Jean-Pierre Chaumont

Use of caryophyllene oxide as an antifungal agent in an in vitro experimental model of onychomycosis

Caryophyllene oxide, an oxygenated terpenoid, well known as preservative in food, drugs and cosmetics, has been tested in vitro as an antifungal against dermatophytes. Its antifungal activity has been compared to ciclopiroxolamine and sulconazole, commonly used in onychomycosis treatment and chosen because of their very different chemical structures. So, a new model has been tested, utilizing sheep hoof plates in order to simulate human nails, which are almost unobtainable for in vitro tests. Three protocols were utilized: pre-treatment. simultaneous treatment and post-treatment. Among these, the post-treatment method was the best to simulate antifungal therapy. as it permitted testing and comparing the efficiency of different antifungal drugs.

Antifungal properties of essential oils and their main components uponCryptococcus neoformans

Cryptococcus neoformans opportunistic fungus met in the last phasis of AIDS is inhibited in vitro by several essential oils on natural volatile compounds. The minimal inhibitory concentration may reach 100 µl/l and minimal fungicidal concentration 200 µl/l with Palmarosa or Cinnamon oils. Among phenolic compounds, thymol and carvacrol are most fungitoxic. Terpenoids, citral, geraniol, and citronellol show best activities.

Antifungal properties of Ocimum gratissimum essential oil (ethyl cinnamate chemotype).

Largely widespread in tropical countries, Ocimum gratissimum has been claimed for many uses in folk medicine. Recent research on its essential oils showed five chemotypes. An Indian chemotype, with a high level of ethyl cinnamate, presents, in vitro, an interesting spectrum of antifungal properties.

Screening fungi for synthesis of keratinolytic enzymes

Almost 300 common fungi were screened for synthesis of extracellular keratinases. About 54% of the fungi grew on agar plates with soluble keratin and excreted the enzymes. Some representatives of Fusarium, Acremonium and Geotrichum were the most active. However, when cultivating the promising strains in submerged conditions in a medium with porcine nail as the sole source of carbon and nitrogen, other fungi proved to be potent. Aspergillus flavus was the most powerful producer of extracellular keratinases, followed by Alternaria radicina, Trichurus spiralis and Stachybotrys atra.

Potentiation of the bactericidal activity of Harungana madagascariensis Lam. ex Poir. (Hypericaceae) leaf extract against oral bacteria using poly (D, L-lactide-co-glycolide) nanoparticles: in vitro study.

Harungana madagascariensis Lam. ex Poir. (Hypericaceae) is known to have biological properties with mainly antibacterial, antifungal, and antiviral effects. The objective of this study was to investigate the in vitro bactericidal activity of the ethyl acetate H. madagascariensis leaf extract (HLE) on the main oral bacterial strains largely implicated in dental caries and gingivitis infections, and the possibility of potentialization of HLE antibacterial effects using the poly (D,L-lactide-co-glycolide) nanoparticles (PLG-NP). The microdilution technique and the interfacial polymer deposition following the solvent diffusion method were used to investigate the in vitro bactericidal activity of ethyl acetate HLE and to prepare nanoparticles, respectively. HLE showed significant bactericidal effects against the bacterial strains tested, with minimal bactericidal concentration (MBC) to 5×102 mg/l or less, except for Lactobacillus casei with 7.5×102 mg/l. With the HLE incorporated into PLG nanoparticles (HLE-PLG-NP), we observed diminution of the bactericidal concentration compared to HLE, the upper MBC being of 1.875×102 mg/l. Incorporation of the HLE into a colloidal carrier optimized its antibacterial performance.

Chemical composition and in vitro antifungal and antioxidant activity of the essential oil and methanolic extract of Teucrium sauvagei Le Houerou

The chemical composition and the in vitro antifungal and antioxidant activity of the essential oil and the methanolic leaf extracts of Teucrium sauvagei Le Houerou, an endemic medicinal plant growing in Tunisia, have been studied. More than 35 constituents having an abundance ≥0.2% were identified in the oil. β-Eudesmol, T-cadinol, α-thujene, γ-cadinene, and sabinene were the prevalent constituents. Results of the antifungal activity tests indicated that the methanolic extract inhibited the in vitro growth of seven dermatophytes, whereas the essential oil showed average inhibition against only three dermatophytes. In vitro antioxidant properties of the essential oil and the methanolic extract were determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid)) assays and compared to those of the synthetic antioxidant Trolox. Due to their antifungal and antioxidant properties, the essential oil and the methanolic extract of T. sauvagei may be of use as natural preservative ingredients in food and/or pharmaceutical industries.

Survey of viable airborne fungal propagules in French wine cellars

A study was carried out of the viable airbornemycological flora of 12 wine cellars in the Arboisregion in France. Results show that there wereconsiderable variations in the quantities ofpropagules: from 57 to 2547 CFU m−3. There was arelatively large number of species (48), which aremore frequently recovered from certain cellar types.The most common were Cladosporium sphaerospermum,Aspergillus versicolor, A. restrictus, Penicilliumglabrum, P. dierckxii, P. implicatum and P.brevicompactum. So the risk of allergies subsequentto inhalation of large quantities of spores is farfrom minimal.

Production of melanin bleaching enzyme of fungal origin and its application in cosmetics

We screened wild fungal isolates for melanolytic activity and found thatSporotrichum pruinosum was the most promising of the very limited number of fungi that decolourised synthetic melanin. We used a submerged aerobic process to produce a skin depigmentation enzyme by this strain, and found that in the medium the presence of Mn2+ ions was necessary, the limitation of carbon source was beneficial, and Zn2+ ions were inhibitory. Cultivation in a stirred bioreactor required immobilization of mycelium and use of low stirring velocity. A partially purified enzyme was prepared and tested for depigmentation of human skin corneocytes and whole epidermis of phototypes III and V. This is the first study demonstrating the effective enzymatic degradation of the skin melanin rather than inhibition of its synthesis. This opens the possibility of using melanolytic enzymes in cosmetic skin lightening.

An aeromycological study of sawmills: Effects of type of installation and timber on mycoflora and inhalation hazards for workers

A study was carried out of the airborne mycoflora in 12 sawmills in order to determine the risk of allergies run by the workers. Each establishment visited harboured a particular type of mycoflora and there were significant quantitative and qualitative differences in mycoflora according to the sites, sawing techniques and efficacy of the systems of particle aspiration. The type of wood processed had a distinct influence on the composition of the mycoflora present in the atmosphere; Penicillium predominated in hardwood and Cladosporium in conifer sawmills. Besides these two high allergy risk genera, the presence of Aspergillus fumigatus and various species of Mucor, Trichoderma and Phoma could adversely affect the personnel of these establishments. The use of efficient aspiration systems and of respirators is particularly recommended.

Chemical Composition and in vitro Cytotoxic Activity of Essential Oils from Two Tropical Lamiaceae: Aeollanthus pubescens Benth. and Ocimum gratissimum L

Abstract Essential oils of Aeollanthus pubescens Benth. and Ocimum gratissimum L. (Lamiaceae) from Togo were investigated for their percentage composition and in vitro cytotoxicity. The GC and GC-MS analyses indicated that the major constituents of both essential oils were thymol, p-cymene and γ-terpinene. Testing of these volatile oils and their major constituents from commercial origin in vitro for possible cytotoxicity on the human epidermic cell line HaCat showed that the toxicity of the essential oil of A. pubescens (IC50: 1800µg.ml−1) was higher than that of the essential oil of O. gratissimum (IC50: 2400 µg.ml−1). Pure commercial thymol standard showed a cytotoxicity (IC50: 1800 µg.ml−1) identical to that of the A. pubescens essential oil. Conversely, p-cymene and γ-terpinene standards were found almost non-toxic (IC50 >3000 µg.ml−1). These findings support the assumption that the cytotoxic activities of the tested essential oils were basically due to their high level content in thymol.