Isolation of trehalamine, the aglycon of trehazolin, from microbial broths and characterization of trehazolin related compounds

Impact of Three Thiazolidinone Compounds with Piperine Skeletons on Trehalase Activity and Development of Spodoptera frugiperda Larvae

Trehalases (TREs) are pivotal enzymes involved in insect development and reproduction, making them prime targets for pest control. We investigated the inhibitory effect of three thiazolidinones with piperine skeletons (6a, 7b, and 7e) on TRE activity and assessed their impact on the growth and development of the fall armyworm (FAW), Spodoptera frugiperda. The compounds were injected into FAW larvae, while the control group was treated with 2% DMSO solvent. All three compounds effectively inhibited TRE activity, resulting in a significant extension of the pupal development stage. Moreover, the treated larvae exhibited significantly decreased survival rates and a higher incidence of abnormal phenotypes related to growth and development compared to the control group. These results suggest that these TRE inhibitors affect the molting of larvae by regulating the chitin metabolism pathway, ultimately reducing their survival rates. Consequently, these compounds hold potential as environmentally friendly insecticides.

Micromonospora: A Prolific Source of Bioactive Secondary Metabolites with Therapeutic Potential

Micromonospora, one of the most important actinomycetes genera, is well-known as the treasure trove of bioactive secondary metabolites (SMs). Herein, together with an in-depth genomic analysis of the reported Micromonospora strains, all SMs from this genus are comprehensively summarized, containing structural features, bioactive properties, and mode of actions as well as their biosynthetic and chemical synthesis pathways. The perspective enables a detailed view of Micromonospora-derived SMs, which will enrich the chemical diversity of natural products and inspire new drug discovery in the pharmaceutical industry.

The chemistry and biology of natural ribomimetics and related compounds

Natural ribomimetics represent an important group of specialized metabolites with significant biological activities. Many of the activities, e.g., inhibition of seryl-tRNA synthetases, glycosidases, or ribosomes, are manifestations of their structural resemblance to ribose or related sugars, which play roles in the structural, physiological, and/or reproductive functions of living organisms. Recent studies on the biosynthesis and biological activities of some natural ribomimetics have expanded our understanding on how they are made in nature and why they have great potential as pharmaceutically relevant products. This review article highlights the discovery, biological activities, biosynthesis, and development of this intriguing class of natural products.

New Frontiers on Human Safe Insecticides and Fungicides: An Opinion on Trehalase Inhibitors

In the era of green economy, trehalase inhibitors represent a valuable chance to develop non-toxic pesticides, being hydrophilic compounds that do not persist in the environment. The lesson on this topic that we learned from the past can be of great help in the research on new specific green pesticides. This review aims to describe the efforts made in the last 50 years in the evaluation of natural compounds and their analogues as trehalase inhibitors, in view of their potential use as insecticides and fungicides. Specifically, we analyzed trehalase inhibitors based on sugars and sugar mimics, focusing on those showing good inhibition properties towards insect trehalases. Despite their attractiveness as a target, up to now there are no trehalase inhibitors that have been developed as commercial insecticides. Although natural complex pseudo di- and trisaccharides were firstly studied to this aim, iminosugars look to be more promising, showing an excellent specificity profile towards insect trehalases. The results reported here represent an overview and a discussion of the best candidates which may lead to the development of an effective insecticide in the future.

Potential trehalase inhibitors: syntheses of trehazolin and its analogues

Trehazolin is a natural pseudodisaccharide obtained from Micromonospora strain SANK 62390 and Amycolaptosis trehalostatica, and later on it was found to be widely distributed in microorganisms, insects, plants, and animals. It has received much attention because of its importance as an inhibitor of the enzyme trehalase. This article is focused on the synthesis of natural trehazolin and its analogues, with details of the synthetic methods. Sufficient information is given to permit the selection of a suitable synthetic route for trehazolin and/or its analogues. Various approaches are provided for the synthesis of natural trehazolin and its analogues in a way that enables the researcher to decide whether to use a certain procedure, modify it, or propose a new synthetic methodology.

Biosynthesis of aminocyclitol-aminoglycoside antibiotics and related compounds

This review covers the biosynthesis of aminocyclitol-aminoglycoside antibiotics and related compounds, particularly from the molecular genetic perspectives. 195 references are cited.

cis-Stereoselective SmI2-promoted reductive coupling of keto-nitrones: first synthesis of 1-epitrehazolamine

An expeditious synthesis of 1-epitrehazolamine is presented from readily available 2,3,4,6-tetra-O-benzyl-D-glucose. The key step involves a samarium diiodide-promoted reductive cyclization of a masked keto-nitrone to form a five-membered ring aminocyclitol. The excellent cis selectivity observed in this nitrone-ketone reductive coupling contrasts surprisingly with the trans selectivity of ketone-oxime reductive couplings.

Synthesis of aminocyclopentitols from chromium carbene complex derived aminocyclobutanones

Functionalized cyclopentenones were synthesized by the diazomethane ring expansion of cyclobutanones, produced by the photochemical reaction of vinyl oxazolidinones with chromium carbene complexes.

Reduction of glycogen in eggs of the silkworm, Bombyx mori, by use of a trehalase inhibitor, trehazolin, and diapause induction in glycogen-reduced eggs

A new trehalase inhibitor, trehazolin, caused a potent inhibition of ovary trehalase in the silkworm, Bombyx mori. A single injection of trehazolin into pupae (40&mgr;g/animal) did not interfere with the accumulation of proteins and lipids, but markedly reduced glycogen content in eggs accompanied by a remarkable increase in hemolymph trehalose levels. The most potent effect of trehazolin was expressed in eggs that developed at the mid-stage of pupal-adult development. In these eggs glycogen content was reduced to a trace level, less than 3% of that of the control. The reduced glycogen content was almost restored to the control level by injection of glucose but not by trehalose. Trehazolin treatment influenced oviposition and larval hatching, whereas embryogenesis went on normally in glycogen-reduced eggs. Injection of synthetic diapause hormone into non-diapause type hosts induced an incidence of 45% diapause in the eggs and increased their glycogen content. Surprisingly, injection of trehazolin never affected diapause induction by the hormone, despite considerably reduced glycogen content in these eggs. Thus, our findings provide a new method for production of eggs containing various amounts of glycogen, and a novel system for analyzing diapause-associated metabolism besides the well-known glycogen-sorbitol metabolism.

Tandem Inter [4 + 2]/Intra [3 + 2] Cycloadditions of Nitroalkenes. Asymmetric Synthesis of Highly Functionalized Aminocyclopentanes Using the Bridged Mode (beta-Tether) Process

An asymmetric, tandem inter [4 + 2]/intra [3 + 2] bridged mode (beta-tether) cycloaddition of nitroalkenes has been developed. This new sequence involves the Lewis acid-promoted [4 + 2] cycloaddition of nitro olefins with enantiopure 1-alkoxy-1,4-dienes. The resulting nitronates, bearing a C(5) tethered dipolarophile, undergo thermal, intramolecular [3 + 2] cycloaddition to afford stable tricyclic nitroso acetals, which can be subsequently reduced to provide interesting aminocyclopentanes. Thus, in three steps, highly functionalized, enantiomerically enriched aminocyclopentanes can be constructed with good yield and high ee. Additionally, the Lewis acid was found to impart a remarkable influence on the stereochemical outcome of the [4 + 2] cycloaddition.

A Highly Efficient Pinacol Coupling Approach to Trehazolamine Starting from D-Glucose

A short and very efficient synthesis of trehazolamine (3), the aglycon of the potent trehalase inhibitor trehazolin (2), has been achieved starting from D-glucose. The key transformation in this approach is a high-yielding two-step, one-pot sequence consisting of a Swern oxidation of a 1,5-diol followed by a reductive carbocyclization of the resultant 1,5-dicarbonyl compound promoted by samarium diiodide. The overall yield of 3 is 39% over nine steps from 2,3,4,6-tetra-O-benzyl-D-glucose (5). An even shorter synthesis of 30, a diastereoisomeric analogue of 3, is also described starting from 5. The key transformation in this second route is a highly stereoselective ketone oxime ether reductive carbocyclization promoted also by samarium diiodide. The overall yield of 30 is 57% over four steps from 5.

Synthesis and biological evaluation of potent glycosidase inhibitors: N-phenyl cyclic isourea derivatives of 5-amino- and 5-amino-C-(hydroxymethyl)-1,2,3,4-cyclopentanetetraols

Twenty-four stereoisomers of 5-amino- and 5-amino-C-(hydroxymethyl)-1,2,3,4-cyclopentanetetraols and twenty-six of the corresponding N-phenyl cyclic isourea derivatives were assayed for inhibitory activity against six glycosidases. Among them, as has been expected for structure mimics of putative transition state glucopyranosyl cation for glycoside hydrolysis, 1L-(1,2,4,5/3)-5-amino-1-C-(hydroxymethyl)-1,2,3,4-cyclopentanetetrao l L-4 and its N-phenyl cyclic isourea derivative S-19 were shown to have strong inhibitory activity, IC50 4 x 10(-7) and 7.6 x 10(-9) M, respectively, against baker's yeast alpha-glucosidase. It has been analogously explained that compounds R,S-22 and R,S-26 possessed high inhibitory potency against Escherichia coli and bovine liver beta-galactosidases, respectively.

Trehazolin, a slow, tight-binding inhibitor of silkworm trehalase

Mechanisms of enzyme inhibition by trehazolin, a new inhibitor of trehalase (Ando et al. (1991) J. Antibiot. 44, 1165), were investigated using purified soluble silkworm trehalase and other glycosidases. Trehazolin inhibited trehalase with an IC50 value of 27 nM, whereas some other exo-alpha-glucosidases were inhibited only weakly, with IC50 values ranging from 7 to 370 microM. Other glycosidases tested were not inhibited by 500 microM trehazolin. The inhibition of trehalase by trehazolin was competitive with respect to trehalose. A notable feature of the inhibition was a slow progression of the association and dissociation of the enzyme-inhibitor complex. Preincubation of the enzyme and the inhibitor at 37 degrees C potentiated the inhibition by 10-times in a time-dependent manner up to 6 h. Dialysis of the inactivated enzyme recovered the enzymatic activity very slowly, and the rate constant for the dissociation at 37 degrees C was (7.3).10(-2) h-1. Trehalamine, a deglucosylated form of trehazolin, inhibited both silkworm trehalase and exo-alpha-glucosidases only weakly. The inhibition of trehalase by trehalamine was reversible. Rat isomaltase inhibition by trehazolin and sucrase inhibition by trehalamine were also reversible. Taken together, trehazolin is a specific slow, tight-binding inhibitor of trehalase, and the glucose moiety of the inhibitor is essential to the tight binding.