Fusarium inhibition by wild populations of the medicinal plant Salvia africana-lutea L. linked to metabolomic profiling
Date
2014-03
Authors
Nkomo, Mpumelelo M.
Katerere, David D. R.
Vismer, Hester H. F.
Cruz, Thomas T.
Balayssac, Stephane S.
Malet-Martino, Myriam M.
Makunga, Nokwanda N. P.
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Abstract
Background: Salvia africana-lutea L., an important medicinal sage used in the Western Cape (South Africa), can be
termed a ‘broad-spectrum remedy’ suggesting the presence of a multiplicity of bioactive metabolites. This study
aimed at assessing wild S. africana-lutea populations for chemotypic variation and anti-Fusarium properties.
Methods: Samples were collected from four wild growing population sites (Yzerfontein, Silwerstroomstrand,
Koeberg and Brackenfell) and one garden growing location in Stellenbosch. Their antifungal activities against
Fusarium verticillioides (strains: MRC 826 and MRC 8267) and F. proliferatum (strains: MRC 6908 and MRC 7140)
that are aggressive mycotoxigenic phytopathogens were compared using an in vitro microdilution assay. To
correlate antifungal activity to chemical profiles, three techniques viz. Gas chromatography-mass spectrometry
(GC-MS); Liquid chromatography-mass spectrometry (LC-MS) and 1H Nuclear Magnetic Resonance (NMR) were
employed. Principal Component Analysis (PCA) was applied to the NMR data. The partial least squares-discriminant
analysis (PLS-DA) was used to integrate LC-MS and NMR data sets. All statistics were performed with the SIMCA-P + 12.0
software.
Results: The dichloromethane:methanol (1:1; v/v) extracts of the plant species collected from Stellenbosch
demonstrated the strongest inhibition of F. verticillioides and F. proliferatum with minimum inhibitory concentration
(MIC) values of 0.031 mg ml-1 and 0.063 mg ml-1 respectively. GC-MS showed four compounds which were unique to
the Stellenbosch extracts. By integrating LC-MS and 1H NMR analyses, large chemotype differences leading to samples
grouping by site when a multivariate analysis was performed, suggested strong plant-environment interactions as
factors influencing metabolite composition. Signals distinguishing the Stellenbosch profile were in the aromatic
part of the 1H NMR spectra.
Conclusions: This study shows the potential of chemotypes of Salvia africana-lutea in controlling fungal growth
and consequently mycotoxin production. Products for use in the agricultural sector may be developed from such
chemotypes.
Description
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at http://www.biomedcentral.com/1472-6882/14/99
The original publication is available at http://www.biomedcentral.com/1472-6882/14/99
Keywords
Salvia africana-lutea, Chemotypes, Gas chromatography-mass spectrometry (GC-MS)
Citation
Nkomo, M. M. et al. 2014. Fusarium inhibition by wild populations of the medicinal plant Salvia africana-lutea L. linked to metabolomic profiling. BMC Complementary and Alternative Medicine, 14:99, doi:10.1186/1472-6882-14-99.