Triterpenes from the Outer Bark of<i>Betula nigra</i>

Hua, Yun; Bentley, Michael D.; Cole, Barbara J. W.; Murray, Kathleen D.; Alford, A. R.

doi:10.1080/02773819108051090

Cited by 26 publications

(10 citation statements)

References 15 publications

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“…As reported in the literature [6][7][8][9][10][11][12][13], birch bark contains especially high amounts of a waxy hydrophobic substance, called suberin, along with triterpenoids. Chemically the suberin is a bio-polyester and it has been studied and characterised using depolymerisation procedures.…”

Section: Introductionmentioning

confidence: 90%

“…The main suberin monomers are long-chain epoxy acids, long-chain α,ω-diacids, and long-chain ω-hydroxyacids, whose yield and variety are dependent on hydrolysis conditions [11,14]. Betulin and lupeol together with small amounts of lupenone, betulinic acid and betulone are known to be the main characteristic triterpenoids present in birch bark [9,10,12,13,17].…”

Section: Introductionmentioning

confidence: 99%

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Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

et al. 2015

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Introduction: Since ancient times, the unique properties of birch barks (Betula genus) have made them a material of choice for producing both everyday-life and artistic objects. Yet archaeological birch bark artefacts are rare, and little is known about the chemical transformations undergone by bark (chemically composed mainly of suberin and triterpenes) in archaeological contexts. Understanding the chemical modifications induced by ageing is essential for selecting suitable preservation and conservation approaches. Thus, the main aim of this research is to assess the preservation and state of degradation of archaeological findings made of birch bark: a Neolithic bow case recovered from a melting ice patch in the Bernese Alps (Switzerland) and a waterlogged birch bark vessel discovered at Moossee Lake (Canton of Bern, Switzerland). Scanning electron microscopy (SEM) and gas chromatography/mass spectrometry (GC/MS) were used to obtain information at micro-morphological and molecular levels on the state of degradation of the birch bark findings. GC/MS analysis followed two different sample preparations, alkaline hydrolysis and solvent extraction, in order to investigate respectively the hydrolysable and soluble constituents, and to test whether part of the suberin structure was depolymerised by the long period of burial. Results and conclusions: SEM investigations on archaeological birch bark samples have shown that the extent of degradation of the microstructure is much higher in waterlogged birch bark than in birch bark preserved in ice. GC/MS analysis revealed that at a molecular level, the birch bark was quite well preserved. In both the archaeological environments, ice patch and lake water, various reactions had taken place leading to the depletion of reactive and sensitive compounds such as unsaturated acids and epoxy-compounds. In addition, archaeological birch bark had undergone depolymerization and oxidation reactions leading to the appearance of free suberin monomers and of oxidised triterpenes (betulone and lupenone). GC/MS data also seems to suggest that the birch bark preserved in the waterlogged site had a more pronounced degradation both in terms of oxidation and depolymerisation.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

et al. 2015

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“…It also showed strong antimolting activity against the last of these. Oleanolic acid (83) had some antifeedant activity against Spodoptera litura (Mallavadhani et al, 2003), and 3-acetoxy-oleanolic acid (84) showed antifeedant activity against Leptinotarsa decemlineata (the Colorado potato beetle) (Hua et al, 1991). (Fig.…”

Section: Insecticidal Activitymentioning

confidence: 99%

Medicinal chemistry and pharmacology of genus Tripterygium (Celastraceae)

et al. 2007

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Plants in the genus Tripterygium, such as Tripterygium wilfordii Hook. f., have a long history of use in traditional Chinese medicine. In recent years there has been considerable interest in the use of Tripterygium extracts and of the main bioactive constituent, the diterpene triepoxide triptolide (1), to treat a variety of autoimmune and inflammation-related conditions. The main mode of action of the Tripterygium extracts and triptolide (1) is the inhibition of expression of proinflammatory genes such as those for interleukin-2 (IL-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and interferon-gamma (IFN-γ). The efficacy and safety of certain types of Tripterygium extracts were confirmed in human clinical trials in the US and abroad. Over 300 compounds have been identified in the genus Tripterygium, and many of these have been evaluated for biological activity. The overall activity of the extract is based on the interaction between its components. Therefore, the safety and efficacy of the extract cannot be fully mimicked by any individual constituent. This review discusses the biochemical composition and biological and pharmacological activities of Tripterygium extracts, and their main bioactive components.

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“…Together with its anti-inflammatory and wound healing effects, this makes birch bark dry extract interesting for the stabilisation of semisolid systems, such as gels and creams, acting as an active ingredient and an excipient in parallel. A common method for obtaining birch bark dry extract or particular triterpenoids is the extraction of birch bark with organic solvents [41,[44][45][46][47]. Some other production methods like Ultrasonic Assisted Extraction (UAE) [48] and sublimation [49] are described in the literature.…”

Section: Pharmacological Effects Of Triterpenoids Contained In Birch mentioning

confidence: 99%

Birch Bark Dry Extract by Supercritical Fluid Technology: Extract Characterisation and Use for Stabilisation of Semisolid Systems

Armbruster

Mönckedieck²,

Scherließ³

et al. 2017

Applied Sciences

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Abstract:Triterpene compounds like betulin, betulinic acid, erythrodiol, oleanolic acid and lupeol are known for many pharmacological effects. All these substances are found in the outer bark of birch. Apart from its pharmacological effects, birch bark extract can be used to stabilise semisolid systems. Normally, birch bark extract is produced for this purpose by extraction with organic solvents. Employing supercritical fluid technology, our aim was to develop a birch bark dry extract suitable for stabilisation of lipophilic gels with improved properties while avoiding the use of toxic solvents. With supercritical carbon dioxide, three different particle formation methods from supercritical solutions have been tested. First, particle deposition was performed from a supercritical solution in an expansion chamber. Second, the Rapid Expansion of Supercritical Solutions (RESS) method was used for particle generation. Third, a modified RESS-procedure, forming the particles directly into the thereby gelated liquid, was developed. All three methods gave yields from 1% to 5.8%, depending on the techniques employed. The triterpene composition of the three extracts was comparable: all three gave more stable oleogels compared to the use of an extract obtained by organic solvent extraction. Characterizing the rheological behaviour of these gels, a faster gelling effect was seen together with a lower concentration of the extract required for the gel formation with the supercritical fluid (SCF)-extracts. This confirms the superiority of the supercritical fluid produced extracts with regard to the oleogel forming properties.

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Triterpenes from the Outer Bark ofBetula nigra

Cited by 26 publications

References 15 publications

Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

Medicinal chemistry and pharmacology of genus Tripterygium (Celastraceae)

Birch Bark Dry Extract by Supercritical Fluid Technology: Extract Characterisation and Use for Stabilisation of Semisolid Systems

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