Plant species of medicinal interest are involved in various sectors in their raw state or in the form of oils, extracts, aqueous or organic solutions. Their preparations contain one or more active ingredients that can be used for therapeutic purposes. Medicinal plants are recognized for physicochemical properties and richness in natural drugs belonging to different molecule classes such as terpenoids and phenolic compounds, like flavonoids, tannins, coumarins and phenolic acids that contribute to effective protection against numerous pathological processes. This study was devoted to phytochemical screening and evaluation of biological properties, namely, the antioxidant activities of hydroethanolic and infusion extracts prepared from Algerian Sahara Nerium oleander. Phytochemical tests applied to the studied plant showed the presence of several families of chemical compounds, including tannins and flavonoids. All samples exhibited interesting antioxidant activity when compared to the standard Trolox, but the hydroethanolic extract (EC50 values between 18 and 75 µg/mL) presented the highest bioactivity. The contemporary presence of bioactivities suggests that the Saharan Nerium oleander may be a source for such new preservatives in the food and pharmaceutical industries.

Soil genesis is closely related to climatic conditions.The low rainfall reduces the phenomenon of leaching and does in no way fertilization. This work shows that the evolution of soils of the steppe region of Tlemcen is not only the fact of a soil and climate but also the nuances of microstationnels factors (vegetation, slope and altitude). To this end, we found it necessary to make the physical and chemical analyzes combined with a statistical-Principal Component Analysis (PCA)-soils of the steppe region of Tlemcen, to identify characteristics and edaphic see their actions on the distribution and physiognomy of vegetation. Pedogenesis in steppe soils remains our primary concern, for their present condition is a certain imprint on these steppe ecosystems, the limit of their ecological rupture (desertisation).

For the management and sustainable use of natural bio-resources it is necessary to quantify and valorize this heritage. In the case of the floristic diversity of Acacia tortilis, the only natural woody stand in Bechar-Algeria, scanty studies have been undertaken. Hence in this study, the general overview of the flora diversity state in the 58 plots of 9 stations was made by the analysis of various indexes: Shannon, Simpson, species evenness, floristic richness, disturbance index, biological and biogeographically spectra. We listed 103 species belonging to 37 families and 85 genus, the important plants belonged to the Asteraceae and Brassicaceae. The most important species are: Pulicaria crispa, Asteriscus graveolens, Launea arborescens, Matricaria pubescens, Moricandia arvensis, Farsetia aegyptiaca, Zilla macroptera. The biological spectrum indicated a dominance of the Chamaephytes and the predominance of the Therophytes; the phytogeographic spectrum showed an important endemism (44%) in which 36% species belong to the SaharoArabian element; The Shannon, Simpson, and Evenness diversity indices, were relatively high, thereby indicating a diversity variation between the stations, witch increased South towards North. It was prominent in Zouzfana, Taghit, and Abadla stations, and the higher values of disturbance Index reflected the greater level of anthropization in these courses. The future accumulation of this regression, many risk loss of the last naturally wall of desertification, biodiversity, national economy and sand advancement. Therefore, it is recommended to apply pastures protection, pastoral charge control, and elaborate an environmental value of this species.

Traditional medicine still remains the main recourse of the majority of populations in developing countries. This medicine uses substances of animal, mineral and especially vegetable origin. Medicinal plants have always been part of the daily life of man since he uses them to feed himself, to cure himself and sometimes in his religious rites. Different traditional plants are used in the treatment of cardiovascular diseases such as hypercholesterolemia, atherosclerosis, hypertension and their associated factors (diabetes, obesity, etc.). The roots and leaves of these plants are used in herbal tea in the treatment of these diseases. Traditional medicine, which is based on traditional knowledge, deserves to be promoted. This valorization requires the availability of improved traditional medicines, that is to say effective, with proven safety and with precise posology. This study is made on the effect of some medicinal plants on some cardiovascular diseases, liver diseases, and cholesterol in the blood as well as the blood pressure. On the other hand a kind of general description on some cardiovascular diseases; hypercholesterolemia and arterial hypertension, as well as the risk factors like obesity, we quote some medicinal plants indicated against these diseases.