Etude de composes bioactifs de plantes aromatiques et medicinalesCladanthus mixtus L. et Matricaria chamomilla L.

Abstract

Plant extracts containing phytochemicals are increasingly marketed as products with a positive impact on the health system. The objective of our study is to analyze the differences in chemical composition and to evaluate the antioxidant, antimicrobial and anticancer activities of extracts from different organs (flowers, leaves, stems, and roots) of two aromatic and medicinal plants from North-West Morocco Cladanthus mixtus and Matricaria chamomilla. The chemical composition of these extracts was analyzed by HPLC-MS and GC-MS. This study also presented a quantification of phytomelatonin content which was analyzed by HPLC-FLUO. M. chamomilla organ samples showed higher phytomelatonin values, especially the leaves (61.31 ng/g DM) compared to C. mixtus. All methanolic extracts contained high amounts of flavonoids and phenolic acids. Other groups of chemical compounds were revealed, such as terpenoids, esters, organic and fatty acids, and other groups. Using methanolic, ethyl acetate, and aqueous extracts, we studied the contents of phenolic compounds and flavonoids. Also, the antioxidant activity was carried out by applying the ABTS and DPPH tests. In ethyl acetate and aqueous extracts, C. mixtus had higher phenolic content than M. chamomilla. However, the flavonoid content of both plants was very close compared to the methanolic extract. The results for both plants showed that hydrophilic antioxidant activity was the most dominant in the ABTS assay, while lipophilic antioxidant activity accounted for the majority of the total antioxidant activity for most organs tested by DPPH. For methanolic extracts, the roots of both plants showed the highest activity using both assays. We found a positive correlation between antioxidant activity and polyphenols and flavonoids amounts. The micro-dilution technique was chosen to study the antimicrobial activity of methanolic extracts against two bacterial strains and three fungi. Between the two bacterial strains tested, Staphylococcus aureus was more sensitive to the extracts compared to Escherichia coli. The extract from the flowers of M. chamomilla was the most active against S. aureus showing the lowest MIC and MBC values (2.50 and 6 mg/mL, respectively) and the extract from the leaves showed bactericidal activity against E. coli (MIC = MBC = 35 mg/mL). Concerning C. mixtus, the best activity was presented by the leaf extract against S. aureus (MIC = MBC = 20 mg/mL) and E. coli (MIC of 30 mg/mL and MBC of 35 mg/mL). Fungal species (Candida albicans, Trichophyton rubrum, and Aspergillus fumigatus) were tested. All extracts showed antifungal activity against T. rubrum strain, with the best efficacy reported by the flower and leaf extracts of both plants (MIC = 1.25 mg/mL, MFC = 2.5 mg/mL). Extracts of C. mixtus and M. chamomilla appear less effective against C. albicans and A. fumigatus. Using the MTT assay and microscopic evaluation, the results of the antitumor activity of the plant extracts against three cancer cell lines: normal human lung fibroblasts (MRC-5), human breast carcinoma (MCF-7) and human prostate carcinoma (PC-3) were very encouraging. Both plants had good activity against the three cell lines studied at a concentration of 500 µg/ mL, with the best results obtained for C. mixtus with leaves and for M. chamomilla with flowers.