Chemical Composition and Phytotoxic and Antibiofilm Activity of the Essential Oils of Two Moroccan Retama Species.

This study reports chemical composition, phytotoxic and antibiofilm activities of essential oils (EOs) of R. dasycarpa and R. sphaerocarpa from Morocco. EOs were analyzed by GC/MS and their phytotoxicities were evaluated against germination and seedling growth of Lolium multiflorum, Sinapis alba and Raphanus sativus. The antimicrobial and anti-biofilm activities were studied against Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes). Both EOs were abundant in oxygenated monoterpenes (40.01% and 23.57 %, respectively). Carvacrol is the predominant component in R. dasycarpa EO (17.80 %), and it also represents an appreciable amount in R. sphaerocarpa (8.96 %). R. sphaerocarpa showed total inhibition at high doses against all seeds. S. alba seeds were the most sensitive to all EOs. Minimum inhibitory concentration (MIC) values indicated significant inhibition for R. sphaerocarpa, between 24 and 30 µg/mL, with a remarkable antibacterial potential and biofilm formation inhibition. R. sphaerocarpa EO showed significant biofilm inhibition with variable efficacy depending on the strain and concentration, except for S. aureus. R. dasycarpa exhibited activity against all bacterial strains and effect on metabolism with activity also on mature biofilms. Results suggest that Retama EOs could have potential applications in the fields of food and health.

Antibacterial activity of Cladanthus arabicus and Bubonium imbricatum essential oils alone and in combination with conventional antibiotics against Enterobacteriaceae isolates.

Multidrug-resistant bacteria have become common all over the world, necessitating the development of new therapeutic strategies. Synergistic interactions between conventional antibiotics and natural bioactive may have therapeutic benefits in a clinical setting. There are plenty of medicinal plants that have proven efficacy against broad spectrum of micro-organisms. The aim of the work was to assess the antibacterial activity of Cladanthus arabicus, a Moroccan medicinal plant, and Bubonium imbricatum, a Moroccan endemic plant. The evaluation of the synergistic effect of extracted essential oils (EOs) together with some conventional antibiotics was also investigated. Checkerboard test was used to evaluate the interaction of EOs in combination with amoxicillin and neomycin. The results showed that EOs contain a potent activity against the tested Enterobacteriaceae isolates, with inhibition zones values in the range of 8·05 ± 0·1 and 13·1 ± 0·11 mm and MIC values between 200 µg ml-1 to 800 µg ml-1 for C. arabicus and from 400 µg ml-1 to 1600 µg ml-1 for B. imbricatum, respectively. Moreover, the current study allowed concluding that both EOs showed not only satisfactory antibacterial properties but also active effects combined with conventional antibiotics demonstrated by the Fractional Inhibitory Concentration Index (FICI). These findings are very interesting since there are no previous studies on synergistic interactions of these two plants with antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The development of antibiotic resistance is multifactorial, including the specific nature of the relationship of bacteria to antibiotics. This situation has forced scientists to search for new antimicrobial substances from various sources as novel antimicrobial chemotherapeutic agents. Recently, medicinal plants and their derivatives (essential oils, extracts) have become very important in therapeutics because they encounter minimal challenges of the emergence of resistance. In this direction, the antimicrobial activity of the endemic Bubonium imbricatum plant and medicinal Cladanthus arabicus plant essential oils against multidrug-resistant Enterobacteriaceae strains was demonstrated.

Investigation of antifungal and analgesic activities of extracts from Sium nodiflorum.

Different extracts of aerial parts of Sium nodiflorum were examined for their antifungal activity against two groups of fungi: the growth of both yeast and mold was significantly inhibited. Analgesic activity study of these extracts was also carried out but showed no significant effect in mice on the writhing induced by acetic acid.

Evaluation of some Moroccan medicinal plant extracts for larvicidal activity.

The larvicidal properties of 16 extracts of four Moroccan medicinal plants: Calotropis procera (Wild.), Cotula cinerea (L.), Solanum sodomaeum (L.) and Solanum elaeagnifolium (CAV.) were tested against Anopheles labranchiae mosquito larvae. Among the extracts tested, nine exhibited high larvicidal activity with LC(50) (24 h) ranging from 28 to 325 ppm.

Triterpenoid saponins from the roots of Silene cucubalus.

A new triterpenoid saponin was isolated from the roots of Silene cucubalus and its structure was determined on the basis of one- and two-dimensional NMR spectroscopy as gypsogenin 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside. A known saponin, quillaic acid 3-O-beta-xylopyranosyl-(1-->3)-[beta-galactopyranosyl-(1-->2)]-beta-glucuronopyranoside, was also isolated.

Preliminary screening of antiprotozoal activity of extracts from Cotula cinerea L.

Ethyl ether, ethyl acetate and n.butanol extracts of Cotula cinerea L. were tested for their antiprotozoal activity against two species of Trichomonas: Trichomonas intestinalis and Trichomonas vaginalis. It has been found that the growth of both Trichomonas was significantly inhibited.

Screening of antibacterial and antiparasitic activities of six Moroccan medicinal plants.

The extracts of six plants selected on the basis of folk-medicine reports were examined for their antibacterial effects against eight pathogenic bacteria. The results showed that n-butanol extract of Calotropis procera proved to be the most effective against the bacteria tested using the paper disc diffusion method. The antiprotozoal activity was also examined and showed that ethyl ether extract of Sium nodiflorum exhibits a parasiticidal effect against Trichomonas intestinalis and vaginalis.

Molluscicidal properties of glycoalkaloid extracts from Moroccan solanum species.

The glycoalkaloid extracts of seeds and leaves of Solanum sodomaeum and berries of Solanum elaeagnifolium were shown to have molluscicidal activity against Bulinus truncatus.

The antipyretic activity of some Moroccan medicinal plants.

The antipyretic activity of different extracts from Calotropis procera, Cotula cinerea and Zygophyllum gaetulum was investigated experimentally in rats. The antipyretic effect was retained in all extracts tested and was comparable to that of acetylsalicylic acid used as the standard drug.

Antibacterial activity of some Moroccan medicinal plants.

The extracts of 12 plants selected on the basis of the folk-medicine reports were examined for their antibacterial effects against eight pathogenic bacteria. The n-butanol extract of Calotropis procera flowers and the aqueous extract of Eugenia caryophyllata proved to be the most effective against the bacteria tested.