The chemical composition of the essential oils of Melaleuca armillaris Sm., Melaleuca styphelioides Sm. and Melaleuca acuminata F. Muell., collected in Tunisia, was studied by means of GC and GC-MS analysis. In all, 46 compounds were identified, 38 for M. armillaris, 20 for M. acuminata and eight for M. styphelioides, respectively. The presence of a sesquiterpenic fraction (52.2%) characterized the oil from M. armillaris; M. sthypheliodes oil was rich in methyl eugenol, a phenolic compound (91.1%), while M. acuminata oil is mainly constituted by oxygenated monoterpenoids (95.6%). The essential oils were evaluated for their in vitro potentially phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of five seeds was inhibited at the highest doses tested, while germination of all seeds was not affected. Moreover, the essential oils showed low antimicrobial activity against eight selected microorganisms.

The chemical composition of essential oils isolated by hydrodistillation from the aerial parts of Tunisian Pinus pinea Linn. was analyzed by GC and GC/MS. Sixty-six compounds were identified, representing 98.5% of total oil, which was found to be rich in monoterpene hydrocarbons (73.1%) particularly limonene (54.1%), a-pinene (7.7%), and b-pinene (3.4%). The yield and the physico-chemical properties were determined. Results of the antifungal activity study by in vitro contact assay showed that P. pinea oil significantly inhibited the growth of ten plant pathogenic fungi. Moreover, herbicidal properties of the oil, tested on Sinapis arvensis L., Lolium rigidum Gaud., and Raphanus raphanistrum L., indicated that the oil completely inhibited the seed germination at a high concentration, while at low doses the oil acted by decreasing and delaying the germination and inhibiting the seedling growth of all tested weeds unlike the commercial herbicide. Our results showed that P. pinea essential oil could be valorized as bioproduct for biocontrol of weeds and fungal plant diseases.

In this study, a detailed phytochemical analysis of the medicinal herb Inula viscosa leaves was performed. Furthermore, in vitro antioxidant and antifungal properties of its methanolic extract were evaluated and compared with the corresponding phenolic profile obtained by high-performance liquid chromatography and mass spectrometry. Data obtained underscore the high amount of total lipids (6.14%) in leaves. Chromatographic analysis revealed its high content of unsaturated fatty acids (UFAs) with the essential ones α-linolenic and linoleic acids being the main compounds. It also showed good nutritional quality because of its high UFA/saturated fatty acid ratio and the lower values of atherogenic and thrombogenic indices. The volatile oil analyzed by gas chromatography-mass spectrometry showed the abundance of nonterpenic compounds, namely aliphatic alkanes. The total phenol content (TPC) and total flavonoid content (TFC) were higher in I. viscosa leaves (103 mg GAE/g dw and 99 mg CE/g dw for TPC and TFC, respectively). The use of HPLC-PDA-ESI-MS/MS allowed the identification of 17 components with hydroxycinnamic acids, namely mono-and dicaffeoylquinic acids being the most prominent components. The presence of these phenolic compound conferred strong free radical scavenging and antifungal properties to the methanol extract. Therefore, I. viscosa leaves could be considered as an excellent source of food functional ingredients with high nutritional value and health benefits.

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