Haoxin Li1, Duncan Webster2, John A Johnson1, Christopher A Gray3. 1. Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5. 2. Department of Medicine, Division of Infectious Diseases, Saint John Regional Hospital, Saint John, New Brunswick, Canada E2L 4L2. 3. Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5; Department of Chemistry, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5. Electronic address: cgray@unb.ca.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Alnus incana, commonly known as the gray or speckled alder, is a medicinal plant used by some Canadian First Nations to treat symptoms associated with tuberculosis. The aim of this study was to assess the anti-mycobacterial activity of an Alnus incana bark extract and to identify the active constituents of the extract. MATERIALS AND METHODS: Methanolic extracts of the bark of A. incana were subjected to bioassay guided fractionation using Mycobacterium tuberculosis (H37Ra). The active constituents were identified by NMR and MS. RESULTS: Four pentacyclic lupane triterpenes were isolated and were identified as betulin, betulinic acid, betulone and lupenone. Betulin displayed a MIC of 12.5 μg/mL and an IC50 of 2.4 μg/mL against M. tuberculosis (H37Ra). Betulinic acid and betulone showed lower anti-mycobacterial activities with IC50 values of 84 and 57 μg/mL respectively. Lupenone was inactive against M. tuberculosis (H37Ra). CONCLUSIONS: Betulin, betulinic acid and betulone were identified as the major anti-mycobacterial constituents in the bark of A. incana and the functionality at carbons 3 and 28 of the lupane skeleton would seem to be important in determining the anti-mycobacterial activity of the triterpenes. This work supports the ethnopharmacological use of A. incana by Canadian First Nations communities as a treatment for tuberculosis.
ETHNOPHARMACOLOGICAL RELEVANCE: Alnus incana, commonly known as the gray or speckled alder, is a medicinal plant used by some Canadian First Nations to treat symptoms associated with tuberculosis. The aim of this study was to assess the anti-mycobacterial activity of an Alnus incana bark extract and to identify the active constituents of the extract. MATERIALS AND METHODS:Methanolic extracts of the bark of A. incana were subjected to bioassay guided fractionation using Mycobacterium tuberculosis (H37Ra). The active constituents were identified by NMR and MS. RESULTS: Four pentacyclic lupanetriterpenes were isolated and were identified as betulin, betulinic acid, betulone and lupenone. Betulin displayed a MIC of 12.5 μg/mL and an IC50 of 2.4 μg/mL against M. tuberculosis (H37Ra). Betulinic acid and betulone showed lower anti-mycobacterial activities with IC50 values of 84 and 57 μg/mL respectively. Lupenone was inactive against M. tuberculosis (H37Ra). CONCLUSIONS:Betulin, betulinic acid and betulone were identified as the major anti-mycobacterial constituents in the bark of A. incana and the functionality at carbons 3 and 28 of the lupane skeleton would seem to be important in determining the anti-mycobacterial activity of the triterpenes. This work supports the ethnopharmacological use of A. incana by Canadian First Nations communities as a treatment for tuberculosis.
Authors: Olga N Pozharitskaya; Marina V Karlina; Alexander N Shikov; Vera M Kosman; Valery G Makarov; Eudald Casals; Jessica M Rosenholm Journal: Eur J Drug Metab Pharmacokinet Date: 2017-04 Impact factor: 2.441
Authors: Oxana Kazakova; Roxana Racoviceanu; Anastasiya Petrova; Marius Mioc; Adrian Militaru; Lucreția Udrescu; Mihai Udrescu; Adrian Voicu; Jason Cummings; Gregory Robertson; Diane J Ordway; Richard A Slayden; Codruța Șoica Journal: Int J Mol Sci Date: 2021-11-21 Impact factor: 5.923