https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/73 2026-03-24T18:16:29Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10417 Title: Contribution à l’étude des effets biocides des extraits végétaux d’espèces spontanées sur des bioagresseurs des cultures en milieu saharien Authors: ARABA, Fatna Abstract: In the context of enhancing and valorizing natural resources, methanolic extracts from two parts of three spontaneous plant species collected in the Algerian Sahara Cotula cinerea Del. (inflorescences and leaves), Peganum harmala L. (seeds and leaves), and Pergularia tomentosa L. (seeds and leaves) were tested for their antifungal activity. Extraction yields ranged from 11% to 24%. The highest yield was obtained from the leaf extract of C. cinerea (24%), followed by the leaf extract of P. harmala (22%) and P. tomentosa (21%). The seed extract of P. harmala showed a yield of 20.1%, while the inflorescence extract of C. cinerea yielded 18%. The lowest extraction yield (11%) was obtained from P. tomentosa seeds. Phytochemical screening of the hydro-methanolic extracts obtained by reflux extraction revealed a rich and diverse composition of secondary metabolites. Tannins were present in all crude extracts except the leaf extract of P. harmala Alkaloids were characteristic of C. cinerea and P. harmala, but absent in P. tomentosa. Flavonoids were detected in all extracts except those of P. harmala. Reducing compounds, free quinones, saponins, and steroids were completely absent in C. cinerea, while P. harmala lacked flavonoids and free quinones, and P. tomentosa was devoid of coumarins and alkaloids. Terpenoids were found in all crude extracts except the seed extract of P. harmala. In vitro evaluation of antifungal activity against the mycelial growth of two pathogenic fungi Mauginiella scaettae Cav. and Fusarium oxysporum f.sp. albedinis using a direct contact test, revealed variable inhibitory effects among the tested extracts. Methanolic extracts of C. cinerea and P. harmala exhibited significant antifungal activity at all tested concentrations against both fungal species, with markedly reduced mycelial growth compared to the control. Notably, the seed extract of P. harmala at 20% concentration completely inhibited the mycelial growth of M. scaettae Cav. For F. oxysporum f.sp. albedinis, inhibition rates of 61.29%, 72.89%, and 83.94% were observed at 40%, 50%, and pure extract concentrations, respectively. Abstract The seed extract of P. tomentosa showed moderate antifungal activity against M. scaettae at lower concentrations, while the inflorescence and leaf extracts of C. cinerea at 40% concentration inhibited F. oxysporum f.sp. albedinis growth by more than 50%. These findings suggest that it would be of particular interest to further investigate the potential synergistic effects of aqueous extracts from the studied plants. 2025-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/8238 Title: Evaluation du pouvoir herbicide des extraits aqueux de trois plantes spontanées récoltées au Sahara Authors: OTMANI, Reguia Abstract: In the context of valorization of natural resources, by the search for new compounds of plant origin and the evaluation of the allelopathic and bioherbicide activity of the leaf extracts of three spontaneous plants, namely Haloxylon scoparium Pomel, Euphorbia guyoniana Boiss. & Reut. and Euphorbia retusa Forsk. harvested in the north-eastern region of Algerian Sahara on a few weeds related to cereal crops: Bromus rubens L., Phalaris minor Retz., Plantago lagopus L., Ammi visnaga L. (LAM) and Triticum durum Desf. The evaluation of the activity of the plant extracts was made by the method of reflux extraction, which allowed us to determine the extraction yields of the different extracts. The extraction yield is of the order of 20.64% for Haloxylon scoparium, followed by the extract of Euphorbia guyoniana with an extraction yield of 17.80%. While the extract of Euphorbia retusa has the lowest yield with 15.45%. Phytochemical screening of leaf extracts of three species shows a remarkable richness in active substances; including alkaloids, flavonoids, steroids, sterols and triterpenes, coumarin, saponosides, free quinone, cyanidin, tannins and reducing compounds are presented in more or less important quantities in all extracts. There is a total absence of reducing compounds in Haloxylon scoparium extract, Alkaloid and coumarin in Euphorbia guyoniana and saponoside in Euphorbia retusa. We also detected the presence of anthocyanin in Euphorbia guyoniana and glycoside in Euphoria retusa. Dosage of total polyphenols and total flavonoids of leaf extracts, shows that the highest levels of polyphenols are found in the extract of Euphorbia guyoniana (2423.80 1.56 mg EAG/100g), while the other plants are less rich in polyphenols, Haloxylon scoparium (588.33 1.87 mg EAG/100g) and Euphorbia retusa (573.8 1.65 mg EAG/100g). Total flavonoids are concentrated mainly in Haloxylon scoparium extract (95.45 1.21 mg EQ/g), and very low in Euphorbia guyoniana extracts (34.88 0.83 mg EQ/100g) and Euphorbia retusa (24.92 0.91 mg EQ/100g). The analysis carried out by LC-MS-MS on plant extracts, allowed us to show the richness of the leaves of these desert species in phenolic compounds and to determine their chemical composition. A wide range of various phenolic compounds have been identified, namely: folic acid, maleic acid, caffeic acid, ascorbic acid and gallic acid, quercetin, rutin, naringenine, myricetin, vanillin, hydroxy-4-coumarin, beta-carotene, BHA and BHT. The evaluation of allelopathic power by two experimental models revealed the bioherbicide capabilities in all extracts. The results obtained are promising, which all extracts significantly inhibit the germination of weed species. However, no extract significantly affected the germination of wheat seeds. The inhibition rates recorded for the different batches of pots treated with plant extracts are relatively lower compared to the results obtained for batches of petri dishes. Germination kinetics and vigor index of weed and cultivated species treated with plant extracts were slower than reported for negative control lots. While according to the calculated values EC50% and EC90%, leaf extracts were found to be more harmful to weed species (Bromus rubens, Phalaris minor, Plantago lagopus, Ammi visnaga) than the cultivated species (Triticum durum). The growth inhibition values of the aerial and root part and the Fisher test results affirm the strong bioherbicide power of the extracts of three plants studied including those of Haloxylon scoparium, where its toxicity at the highest concentration is comparable to that of the herbicide (positive control). On the other hand, the simulator effect at the level of the lots treated by the low concentrations, which is manifested by the elongation or increase of the weight of the aerial and root part compared to the seedlings of the negative control lot. 2024-05-09T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/7650 Title: Etude de la toxicité des trois plantes spontanées sahariennes de la region de Ghardaia à l'égard d'un modèle de laboratoire Drosophila melanogaster (Diptera; Drosophilidae) Authors: CHABI, Lila 2023-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/6145 Title: Action des huiles lourdes de graines de trois plantes spontanées du Sahara Algérien sur quelques paramètres biologiques du Criquet pèlerin Authors: AIT AOUDIA, Ahmed Abstract: Our study’s objective is to test the lethal and sub-lethal effects of heavy seed oils from three spontaneous plants from the Algerian Sahara, which are Peganum harmala L. (Zygophyllaceae) and Cleome arabica L. (Capparidaceae) and Datura stramonium L. ( Solanaceae) against L5 larvae and imagos of Schistocerca gregaria Forsk. (Orthoptera-Acrididae). The treatment technique consists of injecting a dose of pure seed oil into the insect's esophagus using a micropipette. The seed oil doses injected into L5 larvae and imagoes of S. gregaria are 60 µl/individual and 120 µl/individual, respectively. The doses injected into L5 larvae and imagoes of S. gregaria are 60 µl/individual and 120 µl/individual, respectively. Forced buccal injection of heavy vegetable oils in treated L5 larvae and imagoes of S. gregaria showed various toxicological symptoms, i.e. movement disorders, diarrhea, reduction in food intake, weight loss, digestive disorders, retardation and difficulties in molting and in the extreme cases, death. S. gregaria L5 larvae treated with P. harmala seed oil showed a mortality rate of 50% after 12 days. In addition, L5 larvae treated with C. arabica seed oil had a mortality rate of 63.63% after 16 days of treatment. Whereas we obtained with D.stramonium seed oil a mortality rate of 100% after only 7 days of treatment. It seems that the most toxic seed oil on the L5 larvae of S.gregaria is that of D.stramonium followed by the oil of C.arabica and finally that of P.harmala. In addition, imagos of S. gregaria treated with P. harmala and C. arabica seed oils showed mortality rates of 50% and 45.45% respectively after 29 days. Whereas, imagoes treated with D.stramonium seed oil reached 100% mortality rate after 13 days. Similarly, D.stramonium seed oil is also found to be more toxic to S.gregaria imagos than P.harmala and C.arabica seed oils. In addition, it appeared that imagos are more sensitive to the lethal action caused by the seed oil of P.harmala compared to the seed oil of C.arabica. The evaluation of lethal time 50 (TL50), showed that the shortest TL50 are recorded in L5 larvae treated with D.stramonium seed oil, it is 3.54 days in male L5 larvae and 5.97 days in female L5 larvae, followed by male L5 larvae treated with C. arabica seed oil with 7.6 days, then that of male L5 larvae treated with P. harmala with 8.47, then that of female L5 larvae treated with P.harmala and C.arabica seed oil with 9.5 days and 11.09 days respectively. Moreover, in S. gregaria imagos the shortest TL50 are recorded in imagos treated with D. stramonium seed oil, with 5.62 days in males and 5.74 days in females, then that female and male imagos treated with P.harmala seed oil with 22.52 days and 23.48 days respectively. The highest TL50 are recorded in imagos treated with C. arabica seed oil, with 24.54 days in male imagos, and finally that of female imagos with 27.23 days. At the same time, it seems that the lethal action of D.stramonium seed oil is faster compared to the two seed oils of P.harmala and C.arabica in this locust. The deterrent effects of the tested seed oils on the appetite and digestion of this locust are reflected in the weight losses recorded in the L5 larvae and treated imagoes of S. gregaria. S.gregaria L5 larvae treated with P.harmala and C.arabica seed oils show a low weight gain of around 15.64±31.35% and 14.28±38.74% respectively. While, L5 larvae treated with D.stramonium seed oil show a drop in weight of -17.55±36.97%. In addition, a reduction in weight gain was observed in imagos of S. gregaria treated with C. arabica and P. harmala seed oils, which are respectively of the order of 21.28 ± 22.65% and 15.51±31.35%, while the imagos of S. gregaria treated with D. stramonium seed oil recorded a drop in weight gain of the order of -22.44 ± 25.02%. The three heavy vegetable oils tested have toxic effects on L5 larvae and imagos of S. gregaria, the toxic effects vary with the injected seed oil, the treatment dose, the sex and the development stage of the insect. 2023-01-01T00:00:00Z