Apigenin analogues as SARS-CoV-2 main protease inhibitors: In-silico screening approach.

The COVID-19 new variants spread rapidly all over the world, and until now scientists strive to find virus-specific antivirals for its treatment. The main protease of SARS-CoV-2 (Mpro) exhibits high structural and sequence homology to main protease of SARS-CoV (93.23% sequence identity), and their sequence alignment indicated 12 mutated/variant residues. The sequence alignment of SARS-CoV-2 main protease led to identification of only one mutated/variant residue with no significant role in its enzymatic process. Therefore, Mpro was considered as a high-profile drug target in anti-SARS-CoV-2 drug discovery. Apigenin analogues to COVID-19 main protease binding were evaluated. The detailed interactions between the analogues of Apigenin and SARS-CoV-2 Mpro inhibitors were determined as hydrogen bonds, electronic bonds and hydrophobic interactions. The binding energies obtained from the molecular docking of Mpro with Boceprevir, Apigenin, Apigenin 7-glucoside-4'-p-coumarate, Apigenin 7-glucoside-4'-trans-caffeate and Apigenin 7-O-beta-d-glucoside (Cosmosiin) were found to be -6.6, -7.2, -8.8, -8.7 and -8.0 kcal/mol, respectively. Pharmacokinetic parameters and toxicological characteristics obtained by computational techniques and Virtual ADME studies of the Apigenin analogues confirmed that the Apigenin 7-glucoside-4'-p-coumarate is the best candidate for SARS-CoV-2 Mpro inhibition.

Bioactive Polysaccharides from Seaweeds.

Bioactive compounds with diverse chemical structures play a significant role in disease prevention and maintenance of physiological functions. Due to the increase in industrial demand for new biosourced molecules, several types of biomasses are being exploited for the identification of bioactive metabolites and techno-functional biomolecules that are suitable for the subsequent uses in cosmetic, food and pharmaceutical fields. Among the various biomasses available, macroalgae are gaining popularity because of their potential nutraceutical and health benefits. Such health effects are delivered by specific diterpenes, pigments (fucoxanthin, phycocyanin, and carotenoids), bioactive peptides and polysaccharides. Abundant and recent studies have identified valuable biological activities of native algae polysaccharides, but also of their derivatives, including oligosaccharides and (bio)chemically modified polysaccharides. However, only a few of them can be industrially developed and open up new markets of active molecules, extracts or ingredients. In this respect, the health and nutraceutical claims associated with marine algal bioactive polysaccharides are summarized and comprehensively discussed in this review.

Deciphering the Biological Activities of Dunaliella sp. Aqueous Extract from Stressed Conditions on Breast Cancer: from in Vitro to in Vivo Investigations.

In order to harness local resources to improve well-being and human health, we aim in this study to investigate if the microalgae Dunaliella sp. isolated from the Tunisian coastal zone possesses any anticancer activity. Dunaliella sp. was cultured under normal (DSC) or stressed (DSS) conditions and extracted using different procedures. The biological activity assessment was performed on the Triple Negative Breast Cancer (TNBC) using 4T1 murine cells as a model. Results indicate that: (i) aqueous extract was the most cytotoxic compared to ethanolic and hydroalcoholic extracts; (ii) DSS activity was superior to that of DSC. DSS extracts induced apoptosis rather than necrosis, as evidenced by DNA fragmentation, PARP-1 cleavage and caspase-3 activation. Evaluation in an orthotopic TNBC model validated the anticancer activity in vivo. Intratumoral injection of DSS extract resulted in reduced tumor growth and an enhanced immune system activation. On the transcriptional side, the expression level of the immunosuppressive enzyme Arg-1 was decreased, as well as those of NOS-2 and COX-2 genes. These results suggest a potential anticancer activity of Tunisian Dunaliella sp. deserving further attention.

Quality Characteristics and Functional and Antioxidant Capacities of Algae-Fortified Fish Burgers Prepared from Common Barbel (Barbus barbus).

INTRODUCTION: Algae have been used as natural ingredients to produce new canned fish burgers prepared from minced flesh of common barbel. In this research, the impact of the addition of Cystoseira compressa and Jania adhaerens at concentrations of 0.5, 1, and 1.5% w/v on the texture and sensory characteristics of fish burgers were investigated. RESULTS: Compared to controls, fish burgers containing 1% algae had better texture and sensory properties (P < 0.05). Also, these burger formulations had higher water and oil holding capacities as well as swelling ability, due to the important polysaccharides and dietary fibers contents of algae. In addition, algae-supplemented burgers were characterized as having low L⁎, a⁎, and b⁎ values, which made the color appear to be paler. Thanks to their high richness in pigments (chlorophylls and carotenoids) and polysaccharides, algae considerably enhance the antioxidant activities of the new ready-to-eat fish burgers. So, Cystoseira compressa and Jania adhaerens could be used as nutritious additives to produce new fish-based products.

Extraction optimization and in vitro and in vivo anti-postprandial hyperglycemia effects of inhibitor from Phoenix dactylifera L. parthenocarpic fruit.

Phoenix dactylifera L. plays an important role in social, economic, and ecological Tunisian sectors. Some date palms produce parthenocarpic fruit named Sish. The aqueous ethanolic extract from P. dactylifera parthenocarpic dates demonstrated a potent inhibition of the enzymes related to type II diabetes. In this work, extraction optimization of amylase inhibitors was carried out using Box-Behnken Design. Bioactivity-guided fractionation of the 70% aqueous ethanol extract was performed to identify the active compounds. The physicochemical results by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed the presence of 13 phenolic compounds. The in vitro study showed that the extract exhibited a more specific inhibitor of α-glucosidase than α-amylase with an IC50 value of 0.6 and 2.5mg/mL, respectively. The in vivo study of this extract effect on the postprandial hyperglycemia activity showed a decrease in plasma glucose levels after 30min stronger than the Acarbose effect. These results confirmed the anti-postprandial hyperglycemia activity of the aqueous ethanolic extract from P. dactylifera parthenocarpic dates, which could lend support for its pharmaceutical use.

Yield and composition of pectin extracted from Tunisian pomegranate peel.

A central composite design was employed to determine the influence of extraction conditions on production yield and chemical composition of pectin from pomegranate peels. Response surface methodology (RSM) was used to quantify the integral effect of the three processing parameters (extraction duration, temperature and pH) on yield. A second-order polynomial model was developed for predicting the yield of pomegranate peels pectin based on the composite design. Yields ranged from 6.4 to 11.0±0.2%. Optimal temperature, duration and pH value of the extraction were 86°C, 80min and 1.7, respectively. The uronic acid and the total neutral sugar content of the extracted pectins ranged from 377 to 755mg/g and from 161 to 326mg/g, respectively. Moreover, the degree of methylation varied with the extraction conditions and the extracted pectins were low methylated. On high pressure size exclusion chromatography (HPSEC), the elution pattern of the acid-extracted pectins showed that severe conditions were associated with lower hydrodynamic volume.

Oat (Avena sativa L.): Oil and Nutriment Compounds Valorization for Potential Use in Industrial Applications.

Oat is a promising plant for the future. It is edible and beneficial thanks to its nutritional, medicinal and pharmaceutical uses and, hence, recognized to be useful for a healthier world. The assessment of the vital functions of oat components is important for industries requiring correct health labelling, valid during the shelf life of any product. Oil, enzymes and other biomolecules of nutraceutic or dietary usage from oats would be valorized for this purpose. Although oats have a unique and versatile composition including antioxidants and biomolecules indispensable for health, they are undervalued in comparison with other staple cereals such as wheat, barley and rice. Furthermore, oats, apart from maize, comprise a high oil content used for a wide range of beneficial purposes. In addition, they contain beta glucan that has proven to be very helpful in reducing blood cholesterol levels and other cardiovascular diseases risks. In fact, there is diversity in the composition and content of the beneficial oat components within their genotypes and the different environmental conditions and, thus, oats are amenable to be enhanced by agronomic practices and genetic approaches.

Influence of Zeolite on fatty acid composition and egg quality in Tunisian Laying Hens.

BACKGROUND: The health benefits of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) are generally recognized. Unfortunately, in most Mediterranean countries, the recommended daily intake of these compounds is rarely met. Therefore, enrichment of commonly occurring foods can boost intake of these fatty acids. In this regard, eggs are an interesting target, as they form an integral part of the diet. RESULT: Zeolite (Clinoptilolites) was added to Laying Hens feed at concentrations 1% or 2% and was evaluated for its effects on performance of the production and on egg quality. The Laying Hens were given access to 110 g of feed mixtures daily that was either a basal diet or a 'zeolite diet' (the basal diet supplemented with clinoptilolite at a level of 1% or 2%). It was found that zeolite treatment had a positive and significatif (p<0.05) effect on some parameters that were measured like egg height and eggshell strength. While dietary zeolite supplementation tended to/or has no significant effects on total egg, eggshell, yolk and albumen weights. It was found also that zeolite mainly increases level of polyunsaturated fatty acids in egg. CONCLUSION: This study showed the significance of using zeolite, as a feed additive for Laying Hens, as part of a comprehensive program to control egg quality and to increase level of polyunsaturated fatty acids on egg.

Effect of zeolite (clinoptilolite) as feed additive in Tunisian broilers on the total flora, meat texture and the production of omega 3 polyunsaturated fatty acid.

BACKGROUND: Increasing consumer demand for healthier food products has led to the development of governmental policies regarding health claims in many developed countries. In this context, contamination of poultry by food-borne pathogens is considered one of the major problems facing the progress of the poultry industry in Tunisia. RESULT: Zeolite (Clinoptilolites) was added to chicken feed at concentrations 0,5% or 1% and was evaluated for its effectiveness to reduce total flora in chickens and its effects on performance of the production. The broilers were given free and continuous access to a nutritionally non-limiting diet (in meal form)that was either a basal diet or a' zeolite diet' (the basal diet supplemented with clinoptilolite at a level of 0,5% or 1%). It was found that adding zeolite in the broiler diet significantly (p < 0,05) reduced total flora levels, as compared to the control, on the chicken body. In addition, it was found that zeolite treatment had a positive effect on performance production and organoleptic parameters that were measured and mainly on the increase level of Omega 3 fatty acid. CONCLUSION: This study showed the significance of using zeolite, as a feed additive for broilers, as part of a comprehensive program to control total flora at the broiler farm and to increase level of Omega 3 fatty acid on the chicken body.

Carica papaya lipase: a naturally immobilized enzyme with interesting biochemical properties.

Triacylglycerol (TAG) lipases have been thoroughly characterized in mammals and microorganisms, whereas very little is known about plant TAG lipases. The lipolytic activity occurring in all the laticies is known to be associated with sedimentable particles, and all attempts to solubilize the lipolytic activity of Carica papaya latex have been unsuccessful so far. However, some of the biochemical properties of the lipase from Carica papaya latex (CPL) were determined from the insoluble fraction of the latex. The activity was optimum at a temperature of 37°C and a pH of 9.0, and the specific activities of CPL were found to be 2,000 ± 185 and 256 ± 8 U/g when tributyrin and olive oil were used as substrates, respectively. CPL was found to be active in the absence of any detergent, whereas many lipases require detergent to prevent the occurrence of interfacial denaturation. CPL was inactive in the presence of micellar concentrations of Triton X-100, sodium dodecyl sulfate (SDS) and tetradecyl trimethylammonium bromide (TTAB), and still showed high levels of activity in the presence of sodium taurodeoxycholate (NaTDC) and the zwitterionic Chaps detergent. The effects of various proteases on the lipolytic activity of CPL were studied, and CPL was found to be resistant to treatment with various enzymes, except in the presence of trypsin. All these properties suggest that CPL may be a good candidate for various biotechnological applications.