Phytochemical and antioxidant-related investigations on bark of Abies spectabilis (D. Don) Spach. from Nepal.
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 (IC(50) 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 Fe(2+) 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.
Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, Padova 35121, Italy.
Stefano
S
Dall'Acqua
Paola
P
Minesso
Bharat Babu
BB
Shresta
Stefano
S
Comai
Pramod Kumar
PK
Jha
Mohan Bikram
MB
Gewali
Emanuela
E
Greco
Rinaldo
R
Cervellati
Gabbriella
G
Innocenti
D028202:Abies / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D009390:Nepal; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization
D010936:Plant Extracts