Mitchellenes A–E, Cyclic Sesquiterpenes from the Australian Plant <i>Eremophila mitchellii</i>

Barnes, Emma C.; Carroll, Anthony Richard; Davis, Rohan A.

doi:10.1021/np2003676

Cited by 14 publications

(27 citation statements)

References 34 publications

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“…Serrulatic acids were isolated from E. mitchellii but misdetermined as E. sturtii [44]. Conversely, a new class of sesquiterpenes, the mitchellenes, were isolated from E. sturtii but misdermined as E. mitchellii, then named as mitchellenes rather than 'sturtienes' [45]. A revision to the phytochemistry of the two species was published later which increased the number of mitchellenes [4].…”

Section: Eremophila Longifoliamentioning

confidence: 99%

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Sadgrove

Padilla-González

Green

et al. 2021

Plants

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Australia’s endemic desert shrubs are commonly aromatic, with chemically diverse terpenes and phenylpropanoids in their headspace profiles. Species from the genus Eremophila (Scrophulariaceae ex. Myoporaceae) are the most common, with 215 recognised taxa and many more that have not yet been described, widely spread across the arid parts of the Australian continent. Over the years, our research team has collected multiple specimens as part of a survey to investigate the chemical diversity of the genus and create leads for further scientific enquiry. In the current study, the diversity of volatile compounds is studied using hydrodistilled essential oils and leaf solvent extracts from 30 taxa. Several rare terpenes and iridoids were detected in chemical profiles widely across the genus, and three previously undescribed sesquiterpenes were isolated and are assigned by 2D NMR—E-11(12)-dehydroisodendrolasin, Z-11-hydroxyisodendrolasin and 10-hydroxydihydro-α-humulene acetate. Multiple sampling from Eremophila longifolia, Eremophila arbuscular, Eremophila latrobei, Eremophila deserti, Eremophila sturtii, Eremophila oppositifolia and Eremophila alternifolia coneys that species in Eremophila are highly chemovariable. However, taxa are generally grouped according to the expression of (1) furanosesquiterpenes, (2) iridoids or oxides, (3) mixtures of 1 and 2, (4) phenylpropanoids, (5) non-furanoid terpenes, (6) mixtures of 4 and 5, and less commonly (7) mixtures of 1 and 5. Furthermore, GC–MS analysis of solvent-extracted leaves taken from cultivated specimens conveys that many heavier ‘volatiles’ with lower vapour pressure are not detected in hydrodistilled essential oils and have therefore been neglected in past chemical studies. Hence, our data reiterate that chemical studies of the genus Eremophila will continue to describe new metabolites and that taxon determination has limited predictive value for the chemical composition.

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Section: Eremophila Longifoliamentioning

confidence: 99%

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Sadgrove

Padilla-González

Green

et al. 2021

Plants

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“…No reports were found of natural products that had been isolated from E. microtheca, indicating that this plant had the potential to yield new and/or bioactive chemistry. Due to our continuing interest in the chemistry of Eremophila species (Barnes et al, 2011;Barnes et al, 2012) we thus prioritised E. microtheca for chemical investigation.…”

Section: Introductionmentioning

confidence: 99%

Antibacterial serrulatane diterpenes from the Australian native plant Eremophila microtheca

et al. 2013

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Chemical investigations of the aerial parts of the Australian plant Eremophila microtheca resulted in the isolation of three serrulatane diterpenoids, 3-acetoxy-7,8-dihydroxyserrulat-14-en-19-oic acid (1), 3,7,8-trihydroxyserrulat-14-en-19-oic acid (2) and 3,19-diacetoxy-8-hydroxyserrulat-14-ene (3) as well as the previously reported compounds verbascoside (4) and jaceosidin (5). Acetylation and methylation of the major serrulatane diterpenoid 2 afforded 3,8-diacetoxy-7-hydroxyserrulat-14-en-19-oic acid (6) and 3,7,8-trihydroxyserrulat-14-en-19-oic acid methyl ester (7), respectively. The antibacterial activity of 1-7 was assessed against a panel of Gram-positive and Gram-negative bacterial isolates. All of the serrulatane compounds exhibited moderate activity against Streptococcus pyogenes (ATCC 12344) with minimum inhibitory concentrations (MICs) ranging from 64-128 μg/mL. Serrulatane 1 demonstrated activity against all Gram-positive bacterial strains (MICs 64-128 μg/mL) except for Enterococcus faecalis and Enterococcus faecium. This is the first report of natural products from E. microtheca.

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“…It was originally isolated from Eremophila virgata in 1989, 27 and then subsequently from Eremophila mitchellii. 28 This species is native to inland northern New South Wales and Queensland. 33 Oil extracts from this plant 40 have been found to possess termiticidal, insecticidal, cytotoxic, and antimicrobial activity.…”

Section: Introductionmentioning

confidence: 99%

Design and synthesis of screening libraries based on the muurolane natural product scaffold

Barnes¹,

Choomuenwai²,

Andrews³

et al. 2012

Org. Biomol. Chem.

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The plant-derived natural product 14-hydroxy-6,12-muuroloadien-15-oic acid (1) was identified as a unique scaffold that could be chemically elaborated to generate novel lead- or drug-like screening libraries. Prior to synthesis a virtual library was generated and prioritised based on drug-like physicochemical parameters such as log P, log D(5.5), hydrogen bond donors/acceptors, and molecular weight. The natural product scaffold (1) was isolated from the endemic Australian plant Eremophila mitchellii and then utilised in the parallel solution-phase generation of two series of analogues. The first library consisted of six semi-synthetic amide derivatives, whilst the second contained six carbamate analogues. These libraries have been evaluated for antimalarial activity using a chloroquine-sensitive Plasmodium falciparum line (3D7) and several compounds displayed low to moderate activity with IC(50) values ranging from 14 to 33 μM.

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Mitchellenes A–E, Cyclic Sesquiterpenes from the Australian Plant Eremophila mitchellii

Cited by 14 publications

References 34 publications

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Antibacterial serrulatane diterpenes from the Australian native plant Eremophila microtheca

Design and synthesis of screening libraries based on the muurolane natural product scaffold

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