Nigella sativa. Known by the common name "black cumin" is a medicinal plant from the Ranunculaceae family. Widely used in traditional medicine and as a food condiment in the Arab world. Basing on the seeds of this plant. The Nigella Sativa extract prevented bacterial growth; yet their efficiency remains different. The effect of Nigella sativa extract, on Streptococcus faecalis, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa by the method of aromatogramme, shows that these bacteria are inhibited. The extract of Nigella generated a zone of inhibition of 30, 25, 20, and 10mm respectively, Streptococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Evaluation of antioxidant power, which was conducted using the method of trapping the free radical DPPH (1,1-diphenyl-2-picrylhydrazyl), said the methanol extract showed an antioxidant activity (IC50 = 12 256 mg / ml), higher than that recorded in the ascorbic acid (IC50 = 0.097 mg / ml).

The tomato leafminer, Tuta absoluta (Meyrick), is a major pest of tomatoes in Morocco. Since its spread in the 1970s, chemical control was the main method of control. However, reduced effectiveness of some of the recommended insecticides has been observed since the 1980s. This study aims to propose alternative solutions based on the use of natural products "bioinsecticide" to fight against the tomato leafminer, Tuta absoluta (Meyrick), which is considered a serious threat to tomato production in Morocco and worldwide.
To achieve this objective, we evaluated the toxicity of the essential oil of Syzygium aromaticum L. buds against larvae of Tuta absoluta. Bioassays were performed in the laboratory in petri dishes 9 cm in diameter, at an average temperature of 26 ± 2 ° C and a relative humidity of 60 to 70%. The determination the lethal dose 50 (LD50) of this essential oil has been made via an analysis by probit method using the software BioStat Pro 5.9.8. The values of LD50 and LD100 are respectively 0.0047 and 0,0111μl/cm² calculated after fourths hours of exposure confirms the high degree of toxicity of the essential oil of Syzygium aromaticum L. buds on filter paper against the larvae of Tuta absoluta.

Salvadora Persica is a plant known for its medicinal properties whose variety of pharmacological activities have been reported by many studies. Volatile extracts of Salvadora persica are obtained either by hydrodistilation or by using a Soxhlet apparatus from crushed roots by using hexane as solvent. The obtained result by hexane extraction 2.5% has given better results than the one got by steam distillation 0.05%. Thus, the extracts obtained have been analyzed by coupling (GC-MS). The following products are among the many products identified: The Eugenol, the Asarone the Borneol the Carvacrol, vanillin, the Cuminal, Camphor, Acetamide the n-benzyl, the benzyl Isocianate and the oily acids Oleic and palmitic that represents the majority of the products extracted.
The essential oil of action Persica - on Streptococcus faecalis, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa by the method aromatogram- shows that these bacteria are inhibited. Therefore, essential oil Miswak generated a zone of inhibition of 40, 25 and 15mm respectively on Streptococcus faecalis, Escherichia coli and Staphylococcus aureus. Meanwhile, it did not influence Pseudomonas aeruginosa.
The antimicrobial activity of the essential oils has been evaluated by determining the minimum inhibitory concentration (MIC). Comparing the antibacterial effect with antibiotics, it was observed that the Miswak has a noticeable antibacterial power. It may, then, be an excellent oral hygiene agent.

The essential oil isolated from western Moroccan Citrus aurantium L. var. amara peel, by hydrodistillation, is analyzed by Gas Chromatography-mass spectrometry (GC-MS). Fifteen compounds representing 99.86% of total oil are identified. The predominant components in the essential oil are limonene (90.90%), linalool (2.52%), myrcene (1.51%) and β-pinene (1.41%).
Being both dietary and biologically active compounds, flavonoids have attracted much attention of investigations as potent species capable of affecting various biological processes in living organisms. The total flavonoids contents of aqueous and methanolic extracts of bitter orange's peel were found to be 1.43 and 14.82 mg Equivalent Quercetin/g respectively.
Furthermore, the antioxidant activity of aqueous and methanolic extracts of bitter orange's peel is measured using free radical scavenging method with DPPH•. In addition, a preliminary study of the antibacterial activity of extracts of bitter orange's peel is tested against three bacterial stains: Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa.

There is a growing interest in agriculture to replace synthetic chemicals with natural plant products that may have a bactericidal action. we have chosen two plant species to test their antibacterial effect against Xanthomonas fragariae Dw on tomato plants of the variety campbell 33, inoculated with this strain and two extracts pretreated with different concentrations (1%, 3% and 5%) are prepared from the leaves and stems of each species. We tested the one hand, the effect of these extracts on the removal or reduction of Xanthomonas fragariae Dw to the surface of the seeds, and secondly, their effects on growth parameters inoculated tomato plants. The effect of treatment of tomato seeds by the three concentrations of aqueous extracts of Rosmarinus officinalis L has given us a significant reduction compared to treatment with the extracts of Chenopodium ambrosioides L. Analysis of variance at the 5% threshold showed that six treatment plant extracts induced significant responses with degrees variants on vegetative and root biomass as well as the axial growth.