许多植物能够合成精油(EO),在防御杂草方面发挥关键作用,真菌和害虫。本研究旨在分析其化学成分,突出抗氧化剂,来自桉树的EO的抗菌和植物毒性特性,在突尼斯生长的E.sideroxylon和E.citriodora。通过气相色谱-质谱联用(GC/MS)分析EO,并通过总抗氧化能力(TAC)测定其抗氧化性能,DPPH和ABTS测定。对杂草的植物毒性潜力进行了评估(Sinapisarvensis,Phalariscanariensis)和硬粒小麦作物(Triticumdurum),并与化学除草剂草甘膦进行了比较。对8个靶真菌菌株进行了体外抗真菌活性研究。所有EO在含氧单萜(51.3-90%)和含氧倍半萜(4.8-29.4%)中显示出特定的丰富度,和1,8-桉树脑,香茅醛,香茅醇,反式-匹卡维醇,globulol,主要成分为司硫烯醇和醋酸香茅酯。桉树EO表现出显著的抗氧化活性,而与法尔卡塔和西德龙EO相比,西提龙油表现出显著的活性。测试油的植物毒性潜力对种子萌发和幼苗生长具有不同的功效,并且在测试草药及其化学成分变化之间存在差异。它们的效力优于草甘膦。在出现后阶段,观察到萎黄和坏死的症状。此外,叶绿素和相对含水量的减少,电解质渗漏和高水平的MDA和脯氨酸是EO的氧化作用及其作为生物除草剂的有效性的指标。此外,所有EO对所有测试的真菌菌株均表现出中等的真菌毒性。因此,根据获得的结果,桉树EOs可能具有作为天然农药的潜在应用。
Many plants are able to synthesize essential oils (EOs), which play key roles in defense against weeds, fungi and pests. This study aims to analyze the chemical composition and to highlight the antioxidant, antimicrobial and phytotoxic properties of the EOs from Eucalyptus falcata, E. sideroxylon and E. citriodora growing in Tunisia. EOs were analyzed by gas chromatography coupled to mass spectrometry (GC/MS) and their antioxidant properties were determined by total antioxidant capacity (TAC), DPPH and ABTS assays. The phytotoxic potential was assessed against weeds (Sinapis arvensis, Phalaris canariensis) and durum wheat crop (Triticum durum) and compared to chemical herbicide glyphosate. The antifungal activity was investigated in vitro against eight target fungal strains. All EOs displayed a specific richness in oxygenated monoterpenes (51.3-90%) and oxygenated sesquiterpenes (4.8-29.4%), and 1,8-cineole, citronellal, citronellol, trans-pinocarveol, globulol, spathulenol and citronellyl acetate were the main constituents. Eucalyptus EOs exhibited remarkable antioxidant activity and E. citriodora oil exhibited significant activity when compared with E. falcata and E. sideroxylon EOs. The phytotoxic potential of the tested oils had different efficacy on seed germination and the growth of seedlings and varied among tested herbs and their chemical composition variability. Their effectiveness was better than that of glyphosate. At the post-emergence stage, symptoms of chlorosis and necrosis were observed. Furthermore, a decrease in chlorophyll and relative water content, electrolyte leakage and high levels of MDA and proline were indicators of the oxidative effects of EOs and their effectiveness as bioherbicides. Moreover, all the EOs exhibited moderate fungitoxic properties against all the tested fungal strains. Therefore, according to the obtained results, Eucalyptus EOs could have potential application as natural pesticides.