Introduction. Rhein (4, 5-dihydroxyanthraquinone-2-carboxylic acid) has various properties, including anti-inflammatory, antioxidant and anticancer activities. However, the mechanism underlying the role of rhein in antimicrobial activity remains largely unknown.
Aim. This study aims to identify potential natural compounds of rhein that are capable of inhibiting Cutibacterium acnes and elucidate the effects of rhein on NADH dehydrogenase-2 activity in C. acnes.
Methodology. The anti-C. acnes activity of compounds was analysed using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the paper disc diffusion test and the checkerboard dilution test. To check whether rhein was inhibitory, putative type II NADH dehydrogenase (NDH-2) of C. acnes was analysed, cloned and expressed in Escherichia coli, and then NDH-2 purification was assessed with Ni-NTA before rhein inhibition of NADH dehydrogenase-2 activity was checked with ferricyanide [K3Fe(CN)6] as a substrate.
Results. The results showed that the MIC of rhein against C. acnes was 6.25 µg ml−1, while the MBC was 12.5 µg ml−1, and there was a 38 mm inhibition zone in the paper disc diffusion test. Rhein showed an additive two- to fourfold reduction of the MIC value with four antibiotics on the checkerboard dilution test. The purified NADH dehydrogenase gene product showed a size of approximately 51 kDa and had a Vmax of 23 µmol and a Km of 280 µm. The inhibitory effect of rhein against NADH dehydrogenase-2 activity was non-competitive with ferricyanide [K3Fe(CN)6] with a Ki value of 3.5–4.5 µm.
Conclusion. This study provided evidence of the inhibitory effects of rhein on the growth of C. acnes by blocking of NADH dehydrogenase-2 activity. This mechanism of inhibitory activity in the reduction of ROS formation and ATP productivity should be further tested in C. acnes and the question of whether rhein inhibits the natural growth of C. acnes should be investigated.
KeanEA,
GutmanM,
SingerTP.
Rhein, a selective inhibitor of the DPNH-flavin step in mitochondrial electron transport. Biochem Biophys Res Commun1970; 40:1507–1513 [View Article][PubMed][PubMed]
KeanEA,
GutmantM,
SingerTP.
Studies on the respiratory chain-lined nicotinamide adenine dinucleotide dehydrogenase. The Journal of Biological Chemistry1971; 246:2346–2353
MeloAMP,
BandeirasTM,
TeixeiraM.
New insights into type II NAD(P)H:quinone oxidoreductases. Microbiol Mol Biol Rev2004; 68:603–616 [View Article][PubMed][PubMed]
LiuJ,
KrulwichTA,
HicksDB.
Purification of two putative type II NADH dehydrogenases with different substrate specificities from alkaliphilic Bacillus pseudofirmus OF4. Biochim Biophys Acta2008; 1777:453–461 [View Article][PubMed][PubMed]
HarbutMB,
YangB,
LiuR,
YanoT,
VilchèzeC et al. Small Molecules Targeting Mycobacterium tuberculosis type II NADH dehydrogenase exhibit antimycobacterial activity. Angew Chem Int Ed Engl2018; 57:3478–3482 [View Article][PubMed][PubMed]
SanhuezaL,
MeloR,
MonteroR,
MaiseyK,
MendozaL et al. Synergistic interactions between phenolic compounds identified in grape pomace extract with antibiotics of different classes against Staphylococcus aureus and Escherichia coli
. PLoS One2017; 12:e0172273 [View Article][PubMed][PubMed]
MaddenM,
SongC,
TseK,
WongA.
The inhibitory effect of EDTA and Mg2+ on the activity of NADH dehydrogenase in lysome lysis. J Exp Med Immunol2004; 5:8–15
BergsmaJ,
Van DongenMB,
KoningsWN.
Purification and characterization of NADH dehydrogenase from Bacillus subtilis
. Eur J Biochem1982; 128:151–157 [View Article][PubMed][PubMed]
ChungJH,
KarageorgiouP,
YangP,
YangN,
LevittF.
The enzyme kinetics of NADH dehydrogenase after the addition of the inhibitory molecule, EDTA and Mg2+. J Exp Med Immunol2005; 7:7–13