 different assays and more than 150 sets of primers, the methods of cell proliferation by MTT, phagocytosis by neutral red, NO detection by Griess reaction and estimation of expression of TLRs, COX-2, iNOS, TNF-α, IL-6 and IL-1β by PCR have been the most widely used to screen the therapeutics under investigation.Universidade de Vigo/CISUG

ANTIOXIDANT AND FREE RADICAL SCAVENGING CAPACITY OF PHENOLIC EXTRACT FROM RUSSULA LAUROCERASI

Objectives: Cellular damage caused by reactive oxygen species has been implicated in several diseases; hence antioxidants have significant importance in human health. The objective of this study was to evaluate antioxidant properties of phenolic extract from Russula laurocerasi and presence of components responsible for the activity.Methods: The antioxidant properties  were studied using various in vitro assays. Qualitative determination of different bioactive constituents such as phenol, flavonoid, β-carotene, lycopene and ascorbic acid were also done.Results: The extract was strong hydroxyl radical scavenger reflected by its low EC50 value i.e. 0.03 mg/ml. The EC50 values of the extract was in the order of hydroxyl radical scavenging< chelating ability of ferrous ion< DPPH scavenging< superoxide radical scavenging< β-carotene bleaching< reducing power. . The extract presented a relatively strong antioxidant effect which was found to be correlated with total phenols (R2= 0.969) and flavonoids (R2= 0.888) implying that the polyphenols was partly responsible for the antioxidant activities.Conclusion: Our result thus indicates that the fraction of R. laurocerasi may be utilized as a promising source of therapeutics.KEY WORDS: Antioxidant activity, edible mushroom, flavonoid, phenol, reactive oxygen species

Prospecting Russula senecis: a delicacy among the tribes of West Bengal

Russula senecis, a worldwide distributed mushroom, is exclusively popular among the tribal communities of West Bengal for food purposes. The present study focuses on its reliable taxonomic identification through macro- and micro-morphological features, DNA barcoding, confirmation of its systematic placement by phylogenetic analyses, myco-chemicals and functional activities. For the first time, the complete Internal Transcribed Spacer region of R. senecis has been sequenced and its taxonomic position within subsection Foetentinae under series Ingratae of the subgen. Ingratula is confirmed through phylogenetic analysis. For exploration of its medicinal properties, dried basidiocarps were subjected for preparation of a heat stable phenol rich extract (RusePre) using water and ethanol as solvent system. The antioxidant activity was evaluated through hydroxyl radical scavenging (EC50 5 µg/ml), chelating ability of ferrous ion (EC50 0.158 mg/ml), DPPH radical scavenging (EC50 1.34 mg/ml), reducing power (EC50 2.495 mg/ml) and total antioxidant activity methods (13.44 µg ascorbic acid equivalent/mg of extract). RusePre exhibited antimicrobial potentiality against Listeria monocytogenes, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, different parameters were tested to investigate its chemical composition, which revealed the presence of appreciable quantity of phenolic compounds, along with carotenoids and ascorbic acid. HPLC-UV fingerprint indicated the probable existence of at least 13 phenolics, of which 10 were identified (pyrogallol > kaempferol > quercetin > chlorogenic acid > ferulic acid, cinnamic acid > vanillic acid > salicylic acid > p-coumaric acid > gallic acid). Result from the present work suggests that the fraction, RusePre, may open novel prospect as a functional ingredient in antioxidant supplements and in drugs to treat infectious disease

GREEN SYNTHESIS OF SILVER NANOPARTICLES USING MANGROVE FRUIT POLYSACCHARIDE FOR BACTERIAL GROWTH INHIBITION: GREEN SYNTHESIS OF SILVER NANOPARTICLES

Objective: The objective of this study was to find out the antibacterial activity of the silver nanoparticles (Ag-NPs) using a low-cost green synthesis approach for the formulation of Ag-NPs applying polysaccharide extracted from the fruits of a mangrove plant of Sundarban. Methods: Fresh and healthy fruits were collected from Ceriops decandra plant. Sufficient amount of carbohydrates was extracted from those fruits and the physicochemical characterization of the polysaccharide was analyzed by gas chromatography–mass spectrometry and Fourier-transform infrared spectrophotometry. The respective polysaccharide was further applied to generate the Ag-NPs which were characterized by UV visible, dynamic light scattering, transmission electron microscopy, EDAX, and X-ray diffraction. The antibacterial efficacy of the Ag-NPs was also determined against some pathogenic Gram-negative and Gram-positive bacteria using the microdilution method. Results: Glucose and galactose are the major monomers among the extracted carbohydrates. Various types of spectral analysis confirmed the formation of Ag-NPs. The green synthesized Ag-NPs have the average diameter of about 28 nm. Furthermore, the green synthesized Ag-NPs exhibited strong antibacterial activity against some pathogenic Gram-positive (L. cytomonogenes, Bacillus Subtilis, and Staphylococcus aureus) and Gram-negative (Salmonella typhimurium and Escherichia coli) bacteria. Conclusion: The green synthesis of Ag-NPs using plant polysaccharide was an environment-friendly and cost-effective method as compared to the conventional physical and chemical synthesis techniques

Introducing a novel mushroom from mycophagy community with emphasis on biomedical potency.

Mushrooms have been prized by humankind as medicine and culinary wonder since antiquity. Though several species are ethnically valued; many prospective species are still being discovered. One such wild macrofungus has recently been discovered during subsequent field surveys in West Bengal, India which in turn exposed as a traditionally consumed popular myco-food. The collected taxon was found to be unique with regard to its morphological as well as genetical features. After detailed characterizations, the fungus was identified as a novel taxon belonging to the genus Russula (Russulaceae, Basidiomycota). Besides, the investigation was further extended in search of new functional ingredients and in this context, a water soluble crude polysaccharide rich extract (Rusalan) was isolated from dried basidiocarps. Accumulating evidences from GC-MS, HPTLC, FT-IR along with several spectrophotometric methods postulated that the fraction consisted mainly of carbohydrate in triple helical conformation, where glucose was the major monosaccharide mostly with β-type glycosidic linkage. Conversely, Rusalan showed pronounced antioxidant activity in six in vitro assay systems with EC50 value ranging from 190-1328 μg/ml concentration. The crude polysaccharide was also evaluated against six bacterial strains using microdilution method and the growth of Staphylococcus aureus and Bacillus subtilis were found to be inhibited effectively. In addition, immune-stimulatory assays demonstrated that Rusalan could evidently promote proliferation, induce phagocytosis, release NO, produce intracellular ROS and upregulate mRNA expression of iNOS, TNF-α, COX-2, as well as IL-6 genes in in mouse macrophage cells. Therefore, aim of the present study was not only to describe a new taxon to the world mycoflora but also to introduce a potent therapeutic agent that could be explored for food and pharmaceutical purposes. However, isolation of active component and in vivo studies need to be designed further

Unprecedented pseudo-zeroth-order kinetics of the catecholase-like activity of mixed-valence MnIIMn2III complexes

International audienceDuring the past few decades, the synthesis of coordination complexes that exhibit high catalytic efficiencies has received significant attention from bio-inorganic chemists. In this context, two trinuclear mixed-valence manganese complexes, namely [MnIII2MnII(L1)2(OAc)4(H2O)2]·5H2O (1) and [MnIII2MnII(L2)2(OAc)4(CH3OH)2]·3CH3OH (2) [OAc = acetate] have been synthesized and structurally characterized. These complexes are shown to retain their nuclearity in acetonitrile medium, unveiling a new area of catecholase-like activity. In fact, both complexes showed an efficient oxidizing activity in acetonitrile using 3,5-di-tert-butylcatechol (3,5-DTBC) as the model substrate, and they were able to bring about complete oxidation of the substrate at a catalyst-to-substrate ratio of up to 1 : 600. To the best of our knowledge, the catecholase-like activity of trinuclear species is explored here for the first time. Interestingly, pseudo-zero-order kinetics with respect to the substrate are identified for both complexes, which represents the second report of this type of activity and the first report observed for a mixed-valence manganese complex. Details from experimental investigations of the mechanistic pathway revealed that the formation of oxygen radicals is believed to be the rate-limiting step, which supports the observation of the pseudo-zeroth-order kinetics