Antimicrobial, antioxidant and antileishmanial activities of Ziziphus lotus leaves.

The aim of this study was to investigate antimicrobial and antioxidant activities of different fractions obtained from edible Tunisian Ziziphus Lotus leaves of Tozeur region. Different organic extracts were tested: cyclohexane, dichloromethane, ethyl acetate, n-butanol and water. Bio-guided fractionation revealed that dichloromethane fraction is the most active against S. aureus and Methicillin-resistant S. aureus strains. Moreover, this fraction showed the highest antileishmanial activity with IC50 values of 20.55 ± 0.34 µg/mL and 15.37 ± 0.17 µg/mL against L. major and L. infantum, respectively. The potentialities of antibacterial and leishmanicidal activities found in dichloromethane could be explained by the presence of major flavonoids such as catechin, rutin and luteolin 7-O-glucoside as revealed by HPLC system. The observed moderate antifungal activity, which was only given by butanolic fraction against pathogen fungi, may be attributed to the presence of chlorogenic acid. Furthermore, dichloromethane and butanolic fraction showed a good DPPH (2,2-diphenyl-1-picryl hydrazyl) scavenging activity and Ferric reducing power. These results suggest that Ziziphus lotus leaf fractions might be used as antioxidant and antimicrobialagent.

GC-EI-MS identification data of neutral sugars of polysaccharides extracted from Zizyphus lotus fruit.

Gas chromatography coupled to mass spectrometer (GC-MS) was used to identify and to quantify neutral sugars that constitute the water soluble polysaccharides from Zizyphus lotus fruit. The trimethylsilyl (TMS) method was successfully used for derivatization of the monosaccharides units of extracted polysaccharides that were released by hydrolysis method. Sugars were identified based on their retention times compared with those of standards and the NIST MS Spectral Library. All sugars were quantified in TIC (Total Ion Current) mode using calibration curves. Data is related to "Optimization extraction of polysaccharide from Tunisian Zizyphus lotus fruit by response surface methodology: Composition and antioxidant activity" (Mkadmini Hammi et al., 2016) [1].

Optimization of antioxidant and antiglycated activities of polysaccharides from Arthrocnemum indicum leaves.

Central composite design was performed to optimize uronic acid rate, esterification degree, total antioxidant ability and antiglycation capacity of carbohydrates from Arthrocnemum indicum leaves. Three independent variables were opted: extraction temperature, time and ratio (solvent/material). The optimal settings were: extraction temperature of 80°C, time of 288min and (solvent/solid) ratio of 40mL/g. Under these settings, uronic acid rate and esterification degree were 49.29%, 30.24%, respectively, whereas total antioxidant activity and antiglycation capacity was 35.81mg ascorbic acid equivalents/g matter and 69.81%, respectively. Colorimetric assays showed that total sugar and uronic acid contents for polysaccharide were 71.78% and 49.24%, respectively. Furthermore, Preliminary structure study was performed via various methods including FT-IR, NMR and UV-vis analysis. SEC analyzes revealed that polysaccharide had an average molecular weight of 2179kDa. Moreover, GC-MS analyzes showed that extracted polysaccharide was a pectic polysaccharide which formed of arabinose, mannose, galactose, rhamnose, glucose and xylose in the molar percentage of 66.68%, 3.93%, 12.71%, 6.31%, 6.08% and 4.29%, respectively. This results revealed that extracted polysaccharide can be employed as source of natural antioxidants and as possible antiglycated agents.

Characterization, antioxidant and antiglycation properties of polysaccharides extracted from the medicinal halophyte Carpobrotus edulis L.

In this study, Box-Behnken design was used to optimize the ultrasonic extraction of Carpobrotus edulis polysaccharides (CEP), and the effect of time, extraction temperature and water to material ratio was evaluated. Optimum conditions were 1.77h, 78.0°C and 33.04mL/g to improved CEP yield (7.84%), which is in good agreement with the predicted yield 7.77%. Then, the physico-chemical, antioxidant and antiglycation properties of optimized CEP were studied, and the total sugar and galacturonic acid content were 89.7 and 63.2%, respectively. The composition of neutral monosaccharide was arabinose, xylose, rhamnose and mannose in the molar percentage of 71.84, 14.80, 8.57, and 4.79%, respectively. In addition, (1H, and 13C) NMR and FTIR analyses confirmed the presence of uronic acids in the free and methyl ester forms with a degree of esterification of 31.27%. Therefore, this finding showed that CEP is a low methoxyl pectic polysaccharide, with an average molecular weight about 65,000g/mol. Finally, the results indicated that CEP presents strong antioxidant activities in vitro (DPPH, chelating ability and reducing power), and significantly inhibits lipid peroxidation and the formation of fluorescent advanced glycation end products in glucose-BSA system model.

Physico-chemical characterization and pharmacological activities of sulfated polysaccharide from sea urchin, Paracentrotus lividus.

Sulfated polysaccharide (SP) from the eggs of sea urchin Paracentrotus lividus, extracted by papain digestion, was characterized by size exclusion chromatography coupling on-line with light scattering and viscosity detectors (SEC/MALS/VD/DRI), gas chromatography coupled to mass spectrometer (GC-MS), and Fourier transform infrared spectroscopy (FTIR) analysis. The native molecular mass of the extracted polysaccharide is high (≥22 000 KDa) and it is composed mainly of arabinose, accompanied by other monosaccharides (mostly galactose, glucose and fucose), significant amounts of uronic acids (18.4%) and relatively high proportions of sulfate (22.4%). The pharmacological evaluation of SP showed a significant in vivo anti-inflammatory activity (p<0.001), 3h after injection, the edema inhibition was 75.8% at the dose of 100mg/Kg; a significant peripheral analgesic activity (p<0.001), with 64.9% of writhing inhibition, and a significant increase in the hot plate reaction time in mice indicating central analgesic activity. In addition, an interesting gastroprotective effect was observed with this polysaccharide; the gastric ulcer inhibition was 69.7%, at the dose of 100mg/Kg.

Comparison of Phytochemical Composition and Biological Activities of Rubus ulmifolius Extracts Originating from Four Regions of Tunisia.

In the current study, the phenolic composition, antioxidant and antimicrobial activities of extracts from Rubus ulmifolius Schott leaves harvested in four localities (Sejnen, Tabarka, Faija and Ain drahem) in Tunisia were investigated for the first time. Great differences were found for the chemical composition, total phenol contents and biological activities among the evaluated extracts. HPLC analysis of methanolic extracts showed that the dominant compounds were kaempferol 3-O-rutinoside and naringenine. In addition, significant correlations were observed between antioxidant activities and phenolic contents. In fact, leaves collected from Sejnen presented higher total phenol content (53.32 mg GAE/g DW) and antioxidant activities (IC50 = 39.40 mg/l) than the others samples. All extracts showed significant antimicrobial activity against six used bacteria with the inhibition zones diameters and minimal inhibitory concentration values were in the range of 8 - 16 mm and 6.25 - 25 mg/ml, respectively. The highest antimicrobial activities were recorded in Sejnen extract against Gram-positive bacteria.

Inhibition of protein glycation, antioxidant and antiproliferative activities of Carpobrotus edulis extracts.

Carpobrotus edulis is an important South African medicinal plants used as a food and therapeutic agent in traditional medicine. The aim of this study was to determine the phytochemical content, antioxidant, antiglycation and cytotoxic effect against Human Colon Cancer Cell Line (HCT-116) of aqueous and ethanol-water (1:1v/v) extracts of Carpobrotus edulis.The content of total phenolics and flavonoids in aqueous and ethanol-water extract were 151.99µg and 66.35µg gallic acid equivalents/mg of dry extract, and 38.84µg and 21.96µg quercetin/mg of dry extract, respectively. Furthermore, phenolic compositions analysis indicated the presence of seven majority compounds including sinapic acid, ferulic acid, luteolin7-o-glucoside, hyperoside, isoquercitrin, ellagic acid and isorhamnetin 3-O-rutinoside. The ethanol-water extract (100-1000µg/mL) showed better antioxidant activity than aqueous extract. Furthermore, Carpobrotus edulis extracts, especially ethanol-water extract significantly inhibited the formation of fluorescent advanced glycation end products, prevented oxidation-induced protein damage and exhibited a cytotoxic effect against HCT116 cells, with a significant decrease in cell viability after 24h of incubation. The results obtained suggest that the Carpobrotus edulis extracts could be used as an easily accessible source of natural antioxidants and as potential phytochemicals against protein glycation and colon cancer.

Optimization of ultrasound-assisted extraction of antioxidant compounds from Tunisian Zizyphus lotus fruits using response surface methodology.

The optimization of antioxidant extraction conditions from a ripe edible fruits of Zizyphus lotus (L.) with an ultrasound-assisted system was achieved by response surface methodology. The central composite rotatable design was employed for optimization of extraction parameters in terms of total phenolic content and antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and phosphomolybdenum assay. The optimum operating conditions for extraction were as follows: ethanol concentration, 50%; extraction time, 25 min; extraction temperature, 63°C and ratio of solvent to solid, 67 mL/g. Under these conditions, the obtained extract exhibited a high content of phenolic compounds (40.782 mg gallic acid equivalents/g dry matter) with significant antioxidant properties (the total antioxidant activity was 75.981 mg gallic acid equivalents/g dry matter and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity was 0.289 mg/mL).