Polyphenols contents, heavy metals analysis and in vitro antibacterial activity of extracts from Cladanthus arabicus and Bubonium imbricatum of Moroccan Origin.

Aim of this study was to evaluate polyphenols and major and trace elements of Cladanthus arabicus and Bubonium imbricatum, along with their in vitro antibacterial activity against six multidrug resistant Enterobacteriaceae (Escherichia coli S33/16, E. coli S34/16, Proteus mirabilis S32/16, Klebsiella pneumoniae S12/16, Enterobacter cloacae S5/16, and Salmonella sp S12/14). UV spectrophotometry, ultra-high-performance liquid chromatography coupled to mass spectrometry and inductively coupled plasma mass spectrometry were used to evaluate total polyphenol content, quali-quantitative profile of single polyphenols and inorganic elements of the extract. The antibacterial activity was investigated by standard methods. Twelve polyphenols were identified in both plants and these were more concentrated in B. imbricatum than C. arabicus extracts. High levels of minerals, essential trace elements and tolerable levels of heavy metals (Cd, As and Pb) were found. Furthermore, the extracts showed also a strong in vitro antibacterial activity, particularly versus E. coli S33/16 (MIC, 0.125 mg ml-1).

Chemical Composition, Antioxidant, Antimicrobial and Insecticidal Activities of Essential Oil from a Moroccan Endemic Plant: Bubonium imbricatum.

The chemical composition, antioxidant, antimicrobial and insecticidal properties of essential oil obtained by hydro-distillation from Bubonium imbricatum Cav. have been investigated. The essential oil of aerial parts was analyzed by GC-FID and GC-MS. A total of 63 compounds were identified representing more than 82% of the oil. The major components were cis-chrysanthenyl acetate (31.2%) and thymol isobutyrate (3.4%). The antioxidant activity was evaluated by the DPPH and reducing power test. The data showed moderate activity compared with the reference compounds. Our results showed strong activity of the investigated oil against all tested microorganisms. The highest antibacterial activity was observed against Bacillus subtilis (inhibition zone= 18 ± 0.21, MIC= 0.18 mg/mL). In general, Gram-positive bacteria were more susceptible than Gram-negative ones. Candida parapsilosis was the most sensitive among the Candida strains tested. LD50 and LD90 values were 33.1 and 53.1 ppm against 1-d-old larvae of Aedes aegypti L.