Natural products play an invaluable role as a starting point in the drug discovery process, and plants and animals use many interesting biologically active natural products as a chemical defense ...mechanism against predators. Among marine organisms, many nudibranch gastropods are known to derive defensive metabolites from the sponges they eat. Here we investigated the putative sequestration of the toxic compound latrunculin A--a 16-membered macrolide that prevents actin polymerization within cellular processes--which has been identified from sponge sources, by five closely related nudibranch molluscs of the genus Chromodoris. Only latrunculin A was present in the rim of the mantle of these species, where storage reservoirs containing secondary metabolites are located, whilst a variety of secondary metabolites were found in their viscera. The species studied thus selectively accumulate latrunculin A in the part of the mantle that is more exposed to potential predators. This study also demonstrates that latrunculin-containing sponges are not their sole food source. Latrunculin A was found to be several times more potent than other compounds present in these species of nudibranchs when tested by in vitro and in vivo toxicity assays. Anti-feedant assays also indicated that latrunculin A was unpalatable to rock pool shrimps, in a dose-dependent manner. These findings led us to propose that this group of nudibranchs has evolved means both to protect themselves from the toxicity of latrunculin A, and to accumulate this compound in the mantle rim for defensive purposes. The precise mechanism by which the nudibranchs sequester such a potent compound from sponges without disrupting their own key physiological processes is unclear, but this work paves the way for future studies in this direction. Finally, the possible occurrence of both visual and chemosensory Müllerian mimicry in the studied species is discussed.
The absolute configuration of psammaplysin A (1) has been assigned as (6R,7R) using experimental and calculated electronic circular dichroism (ECD) data and NMR analysis of MPA esters prepared from ...the acetamide derivative of 1. Detailed conformational analyses of a truncated model compound of 1 with an in vacuo method and with the PCM solvent model for MeOH have identified the major conformers and factors governing the ECD spectrum of 1. The correlation of the ECD data with the stereochemistry of 1 allows configurational assignment of related psammaplysin analogues on the basis of their ECD spectra.
Kaempferia galanga is a tropical plant with an impressive range of food and medicinal uses. This study, therefore, investigated the variation in yields, physicochemical properties, chemical ...compositions, and antioxidant activities of rhizome oils from two K. galanga varieties, K. galanga bigger rhizomes (V1) and K. galanga smaller rhizomes (V2), isolated by steam distillation (S) and maceration (M) techniques. The air-dried rhizomes' oil contents were found to be 2.81±0.09% (SV1O), 7.93±0.20% (MV1O), 3.60±0.10% (SV2O), and 8.76±0.22% (MV2O), respectively. From the GC-MS analysis, the SV1O, MV1O, SV2O, and MV2O samples contain 49, 48, 61, and 56 compounds, respectively. Furthermore, ethyl trans-p-methoxycinnamate was the most prevalent chemical constituent in four oils with a percentage contribution of 43.37% (SV1O), 60.62% (MV1O), 24.92% (SV2O), and 57.17% (MV2O). Several long-chain alcohols (6Z,9Z-pentadeca-6,9-dien-1-ol, 9E,12E-octadeca-9,12-dien-1-ol, heptadecan-1-ol), aldehyde (Z-octadec-9-enal), carboxylic acids (4-(4-methoxyphenyl)oxane-4-carboxylic acid, hexadecanoic acid), diterpene sandaracopimaradiene, steroid ergosterol, and alkaloid 2-imino-3-(3-nitrophenyl)-1,3-thiazolidin-4-one, were also identified in K. galanga rhizome oils isolated by maceration method. In addition, all oils showed high antioxidant activities with the IC50 values of 86.10±1.51, 85.24±1.48, 89.19±1.72, and 86.49±2.03 μg/mL for SV1O, MV1O, SV2O, and MV2O, respectively.
The current study describes for the first time the chemical compositions and antimicrobial activity of essential oils from ironwood sawdust (Eusideroxylon zwageri) obtained from Borneo Island. ...Fifteen terpene metabolites were identified by GC-MS of the ironwood sawdust essential oil extracted by steam distillation. (E)-β-Caryophyllene was the oil's major compound (35.81 ± 0.25%), while its oxygenated derivative (caryophyllene oxide, 8.78 ± 0.08%) was the third biggest terpene. α-Copaene (13.05 ± 0.02%) was also observed in a significant amount together with other minor sesquiterpene hydrocarbons and oxygenated sesquiterpenes. The oil also exhibited antibacterial activities against Gram-positive Multi-Drug Resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli (strain ESBL) during a disc diffusion assay with inhibition zones of 6.13 ± 0.03 mm and 3.35 ± 0.05 mm, respectively.
The preparation of 4-methylbenzenesulfonyl imidazole by using triethylamine as an effective phase‐transfer catalyst (PTC) under mild biphasic conditions has been studied intensively. The method can ...be used for large-scale preparation with high purity and high yield of 4-methylbenzene-sulfonyl imidazole. The result in 4-methylbenzenesulfonyl imidazole has been successfully applied for the regioselective synthesis of mono-6-(4-methylbenzenesulfonyl)-β-cyclodextrin in an aqueous medium. This synthetic methodology concept, together with the synthetic versatility of PTC, provides a general and reliable general strategy for the practical and industrial regioselective synthesis of highly valuable mono-6-(4-methylbenzenesulfonyl)-β-cyclodextrin as a key intermediate for the single functional isomer mono-substituted cyclodextrin derivatives. As characterized by FTIR, NMR and mass spectrometry, mono-6-(4-methylbenzenesulfonyl)-β-cyclodextrin was obtained in high purity.
The Flabellinidae, a heterogeneous assembly of supposedly plesiomorphic to very derived sea slug groups, have not yet been addressed by integrative studies. Here novel material of rarely seen Arctic ...taxa as well as North Atlantic, North and South Pacific, and tropical Indo-West Pacific flabellinid species is investigated morpho-anatomically and with multi-locus markers (partial COI, 16S rDNA, 28S rDNA and H3) which were generated and analysed in a comprehensive aeolid taxon sampling. It was found that the current family Flabellinidae is polyphyletic and its phylogeny and taxonomic patterns cannot be understood without considering members from all the Aeolidacean families and, based on a robust phylogenetic hypothesis, morpho-anatomical evolution of aeolids is more complex than suspected in earlier works and requires reclassification of the taxon. Morphological diversity of Flabellinidae is corroborated by molecular divergence rates and supports establishing three new families (Apataidae
, Flabellinopsidae
, Samlidae
), 16 new genera, 13 new species, and two new subspecies among the former Flabellinidae. Two families, namely Coryphellidae and Paracoryphellidae, are restored and traditional Flabellinidae is considerably restricted. The distinctness of the recently described family Unidentiidae is confirmed by both morphological and molecular data. Several species complexes among all ex-"Flabellinidae" lineages are recognised using both morphological and molecular data. The present study shows that Facelinidae and Aeolidiidae, together with traditional "Tergipedidae", deeply divide traditional "Flabellinidae." Diagnoses for all aeolidacean families are therefore provided and additionally two new non-flabellinid families (Abronicidae
and Murmaniidae
) within traditional tergipedids are established to accommodate molecular and morphological disparity. To address relationships and disparity, we propose a new family system for aeolids. Here the aeolidacean species are classified into at least 102 genera and 24 families. Operational rules for integration of morphological and molecular data for taxonomy are suggested.
Many plants and animals store toxic or unpalatable compounds in tissues that are easily encountered by predators during attack. Defensive compounds can be produced
de novo
, or obtained from dietary ...sources and stored directly without selection or modification, or can be selectively sequestered or biotransformed. Storage strategies should be optimized to produce effective defence mechanisms but also prevent autotoxicity of the host. Nudibranch molluscs utilize a diverse range of chemical defences, and we investigated the accumulation and distribution of defensive secondary metabolites in body tissues of 19 species of Chromodorididae nudibranchs. We report different patterns of distribution across tissues, where: 1) the mantle had more or different (but structurally related) compounds than the viscera; 2) all compounds in the mantle were also in the viscera; and 3) the mantle had fewer compounds than the viscera. We found no further examples of species that selectively store a single compound, previously reported in
Chromodoris
species. Consistent with other studies, we found high concentrations of metabolites in mantle rim tissues compared to the viscera. Using bioassays, compounds in the mantle were more toxic than compounds found in the viscera for
Glossodoris vespa
Rudman, 1990 and
Ceratosoma brevicaudatum
Abraham, 1876. In
G. vespa
, compounds in the mantle were also more unpalatable to palaemonid shrimp than compounds found in the viscera. This indicates that these species may modify compounds to increase bioactivity for defensive purposes and/or selectively store more toxic compounds. We highlight clear differences in the storage of sequestered chemical defences, which may have important implications for species to employ effective defences against a range of predators.
The aims of this work are to isolate bacterial symbionts from nudibranchs and subsequently to determine anti-Methicillin resistant
(MRSA), cytotoxicity and anti-Herpes simplex virus type 1 (HSV-1) ...activities of bio compounds. A total of 15 species of nudibranchs were collected from Karimunjawa and five species from Bali, respectively. A total of 245 bacteria isolates were obtained. The anti-MRSA activity screening activity indicated two active bacteria. Ethyl acetate extracts from supernatants, indicating extracelullar compounds, showed an inhibition zone against MRSA at concentrations of 500-1,000 µg/ml. DNA sequence analysis showed that the strain KJB-07 from
was closely related to
, whereas the strain NP31-01 isolated from
was closely related to
. The extract of
was cytotoxic to Vero cells at a concentration of 75 µg/ml. The extract of
presented no cytotoxicity at concentrations of 5-1,000 µg/ml. No anti HSV-1 was observed for both isolated bacteria. This is the first study describing research on anti-MRSA, cytotoxicity and anti HSV-1 activity of bacterial symbionts from the viscera of nudibranch. Compounds produced by
and
, had potential anti-MRSA activity. However, only extracts from
showed cytotoxic effects on Vero cells. Three compounds were identified by LC/MS after purification from culture supernatant.
This study examines the ecological traits of heterobranchs, which are found in various habitats associated with reef regions. We use data on heterobranchs abundance, depth, substrates, and seasonal ...observations to analyze their ecological traits, as these factors are often under studied. The species diversity of heterobranch species found in Tulamben, Bali is exceptionally rich. From a total of 41 surveys carried out at depths between 0 and 25 m every week in a one-year period, more than 144 species of heterobranchs belonging to 63 genera were recorded. A total of 1001 individuals were recorded during our survey efforts with 645 individuals in the dry season and 356 during the wet season. Hypselodoris roo and Mexichromis trilineata are the most abundant species of heterobranch recorded in this study. Despite these numbers, no significant difference was found between the abundance of heterobranchs between the dry and wet seasons; however, depth was a significant factor in determining heterobranchs abundance and species richness. The highest abundance was recorded for zone C (between 15 and 20 m depth) where 437 individual heterobranchs were recorded. The lowest abundance of heterobranchs was recorded for zone A (5–9 m depth) where only 72 individuals were recorded. Substrate preference was also observed among the individuals in which the highest abundance of heterobranchs were found on sponges in both dry (47.9 %) and wet (41 %) seasons. The second most dominant substrate was recorded as sand, accounting for 25 % relative abundance in both dry and wet seasons. To learn more about the seasonality of heterobranchs, further research considering tides, temperature, and other environmental factors needs to be considered.
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