SUMMARY: In the last 15 years, the genusMalasseziahas been a topic of intense basic research on taxonomy, physiology, biochemistry, ecology, immunology, and metabolomics. Currently, the genus encompasses 14 species. The 1996 revision of the genus resulted in seven accepted taxa:M. furfur,M. pachydermatis,M. sympodialis,M. globosa,M. obtusa,M. restricta, andM. slooffiae.In the last decade, seven new taxa isolated from healthy and lesional human and animal skin have been accepted:M. dermatis,M. japonica,M. yamatoensis,M. nana,M. caprae,M. equina, andM. cuniculi.However, forthcoming multidisciplinary research is expected to show the etiopathological relationships between these new species and skin diseases. Hitherto, basic and clinical research has established etiological links betweenMalasseziayeasts, pityriasis versicolor, and sepsis of neonates and immunocompromised individuals. Their role in aggravating seborrheic dermatitis, dandruff, folliculitis, and onychomycosis, though often supported by histopathological evidence and favorable antifungal therapeutic outcomes, remains under investigation. A close association between skin andMalasseziaIgE binding allergens in atopic eczema has been shown, while laboratory data support a role in psoriasis exacerbations. Finally, metabolomic research resulted in the proposal of a hypothesis on the contribution ofMalassezia-synthesized aryl hydrocarbon receptor (AhR) ligands to basal cell carcinoma through UV radiation-induced carcinogenesis.

Thgoal of this study was to evaluate the efficacy of the antioxidant olive constituent, oleuropein, on infarct size, oxidative damage, and the metabolic profile in rabbits subjected to ischemia. Oleuropein, 10 or 20 mg/(kg·d), was administered to 8 groups that consumed a normal or hypercholesterolemic diet for 6 wk or only the higher dose for 3 wk. Circulating levels of malondialdehyde, protein carbonyl, nitrite+nitrate, cholesterol, triglycerides, SOD activity, and the metabolic profile were measured using ¹H NMR spectra. In rabbits that consumed the normal diet, the infarct size (percentage of infarct to risk areas) was reduced by the administration of 10 mg oleuropein/(kg·d) (16.1 ± 2.9%) or 20 mg oleuropein/(kg·d) for 3 wk (21.7 ± 2.2%) or for 6 wk (24.3 ± 1.3%) compared with the control group (48.05 ± 2.0%, P < 0.05). Only the higher dose of 20 mg/(kg·d) reduced the infarct size in hypercholesterolemic rabbits (34.7 ± 4.4% for 6 wk and 34.8 ± 6.1% for 3 wk) compared with the cholesterol-fed control group (52.8 ± 2.4%, P < 0.05). Oleuropein decreased the plasma lipid peroxidation product and protein carbonyl concentrations compared with the control groups, in which these factors increased relative to baseline due to ischemia and reperfusion. Furthermore, in rabbits administered oleuropein, RBC superoxide dismutase activity did not change during ischemia and reperfusion. This activity was significantly higher than in both control groups in which it was reduced by ischemia and reperfusion compared with baseline. Treatment for 6 wk with both doses of oleuropein reduced total cholesterol and triglyceride concentrations. ¹H NMR spectra revealed a different profile of glycolysis metabolites in the oleuropein-treated groups compared with the controls. Oleuropein, for 3 or 6 wk, reduced the infarct size, conferred strong antioxidant protection and reduced the circulating lipids. This is the first experimental study in vivo that suggests the possibility of using an olive constituent in the treatment of ischemia.

The extracts and pure major constituents of Chios mastic gum (resin of Pistacia lentiscus var. chia ) were tested for their activities against Helicobacter pylori . A total mastic extract without polymer (TMEWP) was prepared after removal of the contained insoluble polymer in order to ameliorate solubility and enhance in vivo activity. Administration of TMEWP to H. pylori SS1-infected mice over the period of 3 months with an average dose of 0.75 mg/day led to an approximately 30-fold reduction in the H. pylori colonization (1.5 log CFU/g of tissue). However, no attenuation in the H. pylori -associated chronic inflammatory infiltration and the activity of chronic gastritis was observed. To further characterize potential active mastic constituents, the TMEWP was separated into an acidic and a neutral fraction. Both were extensively characterized by nuclear magnetic resonance and mass spectroscopy to elucidate the structure of the components contained within each fraction. After chromatographic separation, the acid fraction gave the major triterpenic acids, while the neutral fraction gave several triterpenic alcohols and aldehydes. Mastic extracts and isolated pure triterpenic acids were tested for in vitro activity against a panel of 11 H. pylori clinical strains. The acid fraction was found to be the most active extract (minimum bactericidal concentration [MBC], 0.139 mg/ml), and the most active pure compound was isomasticadienolic acid (MBC, 0.202 mg/ml [0.443 mM]). Our results show that administration of TMEWP may be effective in reducing H. pylori colonization and that the major triterpenic acids in the acid extract may be responsible for such an activity.