Whole and Purified Aqueous Extracts of Nigella sativa L. Seeds Attenuate Apoptosis and the Overproduction of Reactive Oxygen Species Triggered by p53 Over-Expression in the Yeast Saccharomyces cerevisiae.

Plants are an important source of pharmacologically active compounds. In the present work, we characterize the impact of black cumin (Nigella sativa L.) aqueous extracts on a yeast model of p53-dependent apoptosis. To this end, the Saccharomyces cerevisiae recombinant strain over-expressing p53 was used. The over-expression of p53 triggers the expression of apoptotic markers: the externalization of phosphatidylserine, mitochondrial defect associated with cytochrome-c release and the induction of DNA strand breaks. These different effects were attenuated by Nigella sativa L. aqueous extracts, whereas these extracts have no effect on the level of p53 expression. Thus, we focus on the anti-apoptotic molecules present in the aqueous extract of Nigella sativa L. These extracts were purified and characterized by complementary chromatographic methods. Specific fluorescent probes were used to determine the effect of the extracts on yeast apoptosis. Yeast cells over-expressing p53 decrease in relative size and have lower mitochondrial content. The decrease in cell size was proportional to the decrease in mitochondrial content and of mitochondrial membrane potential (ΔΨm). These effects were prevented by the purified aqueous fraction obtained by fractionation with different columns, named C4 fraction. Yeast cell death was also characterized by reactive oxygen species (ROS) overproduction. In the presence of the C4 fraction, ROS overproduction was strongly reduced. We also noted that the C4 fraction promotes the cell growth of control yeast cells, which do not express p53, supporting the fact that this purified extract acts on cellular mediators activating cell proliferation independently of p53. Altogether, our data obtained on yeast cells over-expressing p53 demonstrate that anti-apoptotic molecules targeting p53-induced apoptosis associated with mitochondrial dysfunction and ROS overproduction are present in the aqueous extracts of Nigella seeds and in the purified aqueous C4 fraction.

Evidence for enhanced dissipation of chlorpyrifos in an agricultural soil inoculated with Serratia rubidaea strain ABS 10.

The insecticide 14C-chlorpyrifos was found mineralized in a Tunisian soil with repeated exposure to it. From this soil, a bacterial strain was isolated that was able to grow in a minimal salt medium (MSM) supplemented with 25 mg L-1 of chlorpyrifos. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In a liquid culture, the S. rubidaea strain ABS 10 was able to dissipate chlorpyrifos almost entirely within 48 h of incubation. Although the S. rubidaea strain ABS 10 was able to grow in an MSM supplemented with chlorpyrifos and dissipate it in a liquid culture, it was not able to mineralize 14C-chlorpyrifos. Therefore, it can be concluded that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. It can also be ascribed to other reasons such as the formation of biogenic non-extractable residues. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in controls with DT50 of 1.38 and 1.05 days, respectively.

Morus alba leaf extract mediates neuroprotection against glyphosate-induced toxicity and biochemical alterations in the brain.

Recent studies demonstrate that glyphosate exposure is associated with oxidative stress and some neurological disorders such as Parkinson's pathology. Therefore, phytochemicals, in particular phenolic compounds, have attracted increasing attention as potential agents for neuroprotection. In the present study, we investigate the impact of glyphosate on the rat brain following i.p. injection and the possible molecular target of neuroprotective activity of the phenolic fraction from Morus alba leaf extract (MALE) and its ability to reduce oxidative damage in the brain. Wistar rats from 180 to 240 g were i.p. treated with a single dose of glyphosate (100 mg kg-1 b.w.) or MALE (100 µg mL-1 kg-1 b.w.) for 2 weeks. Brain homogenates were used to evaluate neurotoxicity induced by the pesticide. For this, biochemical parameters were measured. Data shows that MALE regulated oxidative stress and counteracted glyphosate-induced deleterious effects and oxidative damage in the brain, as it abrogated LDH, protein carbonyls, and malonyldialdehyde. MALE also appears to be able to scavenge H2O2 levels, maintain iron and Ca2+ homeostasis, and increase SOD activity. Thus, in vivo results showed that mulberry leaf extract is a potent protector against glyphosate-induced toxicity, and its protective effect could result from synergism or antagonism between the various bioactive phenolic compounds in the acetonic fraction from M. alba leaf extract.

Biochemical and Molecular Study of Carpobrotus edulis Bioactive Properties and Their Effects on Dugesia sicula (Turbellaria, Tricladida) Regeneration.

The traditional medicinal properties of Carpobrotus edulis are well recognized, particularly in Tunisia where it is used for wound healing. Thus, in this study, biochemical and molecular properties of its leaves' bioactive aqueous-acetone extract were investigated. The total phenolic content (TPC) of the extract was estimated to be 184 ± 5 mg/100 g of fresh matter (FM). The qualitative and quantitative polyphenolic profile was determined by ultra performance liquid chromatography with diode array detection (UPLC-DAD) and showed that chlorogenic acid was the major compound (43.7%). The extract exhibits potent antioxidant capacities with IC50 = 56.19 and 58.91 µg/ml, as accessed via the anionic DPPH and cationic ABTS radical scavenging assays, respectively. The extract has high antibacterial properties, especially against the Gram+ Staphylococcus aureus and Bacillus cereus strains. To investigate the extract effect on regeneration, the flatworm Dugesia sicula Lepori, 1948, was used as a model. The macroscopic analysis of planarian cultures in ordinary medium containing phenolic extract at non-toxic concentrations illustrated that the extract caused morphological changes. Additionally, the molecular study through the fluorescence-activated cell sorting (FACS) technique showed that C. edulis polyphenols can harm the stem cells' development. These results emphasize the ecotoxicological impact of phenolic rejections in the environment on flatworms' physiology.

Comparative analysis of Tunisian wild Crataegus azarolus (yellow azarole) and Crataegus monogyna (red azarole) leaf, fruit, and traditionally derived syrup: phenolic profiles and antioxidant and antimicrobial activities of the aqueous-acetone extracts.

Quantitative and qualitative analyses of the yellow and red azarole phenolic extracts prepared from leaf, fruit peel/pulp, and syrup were comparatively investigated. The yellow azarole was found significantly richer in polyphenols than the red-fruit species. Hyperoside was the main phenolic in both yellow and red azarole leaves and only in yellow fruits, whereas procyanidin B2 was the major compound in red fruits. Yellow azarole leaf and fruit peel extracts exhibited the strongest antioxidant activities using DPPH (≈168 and 79 µmol TEAC/g fw, respectively) and FRAP (≈378 and 161 µmol Fe(2+)/g fw, respectively) assays. The highest antibacterial activities were recorded for the yellow azarole leaf and fruit peel extracts, especially against Staphylococcus aureus and Streptococcus faecalis . The low phenolic content of the syrups contrasted with their significant antioxidant and antimicrobial potentials, which were correlated to their hydroxymethylfurfural (HMF) (furan derivative amounts) content.

Effect of ionising radiation on polyphenolic content and antioxidant potential of parathion-treated sage (Salvia officinalis) leaves.

The γ-irradiation effects on polyphenolic content and antioxidant capacity of parathion-pretreated leaves of Salvia officinalis plant were investigated. The analysis of phenolic extracts of sage without parathion showed that irradiation decreased polyphenolic content significantly (p<0.05) by 30% and 45% at 2 and 4kGy, respectively, compared to non-irradiated samples. The same trend was observed for the Trolox equivalent antioxidant capacity (TEAC), as assessed by the anionic DPPH and cationic ABTS radical-scavenging assays. The antioxidant potential decreased significantly (p<0.01) at 2 and 4kGy, by 11-20% and 40-44%, respectively. The results obtained with a pure chlorogenic acid solution confirmed the degradation of phenols; however, its TEAC was significantly (p<0.01) increased following irradiation. Degradation products of parathion formed by irradiation seem to protect against a decline of antioxidant capacity and reduce polyphenolic loss. Ionising radiation was found to be useful in breaking down pesticide residues without inducing significant losses in polyphenols.

Inhibitory effect of carob (Ceratonia siliqua) leaves methanolic extract on Listeria monocytogenes.

In recent years, there has been great development in the search for new natural compounds for food preservation aimed at a partial or total replacement of currently popular antimicrobial chemicals. Carob (Ceratonia siliqua) offers a natural promising alternative for food safety and bioconservation. In this work, the methanolic extract of carob leaves (MECL) was tested for the ability to inhibit the growth of a range of microorganisms. MECL inhibited the growth of Listeria monocytogenes at 28.12 µg/mL by the broth microdilution method. The effect of this bacteriostatic concentration on the growth of this bacterium revealed a pattern of inhibition characterized by (a) a resumed growth phase, which showed a lower rate of growth if compared with controls; and (b) first a lag and then a stationary phase at a lower bacterium concentration. The study of the chemical composition of MECL by high-performance liquid chromatography and liquid chromatography/mass spectrometry showed the presence of gallic acid, (-)-epigallocatechin-3-gallate, myricitrin, isoquercitin, catechin, chlorogenic acid, and malic acid. L. monocytogenes growth inhibition was recorded for myricitrin and gallic acid at 450 µg/mL and for (-)-epigallocatechin-3-gallate and isoquercitin, respectively, at 225 and 112.5 µg/mL. Taking into account that proline is a ligand of proline dehydrogenase (PDH), the use of this compound leads us to hypothesize the mode of action of MECL constituents.

Quince (Cydonia oblonga Miller) peel polyphenols modulate LPS-induced inflammation in human THP-1-derived macrophages through NF-κB, p38MAPK and Akt inhibition.

Chronic inflammation is a hallmark of several pathologies, such as rheumatoid arthritis, gastritis, inflammatory bowel disease, atherosclerosis and cancer. A wide range of anti-inflammatory chemicals have been used to treat such diseases while presenting high toxicity and numerous side effects. Here, we report the anti-inflammatory effect of a non-toxic, cost-effective natural agent, polyphenolic extract from the Tunisian quince Cydonia oblonga Miller. Lipopolysaccharide (LPS) treatment of human THP-1-derived macrophages induced the secretion of high levels of the pro-inflammatory cytokine TNF-α and the chemokine IL-8, which was inhibited by quince peel polyphenolic extract in a dose-dependent manner. Concomitantly, quince polyphenols enhanced the level of the anti-inflammatory cytokine IL-10 secreted by LPS-treated macrophages. We further demonstrated that the unexpected increase in IL-6 secretion that occurred when quince polyphenols were associated with LPS treatment was partially responsible for the polyphenols-mediated inhibition of TNF-α secretion. Biochemical analysis showed that quince polyphenols extract inhibited the LPS-mediated activation of three major cellular pro-inflammatory effectors, nuclear factor-kappa B (NF-κB), p38MAPK and Akt. Overall, our data indicate that quince peel polyphenolic extract induces a potent anti-inflammatory effect that may prove useful for the treatment of inflammatory diseases and that a quince-rich regimen may help to prevent and improve the treatment of such diseases.

Cell viability effects and antioxidant and antimicrobial activities of Tunisian date syrup (Rub El Tamer) polyphenolic extracts.

The aqueous-acetone polyphenolic extract of the traditionally derived date syrup, known as "Rub El Tamer", was analyzed using RP-HPLC-DAD and ESI-MS. The phenolic content of the extract was 394.53 ± 1.13 mg per 100 g of syrup with caffeoylsinapylquinic acid as the most abundant compound (72.23%). The extract exhibited strong antioxidant activities as evaluated using the ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) methods. The extract antimicrobial potential against a range of microorganism strains showed that Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus were the most sensitive bacteria with MBC in the range of 0.5-0.05 mg/mL. Furthermore, in the presence of the syrup extract (8.18-131 µg/mL), the Human SH-SY5Y neuroblastoma and the 3T3 fibroblast cell lines showed dissimilar reduction of viability suggesting a higher cytotoxic effect against tumorigenic cells. Our results provide new insights into date syrup characterization which should stimulate further studies of this hot desert resource.

Antimicrobial activity of Tunisian quince (Cydonia oblonga Miller) pulp and peel polyphenolic extracts.

Quince (Cydonia oblonga Miller) fruit aqueous acetone extracts were evaluated. High-performance liquid chromatography-diode array detection and electrospray ionization-mass spectrometry were used for the identification and quantification of the phenolic compounds. The total phenolic content of the pulp and peel parts ranged from 37 to 47 and 105 to 157 mg/100 g of fresh weight, respectively. Chlorogenic acid (5-O-caffeoylquinic acid) was the most abundant phenolic compound in the pulp (37%), whereas rutin (quercetin 3-O-rutinoside) was the main one in the peel (36%). The radical scavenging potential of the extracts was determined and compared with that of synthetic antioxidants. The stronger properties corresponded to those obtained from peel material with a 70-80% inhibitory effect on DPPH radicals. The antimicrobial activity of the extracts against different microorganism strains was also investigated. Quince peel extract was the most active for inhibiting bacteria growth with minimum inhibitory and bactericide concentrations in the range of 102-5 x 103 microg polyphenol/mL. It seems that chlorogenic acid acts in synergism with other components of the extracts to exhibit their total antimicrobial activities.