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Papers by Mondher Boulaaba

Food Science & Nutrition

South African Journal of Botany, 2019

Phenolic contents were determined in S. kali leaves, stems, and roots at the beginning, the mid a... more Phenolic contents were determined in S. kali leaves, stems, and roots at the beginning, the mid and the end of the vegetative period, as well as the floral bud and open flower at the reproductive stage. Antioxidant and antimicrobial activities were also assessed. Moreover, the major metabolites were identified by HPLC. Results showed a maximum of total phenol contents in the photosynthetic organs, followed by stems and roots. A similar tendency was found for the flavonoids and condensed tannins. Concerning antioxidant analysis, antiradical and Fe-reduced activities were higher in leaves and stems whereas Fe-chelating activity was higher in leaves and roots. Independently of the plant organ, total phenol and flavonoid contents were maximal at the end of the vegetative period whereas tannin content was maximal at the reproductive one. Phenolic contents were related to the organ, the development stage, and their interaction. Concerning the antimicrobial activity, stem extracts were the most efficient against human pathogen strains (Bacteria: Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. Fungi: Candida kefyr, C. holmii, C. albicans, C. sake and C. glabrata). Moreover, nine natural products were identified in leaf and stem extracts of S. kali known for their biological activities. As a whole, biological activities of S. kali seem to be strongly related to organs and to the development stage. The phytochemical tests by HPLC demonstrated the presence of nine compounds among them two alkaloids: salsoline and fraxidin. Some molecules are presented in both organs (salsoline, resorcinol, luteolin 7-o-glucoside; and hyperoside). Therefore, endogenous factors greatly account for the biological potential of this medicinal halophyte.

South African Journal of Botany, 2022

Nitraria retusa plant samples were collected at the sebkha of El Kélbia, Kairouan and phenolic ex... more Nitraria retusa plant samples were collected at the sebkha of El Kélbia, Kairouan and phenolic extracts with 70% ethanol were prepared. Quantification of total polyphenols, flavonoids and tannins was performed. The results showed the presence of 48.61 mg EAG / g MS for the first group and, respectively 50.53 and 2.7 mg EC / g MS for the flavonoids and the condensed tannins. On the other hand, the shoot extract of N. retusa has an important antioxidant power, first against the DPPH radical (63 μg / ml), then as an iron reducing power (0.92 mg / ml), then as an inhibitor of bleaching of β-carotene (59% for an extract used at 1 mg / ml) and finally capable of reducing molybdenum (VI) ions to molybdenum (V) (166.11 mg EAG / g MS). On the other hand, the content of MDA relative to leaf extracts is equal to 25.55 nmol / g MF and the percentage of electrolyte leakage is 65.4%. Other plant substances were measured with contents equal to 6.16 and 3.08 mg / ml for chlorophylls a and b, 2.05 m...

Industrial Crops and Products, 2012

Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aime... more Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aimed to assess in vitro and ex vivo antioxidant activities of four acetonic extracts Tunisian halophytes (Suaeda fruticosa, Suaeda pruinosa, Suaeda mollis and Suaeda maritima). Various experimental models were used for characterization of antioxidant activities of shoot extracts. Eventually, the promising specie was subjected to phenolic identification using RP-HPLC. The analyzed shoot extracts exhibited that antioxidant activities varied considerably as function of species. The highest DPPH • scavenging ability was found in S. mollis with the lowest IC 50 value (2.5 g/ml), followed by S. pruinosa, S. fruticosa and S. maritima. The same tendency was observed with ferric reducing power. Concerning ␤-carotene bleaching assays and total antioxidant activity, results showed that S. fruticosa exhibited the highest antioxidant ability against the inhibition of ␤-carotene bleaching, and a better total antioxidant capacity. Moreover antioxidant capacities using ORAC method and a cell based-assay showed that S. mollis, S. fruticosa, and S. pruinosa exhibit statistically similar antioxidant activity. The identification of phenolic compounds in S. mollis extract using RP-HPLC revealed that 2,5-dihydroxybenzoic acid and rutin hydrate were the major molecules. These results suggested that Suaeda species showed a variability of their antioxidant activities.

Copyright © 2013 Mondher Boulaaba et al. This is an open access article distributed under the Cre... more Copyright © 2013 Mondher Boulaaba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Arthrocnemum indicum shoot extracts. Moreover, the anticancer effect of this plant on human colon cancer cells and the likely underlying mechanisms were also investigated, and themajor phenols were identified by LC-ESI-TOF-MS. Results showed that shoot extracts had an antiproliferative effect of about 55 % as compared to the control and were characterised by substantial total polyphenol content (19mgGAE/g DW) and high antioxidant activity (IC 50 = 40

International Journal of Molecular Sciences

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is cha... more Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involv...

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multipl... more Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7– 14.8 mg GAE g −1 DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH · scavenging ability with the lowest IC50 value (23 µg ml −1 ), followed by leaves and flowers (over 50 µg ml −1 ). In contrast, leaves showed the highest capacity to quench superoxide (IC50 :1µ g ml −1 ) as compared to seeds (6 µg ml −1 ). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia c...

The edible halophyte Nitraria retusa known in traditional medicine purposes was used as a support... more The edible halophyte Nitraria retusa known in traditional medicine purposes was used as a support in this study. The present study investigated the chemical analyses of the general composition of leaf and stem extracts using RP-HPLC. Results showed the richness of these extracts in phenolics especially flavonoids as luteolin-7-O-glucoside, isorhamnetin-3-O-rutinoside, isorhamnetin, quercetin and others. In total, nine compounds were identified for each organ extract. Luteolin-7-O-glucoside, isorhamnetin-3-O-rutinoside and Isorhamnetin are three flavonoids which are common in leaves and stems. Adipogenesis assay was performed to investigate the effect of organs, as well as the three last compounds on the adipocyte differentiation and on the lipid droplets accumulation in 3T3-L1 cells. Based on Oil-Red-O content quantification in 3T3-L1 cells, results showed that each extract of N. retusa at 25, 50, 100, 200 and 400 μg/mL could not inhibit the lipid droplet accumulation compared to un...

Medicinal Chemistry Research

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2017

Polyphenolic compounds gained interest in the pharmaceutical research area due to their beneficia... more Polyphenolic compounds gained interest in the pharmaceutical research area due to their beneficial properties. Herein, antioxidant and cytoprotective capacities of T. gallica extract on H2O2-challenged rat small intestine epithelial cells were investigated. To set stress conditions, IEC-6 cultures were challenged with numerous H2O2 doses and durations. Then, 40μM H2O2 during 4h were selected to assess the cytoprotective effect of different T. gallica extract concentrations. Oxidative parameters, measured through CAT and SOD activities as well as MDA quantification were assessed. In addition, the expression of possibly involved MAPKs was also valued. Main results reported that T. gallica was rich in polyphenols and exhibited an important antioxidant activity (DPPH Assay, IC50=6μgmL(-1); ABTS(+) test, IC50=50μgmL(-1); Fe-reducing power, EC50=100μgmL(-1)). The exposure of IEC-6 cultures to 40μM H2O2 during 4h caused oxidative stress manifested by (i) over 70% cell mortality, (ii) over-...

Industrial Crops and Products, 2015

Plant Physiology and Biochemistry, 2012

Mesembryanthemum edule L. is an edible and medicinal halophyte widespread in Tunisia seashore. In... more Mesembryanthemum edule L. is an edible and medicinal halophyte widespread in Tunisia seashore. In this study, parameters of oxidative stress, phenolic compounds and antioxidant activities were comparatively investigated in two M. edule provenances (Jerba and Bizerte, respectively sampled from arid and humid bioclimatic stages). Plants were subjected to 0, 300 and 600 mM NaCl treatment under glasshouse conditions. Results showed that M. edule response to salinity depends on provenance (P), salt treatment (T) and their interaction (P Â T). (T) affected more significantly the oxidative stress parameters and antioxidant activities than (P) and (P Â T). Conversely, (P) was much affluent for tannin polymerization degree and interaction between the two factors (P Â T) was more determinants for analyzed antioxidant parameters. The higher salt tolerance of Jerba plants was associated with low levels of malondialdehyde and of electrolyte leakage mainly at 600 mM NaCl. Besides, antioxidant activities of Jerba provenance, were more efficient than Bizerte. In addition, avicularin was the major phenolic in both provenances. This compound concentration increased with salinity in Jerba shoots, while it was reduced in Bizerte especially at 600 mM NaCl. Overall, the higher salt tolerance of plants from Jerba provenance, and to a lower extent of those from Bizerte, may be partly related to their better capacity to limit oxidative damage when salt-challenged, and this is likely the result of redistribution in phenolic composition. Besides, abiotic factors such as salinity could be determinant in antioxidant potentiality of this medicinal plant.

Biosaline Agriculture and High Salinity Tolerance, 2008

South African Journal of Botany, 2012

Mesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human... more Mesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human diseases. In this study, particular importance was attached to the influence of environmental conditions on phenolic composition and antioxidant activities of two M. edule provenances from contrasting climatic regions (Djerba and Monastir sampled from arid and superior semi-arid bioclimatic stages, respectively). Shoot phenolic content was evaluated using colorimetric method and its composition was identified by HPLC analysis with or without thiolysis. Antioxidant activities were assessed by five in vitro antioxidant systems. Results showed that the two M. edule provenances were significantly different according to their antioxidant activity as well as their polyphenol profiles. Indeed, plants from Djerba (lack of rainfall and long light hour periods) exhibited stronger antioxidant activity together with higher phenolic content. For instance, Djerba provenance shoots showed much lower IC 50 (4.8 μg ml −1 ) and EC 50 (80 μg ml − 1 ) values for DPPH and Fe-reducing tests, respectively. In addition, the superiority of this provenance (Djerba) was more marked as compared to positive controls (BHT, BHA, and VitC). HPLC identification revealed also an important difference between the two provenances on major flavonoid components. This difference was confirmed by the mean degrees of tannin polymerization (DPn) which was higher in Djerba plants. These data suggest that M. edule adaptation to environmental stresses proceeds through induced particular phenol quality and DPn for the improvement of their antioxidant capacities to protect plant tissues against oxidative stress.

Evidence-Based Complementary and Alternative Medicine, 2013

This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Art... more This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Arthrocnemum indicum shoot extracts. Moreover, the anticancer effect of this plant on human colon cancer cells and the likely underlying mechanisms were also investigated, and the major phenols were identified by LC-ESI-TOF-MS. Results showed that shoot extracts had an antiproliferative effect of about 55% as compared to the control and were characterised by substantial total polyphenol content (19 mg GAE/g DW) and high antioxidant activity (IC 50 = 40 g/mL for DPPH test). DAPI staining revealed that these extracts decrease DNA synthesis and reduce the proliferation of Caco-2 cells which were stopped at the G 2 /M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2) correlate with the changes in cell cycle distribution. Eight phenolic compounds were also identified. In conclusion, A. indicum showed interesting antioxidant capacities associated with a significant antiproliferative effect explained by a cell cycle blocking at the G 2 /M phase. Taken together, these data suggest that A. indicum could be a promising candidate species as a source of anticancer molecules.

Cytotechnology, 2013

Taking into account that oxidative stress is among the factors causing cancer-related death; chem... more Taking into account that oxidative stress is among the factors causing cancer-related death; chemoprevention which consists in using antioxidant substances such as phenolics could prevent cancer formation and progression. In the present study, phenolic contents and antioxidant activities of methanolic extracts from the halophyte Tamarix gallica shoots were determined. Moreover, the anticancer effect of this species on human colon cancer cells and the likely underlying mechanisms were also investigated. Shoot extracts showed an appreciable total phenolic content (85 mg GAE/g DW) and a high antioxidant activity (IC50 = 3.3 μg/ml for DPPH test). At 50 and 100 μg/ml, shoot, leaf, and flower extracts significantly inhibited Caco-2 cell growth. For instance, almost all plant part extracts inhibited cell growth by 62 % at the concentration 100 μg/ml. DAPI staining results revealed that these extracts decrease DNA synthesis and confirm their effect on Caco-2 cells proliferation, principally at 100 μg/ml. More importantly, cell mitosis was arrested at G2/M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2) are correlated with the changes in cell cycle distribution. Taken together, our data suggest that T. gallica is a promising candidate species to be used as a source of anticancer biomolecules.

Comptes Rendus Biologies, 2008

Halophyte ability to withstand salt-triggered oxidative stress is governed by multiple biochemica... more Halophyte ability to withstand salt-triggered oxidative stress is governed by multiple biochemical mechanisms that facilitate retention and/or acquisition of water, protect chloroplast functioning, and maintain ion homeostasis. Most essential traits include the synthesis of osmolytes, specific proteins, and antioxidant molecules. This might explain the utilization of some halophytes as traditional medicinal and dietary plants. The present study aimed at assessing the phenolic content and antioxidant activities of some Tunisian halophytes (Cakile maritima, Limoniastrum monopetalum, Mesembryanthemum crystallinum, M. edule, Salsola kali, and Tamarix gallica), depending on biological (species, organ and developmental stage), environmental, and technical (extraction solvent) factors. The total polyphenol contents and antioxidant activities (DPPH and superoxide radicals scavenging activities, and iron chelating and reducing powers) were strongly affected by the above-cited factors. Such variability might be of great importance in terms of valorising these halophytes as a source of naturally secondary metabolites, and the methods for phenolic and antioxidant production. To cite this article: R. Ksouri et al., C. R. Biologies 331 (2008). Résumé Influence des facteurs biologiques, environnementaux et techniques sur les teneurs en polyphénols et les activités antioxydantes des halophytes tunisiennes. La capacité des halophytes à surmonter le stress oxydatif déclenché par la salinité est régi par de multiples mécanismes biochimiques qui facilitent le maintien et/ou l'acquisition de l'eau, la protection des chloroplastes et le maintien de l'homéostasie ionique. Ces traits comprennent essentiellement la biosynthèse d'osmolytes, de protéines spécifiques et de molécules antioxydantes. D'où, l'utilisation traditionnelle de ces halophytes comme plantes à intérêts médicinales et alimentaires. On se propose, dans ce travail d'évaluer les teneurs en polyphénols et les activités antioxydantes de quelques halophytes tunisiennes (Cakile maritima, Limoniastrum monopetalum, Mesembryanthemum crystallinum, M. edule, Salsola kali et Tamarix gallica) en fonction des facteurs biologiques, environnementaux et techniques. L'analyse des résultats a montré que les teneurs en polyphénols, les activités antiradicalaires et les pouvoirs chélateur et réducteur sont significativement affectés par ces différents facteurs. Une telle variabilité pourrait être d'une grande importance dans la valorisation de ces halophytes comme source naturelle de biosynthèse d'antioxydants. Pour citer cet article : R. Ksouri et al., C. R. Biologies 331 (2008).

Comptes Rendus Biologies, 2008

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multipl... more Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7-14.8 mg GAE g −1 DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH · scavenging ability with the lowest IC 50 value (23 µg ml −1 ), followed by leaves and flowers (over 50 µg ml −1 ). In contrast, leaves showed the highest capacity to quench superoxide (IC 50 : 1 µg ml −1 ) as compared to seeds (6 µg ml −1 ). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia coli. The identification of phenolic compounds from leaves revealed that syringic and trans-cinnamic acids were the major molecules. To cite this article:

Food Science & Nutrition

South African Journal of Botany, 2019

Phenolic contents were determined in S. kali leaves, stems, and roots at the beginning, the mid a... more Phenolic contents were determined in S. kali leaves, stems, and roots at the beginning, the mid and the end of the vegetative period, as well as the floral bud and open flower at the reproductive stage. Antioxidant and antimicrobial activities were also assessed. Moreover, the major metabolites were identified by HPLC. Results showed a maximum of total phenol contents in the photosynthetic organs, followed by stems and roots. A similar tendency was found for the flavonoids and condensed tannins. Concerning antioxidant analysis, antiradical and Fe-reduced activities were higher in leaves and stems whereas Fe-chelating activity was higher in leaves and roots. Independently of the plant organ, total phenol and flavonoid contents were maximal at the end of the vegetative period whereas tannin content was maximal at the reproductive one. Phenolic contents were related to the organ, the development stage, and their interaction. Concerning the antimicrobial activity, stem extracts were the most efficient against human pathogen strains (Bacteria: Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. Fungi: Candida kefyr, C. holmii, C. albicans, C. sake and C. glabrata). Moreover, nine natural products were identified in leaf and stem extracts of S. kali known for their biological activities. As a whole, biological activities of S. kali seem to be strongly related to organs and to the development stage. The phytochemical tests by HPLC demonstrated the presence of nine compounds among them two alkaloids: salsoline and fraxidin. Some molecules are presented in both organs (salsoline, resorcinol, luteolin 7-o-glucoside; and hyperoside). Therefore, endogenous factors greatly account for the biological potential of this medicinal halophyte.

South African Journal of Botany, 2022

Nitraria retusa plant samples were collected at the sebkha of El Kélbia, Kairouan and phenolic ex... more Nitraria retusa plant samples were collected at the sebkha of El Kélbia, Kairouan and phenolic extracts with 70% ethanol were prepared. Quantification of total polyphenols, flavonoids and tannins was performed. The results showed the presence of 48.61 mg EAG / g MS for the first group and, respectively 50.53 and 2.7 mg EC / g MS for the flavonoids and the condensed tannins. On the other hand, the shoot extract of N. retusa has an important antioxidant power, first against the DPPH radical (63 μg / ml), then as an iron reducing power (0.92 mg / ml), then as an inhibitor of bleaching of β-carotene (59% for an extract used at 1 mg / ml) and finally capable of reducing molybdenum (VI) ions to molybdenum (V) (166.11 mg EAG / g MS). On the other hand, the content of MDA relative to leaf extracts is equal to 25.55 nmol / g MF and the percentage of electrolyte leakage is 65.4%. Other plant substances were measured with contents equal to 6.16 and 3.08 mg / ml for chlorophylls a and b, 2.05 m...

Industrial Crops and Products, 2012

Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aime... more Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aimed to assess in vitro and ex vivo antioxidant activities of four acetonic extracts Tunisian halophytes (Suaeda fruticosa, Suaeda pruinosa, Suaeda mollis and Suaeda maritima). Various experimental models were used for characterization of antioxidant activities of shoot extracts. Eventually, the promising specie was subjected to phenolic identification using RP-HPLC. The analyzed shoot extracts exhibited that antioxidant activities varied considerably as function of species. The highest DPPH • scavenging ability was found in S. mollis with the lowest IC 50 value (2.5 g/ml), followed by S. pruinosa, S. fruticosa and S. maritima. The same tendency was observed with ferric reducing power. Concerning ␤-carotene bleaching assays and total antioxidant activity, results showed that S. fruticosa exhibited the highest antioxidant ability against the inhibition of ␤-carotene bleaching, and a better total antioxidant capacity. Moreover antioxidant capacities using ORAC method and a cell based-assay showed that S. mollis, S. fruticosa, and S. pruinosa exhibit statistically similar antioxidant activity. The identification of phenolic compounds in S. mollis extract using RP-HPLC revealed that 2,5-dihydroxybenzoic acid and rutin hydrate were the major molecules. These results suggested that Suaeda species showed a variability of their antioxidant activities.

Copyright © 2013 Mondher Boulaaba et al. This is an open access article distributed under the Cre... more Copyright © 2013 Mondher Boulaaba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Arthrocnemum indicum shoot extracts. Moreover, the anticancer effect of this plant on human colon cancer cells and the likely underlying mechanisms were also investigated, and themajor phenols were identified by LC-ESI-TOF-MS. Results showed that shoot extracts had an antiproliferative effect of about 55 % as compared to the control and were characterised by substantial total polyphenol content (19mgGAE/g DW) and high antioxidant activity (IC 50 = 40

International Journal of Molecular Sciences

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is cha... more Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involv...

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multipl... more Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7– 14.8 mg GAE g −1 DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH · scavenging ability with the lowest IC50 value (23 µg ml −1 ), followed by leaves and flowers (over 50 µg ml −1 ). In contrast, leaves showed the highest capacity to quench superoxide (IC50 :1µ g ml −1 ) as compared to seeds (6 µg ml −1 ). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia c...

The edible halophyte Nitraria retusa known in traditional medicine purposes was used as a support... more The edible halophyte Nitraria retusa known in traditional medicine purposes was used as a support in this study. The present study investigated the chemical analyses of the general composition of leaf and stem extracts using RP-HPLC. Results showed the richness of these extracts in phenolics especially flavonoids as luteolin-7-O-glucoside, isorhamnetin-3-O-rutinoside, isorhamnetin, quercetin and others. In total, nine compounds were identified for each organ extract. Luteolin-7-O-glucoside, isorhamnetin-3-O-rutinoside and Isorhamnetin are three flavonoids which are common in leaves and stems. Adipogenesis assay was performed to investigate the effect of organs, as well as the three last compounds on the adipocyte differentiation and on the lipid droplets accumulation in 3T3-L1 cells. Based on Oil-Red-O content quantification in 3T3-L1 cells, results showed that each extract of N. retusa at 25, 50, 100, 200 and 400 μg/mL could not inhibit the lipid droplet accumulation compared to un...

Medicinal Chemistry Research

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2017

Polyphenolic compounds gained interest in the pharmaceutical research area due to their beneficia... more Polyphenolic compounds gained interest in the pharmaceutical research area due to their beneficial properties. Herein, antioxidant and cytoprotective capacities of T. gallica extract on H2O2-challenged rat small intestine epithelial cells were investigated. To set stress conditions, IEC-6 cultures were challenged with numerous H2O2 doses and durations. Then, 40μM H2O2 during 4h were selected to assess the cytoprotective effect of different T. gallica extract concentrations. Oxidative parameters, measured through CAT and SOD activities as well as MDA quantification were assessed. In addition, the expression of possibly involved MAPKs was also valued. Main results reported that T. gallica was rich in polyphenols and exhibited an important antioxidant activity (DPPH Assay, IC50=6μgmL(-1); ABTS(+) test, IC50=50μgmL(-1); Fe-reducing power, EC50=100μgmL(-1)). The exposure of IEC-6 cultures to 40μM H2O2 during 4h caused oxidative stress manifested by (i) over 70% cell mortality, (ii) over-...

Industrial Crops and Products, 2015

Plant Physiology and Biochemistry, 2012

Mesembryanthemum edule L. is an edible and medicinal halophyte widespread in Tunisia seashore. In... more Mesembryanthemum edule L. is an edible and medicinal halophyte widespread in Tunisia seashore. In this study, parameters of oxidative stress, phenolic compounds and antioxidant activities were comparatively investigated in two M. edule provenances (Jerba and Bizerte, respectively sampled from arid and humid bioclimatic stages). Plants were subjected to 0, 300 and 600 mM NaCl treatment under glasshouse conditions. Results showed that M. edule response to salinity depends on provenance (P), salt treatment (T) and their interaction (P Â T). (T) affected more significantly the oxidative stress parameters and antioxidant activities than (P) and (P Â T). Conversely, (P) was much affluent for tannin polymerization degree and interaction between the two factors (P Â T) was more determinants for analyzed antioxidant parameters. The higher salt tolerance of Jerba plants was associated with low levels of malondialdehyde and of electrolyte leakage mainly at 600 mM NaCl. Besides, antioxidant activities of Jerba provenance, were more efficient than Bizerte. In addition, avicularin was the major phenolic in both provenances. This compound concentration increased with salinity in Jerba shoots, while it was reduced in Bizerte especially at 600 mM NaCl. Overall, the higher salt tolerance of plants from Jerba provenance, and to a lower extent of those from Bizerte, may be partly related to their better capacity to limit oxidative damage when salt-challenged, and this is likely the result of redistribution in phenolic composition. Besides, abiotic factors such as salinity could be determinant in antioxidant potentiality of this medicinal plant.

Biosaline Agriculture and High Salinity Tolerance, 2008

South African Journal of Botany, 2012

Mesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human... more Mesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human diseases. In this study, particular importance was attached to the influence of environmental conditions on phenolic composition and antioxidant activities of two M. edule provenances from contrasting climatic regions (Djerba and Monastir sampled from arid and superior semi-arid bioclimatic stages, respectively). Shoot phenolic content was evaluated using colorimetric method and its composition was identified by HPLC analysis with or without thiolysis. Antioxidant activities were assessed by five in vitro antioxidant systems. Results showed that the two M. edule provenances were significantly different according to their antioxidant activity as well as their polyphenol profiles. Indeed, plants from Djerba (lack of rainfall and long light hour periods) exhibited stronger antioxidant activity together with higher phenolic content. For instance, Djerba provenance shoots showed much lower IC 50 (4.8 μg ml −1 ) and EC 50 (80 μg ml − 1 ) values for DPPH and Fe-reducing tests, respectively. In addition, the superiority of this provenance (Djerba) was more marked as compared to positive controls (BHT, BHA, and VitC). HPLC identification revealed also an important difference between the two provenances on major flavonoid components. This difference was confirmed by the mean degrees of tannin polymerization (DPn) which was higher in Djerba plants. These data suggest that M. edule adaptation to environmental stresses proceeds through induced particular phenol quality and DPn for the improvement of their antioxidant capacities to protect plant tissues against oxidative stress.

Evidence-Based Complementary and Alternative Medicine, 2013

This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Art... more This study aimed to determinate phenolic contents and antioxidant activities of the halophyte Arthrocnemum indicum shoot extracts. Moreover, the anticancer effect of this plant on human colon cancer cells and the likely underlying mechanisms were also investigated, and the major phenols were identified by LC-ESI-TOF-MS. Results showed that shoot extracts had an antiproliferative effect of about 55% as compared to the control and were characterised by substantial total polyphenol content (19 mg GAE/g DW) and high antioxidant activity (IC 50 = 40 g/mL for DPPH test). DAPI staining revealed that these extracts decrease DNA synthesis and reduce the proliferation of Caco-2 cells which were stopped at the G 2 /M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2) correlate with the changes in cell cycle distribution. Eight phenolic compounds were also identified. In conclusion, A. indicum showed interesting antioxidant capacities associated with a significant antiproliferative effect explained by a cell cycle blocking at the G 2 /M phase. Taken together, these data suggest that A. indicum could be a promising candidate species as a source of anticancer molecules.

Cytotechnology, 2013

Taking into account that oxidative stress is among the factors causing cancer-related death; chem... more Taking into account that oxidative stress is among the factors causing cancer-related death; chemoprevention which consists in using antioxidant substances such as phenolics could prevent cancer formation and progression. In the present study, phenolic contents and antioxidant activities of methanolic extracts from the halophyte Tamarix gallica shoots were determined. Moreover, the anticancer effect of this species on human colon cancer cells and the likely underlying mechanisms were also investigated. Shoot extracts showed an appreciable total phenolic content (85 mg GAE/g DW) and a high antioxidant activity (IC50 = 3.3 μg/ml for DPPH test). At 50 and 100 μg/ml, shoot, leaf, and flower extracts significantly inhibited Caco-2 cell growth. For instance, almost all plant part extracts inhibited cell growth by 62 % at the concentration 100 μg/ml. DAPI staining results revealed that these extracts decrease DNA synthesis and confirm their effect on Caco-2 cells proliferation, principally at 100 μg/ml. More importantly, cell mitosis was arrested at G2/M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2) are correlated with the changes in cell cycle distribution. Taken together, our data suggest that T. gallica is a promising candidate species to be used as a source of anticancer biomolecules.

Comptes Rendus Biologies, 2008

Halophyte ability to withstand salt-triggered oxidative stress is governed by multiple biochemica... more Halophyte ability to withstand salt-triggered oxidative stress is governed by multiple biochemical mechanisms that facilitate retention and/or acquisition of water, protect chloroplast functioning, and maintain ion homeostasis. Most essential traits include the synthesis of osmolytes, specific proteins, and antioxidant molecules. This might explain the utilization of some halophytes as traditional medicinal and dietary plants. The present study aimed at assessing the phenolic content and antioxidant activities of some Tunisian halophytes (Cakile maritima, Limoniastrum monopetalum, Mesembryanthemum crystallinum, M. edule, Salsola kali, and Tamarix gallica), depending on biological (species, organ and developmental stage), environmental, and technical (extraction solvent) factors. The total polyphenol contents and antioxidant activities (DPPH and superoxide radicals scavenging activities, and iron chelating and reducing powers) were strongly affected by the above-cited factors. Such variability might be of great importance in terms of valorising these halophytes as a source of naturally secondary metabolites, and the methods for phenolic and antioxidant production. To cite this article: R. Ksouri et al., C. R. Biologies 331 (2008). Résumé Influence des facteurs biologiques, environnementaux et techniques sur les teneurs en polyphénols et les activités antioxydantes des halophytes tunisiennes. La capacité des halophytes à surmonter le stress oxydatif déclenché par la salinité est régi par de multiples mécanismes biochimiques qui facilitent le maintien et/ou l'acquisition de l'eau, la protection des chloroplastes et le maintien de l'homéostasie ionique. Ces traits comprennent essentiellement la biosynthèse d'osmolytes, de protéines spécifiques et de molécules antioxydantes. D'où, l'utilisation traditionnelle de ces halophytes comme plantes à intérêts médicinales et alimentaires. On se propose, dans ce travail d'évaluer les teneurs en polyphénols et les activités antioxydantes de quelques halophytes tunisiennes (Cakile maritima, Limoniastrum monopetalum, Mesembryanthemum crystallinum, M. edule, Salsola kali et Tamarix gallica) en fonction des facteurs biologiques, environnementaux et techniques. L'analyse des résultats a montré que les teneurs en polyphénols, les activités antiradicalaires et les pouvoirs chélateur et réducteur sont significativement affectés par ces différents facteurs. Une telle variabilité pourrait être d'une grande importance dans la valorisation de ces halophytes comme source naturelle de biosynthèse d'antioxydants. Pour citer cet article : R. Ksouri et al., C. R. Biologies 331 (2008).

Comptes Rendus Biologies, 2008

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multipl... more Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7-14.8 mg GAE g −1 DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH · scavenging ability with the lowest IC 50 value (23 µg ml −1 ), followed by leaves and flowers (over 50 µg ml −1 ). In contrast, leaves showed the highest capacity to quench superoxide (IC 50 : 1 µg ml −1 ) as compared to seeds (6 µg ml −1 ). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia coli. The identification of phenolic compounds from leaves revealed that syringic and trans-cinnamic acids were the major molecules. To cite this article: