Submitted to: Canadian Journal of Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/1/2006
Publication Date: 5/30/2006
Citation: De Lucca II, A.J., Boue, S.M., Palmgren, M.S., Maskos, K., Cleveland, T.E. 2006. Fungicidal properties of two saponins from Capsicum frutescens and the relationship of structure and fungicidal activity. Canadian Journal of Microbiology. 52:336-342. Interpretive Summary: Cayenne pepper contains a detergent-like compound, CAY-1, which kills many fungi. The plant uses a number of steps in a metabolic pathway to make this compound. At each of these steps, another molecule is added until the compound is complete. The last two such 'precursor' molecules have one (precursor 1) and two less (precursor 2) sugars molecules, respectively, than does CAY-1. We found that precursor 1 has a greatly reduced ability to kill fungi than does CAY-1, while precursor 2 does not kill fungi at all. The research shows scientists that there exists a relationship between the number of sugars present in the CAY-1 molecule and the ability to kill fungi.
Technical Abstract: CAY-1 (molecular mass: 1243 Da) is a gitogenin-based, steroidal saponin from Capsicum frutescens fruit (cayenne pepper) having four glucose and one galactose sugars attached to the number three carbon of the steroidal group. Two metabolic precursors of CAY-1, the first lacking the number five glucose (mol. mass 1081 Da), and the second lacking the numbers four and five glucose (mol. mass 919 Da) molecules, were purified from ground cayenne pepper. Solubility in aqueous solution decreased with the loss of the sugar molecules. The first precursor (mol. mass 1081 Da) was much less fungicidal than the intact CAY-1 molecule against the nongerminated and germinating conidia of Aspergillus flavus, A. niger, A. parasiticus, A. fumigatus, Fusarium oxysporum, F. moniliforme, and F. graminearum, while the second precursor (mol. mass 919 Da) was inactive against these fungi. Results show that the loss of one and two sugars from the CAY-1 molecule result in the significant reduction and elimination, respectively, of CAY-1 fungicidal and aqueous solubility properties.