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This research was aimed to optimize the extraction conditions of three phenolic compounds: total phenolics, flavonoids and condensed tannins, from White Horehound's leaves (Marrubium vulgare L.). Distilled water and different organic solvents such as: methanol, ethanol and acetone, were used, with various concentrations (20% -80%, v/v), temperatures (20˚C -60˚C) and extraction times (30 -450 min). Results showed that the maximum total phenolics amounts (293.34 ± 14.60 mg gallic acid equivalent/g dry weigh), were obtained with 60% aqueous methanol at 25˚C for 180 min; total flavonoids (79.52 ± 0.55 mg catechin equivalent/g dry weigh) with 80% aqueous methanol at 20˚C for 450 min, and condensed tannins (28.15 ± 0.80 mg catechin equivalent/g dry weigh) with 60% aqueous acetone at 50˚C and for 180 min. ANOVA test showed the significant effect ( *** P < 0.001) of the extraction conditions tested on phenolic compounds. The Principal Component Analysis (PCA) exhibited the positive effect of low temperatures on total phenolics and flavonoids extraction, and the effect of high temperatures on the condensed tannins extraction. The Response Surface Methodology (RSM) provided predicted values of extraction conditions and maximum polyphenols amounts similar to those obtained experimentally. IntroductionPolyphenols constitute one of the most common and widespread groups of substances in flowering plants, occurring in all vegetative organs, as well as in flowers and fruits. These molecules are involved in many physiological processes such as cell growth, root formation, seed germination and fruit ripening [1]. Moreover, these compounds are considered secondary metabolites involved in the chemical defense of plants against predators, pathogens, environmental stresses and in plant-plant interferences [2].Nowadays, phenolic compounds represent a unique and a functional place, composed of bioactive products, present in plant-derived foods and beverages and included in the formulations of well-marketed cosmetic and parapharmaceutical products [3]. Furthermore, polyphenols exhibit various biological activities such as anticancer [4], antioxidant [5], antimicrobial [6] and anti-inflammatory activities [7]. Therefore, in recent years, the determination of phenolic compounds concentrations in fruits [8] [9], vegetables [10] and some aromatic and medicinal plants [11] [12] has been of increasing interest in the scientific community as well as among health professionals and business partners. It is well known that the content of phenolic compounds could be influenced by environmental conditions, such as season [13] [14], sampling period and geographic origin [15], precipitations and temperatures [16], and soil type [17]. Additionally, there are several experimental factors that can influence the rate of extraction and the quality of extracted bioactive phenolic compounds. These factors include extraction method, solvent type used and concentration [18], particle size of medicinal plants, temperature and pH of extraction [19], extraction t...

The numerous studies carried out on the halophilous vegetation in Oran region (Algeria) still require complementary contributions. Bioclimatically, the pluviometric gradient decreased from North of Algeria (Messerghine and Béni-Saf) to South (Chott El-Gharbi) which influences the floristic composition of the atriplexaies of the two zones. A pedological study showed sandy loam or a silty loam texture in the majority of the stations of the two zones. In addition, the rate of salinity increased in the South compared to North except the station of Messerghine (near to Oran Sebkha), whereas the organic matter rate was very low in the South. The new element brought by this study to the analyses of biologic diversity, it is that we took into account the relative abundance of species as well as their presence. In the Northern zone, the matorralisation and the anthropisation mark the floristic landscape in Béni-Saf. In Messerghine the floristic composition of Atriplexaies remained halophilous. The floristic procession of Atriplexaies of the Southern zone (Chott El-Gharbi) was marked by low species richness in bond with the overgrazing which probably induces probably a floristic succession to steppes dominated by Peganum harmala between El Aricha and Abdelmoula. CA (Correspondance Analyses) carried out using the software Minitab 12 informed us on the factors governing floristic composition of the atriplexaies of the two zones : for the Northern zone, in Messerghine, the edaphic parameters (moisture, O. M and salinity) mainly explained the information brought by the first two axes (41%). In Béni-Saf, while moving away from Oran Sebkha, the anthropic activities accounted for a great part of information (more than 55%). For the Southern zone, in the station of El Kasdir 01 (steppe field), it was both the edaphic parameter (salinity) and the anthropic factor which explained the information brought by the first two axes (61,1%).

Français.  Le cortège floristique de la région sud de l’Oranie (Chott El Gharbi) est marqué par une pauvreté par rapport au nord. Cet écosystème aride se caractérise par la présence très localisée de peuplements végétaux steppiques xérophytes et halophytes souvent exposés a une dégradation irréversible. Afin de comprendre la dynamique et l’évolution de ces taxons, nous avons entamé une étude qui se base sur les variables suivantes: Sol, climat, et végétation. Les sols de cette région sont pauvres en matière organique (0.45%), de texture limono-sableuse avec une salinité élevée (2,42 mS/cm). L’étude de la végétation se base sur la méthode de Braun-blanquet (1951), où 40 relevés floristiques ont étés pris en compte. L’utilisation de l’AFC (analyse factoriel des correspondances) réalisée à partir du logiciel minitab 15 nous a permis de mettre en exergue les différents gradients écologiques qui régissent la composition et la répartition floristique de ces formations dominées par le type biologique thérophyte.English.  The floristic region south of Oran (Chott El Gharbi) is marked by more bareness compared to the north. This arid ecosystem is characterized by the presence of highly localized xerophytic steppe plant populations and halophytes often exposed to irreversible damage. To understand the dynamics and evolution of these taxa, we initiated a study based on the following variables: soil, climate and vegetation. Soils in this region are poor in organic matter (0.45%), sandy loam texture with a high salinity (2.42 mS / cm). The study of vegetation based on the method of Braun-Blanquet (1951), where 40 floristic surveys were taken into account. The use of AFC (factorial correspondence analysis) performed by (minitab15) software, allowed us to highlight the different ecological gradients that govern the floristic composition and distribution of these formations dominated by biological type therophyte.

To know the mode of distribution of halophytes species in the western region of Algeria, it was considered useful to undertake a study based on the achievement of identified linear. Two areas were considered, Northern Tlemcen (Beni Saf and Rachgoun) and Northwest Oran (Sabkha). The trend of climate aridity which is more pronounced in the study area may have influences on floristic halophytes. The study of the floristic composition showed the importance of indicator halophitisation species such as Atriplex halimus, Tamarix gallica, Salicornia fruticosa, Arthrocnemum glaucum and was accompanied by various therophytes such as Sinapis arvensis, Erodium moschatum, Malva sylvestris and Plantago lagopus. ANOVA (analysis of variance) has highlighted the factors that influence the spatial distribution of some halophytes species at five stations studied; some are dispersed aggregates (Tamarix gallica, Suaeda fruticosa) with a coefficient of variation (Cv) greater than 10%; others are regularly dispersed (Atriplex halimus) with a coefficient of variation (Cv) less than 10%.