Nematicidal, larvicidal and antimicrobial activities of some new mannich base imidazole derivatives

Purpose: To synthesize Mannich base imidazole derivatives, and evaluate their antimicrobial, nematicidal and larvicidal properties .Methods: Compounds 1a-g and 2a-g were prepared using a Mannich condensation method. The chemical structures of compounds 2a-g were confirmed by Fourier transform infrared spectroscopy (IR), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and mass spectrometry (MS) and elemental analyses. Compounds 1a-f and 2a-f were screened for antimicrobial properties using an agar diffusion method. The nematicidal activity of the compounds was evaluated against juvenile Meloidogyne javanica as test organism while larvicidal activity was assessed against the urban mosquito, Culex. Quinquefasciatus, using a standard bioassay protocol.Results: Compounds 1b, 1g, 2e and 2g were highly active against a few bacterial organisms compared with the reference antibacterial, ciprofloxacin while the antifungal activity of compound 2d was high compared with the reference, clotrimazole. Compounds 1c, 1e, 1g, and 2e showed high toxicity levels of larvicidal activity based their half maximal lethal dose (LD50) values. Compounds 1d, 1e, 1f, 1g, 2d and 2e were highly toxic to nematodes.Conclusion: Compounds 1b, 1g, 2e and 2g may be useful as lead molecules for the development of new classes of larvicidal, nematicidal and antimicrobial agents

Synthesis and antimicrobial activity of some new pyrrole derivatives

New pyrrole derivatives were synthesized and structures were confirmed by IR, 1H NMR, 13C NMR, mass spectra, and elemental analyses data. The reaction was performed by using ordinary condensation type, which enabled to easy work-up and good yield. Synthesized compounds were screened for antimicrobial activity.KEY WORDS: Pyrrole, 1,3,4-oxadiazol-2-amine, 4H-1,2,4-triazol-3-ol, Cyclization, Antimicrobial activity, Structure activity relationship Bull. Chem. Soc. Ethiop. 2012, 26(3), 429-435.DOI: http://dx.doi.org/10.4314/bcse.v26i3.1

Micro-algal lethality potentials of marine organisms collected from the Indian littoral

Microalgal lethality bioassay was developed to detect the toxic profile of organic extract of marine organisms and their possible significance in the context of antifouling activities. Organic extracts of seaweeds, Ulva fasciata and Hypnea musciformis, sponges, Dendrilla nigra, Axinella donnai and Clathria gorgonoides and a holothurian Holothuria scabra were used for the detection of microalgal lethality potential. The microalgae such as Isochrysis galbana, Chlorella salina and Nanochloropsis sp. were used for the assay. The findings revealed that H. scabra contained toxic secondary metabolites, which might have the reason for its potent antifouling activity. Invariably all extracts inhibited the growth of microalgae at various concentrations except H. musciformis and A. donnani, which induce the growth of microalgae to certain extent. Based on the present findings, it could be inferred that the ‘microalgal lethality bioassay’ could be used as a primary screening assay system for the detection of biotoxic and antifouling agents from marine organisms

Antagonistic Potentials of Marine Sponge Associated Fungi Aspergillus clavatus MFD15

Abstract: The development of resistance to multiple drugs is a major problem in the treatment of these infectious diseases. Multidrug Resistant Staphylococcus aureus (MRSA) and Candida sp, the major infectious agents have been recently reported in quite a large number of studies. With more intensive studies for natural therapies, marine-derived products have been a promising source for the discovery of novel bioactive compounds. A total of 45 marine fungi were isolated from the two sponges F. cavernosa and D. nigra were screened for antimicrobial activity against pathogenic bacteria and fungi. The novel basal media formulated in the present study resulted in increased frequency of fungal isolates when compared to all other media used in the present study. The cell free supernatant of fungi exhibiting the broad spectrum of activity was subjected to chemical analysis using different chromatographic systems including TLC, Column and GC-MS. Of the 15 fungal strains, 20% (3 strains) showed potential antagonistic activity against a panel of clinical pathogens used in the present study. Based on the antimicrobial activity of the isolates, Aspergillus clavatus MFD15 was recorded as potent producer displaying 100% activity against the tested pathogenic organisms. The TLC of the crude ethyl acetate extract produced 3 spots with Rf values of 0.20, 0.79 and 0.95, respectively. The active TLC fraction was purified in column chromatography which yielded 50 fractions. The active column fractions were combined and analyzed with FT-IR, UV-Vis and GC-MS. The chemical analysis of the active compound envisaged the active compound to be a triazole, 1H-1,2,4 Triazole 3-carboxaldehyde 5-methyl. The triazolic compound was bacteriostic for S. aureus and bactericidal for E. coli. The triazole treated fabric showed 50% reduction in the growth of E. coli, S. aureus, and S. epidermidis. Thus the purified compound can find a place in the database for the development of fabrics with antimicrobial properties. This is the first report that envisaged the production of triazole antimicrobial compound from sponge associated marine fungi from the Indian coast

Bioactivity of the red algae Asparagopsis taxiformis collected from the Southwestern coast of India

Among the diverse variety of red algae, Asparagopsis taxiformis constitutes one of the abundant biomass in the Kollam coast (Southwest coast of India). Therefore, in the present study, A. taxiformis was collected, extracted and fractionated using column chromatography. The individual fractions were evaluated in vitro for their antifouling, anticyanobacterial, piscicidal and crustaceans toxicity assays. The fraction eluted with 2:8, petroleum ether and ethyl acetate exhibited strong and broad spectrum of bioactivity. In antifouling assay against Limnea truncatula, the active algal fraction produced 80% of foot repellency at 150 mg/L whereas in anticyanobacterial assay, the active fraction inhibited 100% growth of Trichodesmium sp. at 320 mg/L. The algal fraction showed higher piscicidal effect at the level of 60 mg/L. The crustacean toxicity of the active fraction was also evaluated to find compounds without toxicity in non target organisms, Penaeus monodon and Macrobrachium rosenbergii. It was found that column fraction showed less toxicity against the non target organisms. The chemical constituents of the active fraction were identified by means of chromatographic systems such as TLC, reverse phase HPLC and GC-MS. The overall activity profile envisages that the active column fraction of A. taxiformis might contain synergistic bioactive metabolites that could be utilized for the control of fouling organisms, algal bloom and herbivorous/predaceous fishes in aquaculture ponds

Biological activity of the red alga Laurencia brandenii

The marine red alga Laurencia brandenii collected from the southwest coast of India (Indian Ocean) was extracted and fractioned using column chromatography. The individual fractions were evaluated in vitro via antimicrobial activity against six species of Microbial Type Culture Collection and three species of clinical human pathogens, antipest activity on Sitophilus oryzae, maggoticidal activity against 2nd instar larvae of Sarcophaga sp. and termiticidal activity against Microtermes obesi. It was found that the fraction eluted using petroleum ether:chloroform (6:4) exhibited broader biological activities. The phyco-constituents of the active fraction were identified by gas chromatography- -mass spectrometry (GC-MS) analysis. The GC-MS profile of the active fraction revealed that the main constituent was octadecadienoic acid (49.75%) followed by n-hexadecanoic acid (14.24%), which might have a functional role in the biological activities. The overall activity profile envisages that these bioactive compounds from L. brandenii could be utilized as a renewable natural resource for the development of novel environmental-compatible formulations for the control of human pathogens, pests, termites and maggots

LAP2 Is Widely Overexpressed in Diverse Digestive Tract Cancers and Regulates Motility of Cancer Cells

BACKGROUND: Lamina-associated polypeptides 2 (LAP2) is a nuclear protein that connects the nuclear lamina with chromatin. Although its critical roles in genetic disorders and hematopoietic malignancies have been described, its expression and roles in digestive tract cancers have been poorly characterized. METHODS: To examine the expression of LAP2 in patient tissues, we performed immunohistochemistry and real-time PCR. To examine motility of cancer cells, we employed Boyden chamber, wound healing and Matrigel invasion assays. To reveal its roles in metastasis in vivo, we used a liver metastasis xenograft model. To investigate the underlying mechanism, a cDNA microarray was conducted. RESULTS: Immunohistochemistry in patient tissues showed widespread expression of LAP2 in diverse digestive tract cancers including stomach, pancreas, liver, and bile duct cancers. Real-time PCR confirmed that LAP2β is over-expressed in gastric cancer tissues. Knockdown of LAP2β did not affect proliferation of most digestive tract cancer cells except pancreatic cancer cells. However, knockdown of LAP2β decreased motility of all tested cancer cells. Moreover, overexpression of LAP2β increased motility of gastric and pancreatic cancer cells. In the liver metastasis xenograft model, LAP2β increased metastatic efficacy of gastric cancer cells and mortality in tested mice. cDNA microarrays showed the possibility that myristoylated alanine-rich C kinase substrate (MARCKS) and interleukin6 (IL6) may mediate LAP2β-regulated motility of cancer cells. CONCLUSIONS: From the above results, we conclude that LAP2 is widely overexpressed in diverse digestive tract cancers and LAP2β regulates motility of cancer cells and suggest that LAP2β may have utility for diagnostics and therapeutics in digestive tract cancers