This study was carried out to evaluate the effect of extraction methods (direct maceration (DM) and successive maceration (SM)) and solvents (dichloromethane (DCM), ethyl acetate (EAc), butanol (But), and aqueous extraction (Aqu)) on the phenolic composition and biological activities of Moringa oleifera leaves cultivated for the first time in Tunisia. Total polyphenol content (TPC), total flavonoid content (TFC) and LC-MS analysis were performed for all extracts. Antioxidant potential by DPPH, metal chelating, and FRAP assays, antibacterial activity against Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922) by the minimum inhibitory concentration method (MIC) and cytotoxic properties against lung cancer cells (A549), were determined. Phenolic compounds and biological activities of M. oleifera leaves depend on the method and the solvent used for the extraction of these bioactive substances. The But extract prepared by SM method exhibited the highest amounts of TPC (103.06 ± 0.5 mg GAE/g DE) and showed the strongest potential antioxidant (CI₅₀ = 0.26 mg/mL on DPPH test), antibacterial (MIC = 250 µg/mL) and cytotoxic activities (GI₅₀ = 69.9 µg/mL). LC-MS analysis showed that 28 phenolic compounds of 33 tested standards were found in M. oleifera leaves. The But extract obtained by SM method exhibited the highest amounts of rutin, quercetin and syringic acid.

Eucalyptus species are known to produce metabolites such as essential oils (EOs) that play an important role in the control of weeds, pests and phytopathogenic fungi. The aims of this study were as follows: (i) to determine the chemical composition of the EOs derived from eight Eucalyptus species growing in Tunisia, and (ii) to study their possible antifungal and herbicidal activities. EOs were obtained by hydrodistillation from the dried leaves of eight Eucalyptus species, namely, E. angulosa, E. cladocalyx, E. diversicolor, E. microcoryx, E. ovata, E. resinifera, E. saligna and E. sargentii, and the determination of their composition was achieved by GC and GC-MS. The EOs’ antifungal activities were tested against four Fusarium strains, and the EOs’ herbicidal properties were evaluated on the germination and seedling growth of three annual weeds (Trifolium campestre, Lolium rigidum and Sinapis arvensis) and three cultivated crop species (Lepidium sativum, Raphanus sativus and Triticum durum). The EO yields ranged between 0.12 and 1.32%. The most abundant components found were eucalyptol, α-pinene, p-cymene, trans-pinocarveol, α-terpineol and globulol. All EOs showed significant antifungal activity against the four phytopathogenic Fusarium strains. E. cladocalyx EO exhibited the highest level of antifungal activity, and the greatest inhibition of seed germination was obtained even at lowest concentrations used. These findings suggested that E. resinifera, E. ovata and E. cladocalyx EOs could have applications in agriculture as possible biopesticides, as Fusarium antagonists and as bioherbicides.