Mustapha Larhsini

Cytotoxic withanolides from the leaves of Moroccan Withania frutescens

Abstract Context: Withania species are a rich source of interesting phytochemical substances (withanolides) which have shown several biological properties. Objective: To investigate the cytotoxic potential of Withania frutescens (L.) Pauquy (Solanaceae) leaf extracts and isolated active compounds against cultured tumor cell lines. Materials and methods: The crude methanol extract of W. frutescens leaves was partitioned with dichloromethane, ethyl acetate and n-butanol. MeOH extract and its fractions were tested for their cytotoxic activity against cancer cell lines (HepG2 and HT29) using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Bioassay-guided fractionation was performed for the active CH2Cl2 fraction employing column chromatography and preparative high-performance liquid chromatography. Structural elucidation of the isolated active compounds was carried out mainly by 1D and 2D NMR and mass spectrometry. The compounds were then tested for their cytotoxic activity. Results: The CH2Cl2 fraction was the most active against HT29 cell line. The fractionation procedure resulted in the isolation of 4β,17α,27-trihydroxy-1-oxo-22-R-witha-2,5,24-trienolide (1), 5β,6β-epoxy-4β,17α,27-trihydroxy-1-oxowitha-2,24-dienolide (2) and 2,3-dihydroxywithaferin A-3β-O-sulfate (3). The latter exhibited the strongest cytotoxic activity against HT29 cancer cell lines (IC50 of 1.78 ± 0.09 µM) which was comparable to that of 5-fluorouracil (5-FU) used as the positive antimitotic control. Discussion and conclusion: Compounds 2 and 3 were isolated from W. frutescens for the first time. Data obtained suggest that the sulfated steroidal lactone (3) can be considered as a compound with potential application in the new anticancer drugs development field.

Chemical Composition, in vitro Antioxidant, Antimicrobial and Insecticidal Activities of Essential Oil from Cladanthus arabicus

Abstract The essential oil obtained from the aerial parts of Cladanthus arabicus (L.) Cass was studied for its chemical composition, antioxidant, antimicrobial and insecticidal activities. The essential oil (EO) was analyzed by GC-MS. Sixty seven compounds representing 94.2 % of the oil were identified. The major components of C. arabicus EO were sabinene (31.1 %), β-pinene (16.7 %), myrcene (12.3 %) and α-pinene (5.3 %). Moreover, the antioxidant and antimicrobial activities of the essential oil against six bacteria and four Candida strains were studied. The results showed the existence of a strong antioxidant activity with IC50 of 55.4 ± 0.12 μg/mL and 57.2 ± 0.21 μg/mL, respectively for DPPH and FRAP methods. The EO exhibited great antimicrobial activity especially against Micrococcus luteus (MIC = 0.187 mg/mL) and Candida albicans (MIC = 0.187 mg/mL). LD50 and LD90 values were 43.6 and 74.1 ppm against 1d-old larvae of Aedes aegypti, respectively.

Synergistic antimicrobial and antioxidant activity of saponins-rich extracts from Paronychia argentea and Spergularia marginata.

Aims: The crude saponins extracted from the aerial parts of Paronychia argentea and the roots of Spergularia marginata were tested for their antioxidant, antimicrobial and synergistic effects with antibiotics. Methodology: Antioxidant activity was evaluated using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical, β-carotene-linoleic acid and reducing power assays. However, the antibacterial activity was assessed by the agar disc diffusion method, whereas the MIC determination and the Original Research Article Malika Ait Sidi Brahim et al.; EJMP, 7(4): 193-204, 2015; Article no.EJMP.2015.082 194 synergistic interaction with antibiotics were evaluated using microdilution method. Results: Saponins-rich extract from Paronychia argentea showed a higher antioxidant activity than that from Spergularia marginata. Using DPPH assay, the IC50 values for saponins-rich extracts from P. argentea and S. marginata were 19.08 and 29.65 μg/ml, respectively. For β-carotene-linoleic acid assay, IC50 values were 98.24 and 614 μg/ml respectively for P. argentea and S. marginata. However, for reducing power assays, the IC50 values for saponins-rich extracts from P. argentea and S. marginata were respectively 27.22 and 61.44 μg/ml. The result of MIC assay showed that both saponins-rich extracts was found to be active against the majority of Candida strains and Gram-positive bacteria. However, crude saponins extracted from S. marginata was more active on microorganisms than that from P. argentea. In fact, the in vitro association of saponin extracts and some commercial antibiotics showed a synergistic effect. For bacteria strains, 30 combinations were studied, 17 (56.66%) combinations had total synergism, 7 (23.33%) had partial synergism, 4 (13.33%) had no effect and 2 (6.66%) had antagonism effect. For Candida strains, 8 combinations of saponins extracts and fluconazol are tested. All of these combinations (100%) exhibited a total synergism with FICi ranging from 0,31 to 0,50. Conclusion: The results founded suggested that further work should be performed on the isolation and identification of the antioxidative and antimicrobial components of these saponins-rich extracts.

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.

Antidiabetic potential of Caralluma europaea against alloxan-induced diabetes in mice

Medicinal plants play an important role in the management of diabetes mellitus especially in developing countries where resources are lacking. Herbal of natural origin, unlike the synthetic compounds, are more effective, safer and have less side effects. For continuing research on biological properties of Moroccan medicinal plants, the present work was undertaken to evaluate the potential and mechanism of the antidiabetic activity of the Caralluma europaea methanolic extract in alloxan-induced diabetic mice. A high-performance liquid chromatography technique (HPLC) was used to identify and quantify the major phenolic compounds in the methanolic extract. The in vitro antioxidant property was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging method, reducing power and ß-carotene-linoleic acid assays. The acute toxicity of the extract was evaluated by giving it orally to mice at single doses of 200, 500, 1000, 2000 mg/kg body weight. The antidiabetic effect was conducted on Swiss albino mice. Diabetes was induced with single intraperitonial injection of alloxan monohydrate (200 mg/kg body weight) and animals were treated with methanol extract at a dose of 250 mg/kg and 500 mg/kg body weight. The blood glucose levels were measured and histopathological analysis of pancreas was performed to evaluate alloxan-induced tissue injuries. The main phenols identified and quantified in the extract were ferulic acid, quercetine, 3,4 dihydroxybenzoic acid, rutin, epigallocatechin, and catechin. Ferulic acid was found to be the main phenolic compound ant its proportion was up to 52% of total phenolic compounds, followed by quercetin (36%). The result showed that methanol extract exhibited an antioxidant effect. Acute toxicity studies revealed that C. europaea extract was safe up 2000 mg/kg body weight and approximate LD50 is more than 2000 mg/kg. Moreover, the methanol extract prevented the diabetogenic effect of alloxan and decreased significantly the blood glucose level (P < 0.001) in treated mice. Morphometric study of pancreas revealed that C. europaea extract protected significantly the islets of Langerhans against alloxan-induced tissue alterations.