Epidemiology and Characteristics of Elizabethkingia spp. Infections in Southeast Asia.

Elizabethkingia spp. is a ubiquitous pathogenic bacterium that has been identified as the causal agent for a variety of conditions such as meningitis, pneumonia, necrotizing fasciitis, endophthalmitis, and sepsis and is emerging as a global threat including in Southeast Asia. Elizabethkingia infections tend to be associated with high mortality rates (18.2-41%) and are mostly observed in neonates and immunocompromised patients. Difficulties in precisely identifying Elizabethkingia at the species level by traditional methods have hampered our understanding of this genus in human infections. In Southeast Asian countries, hospital outbreaks have usually been ascribed to E. meningoseptica, whereas in Singapore, E. anophelis was reported as the main Elizabethkingia spp. associated with hospital settings. Misidentification of Elizabethkingia spp. could, however, underestimate the number of cases attributed to the bacterium, as precise identification requires tools such as MALDI-TOF MS, and particularly whole-genome sequencing, which are not available in most hospital laboratories. Elizabethkingia spp. has an unusual antibiotic resistance pattern for a Gram-negative bacterium with a limited number of horizontal gene transfers, which suggests an intrinsic origin for its multidrug resistance. Efforts to prevent and further understand Elizabethkingia spp. infections and limit its spread must rise to this new challenge.

Phytochemical constituents, antioxidant and antibacterial activities of methanolic extract of Ardisia elliptica

Objective: To investigate the antioxidant, antibacterial, and chemical ingredients of Ardisia elliptica (A. elliptica) methanolic extracts. Methods: The plant was extracted using methanol. Antibacterial and antioxidant activ-ities were evaluated. Results: The results showed that both fruit and leaf extract of A. elliptica have significant antibacterial activities against Gram-positive and Gram-negative bacteria. Fruit extracts showed higher content of phenolic (71 ± 0.03 GAE/mg extract dry weight), in com-parison to the leaf extracts (37 ± 0.05 GAE/mg extract dry weight). Flavonoid content, and Fe2+chelating activity of fruit extracts were higher than leaf extract. The percentage radical inhibition of fruit extract is found to be higher (70%) than that of leaf extract (60%). LCMS results indicated that the major compounds in the fruit extract were Gingerol, Aspidin, Kampherol, and Stercuresin, while the leaf extract contained Gingerol, Aspidin, Triangularin, and Salicyl acyl glucuronide. Furthermore, the results of GCMS indicated that fruit extract contained these major compounds:Vitamin E Tocopherol, 5-hepylresornicol, 2-Nonylmalonic acid, 5-pentadecylresornicol, and Stigmasta-7-22-dien-3-ol. However, leaf extract of A. elliptica contained these major compounds: Alpha Amyrenol, 4,4, 6, 6a, 6b, 8, 8a, 9,10, 11,12,12a, 14, 14a, 14b octadehydro-2H-picen-3-one, and Lonasterol, 4-t-Butyl-2-[4-nitrophenyl] phenol. Conclusions: The results provide evidence that fruit and leaf of A. elliptica extracts might indeed be used as a potential source of effective natural antimicrobial and anti-oxidant agents in pharmaceutical and food industries.

A New Bioactive Secondary Metabolite from Artocarpus elasticus.

Detailed phytochemical investigation has been carried out on the bark of Artocarpus elasticus Reinw. ex Blume, which led to the isolation of artonin E (1), a new dihydrobenzoxanthone derivative named elastixanthone (2), cycloartobiloxanthone (3) and artobiloxanthone (4). Structures of these compounds were elucidated on the basis of various spectroscopic (UV, IR, ID-NMR and 2D-NMR) and MS data. Compounds 1-3 displayed outstanding scavenging activity for 1,1-diphenylpicrylhydrazyl (DPPH) with IC5o values of 11.5, 21.6 and 40.0 µg/mL, respectively. In addition, compounds 1-3 displayed broad spectrum antimicrobial activities against thirteen different bacterial strains when tested using the disc diffusion assay. Cytotoxic screening revealed that artonin E (1). constantly exhibited strong cytotoxic activity against human estrogen receptor (ER+) positive breast cancer (MCF-7) and human estrogen receptor (ER-) negative (MDA-MB 231) cells in comparison with the other two, with IC50 values of 2.6 and 13.5 µg/mL, respectively, without being toxic towards the WRL68 (human normal liver) cell line (IC50 value more than 30 [µg/mL). However, the compound was inactive against HepG2 (human liver carcinoma) cancer cells.

Ultrastructural Study on the Antibacterial Activity of Artonin E versus Streptomycin against Staphylococcus aureus Strains.

Staphylococci are facultative anaerobes, perfectly spherical un-encapsulated cocci, with a diameter not exceeding 1 micrometer in diameter. Staphylococcus aureus are generally harmless and remain confined to the skin unless they burrow deep into the body, causing life-threatening infections in bones, joints, bloodstream, heart valves and lungs. Among the 20 medically important staphylococci species, Staphylococcus aureus is one of the emerging human pathogens. Streptomycin had its highest potency against Staphylococcus infections despite the likelihood of getting a resistant type of staphylococcus strains. Methicillin-resistant S. aureus (MRSA) is the persister type of Staphylococcus aureus and was evolved after decades of antibiotic misuse. Inadequate penetration of the antibiotic is one of the principal factors related to success/failure of the therapy. The active drug needs to reach the bacteria at concentrations necessary to kill or suppress the pathogen's growth. In turn the effectiveness of the treatment relied on the physical properties of Staphylococcus aureus. Thus understanding the cell integrity, shape and roughness is crucial to the overall influence of the therapeutic agent on S. aureus of different origins. Hence our experiments were designed to clarify ultrastructural changes of S. aureus treated with streptomycin (synthetic compound) in comparison to artonin E (natural compound). In addition to the standard in vitro microbial techniques, we used transmission electron microscopy to study the disrupted cell architecture under antibacterial regimen and we correlate this with scanning electron microscopy (SEM) to compare results of both techniques.

Aporphine alkaloids from the leaves of Phoebe grandis (Nees) Mer. (Lauraceae) and their cytotoxic and antibacterial activities.

The oxoaporphine alkaloid lysicamine (1), and three proaporphine alkaloids, litsericinone (2), 8,9,11,12-tetrahydromecambrine (3) and hexahydromecambrine A (4) were isolated from the leaves of Phoebe grandis (Nees) Merr. (Lauraceae). Compounds 2 and 3 were first time isolated as new naturally occurring compounds from plants. The NMR data for the compounds 2-4 have never been reported so far. Compounds 1 and 2 showed significant cytotoxic activity against a MCF7 (human estrogen receptor (ER+) positive breast cancer) cell line with IC50 values of 26 and 60 µg/mL, respectively. Furthermore, in vitro cytotoxic activity against HepG2 (human liver cancer) cell line was evaluated for compounds 1-4 with IC50 values of 27, 14, 81 and 20 µg/mL, respectively. Lysicamine (1) displayed strong antibacterial activity against Bacillus subtilis (B145), Staphylococcus aureus (S1434) and Staphylococus epidermidis (a clinically isolated strain) with inhibition zones of 15.50 ± 0.57, 13.33 ± 0.57 and 12.00 ± 0.00 mm, respectively. However, none of the tested pathogenic bacteria were susceptible towards compounds 2 and 3.

Involvement of NF-κB and Bcl2/Bax signaling pathways in the apoptosis of MCF7 cells induced by a xanthone compound Pyranocycloartobiloxanthone A.

The plant Artocarpus obtusus is a tropical plant that belongs to the family Moraceae. In the present study a xanthone compound Pyranocycloartobiloxanthone A (PA) was isolated from this plant and the apoptosis mechanism was investigated. PA induced cytotoxicity was observed using MTT assay. High content screening (HCS) was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and cytochrome c release. Reactive oxygen species formation was investigated on treated cells by using fluorescent analysis. Human apoptosis proteome profiler assays were performed to investigate the mechanism of cell death. In addition mRNA levels of Bax and Bcl2 were also checked using RT-PCR. Caspase 3/7, 8 and 9 were measured for their induction while treatment. The involvement of NF-κB was analyzed using HCS assay. The results showed that PA possesses the characteristics of selectively inducing cell death of tumor cells as no inhibition was observed in non-tumorigenic cells even at 30 µg/ml. Treatment of MCF7 cells with PA induced apoptosis with cell death-transducing signals, that regulate the MMP by down-regulation of Bcl2 and up-regulation of Bax, triggering the cytochrome c release from mitochondria to cytosol. The release of cytochrome c triggered the activation of caspases-9, then activates downstream executioner caspase-3/7 and consequently cleaved specific substrates leading to apoptotic changes. This form of apoptosis was found closely associated with the extrinsic pathway caspase (caspase-8) and inhibition of translocation of NF-κB from cytoplasm to nucleus. The results demonstrated that PA induced apoptosis of MCF7 cells through NF-κB and Bcl2/Bax signaling pathways with the involvement of caspases.