Story of Helianane and Heliannuols - Unique Structurally Diverse Benzoxacycles, Interesting Intrigues and Structural Anomaly

Free-caged rearing modes regulate chicken intestinal metabolism by influencing gut microbial homeostasis

Free-caged rearing modes, which prioritize animal welfare, are believed to enhance the quality of animal products. The impact of rearing modes on meat quality may play a key role in the superior quality of local chicken breeds. This study analyzed the cecal contents of free-range and caged black-bone chickens at different ages using metagenomic and metabolomic sequencing. We identified 32 metabolites and 367 microbial species significantly affected by the rearing mode. Linear discriminant analysis Effect Size (LefSe) highlighted five key microorganisms, Gemmiger formicilis, Bacteria unclassified, Bacteroides sp. ET225, Massilistercora timonensis, and Bacteroidales unclassified, that showed distinct abundance patterns across all age points. Among them, Bacteroides sp. ET225 and Massilistercora timonensis were positively associated with certain phospholipids and plant-derived metabolites, while negatively correlated with others like demissidine and acylcarnitine. Functional analysis revealed that rearing modes impact gut metabolites involved in gut metabolism as well as broader processes such as signal transduction, protein digestion, and autophagy. This study offers new insights into how rearing modes influence gut microbiota and metabolites, shedding light on the study of rearing mode-mediated muscle development and fat deposition.

Arene Activation through Iminium Ions: Product Diversity from Intramolecular Photocycloaddition Reactions

While 2-alk-ω-enyloxy-sustituted benzaldehydes do not display any photochemical reactivity at the arene core, the respective iminium perchlorates were found to undergo efficient reactions either upon direct irradiation (λ=366 nm) or under sensitizing conditions (λ=420 nm, 2.5 mol% thioxanthen-9-one). Three pathways were found: (a) Most commonly, the reaction led to benzoxacyclic products in which the olefin in the tether underwent a formal, yet unprecedented carboformylation (13 examples, 44-99 % yield). The cascade process occurred with high diastereoselectivity and was found to be stereoconvergent. (b) If a substituent resides in the 3-position of the benzene ring, a meta photocycloaddition was observed which produced tetracyclic skeletons with five stereogenic centers in excellent regio- and diastereoselectivity (2 examples, 58-79 % yield). (c) If the tether was internally substituted at the alkene, an arene photocycloaddition was avoided and an azetidine was formed in an aza Paternò-Büchi reaction (2 examples, 95-98 % yield).

Revisiting the structure of Heliannuol L: A computational approach

Recently, structural elucidation of natural products has undergone a revolution. The combined use of different modern spectroscopic methods has allowed obtaining a complete structural assignment of natural products using small amounts of sample. However, despite the extraordinary ongoing advances in spectroscopy, the mischaracterization of natural products has been and remains a recurrent problem, especially when the substance presents several stereogenic centers. The misinterpretation of nuclear magnetic resonance (NMR) data has resulted in frequent reports addressing structural reassignment. In this context, a great effort has been devoted to developing quantum chemical calculations that simulate NMR parameters accurately, allowing to achieve a more precise spectral interpretation. In this work, we employed a protocol for theoretical calculations of ¹ H NMR chemical shifts and coupling constants using density functional theory (DFT), followed by the application of the DP4+ method to revisit the structure of Heliannuol L, a member of the Heliannuol class, isolated from Helianthus annuus. Our results indicate that the originally proposed structure of Heliannuol L needs a stereochemical reassignment, placing the hydroxyl bonded to C10 in the opposite side of the methyl and hydroxyl groups bonded to C7 and C8, respectively.

The formation of benzoxacin-3-ones via intramolecular Nicholas reactions and synthesis of 8-membered heliannuols

The γ-carbonyl cations generated from propargyl ether-Co₂(CO)₆ complexes undergo intramolecular Nicholas reactions to give dehydrobenzoxacin-3-one-Co₂(CO)₆ complexes in good yields. Reductive decomplexation and subsequent manipulation allows the synthesis of (±)-heliannuol K methyl ether and the formal syntheses of (±)-heliannuol K, (±)-heliannuol A, and (-)-heliannuol L.

Benzannulated 5,5-spiroketal sesquiterpenes from the roots of Angelica Pubescens

Two new tetrahydrobenzannulated 5,5-spiroketal sesquiterpenes (1 and 2) and three novel benzannulated 5,5-spiroketal sesquiterpenes (3-5) namely angepubesins A-E, together with a new heliannane-type benzannulated sesquiterpene namely angepubesin F (6) and two known monoterpenes (7 and 8), were isolated from the roots of Angelica Pubescens. Their structures were identified by various spectroscopic analyses (NMR, MS, UV, IR), in combination with ¹³C NMR calculation as well as MAE, CMAE, DP4 + and MAE_ΔΔδ values analyses. The absolute configurations of 1-6 were determined by modified Mosher's method, ECD calculation and single-crystal X-ray diffraction (Cu Kα). Furthermore, the inhibitory activities of these isolated compounds against nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells were evaluated. The results showed that compounds 2-4, 6 and 7, especially 6, displayed markedly inhibitory effects on NO production in a concentration-dependent manner. Mechanical study revealed that compound 6 could significantly inhibit the expression of nitric oxide synthase (iNOS) protein at a concentration of 10 μM. In addition, compound 6 suppressed the activation of JAK-STAT and NF-κB pathways.

Allelopathy: The Chemical Language of Plants

In Nature, the oldest method of communication between living systems is the chemical language. Plants, due to their lack of mobility, have developed the most sophisticated way of chemical communication. Despite that many examples involve this chemical communication process-allelopathy, there is still a lack of information about specific allelochemicals released into the environment, their purpose, as well as in-depth studies on the chemistry underground. These findings are critical to gain a better understanding of the role of these compounds and open up a wide range of possibilities and applications, especially in agriculture and phytomedicine. The most relevant aspects regarding the chemical language of plants, namely kind of allelochemicals, have been investigated, as well as their releasing mechanisms and their purpose will be described in this chapter.

Heliannuol: Distribution, Biological Activities, 1H and 13C-NMR Spectral Data

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Heliannuols are an important class of compounds isolated from Helianthus annuus, a common sunflower, with allelopathic properties. Interestingly, two of these fourteen compounds have been isolated from a gorgonian, Pseudopterogorgia rigida. This review compiles data on the isolation and biological activity of heliannuols described in the literature and briefly reports the papers describing their syntheses. This review could stimulate research into other natural species and syntheses. Further, it describes the 1H and 13C-NMR spectral data described in the literature for the 14 heliannuols already isolated and correlates them with their respective structures. Therefore, we believe that these searchable data enable a rapid identification in routine analysis of the crude extracts of sunflowers or gorgonians.

dos Santos Junior F. Unraveling the helianane family: a complementary quantum mechanical study

Comprehensive work suggesting the amendment of helianane to the open ring curcudiol by means of computational spectroscopy and thermodynamic reasons.