الخلاصة:
"Medicinal plants are an immense source of bioactive molecules, with many activities. The objective of our work is to achieve a phytochemical and biological study of alcoholic extracts and acetate ethyl phases (AE ) diethyl ether (DE ) and 1 -butanol (1B) of the bark of Pinus pinaster (PPI ), flower buds of Marrubium vulgare ( MUV ) and aerial parts of Artemisia herba alba (AHA) . These three Algerian plants species are used in traditional medicine. The phytochemical screening showed that three plants contain flavonoids, sterols and terpenes, tannins and coumarins. However, only PPI contains alkaloids. Spectral analysis of the methanol extracts reveals the presence of flavonoids such Flavonol, Flavone, Flavanone, Flavanol or anthocyanin.
Studies have been carried out in order to demonstrate the in vitro antibacterial properties of alcoholic extracts and AE, ED and 1B phases of Pinus pinaster bark, flowering tops of Marubium vulgare and the aerial part of Artemesia herba alba obtained after exhaustion with organic solvents of increasing polarity. All the plants proved to be active on one or more bacteria in 25 mg / ml, the effects of the extracts were compared to that of ampicillin, a positive control. By the method of diffusion in solid media (disk), and the diffusion method in liquid medium (MIC), both PPI and MUV extracts showed higher antibacterial activity on Escherichia coli than AHA, the areas of inhibition were 14.33 ± 3.51 and 15.33 ± 2.08 mm respectively . This important activity has been demonstrated in Escherichia coli with an MIC of 0.195mg/ml. The hydroalcoholic extract of AHA showed significant activity compared to positive control (AMPIC ) equal to 19 ± 1.00 with an MIC of 0.097 mg / ml against Pseudomonas aeruginosa. An inhibition diameter of 10 ± 1.00 mm was observed with the hydroalcoholic extract of MUV against Proteus vulgaris with an MIC equal to 0.048mg/ml. The MUV, AHA and PPI extracts were active with inhibition diameters of 16.66 ± 1.53, 13.66 ± 3.21 and 12.33 ± 2.52 respectively against Pseudomonas aeroginosa. Our results also indicate that the phases of plant extracts are little or no active which shows the existence of a synergistic action at the level of molecules present in hydro ethanolic extract. Analysis by thin layer chromatography (TLC) of the three plant extracts showed their high flavonoid, terpene and tannin compounds suggesting the presence of a correlation between the antibacterial activity and the content of the plant."
