Mild hydroxypropylation of polyflavonoids obtained under pilot-plant scale

García, Danny E.; Fuentealba, Cecilia; Salazar, Juan Pablo Hinestrosa; Pérez, Mónica A.; Escobar, Danilo; Pizzi, A.

doi:10.1016/j.indcrop.2016.04.034

Cited by 23 publications

(16 citation statements)

References 19 publications

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“…This peak coincides with the degradation peak of cellulose according to Shen et al [37], which is the principal constituent of pine bark (30-40 wt%) [5]. These two differences between bark and W-I tannins reveal a low carbohydrate content in the latter in agreement with the characterization of Garcia et al [14]. Subsequently, this point is relevant for fractionation of phenolic compounds obtained from W-I tannins pyrolysis products.…”

Section: Elemental Composition and Thermal Behavior Of Water-insolublsupporting

confidence: 85%

“…However, in the case of W-I tannins, is suspected to be formed when the acetyl groups (dominant substituent groups of the polyphenolic compounds) are released [29,35]; but also could be a side product from the C-ring decomposition [33]. The low concentrations of levoglucosan or furfurals in pyrolysis-oil fractions is consequential from the low carbohydrate content in W-I tannins (3.2 wt%) [14]. This could be beneficial to the recovery rates and improves the isolation of catechols from pyrolysis-oil given the difficulty of their separation [44].…”

Section: Pyrolysis-oil Characterization and Yield Of Catecholsmentioning

confidence: 99%

“…In contrast, the W-I tannins fraction has received less attention. García et al [14] characterized this fraction and reported contents in tannins and carbohydrates of 78 wt% and 3.2 wt%, respectively while the remaining content was not reported.…”

Section: Introductionmentioning

confidence: 99%

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Fast pyrolysis of tannins from pine bark as a renewable source of catechols

Pinto

Romero

Carrier

et al. 2018

Journal of Analytical and Applied Pyrolysis

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Fast pyrolysis of water-insoluble (W-I) tannins-mainly composed of condensed tannins-obtained from Pinus radiata bark methanol-water extraction was carried out in pursuit of a renewable source of high-value chemicals, in particular catechols. Micropyrolysis in an isothermal furnace unit (Py-GC-MS/FID) was performed between 450-600°C. Catechin and W-I tannins were compared to establish thermal degradation behavior between this fraction and its representative monomer constituent. Additionally, W-I tannins were compared with typical sources of renewable phenols such as pine bark and organosolv-lignin in order to highlight its potential. Benchscale experiments of W-I tannins were performed in a fluidized bed reactor between 400-600°C to provide information related to yield and concentration of catechols. The Py-GC-MS/FID results showed that W-I tannins are prolific of catechol and 4-methylcatechol, similar to their most abundant monomer constituent catechin. However, W-I tannins are not only composed of condensed tannins and some substituted polycyclic aromatic hydrocarbons, triterpenes and carbohydrate-derived compounds were detected. The comparison of pyrolysis products among the renewable sources of phenols showed that W-I tannins yielded the highest relative content of catechols while guaiacols and carbohydrate-derived compounds predominated in the composition of lignin and bark products, respectively. The optimal pyrolysis-oil yield for bench scale assays (37 wt%) was found at 550°C and maximum yield of both catechol (4.4 wt%) and 4methylcatechol (2.3 wt%) were also obtained at 550°C.

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Section: Elemental Composition and Thermal Behavior Of Water-insolublsupporting

confidence: 85%

Section: Pyrolysis-oil Characterization and Yield Of Catecholsmentioning

confidence: 99%

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Fast pyrolysis of tannins from pine bark as a renewable source of catechols

Pinto

Romero

Carrier

et al. 2018

Journal of Analytical and Applied Pyrolysis

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“…PVPP was chosen to evaluate the binding capacity of GA and TA with biological molecules. As nitrogenous‐based polymer, PVPP can interact with polyphenols to a high extent . Hydrogen bonds, hydrophobic binding and covalent crosslinking may be involved in the complexes of polyphenols and PVPP .…”

Section: Resultsmentioning

confidence: 99%

“…The binding capacity of GA and TA with crosslinked pyrrolidone (PVPP) was tested based on a previous procedure described by García et al . Briefly, 1 mL of polyphenol dissolved in methanol (1.0 mg mL −1 ) was mixed with 120.0 mg of PVPP, then vortexed and left for 15 min at 4 °C.…”

Section: Methodsmentioning

confidence: 99%

In vitro studies on the interactions of blood lipid level‐related biological molecules with gallic acid and tannic acid

Zeng

Sheng

et al. 2019

J Sci Food Agric

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BACKGROUND To provide the scientific evidence for a possible new mechanism of hypolipidemic effects of gallic acid (GA) and tannic acid (TA), the binding capacity of GA and TA with blood lipid level‐related biological molecules, including fat, cholesterol and cholates, were investigated in vitro. Additionally, we attempted to study the interactions of cholates with GA and TA by spectroscopic methods, high‐performance liquid chromatography electrospray‐ionization mass spectrometry (HPLC‐ESI‐MS) analysis and molecular modeling studies. RESULTS Our results demonstrated that both GA and TA were capable of binding with the blood lipid level‐related biological molecules in vitro. The fat‐binding capacity of TA was 122.1% that of GA when the addition of polyphenol was 90 mg. The inhibitory effects of GA and TA on the cholesterol solubility in mixed micelles and liquid egg yolk exhibited a dose‐dependent relationship (0.5–2.0 mg mL−1). In cholate‐binding tests, TA showed higher affinity for sodium cholate than GA at a concentration of 2.0 mg mL−1, while no significant difference in the affinity for sodium deoxycholate was found between GA and TA. Moreover, the data of spectroscopic methods, HPLC‐ESI‐MS analysis and molecular modeling studies indicated that GA and TA might precipitate cholates through hydrophobic interactions and intermolecular hydrogen bonds rather than covalent bonds. CONCLUSION The findings of the present study suggested that the binding capacity of GA and TA with blood lipid level‐related biological molecules might play a crucial role in their hypolipidemic effects in animals. © 2019 Society of Chemical Industry

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