Synthesis and QSAR study of novel α-methylene-γ-butyrolactone derivatives as antifungal agents

Thirty-six new α-benzylidene-γ-lactone compounds based α-methylene-γ-butyrolactone substructure were prepared and characterized by spectroscopic analysis. All compounds were evaluated for antifungal activities in vitro against six plant pathogenic fungi and the half maximal inhibitory concentration (IC₅₀) against Botrytis cinerea and Colletotrichum lagenarium were investigated. Compounds 5c-3 and 5c-5 with the halogen atom exhibited excellent fungicidal activity against B. cinerea (IC₅₀ = 22.91, 18.89 μM). The structure-activity relationships (SARs) analysis indicated that the derivatives with electron-withdrawing substituents at the meta- or para-positions improves the activity. Via the heuristic method, the generated quantitative structure-activity relationship (QSAR) model (R² = 0.961) revealed a strong correlation of antifungal activity against B. cinerea with molecular structures of these compounds. Meanwhile, the cytotoxicity of 20 representative derivatives was tested in the human tumor cells line (HepG2) and the hepatic L02 cells line, the result indicated that the synthesized compounds showed significant inhibitory activity and limited selectivity. Compound 5c-5 has the highest fungicidal activity with IC₅₀ = 18.89 μM (against B. cinerea.) but low cytotoxicity with IC₅₀ = 35.4 μM (against HepG2 cell line) and IC₅₀ = 68.8 μM (against Hepatic L02 cell line). These encouraging results can be providing an alternative, promising use of α-benzylidene-γ-lactone through the design and exploration of eco-friendly fungicides with low toxicity and high efficiency.     

New antifungal scaffold derived from a natural pharmacophore: Synthesis of α-methylene-γ-butyrolactone derivatives and their antifungal activity against Colletotrichum lagenarium

Thirty new and thirty-four known analogues were designed and synthesized to improve the potential use of the α-methylene-γ-butyrolactone ring, a natural pharmacophore. All structures were confirmed by ¹H and ¹³C NMR, MS, and single-crystal X-ray diffraction analyses. The results of antifungal and cytotoxic activity indicated that the synthesized analogues showed significant inhibitory activity and limited selectivity. Compound 45 exhibited the highest antifungal activity with IC₅₀ = 22.8 μM but moderate cytotoxic activity with IC₅₀ = 28.5 μM (against BGC823 cell line) and 7.7 μM (against HeLa cell line). Analysis of structure–activity relationships revealed that the incorporation of an aromatic ring into the β, γ positions of the lactone ring improved antifungal activity, and that the introduction of electron-withdrawing groups into the aromatic rings increased the activity compared with electron-donating groups. The above results identified 4-phenyl-3-phenyl-2-methylenebutyrolactone (33) as a lead scaffold for discovering and developing novel and improved crop-protection agents.     

Free radical copolymerization kinetics of γ-methyl-α-methylene-γ-butyrolactone (MeMBL)

The propagation kinetics and copolymerization behavior of the biorenewable monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL) are studied using the pulsed laser polymerization (PLP)/size exclusion chromatography (SEC) technique. The propagation rate coefficient for MeMBL is 15% higher than that of its structural analogue, methyl methacrylate (MMA), with a similar activation energy of 21.8 kJ·mol(-1). When compared to MMA, MeMBL is preferentially incorporated into copolymers when reacted with styrene (ST), MMA, and n-butyl acrylate (BA); the monomer reactivity ratios fit from bulk MeMBL/ST, MeMBL/MMA, and MeMBL/BA copolymerizations are r(MeMBL) = 0.80 ± 0.04 and r(ST) = 0.34 ± 0.04, r(MeMBL) = 3.0 ± 0.3 and r(MMA) = 0.33 ± 0.01, and r(MeMBL) = 7.0 ± 2.0 and r(BA) = 0.16 ± 0.03, respectively. In all cases, no significant variation with temperature was found between 50 and 90 °C. The implicit penultimate unit effect (IPUE) model was found to adequately fit the composition-averaged copolymerization propagation rate coefficient, k(p,cop), for the three systems.     

The microbiological activity of α-keto-β,β-dimethyl-γ-butyrolactone

α-Keto-β,β-dimethyl-γ-butyrolactone is as active as pantoic acid in promoting growth of E. coli M-99-3, and is approximately three times as active as pantoic acid in promoting growth of E. coli M-99-4 and in reversing salicylate inhibition of E. coli; it is inactive in promoting growth of E. coli M-99-1 and only about 3% as effective as pantoic acid in promoting the growth of Acetobacter suboxydans.     

Internally elongated rodent α-crystallin A chain: Resulting from incomplete RNA splicing?

αA^Ins, an elongated α-crystallin A chain previously observed in rat, was present beside the normal αA chain in mouse, gerbil and hamster, which places its origin at least 30 million years ago. Like in rat the sequences of golden hamster αA^Ins and αA were found to be identical, apart from the internal insertion of 22 residues in αA^Ins. The hamster chains only differed from the rat chains by a single substitution in the inserted sequence of αA^Ins. The origin of αA^Ins, by insertion of 22 residues in an otherwise unchanged αA chain, and its rigid evolutionary conservation are most easily explained by assuming the incomplete removal of a putative intervening sequence from the precursor mRNA of αA, leaving an intracistronic insert of 66 nucleotides in part of the eventually translated mRNA.     

Frequency of human Aγ75Thr globin chain in a population from Tunisia

Summary Cord blood samples, collected at Sousse and Monastir, from Tunisian newborns were focused on a thin layer of agarose in order to detect the carriers of the ^A75Thr chain (^A chain bearing a replacement IleThr at position 75). Nineteen individuals (10%) were positive for this variant. The frequency of the ^A75Thr gene in the Tunisian population (0.050) is compared with that of various ethnic populations.This work was supported in part by the Faculté de Pharmacie et de Médecine Dentaire of Monastir and by a grant from the Ambassade de France in Tunisia     

Synthesis of Optically Active β-Amino-γ-butyrolactone Derivatives from Aspartic Acid

(3S, 4R)-3-Methoxycarbonylamino-4-phenyl-4-butanolide (4a) was prepared from l-aspartic acid by stereoselective reduction of ethyl (*S)-3-methoxycarbonylamino-4-oxo-4-phenylbutyrate (3a).     

Tailored α-methylene-γ-butyrolactones and their effects on growth suppression in pancreatic carcinoma cells

A selected series of racemic α-methylene-γ-butyrolactones (AMGBL) were synthesized via allylboration and screened against three human pancreatic cancer cell lines (Panc-1, MIA PaCa-2, and BxPC-3). This systematic study established a discernible relationship between the substitution pattern of AMGBL and their anti-proliferative activity. β,γ-diaryl-AMGBLs, particularly those with a trans-relationship exhibited higher potency than parthenolide and LC-1 against all three cell lines.     

A galactomannan-hydrolysing α-galactosidase from jack fruit (Artocarpus integrifolia) seed: Affinity chromatographic purification and properties

An acid α-galactosidase from the seeds of the jack fruit seed (Artocarpus integrifolia) has been purified to homogeneity by affinity chromatography on a matrix formed by cross-linking the soluble α-galactose-bearing guar seed galactomannan. The 35kDa enzyme was a homotetramer of 9.5kDa subunits. Its carbohydrate part (5.5%) was composed of galactose and arabinose. TheK _m withp-nitrophenyl α-D-galactoside as substrate was 0.35 mM. TheK _i values indicated inhibition by galactose, 1-O-methyl α-galactose and melibiose in the decreasing order. Among α-galactosides, the enzyme liberated galactose from melibiose, but not from raffinose or stachyose at its pH optimum (5.2). The guar seed galactomannan was however efficiently degalactosidated; limited enzyme treatment abolished the precipitability of the polysaccharide by the α-galactose-specific jack fruit seed lectin, and complete hydrolysis yielded insoluble polysaccharide. Though similar in sugar specificity and subunit assembly, α-galactosidase and the lectin coexisting in the jack fruit seed gave no indication of immunological identity.     

Screening of integrin-binding peptides from the laminin α4 and α5 chain G domain peptide library

Laminins, a multifunctional protein family of extracellular matrix, interact with various types of integrin. Here, integrin-mediated cell adhesive peptides have been systematically screened in the laminin α4 and α5 chain G domain peptide library consisting of 211 peptides by both the peptide-coated plastic plates and peptide-conjugated Sepharose bead assays using human dermal fibroblasts. Thirteen peptides promoted cell spreading and the activity was specifically inhibited by EDTA. Cell attachment to 11 peptides was inhibited by anti-integrin β1 antibody. Additionally, cell attachment to the A5G81 (AGQWHRVSVRWG) and A5G84 (TWSQKALHHRVP) peptides was specifically inhibited by anti-integrin α3 and α6 antibodies. These results suggest that the A5G81 and A5G84 peptides promote integrin α3β1- and α6β1-mediated cell attachment. Further, most of the integrin-mediated cell adhesive peptides are located in the loop regions in the G domains, suggesting that structure is important for the integrin specific recognition. Integrin binding peptides are useful for understanding laminin functions and have a potential to use for biomaterials and drug development.     

The effect of vitamin E analogues and long hydrocarbon chain compounds on calcium-induced muscle damage. A novel role for α-tocopherol?

Previous studies have demonstrated that supplemental α-tocopherol inhibited calcium-induced cytosolic enzyme efflux from normal rat skeletal muscles incubated in vitro and suggested that the protective action was mediated by the phytyl chain of α-tocopherol [1]. In order to investigate this further a number of hydrocarbon chain analogues of tocopherol (7.8-dimethyl tocol, 5,7-dimethyl tocol, tocol, α-tocotrienol, α-tocopherol [10], vitamin K1, vitamin K1 [10], vitamin K1 diacetate, vitamin K2 [20], phytyl ubiquinone and retinol) were tested for any ability to inhibit calcium ionophore, A23187, induced creatine kinase (CK) enzyme efflux. Some compounds were found to be very effective inhibitors and comparison of their structures and ability and to inhibit TBARS production in muscle homogenates revealed that the effects did not appear related to antioxidant capacity or chromanol methyl groups, but rather the length and structure of the hydrocarbon chain was the important mediator of the effects seen.     

α-D-galactose-specific lectin from jack fruit (A rtocarpus integra) seed

An α-D-galactose-specific lectin from the seeds of jack fruit (Artocarpus integra) has been isolated in pure form by affinity chromatography on immobilised guar gum (a galactomannan). The lectin is shown to be a glycoprotein containing 3% carbohydrate and having a molecular weight of 39,500 as determined by gel filtration. Sodium dodecyl sulphate gel electrophoresis revealed a single polypeptide of 10,500 dalton, indicating that the native lectin is a tetrarner of identical subunits. The hemagglutinating activity of the lectin towards erythrocytes of all blood groups is found to be the same.     

Polysaccharides isolated from Açaí fruit induce innate immune responses

The Açaí (Acai) fruit is a popular nutritional supplement that purportedly enhances immune system function. These anecdotal claims are supported by limited studies describing immune responses to the Acai polyphenol fraction. Previously, we characterized γδ T cell responses to both polyphenol and polysaccharide fractions from several plant-derived nutritional supplements. Similar polyphenol and polysaccharide fractions are found in Acai fruit. Thus, we hypothesized that one or both of these fractions could activate γδ T cells. Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures. To characterize the immune response to Acai polysaccharides, we fractionated the crude polysaccharide preparation and tested these fractions for activity in human PBMC cultures. The largest Acai polysaccharides were the most active in vitro as indicated by activation of myeloid and γδ T cells. When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production. These results define innate immune responses induced by the polysaccharide component of Acai and have implications for the treatment of asthma and infectious disease.     

A tetrameric inhibitor of insect α-amylase from barley

A tetrameric inhibitor that is active against α-amylase from the larvae of the insect Tenebrio molitor, but inactive against the enzyme from human saliva and against the endogenous one, has been described in barley endosperm. The subunits of the inhibitor have been identified as the previously characterized proteins CMa, CMb and CMd, of which only CMa was inhibitory by itself.     

A highly conserved α-tubulin sequence from Prunus amygdalus

The sequence of an -tubulin from Prunus amygdalus has been obtained by cDNA cloning. When this sequence is compared to that of the Tub1 gene from maize it shows a very high degree of similarity, much higher than any of the -tubulin sequences reported so far from plants. The expression of this gene is high in the stages of seed development where a high divisional activity is present. It is preferentially expressed in the radicular tissues as it is gene Tub1 in maize. Southern analysis indicates that this gene may from a subfamily of -tubulin genes having similar sequence and tissue specificity and existing at least in maize and in Prunus.     

A Novel Class of Fungicides: α-Benzylidene-γ-valerolactones

Enzyme activities involved in the initial step of glycerol metabolism were determined in cells of methylotrophic yeasts grown on glycerol, methanol or glucose. In Candida boidinii (Kloeckera sp.) No. 2201, the activities of glycerol kinase and dihydroxyacetone kinase were detected in cells grown on glycerol and methanol, respectively. The activity of NAD⁺-linked glycerol dehydrogenase of Hansenula polymorpha dl-1 was induced by glycerol and methanol, while that of Hansenula ofunaensis was induced by glycerol. The enzymes of both strains were subject to catabolite repression by glucose.

The yeasts tested were divided into three groups as to the glycerol dissimilation patterns. Strains of the genera Candida, Saccharomyces, Pichia and Torulopsis had the phosphorylative pathway, in which glycerol is first phosphorylated. H. ofunaensis had the oxidative pathway, in which glycerol is first oxidized. H. polymorpha dl-1 had both the phosphorylative and oxidative pathways.     

Phloem bleeding from legume fruits—A technique for study of fruit nutrition

Summary Bleeding from phloem of cut distal tips of attached fruits was demonstrated in the genera Spartium, Genista, Lupinus and Jacksonia. Bleeding occurred over a 2–25 min period enabling 0.5–10 l of sap to be collected from a fruit. A detailed study of Lupinus albus L. showed that exudation rate declined exponentially after cutting, but without any change with time in solute levels in exudate. Bleeding resumed at its initial rate and solute concentration on recutting the fruit tip.Phloem exudates had a high pH (7.8-8.0), a sucrose content of 100–210 mg ml^-1 but only traces of monosaccharides. Surrounding pod tissues contained only 15–35 mg ml^-1 of sugars (tissue water basis) more than two thirds of this monosaccharide. Amino compounds were present in phloem exudates at 8–28 mg ml^-1, asparagine and glutamine predominating but a wide spectrum of other amino acids being also present. No significant differences in levels of organic solutes were observed in phloem exudates collected from tips of attached versus detached fruits, from phloem exudates collected from fruit tips versus pedicels, or from basal versus distal ends of a detached fruit.Potassium was the major cation (1.5–2.2 mg ml^-1) of the phloem exudate, Ca²⁺ was at a much lower level than either Mg²⁺ or Na⁺. Trace element levels in phloem exudates appeared to be influenced by availability to the plant from the rooting medium. Nitrate was absent though detectable in non-vascular tissues of the shoot. ¹⁴C- labelled assimilates were detected in exudates of L. albus one hour after feeding a source leaf ¹⁴CO₂; sucrose, organic acids and certain amino compounds achieved high specific labelling. ¹⁴CO₂ feeding studies coupled with the phloem bleeding technique revealed highly specific source-sink relationships between foliar organs and fruits of the primary inflorescence.     

A new thermostable α-l-arabinofuranosidase from a novel thermophilic bacterium

An alpha-L-arabinofuranosidase gene was identified in a sequenced genome of a novel thermophilic bacterium, which belongs to the recently described phylum of Thermomicrobia. Amino acid sequence comparison of the enzyme (designated AraF) revealed similarity to glycoside hydrolases of family 51. The gene was cloned into Escherichia coli and its recombinant product expressed and purified. The enzyme appeared to be a hexamer. AraF was optimally active at 70 degrees C (over 10 min) and pH 6 having 92% residual activity after 1 h at 70 degrees C. AraF had a Km) value of 0.6 mM and V(max) value of 122 U mg(-1) on p-nitrophenyl-alpha-L-arabinofuranoside. AraF was almost equally active on branched arabinan and debranched arabinan, properties not previously found in alpha-L-arabinofuranosidases in GH family 51.