Phytochemical profiling, antioxidant and anticancer activities of Gastrocotyle hispida growing in Saudi Arabia.

The present study aimed at isolation the phytocompounds from the aerial parts of Gastrocotyle hispida and to evaluate its antioxidant and anticancer potential using in vitro assay. Gastrocotyle hispida is belonging to the family Boraginaceae used as a refreshing drink like tea. The decoction of the leaves is diuretic and is used in the treatment of rheumatism. Phytochemical study of a methanol extract yielded five known compounds viz: ß-sitosterol (GH-1), ß-sitosterol 3-glucoside (GH-2), 1-O-ß-glucopyranosyl-1,4-dihydroxy-2-prenylbenzene (GH-3), 6-Hydroxy-2,2-dimethyl-3-chrom (GH-4) and rosmarinic acid (GH-5). Total phenolic and flavonoid contents were calculated for the extract and fractions, the methanolic extract contained the highest content of total flavonoids (178 mg/g, expressed as quercetin equivalents) and total polyphenol (98.4 mg/g, expressed as gallic acid equivalent). Compounds were isolated by using column chromatography. In vitro, antioxidant activity of the extract and isolated compounds was investigated by DPPH and ABTS radical scavenging assays. The four different cell lines HepG2 (Liver), HEK-293 (Kidney) MCF-7 (Breast) and MDA-MB 231 (Breast) were used against the compounds. The isolated compounds showed dose-dependent free radical scavenging property in all tested models with the IC50 values of 10.2 µg/mL rosmarinic acid (GH-5), 52.1 µg/mL ß-sitosterol (GH-1) and 85 µg/mL for ß-sitosterol 3-glucoside (GH-2). The ß-sitosterol (GH-1) showed significant activity against HepG2 and HEK 293 cell lines. Rosmarinic acid (GH-5) possesses potent anticancer activity against breast cancer cells (MCF7) with the IC50 value of 4.2 µg/mL. It can be concluded that Gastrocotyle hispida has potential antioxidant, anticancer activities and further used as an anticancer agent.

Alpha-Amylase and Alpha-Glucosidase Enzyme Inhibition and Antioxidant Potential of 3-Oxolupenal and Katononic Acid Isolated from Nuxia oppositifolia.

Nuxia oppositifolia is traditionally used in diabetes treatment in many Arabian countries; however, scientific evidence is lacking. Hence, the present study explored the antidiabetic and antioxidant activities of the plant extracts and their purified compounds. The methanolic crude extract of N. oppositifolia was partitioned using a two-solvent system. The n-hexane fraction was purified by silica gel column chromatography to yield several compounds including katononic acid and 3-oxolupenal. Antidiabetic activities were assessed by α-amylase and α-glucosidase enzyme inhibition. Antioxidant capacities were examined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) scavenging assays. Further, the interaction between enzymes (α-amylase and α-glucosidase) and ligands (3-oxolupenal and katononic acid) was followed by fluorescence quenching and molecular docking studies. 3-oxolupenal and katononic acid showed IC50 values of 46.2 µg/mL (101.6 µM) and 52.4 µg/mL (119.3 µM), respectively against the amylase inhibition. 3-oxolupenal (62.3 µg/mL or 141.9 µM) exhibited more potent inhibition against α-glucosidases compared to katononic acid (88.6 µg/mL or 194.8 µM). In terms of antioxidant activity, the relatively polar crude extract and n-butanol fraction showed the greatest DPPH and ABTS scavenging activity. However, the antioxidant activities of the purified compounds were in the low to moderate range. Molecular docking studies confirmed that 3-oxolupenal and katononic acid interacted strongly with the active site residues of both α-amylase and α-glucosidase. Fluorescence quenching results also suggest that 3-oxolupenal and katononic acid have a good affinity towards both α-amylase and α-glucosidase enzymes. This study provides preliminary data for the plant's use in the treatment of type 2 diabetes mellitus.

Unraveling the molecular mechanism of the effects of sodium dodecyl sulfate, salts, and sugars on amyloid fibril formation in camel IgG.

Sodium dodecyl sulfate (SDS) is an anionic surfactant that can be used to stimulate protein fibrillation in vitro. Here, we investigated the effects of SDS on camel IgG aggregation at pH 3.5 and 7.4. SDS-induced amyloid fibril formation in camel IgG was examined by turbidity measurements, Rayleigh scattering, Thioflavin T (ThT) fluorescence, intrinsic fluorescence, circular dichroism (CD), and transmission electron microscopy (TEM). The results suggest that low SDS concentrations (0.2-2.0 mM) induce amyloid-like aggregates of camel IgG at pH 3.5, indicating an SDS/camel IgG ratio below 1000. However, in the presence of higher concentrations of SDS (2.5-10.0 mM), amyloid fibril formation was not observed. Furthermore, at the higher concentrations, the ß-sheet structure of camel IgG was transformed into a α-helical structure. The amyloid fibril formation was not observed in the presence of SDS at pH 7.4. Additionally, the role of salts and sugars was evaluated in the SDS-induced aggregation process. Interestingly, in the presence of 0.15 N of NaCl and (NH4)2SO4, SDS promoted camel IgG aggregation up to very high concentrations of SDS (0.2-10.0 mM; SDS/camel IgG ratio, 95-4750) and no suppression was observed. Moreover, osmoprotectants (trehalose and sucrose) were ineffective, neither promoting nor inhibiting the SDS-induced aggregation process. However, at pH 3.5, electrostatic and hydrophobic interactions, and hydrogen bonds were the major contributing factors in SDS-induced fibrillation. However, no aggregation was observed at pH 7.4 due to electrostatic repulsion between SDS and camel IgG because both of these molecules have overall similar charges.

Optimization of physicochemical parameters of tannase post-purification and its versatile bioactivity.

The present study investigates the optimization of tannase production from Aspergillus nidulans for various physicochemical parameters and harvests tannase for its chemical characterization. The maximum tannase activity was observed on the third day of incubation at 35°C and the stability was observed at pH 5.5-6.0 by holding its 100% activity. The tannase was partially purified from A. nidulans [FT10] by ammonium sulfate precipitation at different concentrations, and it was found that at 80% of ammonium sulfate concentration, the precipitate exhibited the maximum activity for tannase of 96 U/ml. LCMS showed its M/Z value as 162.3 which was reconfirmed by SDS-PAGE. The UV spectrum and FTIR confirmed the presence of two oxy- and three hydroxyl groups in the benzene ring structure. The antibacterial activity of tannase was enhanced with antibiotics such as streptomycin and ceftazidime whereas the biofilm formation was significantly inhibited by the purified tannase. The scavenging activity was greatly increased with purified component and when the concentration of the purified tannase, FT10 was increased. To the best of our knowledge, this is one of the few reports where microbial species was used as the source for producing tannase enzyme and its role in various bioactivities such as antibacterial, anti-biofilm and antioxidant activity was evaluated.

Nano-composites chitosan-curcumin synergistically inhibits the oxidative stress induced by toxic metal cadmium.

The present study intends to compare the influence of pre-treatment with nanoparticles of curcumin (Cr-NPS), chitosan (Ch-NPS) and nanocomposites chitosan-curcumin (CC-NPS) on cadmium (Cd)-induced oxidative damage in the liver, kidneys, and blood indices in Swiss strain adult male mice. The pretreated mice with Cr-NPS, Ch-NPS, and CC-NPS were exposed to Cd (10mg/kg) for three weeks. The non-enzymatic Oxidative Stress (OS) indices like lipid peroxides (TBARS), reduced total glutathione (GSH), enzymatic OS indices like catalase (CAT), glutathione S-transferase (GST) and superoxide dismutase (SOD) were estimated together with some blood indices. Cadmium was able to induce a significant increase in TBARS and a significant decrease in GSH, GST, CAT and SOD levels in all the tissues, which were pretreated with nanocomposite. Furthermore, the blood indices like counts of red and white blood cells, platelets, hemoglobin and packed cell volume were also depleted due to Cd exposure but remained unaffected and kept under normal levels in pretreated mice group. The results indicate that Cr-NPS, Ch-NPS, and CC-NPS may act as natural antioxidants and when compared among the three, CC-NPS appears to be the best antioxidant.

Negatively charged food additive dye "Allura Red" rapidly induces SDS-soluble amyloid fibril in beta-lactoglobulin protein.

Recent studies have led to an increased interest to categorize small molecular inhibitors of protein fibrillation. In this study, we used spectroscopy, microscopy and gel electrophoresis techniques that provides an elaborated description of the Allura Red-induced amyloid fibrillation in the ß-LG protein at two pHs (7.4 and 3.5). The spectroscopy results show that ß-LG protein form aggregates in the presence of Allura Red (0.04-15.0mM) at pH 3.5 due to electrostatic and hydrophobic interactions. However, at pH 7.4, the ß-LG does not interact electrostatically with Allura Red and therefore no aggregation occurred. The Allura Red-induced aggregates have an amyloid-like structure that was confirmed by far-UV CD, Congo Red and transmission electron microscopy (TEM). The CD spectrum of ß-LG contains single minima at ∼218nm, which shifts towards higher wavelength minima at ∼225nm in the presence of Allura Red, characteristics of the cross ß-sheet structure. The TEM results suggest that ß-LG form long straight fibril when exposed to Allura Red at pH 3.5. The Allura Red-induced amyloid fibril is SDS-soluble confirmed by SDS-PAGE techniques. A far UV CD result shows the conversion of Allura Red induced cross ß-sheet structure into alpha-helical structure in the presence of increasing concentration of SDS. The results of this study suggest that the electrostatic, as well as hydrophobic interactions play an important role during Allura Red-induced ß-LG fibrillation.