The steppe areas of El Bayadh are characterized by a great diversity of medicinal plants (South-West Algeria). This work aims to determine the traditional uses of medicinal plants in the Wilaya (Province) of El Bayadh and evaluate their sensibility. The ethnobotanical surveys carried out using 400 questionnaire sheets made it possible to inventory 40 medicinal species belonging to 23 botanical families the most important family is that of the Lamiaceae and the Fabaceae. The leaves are the most used part of the plant, and the majority of treated illnesses are those of the respiratory system (the flu). The result of the index invented to indicate the state of the sensibility of the plants is important to develop a conservation strategy for these medicinal plants in the context of sustainable development.

Inula viscosa is a medicinal plant belonging to the Asteraceae family. This species is known under the name of Magramen. It is widespread in the Mediterranean region. An ethnobotanical survey was carried out in the city of Sidi Bel Abbes where this plant abounds. On the other hand, a phytochemical study of Inula viscosa is carried out. The determination of total phenols was carried out by using the Folin-Ciocalteu reagent, the quantification of flavonoids by the method with aluminum trichloride and sodium hydroxide, and that of the tannins condensed by the vanillin method under acidic conditions. Antioxidant activity was assessed using the free radical reduction method (DPPH). Thus, a toxicity test was carried out according to line 420 of the OECD. The results showed that this plant is involved in: the treatment of osteoarticular or rheumatic diseases (33%), dermatological infections (33%), nervous system (11%), digestive disorders (11%), and cardiovascular diseases (6%). The phytochemical screening allowed us to highlight the presence of secondary metabolites in the leaves of our plant; such as flavonoids, terpenoids, tannins, glycosides, and carotenoids. The content of the leaves in total phenols (31.46 mg AGE / g) is higher than that of the twigs (30.28 mg GAE / g). The amount of flavonoids is slightly higher in the leaves (133.93 mg EC / g) than in the twigs (37.12 mg EC / g). The prepared extracts have very significant antifree radical activities since they recorded very remarkable IC50 values of 0.1 to 4.1 mg/ml. Inula viscosa is non-toxic for a dose of 2000 mg/ml or less.

This work focuses on a qualitative and quantitative study of some secondary metabolites of the species Artemisia campestris growing in the region of El Bayadh_Algeria. Accordingly, the total polyphenol content of the leaves is (89.12 ± 0.12 mg GAE / g) followed by stems and roots (85.11 ± 4.78 mg GAE / g) and (82.78 ± 4, 78 mg GAE / g) respectively. Moreover, the flavonoids content is also very high (119.12 ± 0.22 mg EC / g) for the leaves, (110.61 ± 0.09 mg EC / g) for the stems, and (105.71 ± 0.26 mg EC / g) for the roots. Therefore, the scavenger potential of free radicals of this species is very high. Henceforth, the classification of the three organs according to the DPPH test and the β-carotene bleaching test in descending order is leaves> stems> root. Thus, carrageenan in mice induced a remarkable anti-inflammatory dose-effect (600 mg/kg) recorded with an 82% inhibition of plantar edema.

Our work focuses on endorsing the biological effects of Rosmarinus Officinalis L essential oils from the arid zone in Algeria by studying its chemical composition, and biological activities; in vitro and in vivo. The chemical compounds of the essential oil have been identified by gas chromatography and mass spectrometry. Thirty-two constituents, accounting for 99.97% of the total oil composition were identified. the main compounds of the essential oil were Eucalyptol (70,90%), Borneol (16.63%), ⍺-Pinene (10,52%) β-Pinene (5,77%), Camphor (2,15 %), and ⍺-terpineol (1,45%), respectively. The antioxidant activity of the hydro distilled oil was studied using DPPH to determine IC50 of 18.04μg/ml. The antibacterial activity of essential oils was evaluated against five microorganisms using the diffusion disc method on bacteria: Candida Albicans ATCC 10231, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), Staphylococcus aureus ATCC 25923, Bacillus ATCC 11778, diameters vary between 6 and 19 mm. The toxicity was tested on Winstar rats; for a dose less than or equal to 2000mg/kg no toxicity signs were shown. In vivo, the Anti-Inflammatory properties were evaluated using the Induction of edema by carrageenan, the essential oil has a great effect at the concentration of 600mg /kg.