Paracoccidioides brasiliensis by ajoene is associated with blockade of phosphatidylcholine biosynthesis

Abstract

In Paracoccidioides brasiliensis, a dimorphic fungus pathogenic for humans, no significant differences were observed in the phospholipid species of both morphological phases. The species observed were phosphatidylcholine (PC, 30-40 O h ) , p hosp hat idy let hanolami ne (PE, 27-28 O h ) , phosp hat id y lser i ne (16-19%), phosphatidylinositol (1347%) and sphingomyelin (3-50' 0). The main fatty acids found in the yeast (Y) phase were palmitate (56%), linoleate (18%) and oleate (15%), while linoleate predominated (61 YO) in the mycelial (M) phase, followed by palmitate (27 YO) and oleate (7 YO). In the Y phase the main free sterol was ergosta=5,22=dien=3/%ol (82 YO) plus some lanosterol (12 YO) and ergosterol (6%), while in the M phase, the latter predominated (88%), followed by low levels of ergosta-5,22-dien-3/%ol (12 YO). Ajoene [(€,2)-4,5,9-trithiadodeca-l,6,11-triene 9-oxide], a platelet aggregation inhibitor derived from garlic, induced alterations in phospholipid and fatty acid proportions such that PC was reduced to about 18% in both phases and PE increased to 38% (Y phase) or 44% (M phase), suggesting inhibition of PC synthesis. Ajoene also reduced saturated fatty acids (16:O and 18:O) from 67 to 35% in the Y phase, with a corresponding increase in the unsaturated components. This effect was not seen in the M phase.

Paracoccidioides brasiliensis: chemical and molecular tools for research on cell walls, antifungals, diagnosis, taxonomy

“…In control cells, main sterols were brassicasterol (G) (69.1%), ergosterol (F) (26.8%) and lanosterol (A) (4.1%), as reported before [63]. On exposure to AZA-1, ergosta-5,7,24(28)-trien-3b-ol (D 0 ) (17.1%) and lanosterol (A) (11%) accumulated, while AZA-2 led to an important accumulation of ergosta-5,7,22,24(28)-tetraen-3b-ol (E) (50.5%).…”

S -Adenosyl- l -Methionine Inhibitors Δ 24 -Sterol Methyltransferase and Δ 24(28) -Sterol Methylreductase as Possible Agents against Paracoccidioides brasiliensis

“…In control cells, the main sterols were brassicasterol (compound G) (69.1%), ergosterol (compound F) (26.8%), and lanosterol (compound A) (4.1%) (Fig. 3), as reported previously (10). On exposure to AZA-1, ergosta-5,7,24(28)-trien-3␤-ol (17.1%) (compound DЈ) and lanosterol (compound A) (10.8%) accumulated, while exposure to AZA-2 led to an important accumulation of ergosta-5,7,22,24(28)-tetraen-3␤-ol (compound E) (50.5%).…”

“…Cultures were incubated for 5 days at 37°C (Y phase) with continuous shaking on a gyratory shaker operated at 120 rpm. Cell density was measured by turbidimetry in Klett units (9,10). For lipid analysis, cells were treated as described previously (11,12), followed by gas-liquid chromatography coupled to mass spectrometry (11,12).…”

Antiproliferative and leishmanicidal effect of ajoene on various Leishmania species: ultrastructural study

“…In this regard, previously published results on the effect of ajoene in the phospholipid metabolism of Trypanosoma cruzi and the pathogenic fungus Paracoccidioides brasiliensis indicate that at least one of the main metabolic pathways for the biosynthesis of phosphatidyl choline is selectively blocked, leading to a drastic perturbation of the plasma membrane that results in the death of the organism (Urbina et al 1993;San Blas et al 1997). It has been also shown that ajoene is an inhibitor and subversive substrate of the enzyme trypanotion reductase (Gallwitz et al 1999).…”

“…Ajoene, an organosulphur compound derived from garlic (Apitz-Castro et al 1983 ), has shown potent antiparasitic and antimicotic activity (Ledezma and Apitz-Castro 1998) and has been used topically as an antimicotic in humans without noticeable side-effects (Ledezma et al 1996a(Ledezma et al , b, 1999. Its effect seems to be mediated through the selective perturbation of phosphatidilcholine biosynthesis, which differs from the antimicotic effect of commonly used imidazole-derivatives (Urbina et al 1993;San Blas et al 1997). The lack of side-effects when topically applied, and its different mode of action, prompted us to study the possible leishmanicidal action of ajoene against several Leishmania species.…”