lactone

OBJECTIVES: Ranunculus L. genus contains 413 species, and it is the biggest genus in the family Ranunculaceae Juss. This review is to provide botanical characteristics, traditional uses, phytochemistry, pharmacology, toxicity, and pharmaceutical preparations of the genus Ranunculus. KEY FINDINGS: The genus Ranunculus contains flavonoids, organic acids, coumarins, lactones, glycosides, sterols, polysaccharides, and trace elements. These chemical constituents complement the pharmacological actions and work together to exert anti-inflammatory, anticancer, antitubercular, antibacterial, antimalarial, etc...

Several natural cytotoxic C 2 -symmetric bis-lactones, such as swinholide A and rhizopodin, sequester actin dimer from the actin network and potently inhibit actin dynamics. To develop new protein-protein interaction (PPI) modulators, we synthesized structurally simplified actin-binding side-chain dimers of antitumor macrolide aplyronine A. By fixing the two side-chains closer than those of rhizopodin, the C4 linker analog depolymerized filamentous actin more potently than natural aplyronines. Cross-link experiments revealed that actin dimer was formed by treatment with the C4 linker analog...

Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an assembly line strategy in which the growing peptide is tethered to carrier domains that deliver the intermediates to neighboring catalytic domains. While most NRPS domains catalyze standard chemistry of amino acid activation, peptide bond formation and product release, some canonical NRPS catalytic domains promote unexpected chemistry. The paradigm monobactam antibiotic sulfazecin is produced through the activity of a terminal thioesterase domain that catalyzes an unusual β-lactam forming reaction in which the nitrogen of the C-terminal N -sulfo-2,3-diaminopropionate residue attacks its thioester tether to release the β-lactam product...

The development of new sustainable polymeric materials endowed with improved performances but minimal environmental impact is a major concern, with polyesters as primary targets. Lactones are key monomers thanks to ring-opening polymerization, but their use in step-growth polymerization has remained scarce and challenging. Herein, we report a powerful bis(γ-lactone) ( γSL ) that was efficiently prepared on a gram scale from malonic acid by Pd-catalyzed cycloisomerization. The γ-exomethylene moieties and the spiro structure greatly enhance its reactivity toward ring-opening and enable step-growth polymerization under mild conditions...

Silicosis is a hazardous occupational disease caused by inhalation of silica, characterized by persistent lung inflammation that leads to fibrosis and subsequent lung dysfunction. Moreover, the complex pathophysiology of silicosis, the challenges associated with early detection, and the unfavorable prognosis contribute to the limited availability of treatment options. Daphnetin (DAP), a natural lactone, has demonstrated various pharmacological properties, including anti-inflammatory, anti-fibrotic, and pulmonary protective effects...

Carbon (C) and nitrogen (N) metabolisms participate in N source-regulated secondary metabolism in medicinal plants, but the specific mechanisms involved remain to be investigated. By using nitrate (NN), ammonium (AN), urea (UN), and glycine (GN), respectively, as sole N sources, we found that N sources remarkably affected the contents of diterpenoid lactone components along with C and N metabolisms reprograming in Andrographis paniculata , as compared to NN, the other three N sources raised the levels of 14-deoxyandrographolide, andrographolide, dehydroandrographolide (except UN), and neoandrographolide (except AN) with a prominent accumulation of farnesyl pyrophosphate (FPP)...

The traditional Chinese medicine toad venom ( Venenum bufonis ) has been extensively used to treat various diseases, including cancers, in China and other Southeast Asian countries. The major constituents of toad venom, e.g., bufadienolides and alkaloids, exhibit broad-spectrum pharmacological effects in cancers. Herein, two new bufadienolides ( 1 and 2 ), along with eleven known compounds ( 3 - 13 ) were successfully isolated from Bufo melanostictus Schneider. Their structures were elucidated by extensive spectroscopic data and X-ray diffraction analysis...

Podophyllotoxin, a cyclolignan natural product, has been the object of extensive chemomodulation to obtain better chemotherapeutic agents. Among the obtained podophyllotoxin derivatives, podophyllic aldehyde showed very interesting potency and selectivity against several tumoral cell lines, so it became our lead compound for further modifications, as described in this work, oriented toward the enlargement of the cyclolignan skeleton. Thus, modifications performed at the aldehyde function included nucleophilic addition reactions and the incorporation of the aldehyde carbon into several five-membered rings, such as thiazolidinones and benzo-fused azoles...

Continuous spring cropping of Qingke ( Hordeum viilgare L. var. nudum Hook. f.) results in a reduction in grain yield in the Xizang autonomous region. However, knowledge on the influence of continuous cropping on grain yield caused by reactive oxygen species (ROS)-induced stress remains scarce. A systematic comparison of the antioxidant defensive profile at seedling, tillering, jointing, flowering, and filling stages (T1 to T5) of Qingke was conducted based on a field experiment including 23-year continuous cropping (23y-CC) and control (the first year planted) treatments...

The potential to produce protein-structured vegan yogurts with legumes was explored to offer an alternative to conventional polysaccharide-based varieties. Glucono-δ-lactone (GDL) was employed as a slow acidifying agent and was investigated for its ability to generate cold-set, yogurt-like gels using soy and lentil milks made using minimal processing steps. Soy (5.3 % protein) and lentil (6.1 % protein) milks were successfully gelled by GDL at concentrations of 0.5 % and 1 % w/w. Soy and lentil milks experienced similar acidification profiles and demonstrated good fits with double-exponential decay models...

This study aimed to characterize the sensory profiles of wines produced using the flash détente (FD) technique and to identify the flavor compounds contributing to the sensory characteristics. The FD technique was applied to two major grape varieties, Cabernet Sauvignon and Marselan, from the Changli region of China to produce high-quality wines with aging potential. Compared to the traditional macerated wines, the FD wines showed greater color intensity, mainly due to the higher levels of anthocyanins...

This study investigated the mechanisms of microbial growth and metabolism during biofilm cultivation in the biofilm sequencing batch reactor (BSBR) process for phosphate (P) enrichment. The results showed that the sludge discharge was key to biofilm growth, as it terminated the competition for carbon (C) source between the nascent biofilm and the activated sludge. For the tested reactor, after the sludge discharge on 18 d, P metabolism and C source utilization improved significantly, and the biofilm grew rapidly...

By co-culturing two endophytic fungi (Chaetomium virescens and Xylaria grammica) collected from the medicinal and edible plant Smilax glabra Roxb. and analyzing them with MolNetEnhancer module on GNPS platform, seven undescribed chromone-derived polyketides (chaetoxylariones A-G), including three pairs of enantiomer ones (2a/2b, 4a/4b and 6a/6b) and four optical pure ones (1, 3, 5 and 7), as well as five known structural analogues (8-12), were obtained. The structures of these new compounds were characterized by NMR spectroscopy, single-crystal X-ray diffraction, 13 C NMR calculation and DP4+ probability analyses, as well as the comparison of the experimental electronic circular dichroism (ECD) data...

The structural identification and efficient synthesis of bioactive 2,6-dideoxyglycosides are daunting challenges. Here, we report the total synthesis and structural revision of a series of 2,6-dideoxyglycosides from folk medicinal plants Ecdysanthera rosea and Chonemorpha megacalyx , which feature pregnane steroidal aglycones bearing an 18,20-lactone and glycans consisting of 2,6-dideoxy-3- O -methyl-β-pyranose residues, including ecdysosides A, B, and F and ecdysantheroside A. All the eight possible 2,6-dideoxy-3- O -methyl-β-pyranoside stereoisomers (of the proposed ecdysantheroside A) have been synthesized that testify the effective gold(I)-catalyzed glycosylation methods for the synthesis of various 2-deoxy-β-pyranosidic linkages and lays a foundation via nuclear magnetic resonance data mapping to identify these sugar units which occur promiscuously in the present and other natural glycosides...

Sophorolipids (SLs) are promising glycolipid biosurfactants as they are easily produced and functional. SLs from microorganisms are comprised of mixtures of multiple derivatives that have different structures and properties, including well-known acidic and lactonic SL (ASLs and LSLs, respectively). In this study, we established a method for analyzing all SL derivatives in the products of Starmerella bombicola, a typical SL-producing yeast. Detailed component analyses of S. bombicola products were carried out using reversed-phase high-performance liquid chromatography and mass spectrometry...

Three new C10 and C12 aliphatic δ-lactones (1-3), three new fatty acid methyl esters (4-6), and eight known compounds (7-14) were isolated from the marine Aureobasidium sp. LUO5. Their structures were established by detailed analyses of the NMR, HRESIMS, optical rotation, and ECD data. All isolates were tested for their inhibitory effects on nitric oxide production in LPS-induced BV-2 cells. Notably, compound 4 displayed the strongest inhibitory effect with the IC50 value of 120.3 nM.

While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation of C-C and C-heteroatom bonds, their potential as energy-transfer reactive groups has remained unexplored. Yet, this potential holds the key to generating elusive polyborylated biradical species, which can be captured by olefins, thereby leading to the construction of new highly-borylated scaffolds...

Meroterpenoid clavilactones feature a unique benzo-fused ten-membered carbocyclic ring unit with an α,β-epoxy-γ-lactone moiety, forming an intriguing 10/5/3 tricyclic nested skeleton. These compounds are good inhibitors of the tyrosine kinase, attracting a lot of chemical synthesis studies. However, the natural enzymes involved in the formation of the 10/5/3 tricyclic nested skeleton remain unexplored. Here, we identified a gene cluster responsible for the biosynthesis of clavilactone A in the basidiomycetous fungus Clitocybe clavipes ...

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of a feed additive obtained from the dried leaves of Ginkgo biloba L. (ginkgo extract) when used as a sensory additive in feed for horses, dogs, cats, rabbits and guinea pigs. Ginkgo extract contains ≥ 24% total flavonoids, ≥ 6% total terpene lactones and ≤ 1 mg/kg ginkgolic acids. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that ginkgo extract is safe for the target species at the following concentrations in complete feed: 2...

We herein report a two-step protocol for the asymmetric synthesis of novel chiral benzofused ϵ-lactones starting from O-protected hydroxymethyl-para-quinone methides and activated aryl esters. By using chiral isothiourea Lewis base catalysts a broad variety of differently substituted products could be obtained in yields of around 50 % over both steps with high levels of enantioselectivities, albeit low diastereoselectivities only.