Abstract
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.
Highlights
The bark of coniferous tree species is considered as a waste product in the timber industry, it is rich in secondary metabolites, especially phenol and lignan derivatives [1,2,3,4]
The values obtained with the Briggs-Rauscher oscillating reaction (BR) method
Eq resocinol) and Trolox Equivalent Antioxidant Capacity (TEAC) assay (4.2 ± 0.2 mM eq Tr) were far higher than those reported for extracts of several plants used in folk medicine [19]
Summary
The bark of coniferous tree species is considered as a waste product in the timber industry, it is rich in secondary metabolites, especially phenol and lignan derivatives [1,2,3,4]. The highest mountain peak in the world (8,848 m), presents rich and varied plant and animal biodiversity [13] This great biodiversity, as well as abnormal and harsh growing conditions for plant species in several areas (e.g., at high altitudes) result in great chemical diversity in secondary metabolites. We examined the bark of Abies spectabilis (Pinaceae) This plant is a evergreen coniferous tree about 50 mt high, distributed throughout Nepal at 2,400–4,200 m a.s.l. in moist, open areas; it is distributed in India and Bhutan. This fir has many uses in the traditional medicine of several mountain areas in Nepal. Extracts obtained from the bark were examined for their in vitro antioxidant activity, and phytochemical fingerprints were obtained by both non-chromatographic (NMR and MS) and chromatographic (HPLC-DAD, HPLC-MS/MS) methods
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
