Nineteen aromatic nitro compounds were isolated from the culture broth of an Artic sea ice bacterium. Four of these compounds are new and six compounds are reported from a natural source for the first time. The new natural products showed weak antimicrobial and cytotoxic activities. 2-Nitro-4-(2Ј-nitroethenyl)-phenol was the most potent antimicrobial and cytotoxic substance. Some of the compounds exhibit plant growth modulating activities. Based on its biochemical properties and the 16S rRNA gene sequence, the producing strain can be described as a distinct species within the genus Salegentibacter.

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Introduction: A high rate of infections with methicillin-resistant Staphylococcus aureus (MRSA) has been documented, in both hospital-(HA-MRSA) and community-acquired (CA-MRSA) diseases in Jordan. Erythromycin and clindamycin are considered treatments of choice. However, resistance to erythromycin with false susceptibility to clindamycin in vitro may lead to therapeutic failure. Hence, it is mandatory to study the prevalence of inducible resistance to macrolide-lincosamide-streptogramin B (iMLSB) antibiotics conferred by erm genes in those bacteria. Methodology: S. aureus isolates were identified morphologically and biochemically, and MRSA were appraised using standard procedures. Induction in resistance to MLSB antibiotics among MRSA isolates was detected phenotypically using the D-test, and the presence of erm genes was revealed by polymerase chain reaction (PCR). Results: Of 126 collected Staphylococcus isolates, 71 (56.3%) isolates were S. aureus, of which 55 (77.5%) were MRSA. A total of 43 (78.2%) MRSA-discordant isolates were resistant to erythromycin, of which 33 (76.7%) exhibited the iMLSB (D-test positive), 2 (4.7%) the MSB (Dtest negative), and 8 (18.6%) the constitutive resistant (cMLSB) phenotypes. Induction of clindamycin resistance was 1.6 times greater in CA-MRSA than in HA-MRSA. Furthermore, ermA and ermC were significantly prevalent in HA-MRSA and CA-MRSA, respectively. Conclusions: Continuous surveillance of the MLSB resistance is important and required before the prescription of clindamycin to treat MRSA infections.

Twenty-five aromatic nitro, dinitro and trinitro compounds were isolated in low yields of less than 1 mg l À1 from a Salegentibacter sp. strain T436 derived from Arctic pack ice. Their structures were elucidated by MS and NMR techniques. Seven of these compounds, namely, 2-hydroxy-3-(4¢-hydroxy-3¢-nitrophenyl)-propionic acid methyl ester (6), 2-chloro-3-(4¢-hydroxy-3¢-nitrophenyl)propionic acid methyl ester (7), 3-(4¢-hydroxy-3¢,5¢-dinitrophenyl)-propionic acid methyl ester (14), 4¢-hydroxy-3¢,5¢-dinitrophenylethylchloride (16), (4¢-hydroxy-3¢,5¢-dinitrophenyl)-2-chloropropionic acid methyl ester (17), N-acetyl-3¢,5¢-dinitrotyramine (18) and 2,6-dinitro-4-(2¢-nitroethenyl)phenol (19) are new, and five are reported in this study from a natural source for the first time.

The rapid development of nanotechnology and its applications in medicine has provided the perfect solution against a wide range of different microbes, especially antibiotic-resistant ones. In this study, a one-step approach was used in preparing silver nanoparticles (AgNPs) by mixing silver nitrate with hot Hypericum perforatum (St. John’s wort) aqueous extract under high stirring to prevent agglomeration. The formation of silver nanoparticles was monitored by continuous measurement of the surface plasma resonance spectra (UV-VIS). The effect of St. John’s wort aqueous extract on the formation of silver nanoparticles was evaluated and fully characterized by using different physicochemical techniques. The obtained silver nanoparticles were spherical, monodisperse, face-centered cubic (fcc) crystal structures, and the size ranges between 20 to 40 nm. They were covered with a capping layer of organic compounds considered as a nano dimension protective layer that prevents agglomeration and sedimentation. AgNPs revealed antibacterial activity against both tested Gram-positive and Gram-negative bacterial strains causing the formation of 13–32 mm inhibition zones with MIC 6.25–12.5 µg/mL; Escherichia coli strains were resistant to tested AgNPs. The specific growth rate of S. aureus was significantly reduced due to tested AgNPs at concentrations ≥½ MIC. AgNPs did not affect wound migration in fibroblast cell lines compared to control. Our results highlighted the potential use of AgNPs capped with plant extracts in the pharmaceutical and food industries to control bacterial pathogens’ growth; however, further studies are required to confirm their wound healing capability and their health impact must be critically evaluated.

Context: Elettaria cardamomum (L.) Maton grains and Cinnamomum verum J. Presl barks are immensely consumed by Jordanian population as food flavoring and remedies in treating different disorders without awareness of their effect or dose toxicity. Aims: To evaluate the antibacterial, antioxidant and cytotoxic effects of essential oils (EOs) hydro-distilled from E. cardamomum grains and C. verum barks. Methods: Hydro-distillation was carried out using Clevenger apparatus; the EOs were analyzed using GC/MS, and their constituents were quantified using GC/FID. The antibacterial activity was determined by agar diffusion test and micro-broth dilution assay, while the antioxidant activity was evaluated by DPPH and ABTS scavenging assays. The cytotoxic activity was evaluated against the MDA-MB-231 breast cancer cell line. Results: E. cardamomum EO was most effective against Bacillus subtilis with MIC 3.75 µL/mL and exhibited antioxidant activity in DPPH assay with IC50 0.057 ±0.013 µL/mL (0.076 ±0.017 µL EO/µg Trolox®) but was ineffective in the ABTS test up to 5 µL/mL; 86.22% of its EO constituent are oxygenated monoterpenes with α-terpinyl acetate as the major component. Whilst C. verum EO was active against both tested Gram-positive and negative bacterial strains with MIC 1.25-5.00 µL/mL but was devoid of significant antioxidant activity up to 5 µL/mL; phenylpropanoids constituted 69.48% of its EO with E-cinnamaldehyde as the major component. Both EOs showed cytotoxic activity against the breast cancer cell line withIC50 0.14-0.46 µL/mL. Conclusions: The current results unveil the potential application of C. verum and E. cardamomum in complementary and alternative medicine as biosafe remedies besides their usage as flavoring and seasoning sources.

Soil is considered as a promising environment for discovering and isolating bacterial strains that are able to produce novel natural products. Therefore, a Gram positive Bacillus sp. 7B1 was isolated from a soil sample collected from south Al-Karak, Jordan. The bacterial isolate was cultivated, identified and its culture medium was extracted. The crude extract was purified using silica gel column chromatography. The antibacterial activity of the crude extract and the purified fractions was evaluated by agar diffusion test as well as by measuring the minimum inhibitory concentration in microbroth dilution assay. The produced crude extract was active only against the tested Gram positive bacteria, namely Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus. Bioactivity-guided fractionations of the resulted crude extract led to the purification of compound (C 2). In the present work, Micrococcus luteus was the most susceptible bacterial test strain to compound (C 2) with a minimum inhibitory concentration of 25 µg/ml. Our findings highlighted the importance of soil bacterial isolates for production of compounds with interesting bioactivities that may contribute to the drug research field.

The structures of secondary metabolites with antibacterial and cytotoxic activities produced by a marine Vibrio strain from the Red Sea were elucidated. Aqabamycin A (1a) and seven further nitro-substituted maleimide derivates named aqabamycins B-G (1b-f and 2) were obtained together with 12 known metabolites, 3-nitro-1H-indazole (3), indazole-3-carbaldehyde (4), 3-nitro-4-hydroxycinnamic acid, 4-hydroxycinnamic acid, 3-nitro-4-hydroxybenzaldehyde, phenyl-2-bis-indolylmethane (5a), turbomycin B (5b), vibrindole A (6), phenylacetic acid, 3-hydroxybenzoic acid, benzoic acid and 1,4-dithiane (7). Some of the known metabolites (for example, 3, 4 and 7) are described in this study for the first time as natural products. Their structures were elucidated based on 1D and 2D NMR, MS spectra and by comparison with synthetic material.