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Euphorbia guyoniana Boiss. & Reut. (Euphorbiaceae) is well known for the chemical diversity of its phytoconstituents, and toxicological properties that have been found in literature. However, research articles about their allelopathic characteristics are rarely reported. The current research study was conducted to explore phytochemical screening, allelopathic effects and their potential uses as natural herbicide of Euphorbia guyoniana Leaf extract, harvested from Oued Metlili, Algerian Sahara, on germination and seedling growth of four adventitious species (Bromus rubens L., Phalaris minor Retz., Plantago lagopus L., Ammi visnaga L.) and one cultivated species (Triticum durum L.) in laboratory conditions. The analyses of crude plant extract confirmed the flavonoids, anthocyanins, phenols and tannins, steroids, saponins, free quinone, sterols and triterpenes as well as carohydrates in the extract. Our results show that the leaf extract of Euphorbia guyoniana had significant allelopathic and bioherbicidal activity on germination and seedling growth of adventitious species and stimulatory activity on cultivated species at lower concentrations.

The Algerian steppes face ecological imbalances due to overgrazing, cereal cultivation, and resource pressure. In response, the government implemented the "Great Works for the Development of Steppe Pastures" program in 1994, planting the nonnative Atriplex canescens, a shrub resistant to cold, drought, and salinity. However, introducing exotic plants can harm native biodiversity through allelopathy interaction. This work aims to test the allelopathic potentiel of A. canescens on the most representative North African steppe plant Macrochloa Tenacissima. Phytochemical tests are performed on the aerial parts of these two plants. Aqueous extracts are prepared from the aerial parts of A. canescens with three concentrations respectively T0 (0%), T1 (2.5%) and T2 (5%), and are applied in situ for 45 days on M. tenacissima plants. The response of M. tenacissima to the extract of A. canescens is monitored by measuring chlorophyll and proline in the fresh leaves of the target plant M. tenacissima. The results showed the presence of allopathic molecules in the aerial parts of both plants, notably Alkaloide, flavoniode, tannins, triterpnoide, Quinon and phenolic acid. The response of M. tenacissima to the application of A. canescens extract caused during the trial remarkable change in the total chlorophyll content of M. tenacissima, with reductions of 1 to 4 (mg/g FM) observed at the end of 45 days of application. The highest decrease is observed for treatment T3. After 45 days of treatment with A. canescens extract aqueous, M. tenacissima showed the highest proline accumulation 2.6 (mmol/g MF) for the treatment T3. Our findings show that A. canescens can induce physiological disruptions in M. tenacissima. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the antibacterial activity of the metronidazole cocrystal, an antibiotic widely used in the treatment of infectious diseases caused by anaerobic bacteria. The cocrystal was prepared by mixing metronidazole (MNZ) and nicotinamide (NIC) in a 1:1 molar ratio, using an environmentally friendly mechanical process based on liquid assisted grinding method. The MNZ-NIC cocrystal was then characterized by differential scanning calorimetry (DSC), powder X-ray diffraction and scanning electron microscopy (SEM) and tested against four aerobic and anaerobic bacterial strains: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. The thermal analysis of MNZ-NIC cocrystal showed a single endothermic peak at 110 °C identified as the cocrystal's melting point. The SEM microscopy revealed a distinct morphology compared to the individual compound. A comparative analysis of antibacterial efficacy was conducted on MNZ drug and its cocrystal. The results demonstrated that the cocrystal displayed superior antibacterial effectiveness against Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

The greatest weed management challenge is the lack of effective natural products based herbicides. Allelochemicals of plant origin can substitute synthetic chemicals as nature's own herbicide. The use of allelopathic properties of native planVcrop species offers promising opportunities for this purpose. In this study Retama raetam invasive Mediterranean plant species is selected, to test its allelopathic potential on the germination of seeds and the growth of weed seedlings of Avena sterilis, Bromus secalinus and on the wheat Triticum durum (SIMETO variety). The chemical characterization of aerial the part ofR. raetam reveals that it contains Allelochemicals compounds of flavonoids, triterpenes, alkaloids and tannins groups. Four concentration 5% (Dl), 10% (D2), 15% (D3) and control 0% (DO) of aqueous extracts of the aerial part ofR. raetam were applied in A. sterilis, B. secalinus and T durum through germination and growth bioassays in a climate-controlled incubator at a temperature 25°C. The application of these treatments revealed significant differences on the measured parameters. They showed that the germination inhibition of the two weeds increases with the increase of the concentration of aqueous extracts of R. raetam. For the two weeds, the inhibiting effect on germination is 100% with treatment D3 (15%). According to the applied concentration wheat stem length varies between 0.46 and 4.67 cm, its radicle length fluctuate between 0.09-2.41cm. The inhibition of the growth seedlings, especially on the roots ofB. secalinus weed is complete (0 cm) whatever the applied concentration of R. raetam aqueous extract. Inhibition of stem growth is noticeable in A. sterilis with treatment D3 (15%). The seedling vigor index is increasing with the decrease of concentration of aqueous extract of R. raetam. Results of this study are relatively promising in the field of biological weed control using R. raetam metabolites. [ABSTRACT FROM AUTHOR]

In Algeria, overgrazing has long threatened the sustainable use of the nearly 20 million hectares of steppe lands. More recently, governmental policies favouring extensive rainfed cereal cropping in the steppe region have increased anthropic pressure on this fragile environment. Low rainfall, weak crop development and sandy soils lead to a high risk of wind erosion, yet no studies have been carried out in this region to this date to quantify the effect of steppe conversion on wind erosion. A 1·3-ha field in the central steppe of Algeria (Laghouat) was converted to cropland ( Hordeum Vulgare L.) and equipped with a weather station and Big Spring Number Eight sand straps to monitor climate-related parameters and sediment fluxes over a 25-month period. Threshold wind velocities (3·6 m height) varied between 6 and 7 m s−1 with a weak seasonal variation. More than 70% of the saltation-producing winds originated from the NW. For these winds, a soil loss of 155 Mg ha−1 was measured. Half of the sediment loss occurred during a single, 12-day period. Deposition of 26·5 Mg ha−1 was observed for SW winds. The measured erosion rates by far exceeded all norms of tolerable soil loss, indicating that rainfed cereal cropping is a highly unsustainable form of land use in the steppe region around Laghouat. National agricultural policies should be revised to take this into account. © 2014 The Authors. Land Degradation and Development published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]