CONFORMATIONALSTUDIESOF LlGNANSFROMDurio oxleyanus Griff. (Bombacaceae)

ABSTRACT Searching for secondary metabolites from the wood bark of Durio oxleyanus has afforded two new lignans, namely threo-carolignan Y (1) and erythro-carolignan Y \u27(2) together with three other known lignans erythrocarolignan X (3), boehmenan X (4) and boehmenan (5). The relative configurations of compounds 1 and 2 were establishedby J-based configurationalanalysis and 2D NOESYstudies. Keywords: carolignan, threo, erythro, Durio, Bombacacea

Isolation and absolute configuration of boehmenan from Durio affinis Becc

Boehmenan (1) is a lignan which has two feruloyl moieties at C-9 and C-9' respectively. The structural characterization of (+)-boehmenan was confirmed by H-NMR, C NMR and HRESIMS as well as by direct comparison with the literature. CD measurements established a 7S', 8R' configuration. Cytotoxicity evaluation showed that boehmenan is moderately active against the T47D cell line with IC 13.7 μg/mL and shows weak activity against the HeLa cancer cell line with IC 93.5 μg/mL. Boehmenan is also non-cytotoxic to the Vero cell line. From this study, boehmenan X and erythro-carolignan E were also obtained

Absolute structures and conformations of the spongian diterpenes spongia-13(16), 14-dien-3-one, epispongiadiol and spongiadiol

The absolute configurations of spongia-13(16),14-dien-3-one [systematic name: (3bR,5aR,9aR,9bR)-3b,6,6,9a-tetra-methyl-4,5,5a,6,8,9,9a,9b,10,11-deca- hydro-phenanthro[1,2-c]furan-7(3bH)-one], C20H28O2, (I), epispongiadiol [systematic name: (3bR,5aR,6S,7R,9aR,9bR)-7-hydr-oxy-6-hydroxy-methyl-3b,6,9a- trimethyl-3b,5,5a,6,7,9,9a,9b,10,11-deca-hydro-phenanthro[1,2-c]furan-8(4H)-one] , C20H28O4, (II), and spongiadiol [systematic name: (3bR,5aR,6S,7S,9aR,9bR)-7- hydr-oxy-6-hy-droxy-methyl-3b,6,9a-trimethyl-3b,5,5a,6,7,9,9a,9b,10, 11-deca-hydro-phenanthro[1,2-c]furan-8(4H)-one], C20H28O4, (III), were assigned by analysis of anomalous dispersion data collected at 130 K with Cu K radiation. Compounds (II) and (III) are epimers. The equatorial 3-hydroxyl group on the cyclo-hexa-none ring (A) of (II) is syn with respect to the 4-hydroxy-methyl group, leading to a chair conformation. In contrast, isomer (III), where the 3-hydroxyl group is anti to the 4-hydroxy-methyl group, is conformationally disordered between a major chair conformer where the OH group is axial and a minor boat conformer where it is equatorial. In compound (I), a carbonyl group is present at position 3 and ring A adopts a distorted-boat conformation

Antimalarial, anticancer, antimicrobial activities and chemical constituents of essential oil from the aerial parts of Cyperus kyllingia Endl.

The chemical constituents of the essential oil from Cyperus kyllingia Endl. were analyzed by a GC, GC-MS. Twenty-three compounds were identified, accounting for 93.75% of the total oil that consisted mainly of oxygenated sesquiterpenes (53.52%), particularly sesquiterpene hydrocarbons (38.97%), and carboxylic acid (1.26%). The most representative compounds were α-cadinol (19.32%), caryophyllene oxide (12.17%), α-muurolol (11.58%), α-humulene (9.85%), and α-atlantone (6.07%). The oil showed significant activities against Plasmodium falcipalum (K1, multi drug resistant strain) and NCI-H187 (Small Cell Lung Cancer) with the IC50 values of 7.52 and 7.72 μg/mL, respectively. The oil exhibited highly active against Staphylococcus aureus ATCC25923 and moderately active against Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27553, Aspergillus flavus and Candida albicans

The 293 K structure of tetradehydrohaliclonacyclamine A

The polycyclic title compound {systematic name: (1S,16S,17S,31S)-3,20- diaza-tetra-cyclo-[15.15.0.1.1] tetra-tria-conta-6,8,23,25-tetra-ene}, CHN , has recently been isolated and characterized structurally, in solution by NMR spectroscopy and in the solid state by X-ray crystallography. At 130 K the structure is monoclinic (P21, Z = 4) and comprises two mol-ecules in the asymmetric unit with distinctly different conformations in the twelve-C-atom bridging chains. We report that, at 250 K, a phase change from monoclinic to ortho-rhom-bic (P22121, Z = 4) occurs. The higher-temperature phase is structurally characterized herein at 293 K. The two different conformers resolved in the monoclinic low-temperature form merge to give a single disordered mol-ecule in the asymmetric unit of the high-temperature phase

Chemoecological studies on marine natural products: terpene chemistry from marine mollusks

Some species of nudibranchs (Mollusca) protect themselves from predatory attacks by storing defensive terpene chemicals acquired from dietary sponges (Porifera) in specialized body parts called MDFs (mantle dermal formations), often advertising their unpalatability to potential predators by means of bright coloration patterns. Consequently, the survival of these trophic specialist species is closely related to the possibility of obtaining the defensive tools from sponges that live in their immediate vicinity; therefore, it is important to determine as precisely as possible the chemical composition of nudibranch extracts prior to any ecological studies addressing issues that involve their alimentary behavior and their defensive strategies, including the significance of their color patterns. Some of our recent studies on the chemical composition of terpene extracts from nudibranchs belonging to the genera Chromodoris and Hypselodoris are summarized. We also report the development of a method to assay extracts and purified metabolites for their feeding deterrent activity against co-occurring generalist predators. In a recent chemoecological study, showing that repugnant terpene chemicals are accumulated at extremely high concentrations in exposed parts of the nudibranchs' bodies, the feeding deterrence assays were carried out on the generalist marine shrimp Palaemon elegans, very common in the Mediterranean. We have modified this assay for use with the Australian shrimp species P. serenus, and confirmed the ecological validity of the assay by analysis of extracts from species of sponges and mollusks that live in the same habitat as P. serenus. The deterrent properties of haliclonacyclamine alkaloids isolated from the sponge Haliclona sp. were demonstrated, with the alkaloid mixture demonstrating palatability deterrence at concentrations as low as 0.05 mg/mL, and complete deterrence at 0.75 mg/mL. In contrast, the diterpene thuridillin metabolites from the sacoglossan mollusk Thuridilla splendens did not deter feeding by P. serenus

Taste and Smell: A Unifying Chemosensory Theory

Since antiquity, the sense of smell (olfaction) is considered as a distance sense, just like sight and hear- ing. Conversely, the sense of taste (gustation) is thought to operate by direct contact, similarly to touch. With the progress of natural sciences, information at molecular, anatomical, and neurobiological levels has also contributed to the taste-smell dichotomy, but much evidence inconsistent with a sharp differenti- ation of these two senses has emerged, especially when considering species other than humans. In spite of this, conflicting information has been interpreted so that it could conform to the traditional differentia- tion. As a result, a confirmation bias is currently affecting scientific research on chemosensory systems and is also hindering the development of a satisfactory narrative of the evolution of chemical communi- cation across taxa. From this perspective, the chemosensory dichotomy loses its validity and usefulness. We thus propose the unification of all chemosensory modalities into a single sense, moving toward a synthetic, complex, and interconnected perspective on the gradual processes by which a vast variety of chemicals have become signals that are crucially important to communication among and within cells, organs, and or- ganisms in a wide variety of environmental conditions

Taste and Smell: A Unifying Chemosensory Theory

Since antiquity, the sense of smell (olfaction) is considered as a distance sense, just like sight and hearing. Conversely, the sense of taste (gustation) is thought to operate by direct contact, similarly to touch. With the progress of natural sciences, information at molecular, anatomical, and neurobiological levels has also contributed to the taste-smell dichotomy, but much evidence inconsistent with a sharp differentiation of these two senses has emerged, especially when considering species other than humans. In spite of this, conflicting information has been interpreted so that it could conform to the traditional differentiation. As a result, a confirmation bias is currently affecting scientific research on chemosensory systems and is also hindering the development of a satisfactory narrative of the evolution of chemical communication across taxa. From this perspective, the chemosensory dichotomy loses its validity and usefulness. We thus propose the unification of all chemosensory modalities into a single sense, moving toward a synthetic, complex, and interconnected perspective on the gradual processes by which a vast variety of chemicals have become signals that are crucially important to communication among and within cells, organs, and organisms in a wide variety of environmental condition

Toxicity and taste:unequal chemical defences in a mimicry ring

Mimicry of warning signals is common, and can be mutualistic when mimetic species harbour equal levels of defence (Müllerian), or parasitic when mimics are undefended but still gain protection from their resemblance to the model (Batesian). However, whether chemically defended mimics should be similar in terms of toxicity (i.e. causing damage to the consumer) and/or unpalatability (i.e. distasteful to consumer) is unclear and in many studies remains undifferentiated. In this study, we investigated the evolution of visual signals and chemical defences in a putative mimicry ring of nudibranch molluscs. First, we demonstrated that the appearance of a group of red spotted nudibranchs molluscs was similar from the perspective of potential fish predators using visual modelling and pattern analysis. Second, using phylogenetic reconstruction, we demonstrated that this colour pattern has evolved multiple times in distantly related individuals. Third, we showed that these nudibranchs contained different chemical profiles used for defensive purposes. Finally, we demonstrated that although levels of distastefulness towards Palaemon shrimp remained relatively constant between species, toxicity levels towards brine shrimp varied significantly. We highlight the need to disentangle toxicity and taste when considering chemical defences in aposematic and mimetic species, and discuss the implications for aposematic and mimicry signal evolution

Izolacija bioaktivnih flavonoida iz biljke Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

The paper describes the bioassay-guided isolation, structure elucidation and anticancer evaluation of five flavonoids ()-liquiritigenin (1), ()-neoliquiritin (2), isoliquiritigenin (3), isoliquiritin (4) and formononetin (5) from the twigs of Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry. The structures were elucidated based on 1H, 13C NMR, comprehensive 2D NMR, MS analyses and comparison with previously reported spectral data. Compounds 1 and 3 were demonstrated to be inhibitory in vitro against NCI-H187 (small cell lung cancer) with IC50 values of 30.1 and 16.6 µg mL1, respectively. The isolates were non-cytotoxic to Vero cells (African green monkey kidney).U radu je opisana izolacija, određivanje strukture i antitumorsko djelovanje pet flavonoida: ()-likviritigenina (1), ()-neolikviritina (2), izolikviritigenina (3), izolikviritina (4) i formononetina (5) iz plodova biljke Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry. Strukture su određene na temelju 1H, 13C NMR, 2D NMR, MS i usporedbom s ranije objavljenim spektroskopskim podacima. Spojevi 1 i 3 imaju inhibitorni učinak in vitro na tumorsku staničnu liniju raka pluća NCI-H187 (IC50 vrijednost 30,1, odnosno 16,6 µg mL1). Izolirani flavonoidi nisu citotoksični za Vero stanice (bubrežne stanice afričkog zelenog majmuna)