New luffariellolide derivatives from the Indonesian sponge Acanthodendrilla sp

Investigation of the Indonesian sponge Acanthodendrilla sp. afforded five new luffariellolide-related sesterterpenes, acantholides A-E (1-5), in addition to luffariellolide and its 25-O-methyl and 25-O-ethyl derivatives. All structures were unambiguously established by 1D and 2D NMR and MS spectroscopy. Acantholide D and E are derivatives comprising the 1-acetylcyclopentan-5-ol moiety, which are new variants of the C(14)-C(20) segment for this type of linear sesterterpenes. Luffariellolide and its 25-O-methyl congener as well as acantholide E (5) were cytotoxic against the mouse lymphoma L5187Y cell line. Acantholide B (2), luffariellolide, and its 25-O-methyl congener were active against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, the Gram-negative bacterium Escherichia coli, the yeast Candida albicans, and the plant pathogenic fungus Cladosporium herbarum.     

Perfusion culture enhanced human endometrial stromal cell growth in alginate-multivalent integrin α5β1 ligand scaffolds

A method to functionalize alginate by introducing monomeric or self-assembling (tetrameric) fibronectin (FN) domains is described, leading to a functional scaffold, which is used for three dimensional (3D) culture of human endometrial stromal cells (EnSCs). EnSCs encapsulated in the functional alginate were cultured under perfusion using the TissueFlex? platform, a multiple parallel microbioreactor system for 3D cell culture. The effect of the novel scaffold and the effect of perfusion were examined. Cell viability, proliferation, and extracellular matrix (ECM) deposition were determined and the results compared with those obtained with cells encapsulated in non-functionalized alginate, and also those without perfusion. Staining for focal adhesions and actin showed maximal cell adhesion only for alginate-tetrameric FN scaffolds under perfusion, associated with a significant increase in cell number over 7 days culture; in contrast to poor cell adhesion and a decrease in cell number for non-functionalized alginate scaffolds (irrespective of perfused/static culture) and 3D static culture (irrespective of the scaffold). Conjugation of alginate to FN was an absolute requirement to attenuate the loss of cell metabolic activity over 7 days culture. ECM deposition for blank alginate and alginate-monomeric FN was similar, but increased around 2-fold and 3-fold for alginate-tetrameric FN under static and perfusion culture, respectively. It is concluded that the requirement for EnSC engagement with multivalent integrin α5β1 ligands and perfused culture are both essential as a first step toward endometrial tissue engineering.     

Biologically active natural products from Mongolian medicinal plants Scorzonera divaricata and Scorzonera pseudodivaricata

Chromatographic separation of a crude extract obtained from the aerial parts of the Mongolian medicinal plant Scorzonera divaricata yielded the two new quinic acid derivatives feruloylpodospermic acids A and B. Both compounds feature a feruloyl group and two dihydrocaffeoyl substituents. For feruloylpodospermic acid A, the dihydrocaffeic acid substituents were found esterified at positions 1 and 5 of the quinic acid moiety, while the feruloyl group was attached at position 3. For feruloylpodospermic acid B, the substituents were linked at positions 1, 3, and 4. The aerial parts of S. pseudodivaricata that are likewise used in Mongolian traditional medicine yielded two further new natural products, for which the names scorzoneric acid and scorzonerin are proposed. Scorzoneric acid is an unusual phenolic compound featuring a central tetrasubstituted phenyl ring to which a glucose unit is bound, which in turn is substituted by an esterified acyl side chain. Further substituents of the central phenyl ring system include a butan-2-one group, which is linked to a second para-substituted phenyl ring system. Scorzonerin is a matricarin-based sesquiterpene lactone that carries an esterified dihydrocoumaric acid moiety, which in turn is glycosidically bound to glucose. The structures of all new compounds were unambiguously established from NMR (1H, 13C, COSY, HMBC) spectroscopic and mass spectrometric data. The new quinic acid derivatives feruloylpodospermic acids A and B exhibited strong antioxidative activity when analyzed in the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay.     

Kahalalide derivatives from the Indian sacoglossan mollusk Elysia grandifolia

Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known congeners, kahalalides F (3) and D (4), were isolated from the Indian sacoglossan mollusk Elysia grandifolia. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, HMBC) and mass spectrometric (FABMS, ESIMS, MALDI-TOF/PSD) data, which also included Marfey amino acid analyses. The new derivative kahalalide R was found to exert comparable or even higher cytotoxicity than the potential drug candidate kahalalide F toward the MCF7 human mammary carcinoma cell line.     

Eudistomins W and X,two new beta-carbolines from the micronesian tunicate Eudistoma sp

Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin congeners, which were designated eudistomins W (1) and X (2). The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ((1)H, (13)C, COSY, (1)H detected direct, and long-range (13)C-(1)H correlations) and mass spectrometric (EI and ESIMS) data. Compound 2 exhibited antibiotic activity toward Bacillus subtilis, Staphyloccocus aureus, and Escherichia coli and was also found to be fungicidal against Candida albicans in an agar diffusion assay. Compound 1 was selectively active against C. albicans but showed no antibacterial activity.     

Enhanced gene expression in tumors after intravenous administration of arginine-, lysine- and leucine-bearing polyethylenimine polyplex

The potential of gene therapy to treat cancer is currently limited by the low expression of therapeutic genes in the tumors. Because amino acids are known to have excellent properties in cell penetration and gene expression regulation, we investigated if the conjugation of arginine (Arg), lysine (Lys) and leucine (Leu) onto the surface of the gene delivery system polyethylenimine (PEI) could lead to an improved gene expression in tumors. The intravenous administration of Arg-, Lys- and Leu-bearing PEI polyplexes led to a significant increase of gene expression in the tumor, with a β-galactosidase expression amount at least threefold higher than that obtained after treatment with unmodified PEI polyplex. The three amino acid-bearing PEI polyplexes led to similar levels of gene expression in the tumor. The treatments were well tolerated by the mice. Arg-, Lys- and Leu-bearing PEI polyplexes are therefore highly promising gene delivery systems for cancer therapy.

From the Clinical Editor

In this paper, amino-acid based modulations of gene delivery enhancement are reported. Intravenous administration of Arg-, Lys- and Leu-bearing polyethylenimine polyplexes led to a significant increase of gene expression in the studied tumor model, which may enable the development of more efficient gene delivery strategies for future clinical applications.     

Metabolomics of the Bio-Degradation Process of Aflatoxin B1 by Actinomycetes at an Initial pH of 6.0

Contamination of food and feed by Aflatoxin B1 (AFB1) is a cause of serious economic and health problems. Different processes have been used to degrade AFB1. In this study, biological degradation of AFB1 was carried out using three Actinomycete species, Rhodococcus erythropolis ATCC 4277, Streptomyces lividans TK 24, and S. aureofaciens ATCC 10762, in liquid cultures. Biodegradation of AFB1 was optimised under a range of temperatures from 25 to 40 °C and pH values of 4.0 to 8.0. An initial concentration of 20 µg/mL of AFB1 was used in this study. The amount of AFB1 remaining was measured against time by thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC), coupled with UV and mass spectrometry (LC-MS). All species were able to degrade the AFB1, and no significant difference was found between them. AFB1 remained in the liquid culture for R. erythropolis, S. lividans and S. aureofaciens were 0.81 µg/mL, 2.41 µg/mL and 2.78 µg/mL respectively, at the end of the first 24 h. Degradation occurred at all incubation temperatures and the pH with the optimal conditions for R. erythropolis was achieved at 30 °C and pH 6, whereas for S. lividans and S. aureofaciens the optimum conditions for degradation were 30 °C and pH 5. Analysis of the degradative route indicated that each microorganism has a different way of degrading AFB1. The metabolites produced by R. erythropolis were significantly different from the other two microorganisms. Products of degradation were identified through metabolomic studies by utilizing high-resolution mass spectral data. Mass spectrometric analysis indicated that the degradation of AFB1 was associated with the appearance of a range of lower molecular weight compounds. The pathway of degradation or chemical alteration of AFB1 was followed by means of high resolution Fourier transform mass spectrometry (HR-FTMS) analysis as well as through the MS² fragmentation to unravel the degradative pathway for AFB1. AFB1 bio-degradation was coupled with the accumulation of intermediates of fatty acid metabolism and glycolysis. A plausible mechanism of degradation of AFB1 by Rhodococcus was hypothesized.     

Cytotoxic metabolites from the fungal endophyte Alternaria sp. and their subsequent detection in its host plant Polygonum senegalense

From the Egyptian medicinal plant Polygonum senegalense the fungal endophyte Alternaria sp. was isolated. Extracts of the fungus grown either in liquid culture or on solid rice media exhibited cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation of the extracts yielded 15 natural products, out of which seven were new compounds, with both fungal extracts differing considerably with regard to their secondary metabolites. Compounds 1, 2, 3, 6, and 7 showed cytotoxic activity with EC 50 values ranging from 1.7 to 7.8 microg/mL. When analyzed in vitro for their inhibitory potential against 24 different protein kinases, compounds 1- 3, 5- 8, and 15 inhibited several of these enzymes (IC 50 values 0.22-9.8 microg/mL). Interestingly, compounds 1, 3, and 6 were also identified as constituents of an extract derived from healthy leaves of the host plant P. senegalense, thereby indicating that the production of natural products by the endophyte proceeds also under in situ conditions within the plant host.     

The leaves of Ficus exasperata Vahl (Moraceae) generates uterine active chemical constituents

Ethnopharmacological Relevance

In the search for new, safe and efficacious uterine active agents, the plant Ficus exasperata was subjected to phytochemical screening and pharmacological analysis.

Materials and methods

Ethyl acetate and methanolic leaf extracts of Ficus exasperata were fractionated and purified by a series of chromatographic techniques. The isolation process was guided by in vitro functional uterine assays involving the use of C57Bl/6 female mice. Identification of the active chemical constituents was performed by several spectroscopic techniques which included 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). The uterine effects of these compounds were investigated on spontaneous, oxytocin-induced and high KCl-induced contractions using isolated uterine segments of non-pregnant female mice. The activity of different compounds on the amplitude (maximum tension above basal force) and frequency of uterine contractions were simultaneously measured and then statistically analysed. The structure–activity relationships were also examined where possible.

Results

These studies led to the identification of some new phytochemical derivatives. Pharmacological assay revealed the presence of both uterine stimulatory and inhibitory constituents. The new pheophytin/pheophorbide derivatives, flavonoids, fatty acids and glycerol derivatives significantly reduced the frequency and amplitude of uterine contraction, while KCl salt, pyrimidine and pheophorbide-b derivatives significantly augmented both spontaneous and agonist-induced contractions.

Conclusion

This study has demonstrated that Ficus exasperata generates secondary metabolites which have proven effective in the significant inhibition of uterine contractions and thus a potential source of new tocolytic agents. Additionally, uterine stimulatory constituents were also generated some of which may be potential drugs for contraception and/or labour facilitation. Lead compounds generated from this study are the pheophytin/pheophorbide derivatives, pyrimidine derivatives and flavonoid derivatives.     

Enhanced gene expression in tumors after intravenous administration of arginine-, lysine- and leucine-bearing polypropylenimine polyplex

The possibility of using non-viral gene delivery systems for the treatment of cancer is currently limited by their lower transfection efficacy compared to viral systems. On the basis that amino acids such as arginine, lysine and leucine were involved in enhancing DNA transportation into cells, we hypothesized that the grafting of these amino acids to the highly promising generation 3 diaminobutyric polypropylenimine (DAB) dendrimer would improve its transfection efficacy in cancer cells. In this work we demonstrated that the conjugation of arginine, lysine and leucine to the dendrimer led to an enhanced anti-proliferative activity of the polyplexes, by up to 47-fold for DAB-Lys in T98G cancer cells compared to the unmodified polyplex in vitro. In vivo, the intravenous administration of amino acid-bearing DAB polyplexes resulted in a significantly improved tumor gene expression, with the highest gene expression level observed after treatment with DAB-Lys polyplex. Arginine, lysine and leucine-bearing generation 3 polypropylenimine polymers are therefore highly promising gene delivery systems for gene transfection in tumors.