Phytochemical and Antioxidant-Related Investigations on Bark of Abies spectabilis (D. Don) Spach. from Nepal

Molecules

Stefano Dall’Acqua¹  Paola Minesso¹  Bharat Babu Shresta¹  Stefano Comai¹  Pramod Kumar Jha¹  Mohan Bikram Gewali¹  Emanuela Greco¹  Rinaldo Cervellati¹ 

[1] ¹Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, Padova 35121, Italy

关键词: Abies spectabilis;    HPLC-MS/MS;    NMR;    phenols;    antioxidant activity;   

DOI  :  10.3390/molecules17021686

来源: mdpi

【 摘 要 】

The bark of several coniferous species, a waste product of the timber industry, contains significant amounts of natural antioxidants. In our ongoing studies of Nepalese medicinal plants, we examined the bark from Abies spectabilis as the starting material for extracting antioxidant compounds. In vitro antioxidant activity evaluated by means of three antioxidant methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), Briggs-Rauscher oscillating reaction (BR) and Trolox Equivalent Antioxidant Capacity (TEAC) and total phenol contents with the Folin-Ciocalteau reagent; the ferrous iron chelating capacity was also assessed. The methanol extract of A. spectabilis showed significant antioxidant activity and polyphenol contents (IC₅₀ 4.13 µg/mL, 0.20 μg/mL eq. resorcinol, 4.22 mM eq. Trolox, 3.9 µg/g eq. gallic Acid in the DPPH, BR, TEAC and Folin-Ciocalteau tests, respectively) and weak Fe²⁺ chelating capacity. Phytochemical studies were also carried out with 1D- and 2D NMR experiments and DI-ESI-MS, HPLC-DAD and LC-MSn measurements. Oligomeric C-type proanthocyanidins, mainly trimeric gallocatechin derivatives, were the most abundant compounds (16% of extract expressed as procyanindin B1). Gallocatechin oligomers (up to six units) and prodelphynidin-gallocatechin polymers were also identified in the extract. Prodelphynidin B4, cyclograndisolide and trans-docosanil ferulate were also isolated and characterized by NMR and MS spectroscopy.

【 授权许可】

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