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The present study consists in evaluating the inter- and intraspecific variability of phenolic contents and biological capacities of Limoniastrum monopetalum L. and L. guyonianum Boiss. extracts. Ultimately, they were subjected to HPLC for phenolic identification. Results showed a great variation of phenolic content as function of species and localities. In fact, L. guyonianum extracts (El Akarit) contained the highest polyphenol (57 mg GAE g DW), flavonoid (9.47 mg CE g DW) and condensed tannin contents (106.58 mg CE g DW). These amounts were accompanied by the greatest total antioxidant activity (128.53 mg GAE g DW), antiradical capacity (IC = 4.68 μg/ml) and reducing power (EC = 120 μg/ml). In addition, L. monopetalum and L. guyonianum extracts exhibited an important and variable antibacterial activity with a diameter of inhibition zone ranging from 6.00 to 14.83 mm. Furthermore, these extracts displayed considerable antifungal activity. L. monopetalum extracts (Enfidha) showed the strongest activity against Candida glabrata and C. krusei with a diameter exceeding 12 mm. The phytochemical investigation of these extracts confirmed the variability of phenolic composition, since the major phenolic compound varied as a function of species and locality. These findings suggest that these two halophytes may be a new source of natural antioxidants that are increasingly important for human consumption, as well as for agro-food, cosmetic and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 O 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. [ABSTRACT FROM AUTHOR]