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1

Changes in phenolic composition and antioxidant activities of the edible halophyte Crithmum maritimum L. with Physiological stage and extraction method

100%
Jallali I., Megdiche W., M'Hamdi B., Oueslati S., Smaoui A., Abdelly C., Ksouri R.
Acta Physiologiae Plantarum
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2012
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tom 34
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nr 4
Most antioxidant phytochemicals isolated from higher plants are polyphenols exhibiting different biological activities. Previous studies have shown that plant phenolic contents and antioxidant activities depend on several factors, mainly environmental conditions, and post-harvesting procedures. The present study aims to assess the influence of these interfering factors on phenolic composition and antioxidant activities (DPPH test, reducing power) of Crithmum maritimum L., a promising food halophyte which attracts an increasing interest in recent years. Results showed that the summer plants (reproductive stage) were richer on phenolic compounds than spring ones (vegetative stage), and consequently exhibited higher antioxidant activities. The comparison of two extraction methods showed that maceration extracts contained greatest amounts of phenolic compounds, while soxhlet ones exhibited higher antiradical and reducing power capacities. Besides, the analysis of variance disclosed that the effect of extraction method (E) was the predominant contributor to these antioxidant properties than the physiological development stage (D) and their interaction (E × D). Chromatographic characterization of C. maritimum phenolic composition using the RP-HPLC revealed the presence of phenolic acids and flavonoids with epigallocatechin as major component. Almost all of the identified compounds were described in the literature as interesting bioactive natural substances that may be used in several fields, such as nutraceuticals, cosmetics and agro-food industry.
2

Different antioxidant responses to salt stress in two different provenances of Carthamus tinctorius L.

84%
Karray-Bouraoui N., Harbaoui F., Rabhi M., Jallali I., Ksouri R., Attia H., Msilini N., Lachaal M.
Acta Physiologiae Plantarum
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2011
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tom 33
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nr 4
Seedlings of two Tunisian Carthamus tinctorius L. provenances (Kairouan and Tazarka) differing in salt sensitivity were hydroponically grown at 0 and 50 mM NaCl over 21 days. Leaves of Kairouan (saltsensitive) showed a 48% restriction in their growth at 50 mM NaCl although they accumulated less sodium than those of Tazarka (less salt-sensitive) that maintained an unchanged growth. Salt treatment induced oxidative stress in C. tinctorius and the effect was more pronounced in the leaves of the more salt sensitive provenance, Kairouan. Both provenances exhibited a stimulation of antioxidant enzyme activities with higher catalase (CAT) and superoxide dismutase (SOD) activities in Tazarka and higher peroxidase (POD) activity in Kairouan. But, it seems that antioxidant activities were more correlated with polyphenol content. Actually, leaves of Tazarka experienced higher polyphenol and antioxidant activity than Kairouan at 50 mM NaCl. Hence, moderate salinity (3 g NaCl L⁻¹) enhanced bioactive molecule yield in the less salt sensitive provenance, Tazarka. In addition, C. tinctorius was found rich in ascorbic acid, but the moderate salt stress enhanced its production only in the sensitive provenance.
3

Variation of phenolic composition and biological activities in Limoniastrum monopetalum L. organs

84%
Trabelsi N., Falleh H., Jallali I., Daly A. B., Hajlaoui H., Smaoui A., Abdelly C., Ksouri R.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 1
Changes in phenolic composition and biological activities were investigated in different Limoniastrum monopetalum L. organs. For that, 80% aqueous acetone extracts were used to estimate total phenolic contents and their antioxidant activities were evaluated using DPPH and O₂ radical scavenging activities and reducing power. The efficiency of organ extracts was tested against human pathogen strains. Ultimately, acid hydrolysis of all organs was subjected to RP-HPLC for phenolic identification. Results showed that flower extracts exhibited the highest polyphenol (65.42 GAE/g DW) and flavonoid (35.36 CE/g DW) contents. Stems were enriched in condensed tannin content (21.4 mg CE/g DW) and displayed the best antiradical activities and the highest reducing power. Besides, stem and gall extracts showed the highest efficiency against pathogenic bacteria as compared with those of flower. Concerning the antifungal test, a slight activity was found in gall extracts. The RP-HPLC showed a difference in phenolic compounds that varied as function of organ. In fact, the major phenolic compound varied as function of organ. Results suggest that L. monopetalum could be a promising source of biomolecules for therapeutic and nutraceutical industries and the difference between organs may be related to their physiological role.
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