Anti-inflammatory activity of essential oils from Tunisian aromatic and medicinal plants and their major constituents in THP-1 macrophages.

In this study, the capacity of eight essential oils (EOs), sage (Salvia officinalis), coriander (Coriandrum sativum), rosemary (Rosmarinus officinalis), black cumin (Nigella sativa), prickly juniper (Juniperus oxycedrus), geranium (Pelargonium graveolens), oregano (Origanum vulgare) and wormwood (Artemisia herba-alba), on the inhibition of NF-κB activation was screened at concentrations up to 0.25 µL/mL using THP-1 human macrophages bearing a NF-κB reporter. This screening selected coriander, geranium, and wormwood EOs as the most active, which later evidenced the ability to decrease over 50 % IL-6, IL-1ß, TNF-α and COX-2 mRNA expression in LPS-stimulated THP-1 macrophages. The chemical composition of selected EOs was performed by gas chromatography-mass spectrometry (GC-MS). The two major constituents (>50 % of each EO) were tested at the same concentrations presented in each EO. It was demonstrated that the major compound or the binary mixtures of the two major compounds could explain the anti-inflammatory effects reported for the crude EOs. Additionally, the selected EOs also inhibit>50 % caspase-1 activity. However, this effect could not be attributed to the major components (except for ß-citronellol/geranium oil, 40 %/65 % caspase-1 inhibition), suggesting, in addition to potential synergistic effects, the presence of minor compounds with caspase-1 inhibitory activity. These results demonstrated the potential use of the EOs obtained from Tunisian flora as valuable sources of anti-inflammatory agents providing beneficial health effects by reducing the levels of inflammatory mediators involved in the genesis of several diseases.

Metabolite profiles of essential oils and molecular markers analysis to explore the biodiversity of Ferula communis: Towards conservation of the endemic giant fennel.

Giant fennel (Ferula communis L.) is well known in folk medicine for the treatment of various organ disorders. The biological importance of members of genus Ferula prompted us to investigate the leaves of the endangered Tunisian medicinal plant F. communis L. not previously investigated. An estimate of genetic diversity and differentiation between genotypes of breeding germplasm is of key importance for its improvement. Thus, four F. communis populations were RAPD fingerprinted (63 RAPD markers generated by 7 primers) and the composition of their leaf essential oils (EO) (134 EO compounds) was characterized by GC-MS. Cluster analysis based on the leaf volatiles chemical composition of F. communis accessions defined three chemotypes according to main compounds have been distinguished: α-eudesmol/ß-eudesmol/γ-terpinene; α-eudesmol/α-pinene/caryophyllene oxide and chamazulene/α-humulene chemotypes. A high genetic diversity within population and high genetic differentiation among them, based on RAPDs, were revealed (H(pop)=0.320 and GST=0.288) caused both by the habitat fragmentation, the low size of most populations and the low level of gene flow among them. The RAPD dendrogram showed separation of three groups. Populations dominated by individuals from the ß-eudesmol/γ-terpinene; chemotype showed the lowest gene diversity (H=0.104), while populations with exclusively α-pinene/caryophyllene oxide chemotype showed the highest value (H=0.285). The UPGMA dendrogram and PCA analysis based on volatiles yielded higher separation among populations, indicated specific adaptation of populations to the local environments. Correlation analysis showed a non-significant association between the distance matrices based on the genetic markers (RAPD) and chemical compounds of essential oil (P>0.05) indicating no influence of genetic background on the observed chemical profiles. These results reinforce the use of both volatile compounds and RAPD markers as a starting point for in situ conservation. The analysis of chemical constitution of oil of the populations from a specific region revealed predominance of specific constituents indicating possibility of their collection/selection for specific end uses like phytomedicines. Sufficient molecular and biochemical diversity detected among natural populations of this species will form the basis for the future improvement. The correlation between matrices of RAPD and essential oils was not significant. The conservation strategies of populations should be made according to their level of genetic and chemical diversity in relation to geographic location of populations. Our results give some insights into the characterization of this as yet little investigated plant.