Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase ...in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained commercially had its identity confirmed by nuclear magnetic resonance and infrared spectroscopy. In several tests, this chitosan showed low or no antioxidant activity. However, it also showed excellent copper-chelating activity. In vitro, chitosan acted as an inducer mainly of monohydrate CaOx crystal formation, which is more prevalent in patients with urolithiasis. We also observed that chitosan modifies the morphology and size of these crystals, as well as changes the surface charge of the crystals, making them even more positive, which can facilitate the interaction of these crystals with renal cells. Chitosan greatly influences the formation of crystals in vitro, and in vivo analyses should be conducted to assess the risk of using chitosan.
The Ascomycete Cordyceps militaris, an entomopathogenic fungus, is one of the most important traditional Chinese medicines. Studies related to its pharmacological properties suggest that this ...mushroom can exert interesting biological activities. Aqueous (CW and HW) and alkaline (K5) extracts containing polysaccharides were prepared from this mushroom, and a β-D-glucan was purified. This polymer was analysed by GC-MS and NMR spectrometry, showing a linear chain composed of β-D-Glcp (1→3)-linked. The six main signals in the 13C-NMR spectrum were assigned by comparison to reported data. The aqueous (CW, HW) extracts stimulated the expression of IL-1β, TNF-α, and COX-2 by THP-1 macrophages, while the alkaline (K5) extract did not show any effect. However, when the extracts were added to the cells in the presence of LPS, K5 showed the highest inhibition of the pro-inflammatory genes expression. This inhibitory effect was also observed for the purified β-(1→3)-D-glucan, that seems to be the most potent anti-inflammatory compound present in the polysaccharide extracts of C. militaris. In vivo, β-(1→3)-D-glucan also inhibited significantly the inflammatory phase of formalin-induced nociceptive response, and, in addition, it reduced the migration of total leukocytes but not the neutrophils induced by LPS. In conclusion, this study clearly demonstrates the anti-inflammatory effect of β-(1→3)-D-glucan.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Total lipids from the Brazilian brown seaweed Sargassum vulgare were extracted with chloroform/methanol 2:1 and 1:2 (v/v) at room temperature. After performing Folch partition of the crude lipid ...extract, the lipids recovered from the Folch lower layer were fractionated on a silica gel column eluted with chloroform, acetone and methanol. The fraction eluted with methanol, presented a strong orcinol-positive band characteristic of the presence of sulfatides when examined by TLC. This fraction was then purified by two successive silica gel column chromatography giving rise to fractions F4I86 and F4II90 that exhibited strong activity against herpes simplex virus type 1 and 2. The chemical structures present in both fractions were elucidated by ESI-MS and ¹H/¹³C NMR analysis HSQC fingerprints based on their tandem-MS behavior as Sulfoquinovosyldiacylglycerols (SQDGs). The main SQDG present in both fractions and responsible for the anti-herpes activity observed was identified as 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)-glycerol.
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Mixtures containing the majority of partially O-methylated alditol acetates (PMAAs), necessary for the GC–MS based identification of glycosidic linkages in oligo- and polymeric ...structures were prepared. Rha, Fuc, Rib, Ara, Xyl, Man, Gal, and Glc were converted to their Me glycosides, and the products were progressively O-methylated using the Purdie reagent at 25
°C. Resulting PMGs were assayed by TLC and at times that were optimum for formation of mono-
O-methyl derivatives and later for higher degrees of methylation; they were converted to PMAAs, in a process incorporating NaB
2H
4 reduction. The majority of these can be used as standards for simultaneous identification of pyranosides and some furanosyl units particularly in heteropolysaccharides. The relative reactivities of OH-groups were determined by GC–MS as: Me α- and β-Glc
p, HO-2
>
HO-4
>
HO-3
>
HO-6, Me α- and β-Gal
p, HO-3
>
HO-2
>
HO-4
>
HO-6, Me α-Man
p, HO-3
>
HO-2
>
HO-4
>
HO-6, Me β-Man
p, HO-3
>
HO-4
⩾
HO-6
>
HO-2, Me α-Rha
p, OH-3
>
OH-2
>
OH-4; Me αβ-Fuc
p, OH-2
>
OH-3
>
OH-4, and Me αβ-Xyl
p, OH-2
>
OH-4
>
OH-3. The results differ from those obtained with Haworth, Hakomori, and Ciucanu methylation techniques, although some similarities occurred with the more rapid Kuhn method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Cell wall polysaccharides of seeds of quinoa (Chenopodium quinoa) were studied. ► Quinoa has a linear arabinan with (1→5)-linked α-l-arabinofuranosyl units. ► Quinoa has a rhamnogalacturonan with a ...branched arabinan and galactan side-chains. ► The polysaccharides showed gastroprotective activity.
After removal of starch, cell wall polysaccharides of seeds of quinoa were studied. They were extracted successively with water and with aq. 10% KOH. The extracted polysaccharides were fractionated and purified by freeze–thaw treatment and by sequential ultrafiltration through membranes. The purified fractions (PQW, K2-30EM, K1-10RM and K1-30RM) were analyzed by sugar composition, HPSEC, methylation and 13C NMR spectroscopy analysis. The results showed that PQW consisted of a linear arabinan with (1→5)-linked α-l-arabinofuranosyl units. Fractions K2-30EM, K1-10RM and K1-30RM were related to rhamnogalacturonan type I with a branched arabinan and galactan side-chains. This arabinan has (1→5)-linked α-l-arabinofuranosyl units substituted exclusively in O-3. The main differences between these fractions were their molecular mass and content of Rha and GalA, which probably arise from an increase in their rhamnogalacturonan backbone. A pool of these polysaccharides (arabinan and arabinan-rich pectic polysaccharides) showed gastroprotective activity on ethanol-induced acute gastric lesions in rats.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Angomonas deanei belongs to Trypanosomatidae family, a family of parasites that only infect insects. It hosts a bacterial endosymbiont in a mutualistic relationship, constituting an excellent model ...for studying organelle origin and cellular evolution. A lipidomic approach, which allows for a comprehensive analysis of all lipids in a biological system (lipidome), is a useful tool for identifying and measuring different expression patterns of lipid classes. The present study applied GC-MS and NMR techniques, coupled with principal component analysis (PCA), in order to perform a comparative lipidomic study of wild and aposymbiotic A. deanei grown in the presence or absence of FBS. Unusual contents of branched-chain iso C17:0 and C19:0-cis-9,10 and-11,12 fatty acids were identified in A. deanei cultures, and it was interesting to note that their content slightly decreased at the log phase culture, indicating that in the latter growth stages the cell must promote the remodeling of lipid synthesis in order to maintain the fluidity of the membrane. The combination of analytical techniques used in this work allowed for the detection and characterization of lipids and relevant contributors in a variety of A. deanei growth conditions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The breakdown of
O
,
O
-diethyl-2,4-dinitrophenyl phosphate in formamide (FMD) solutions is assessed using kinetic studies and
31
P nuclear magnetic resonance (NMR) analysis. Regiospecific ...nucleophilic amidolysis
via
P-O bond cleavage is observed, leading to non-toxic diester and FMD regeneration. In the systems evaluated, water plays an antagonistic role: while it is key for the breakdown of the reaction intermediate, it inhibits the nucleophilic activity of FMD by hydrogen bonding effects.
Aqueous formamide solutions can promote catalytic amidolysis of an activated organophosphate in a regiospecific process.
Glycolipids were extracted from the red alga Osmundaria obtusiloba from Southeastern Brazilian coast. The acetone insoluble material was extracted with chloroform/methanol and the lipids, enriched in ...glycolipids, were fractionated on a silica gel column eluted with chloroform, acetone and then methanol. Three major orcinol-positive bands were found in the acetone and methanol fractions, being detected by thin layer chromatography. The structures of the corresponding glycolipids were elucidated by ESI-MS and (1)H/(13)C NMR analysis, on the basis of their tandem-MS behavior and HSQC, TOCSY fingerprints. For the first time, the structure of sulfoquinovosyldiacylglycerol from the red alga Osmundaria obtusiloba was characterized. This molecule exhibited potent antiviral activity against HSV-1 and HSV-2 with EC(50) values of 42 µg/mL to HSV-1 and 12 µg/mL to HSV-2, respectively. Two other glycolipids, mono- and digalactosyldiacylglycerol, were also found in the alga, being characterized by ESI-MS/MS. The structural elucidation of algae glycolipids is a first step for a better understanding of the relation between these structures and their biological activities.
Differential interactions between influenza A virus protein hemagglutinin (HA) and α2→3 (avian) or α2→6 (human) sialylated glycan receptors play an important role in governing host specificity and ...adaptation of the virus. Previous analysis of HA–glycan interactions with trisaccharides showed that, in addition to the terminal sialic acid linkage, the conformation and topology of the glycans, while they are bound to HA, are key factors in regulating these interactions. Here, the solution conformation and dynamics of two representative avian and human glycan pentasaccharide receptors LSTa, Neu5Ac-α(2→3)-Gal-β(1→3)-GlcNAc-β(1→3)-Gal-β(1→4)-Glc; LSTc, (Neu5Ac-α(2→6)-Gal-β(1→4)-GlcNAc-β(1→3)-Gal-β(1→4)-Glc have been explored using nuclear magnetic resonance and molecular dynamics simulation. Analyses demonstrate that, in solution, human and avian receptors sample distinct conformations, topologies, and dynamics. These unique features of avian and human receptors in solution could represent distinct molecular characteristics for recognition by HA, thereby providing the HA–glycan interaction specificity in influenza.
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