Discovery of evodiamine derivatives as potential lead antifungal agents for the treatment of superficial fungal infections

Mycosis, especially superficial fungal infections (SFIs), has been a serious threat to humans in recent years. Evodiamine (EVO), as an effective component of the Traditional Chinese Medicine Evodia rutaecarpa, has good antibacterial effects and low toxicity. In order to find out the potential therapeutic agents against SFIs, a series of EVO derivatives were synthesized and systematic evaluations of antifungal activity were carried out. Among them, compound A7 exhibited great antifungal activity with the values of MIC₁₀₀ were 38, 38 and 2 μg/mL, respectively, against T. rubrum, T. mentagrophytes and C. albicans, and even stronger than that of ketoconazole (KCZ) with the values of MIC₁₀₀ were 106, 106 and 3 μg/mL, respectively. Further antifungal evaluations in vitro verified that compound A7 indeed had favorable antifungal activity. Moreover, compound A7 could exert excellent antifungal effect on T. rubrum-infected guinea pigs, suggesting that A7 was an attractive molecule and could be a potential lead compound for the development of anti-fungal agents, and providing a great promising therapeutic strategy for fungal disease.

[Epidemiological and etiological aspects of superficial fungal infections among prison inmates in Ouagadougou, Burkina Faso]

OBJECTIVE

The fight against fungal infections in prisons is within the overall framework of the fight against these diseases in the general population. To contribute to the fight against these diseases, we conducted this study among inmates of the big prison of Ouagadougou. It aimed to analyze the epidemiological and etiological aspects of superficial fungal infections among prison inmates in Ouagadougou.

MATERIALS AND METHODS

It was a matter of an analytical descriptive study (December 2011-April 2012) that examined 212 selected using a stratified sampling detainees. It consisted firstly of a survey on risk factors. Secondly, samples were taken from prisoners with suspicious lesions of superficial mycoses. For each lesion, some fragments were examined directly between slide and coverslip in KOH (10% or 30%). The remaining fragments were cultured on Sabouraud-Chloramphenicol and Sabouraud-Chloramphenicol-Actidione. The media were then incubated at 27°C for 1 month before declaring any negativity.

RESULTS

The overall prevalence of superficial fungal infections among prison inmates Ouagadougou was 25.5%. The recent prison inmates (≤24 months) were the most affected (89.8%). Dermatophytes (15.56%) were more isolated than non-dermatophytes (12.26%) Anthropophilic species predominated among dermatophytes: T. mentagrophytes (7.0%), T. rubrum (3.3%), M. langeronii (23%), E. floccosum (1.41%) and T. violaceum (0.94%). M. gypseum (0.47%) was the only land-based species encountered. Non-dermatophytes were Malassezia sp. (11.79%) and Candida sp. (0.47%). Polyparasitism was less represented (7.4% of infected prisoners). Several body sites were mostly infected by one fungal agent. Pityriasis versicolor was the most common fungal infection (37.31%).

CONCLUSION

Considering the results, specific control measures are to be taken against the superficial fungal infections in prisons and in the general population.

Antifungal activity of 40 TCMs used individually and in combination for treatment of superficial fungal infections

ETHNOPHARMACOLOGICAL RELEVANCE

A series of 40 important Traditional Chinese Medicines (TCMs), which were reported effective in treating superficial fungal infections of the skin in Chinese clinical trial publications and Chinese Herbal Classics, were chosen for the investigation of the individual and combination antifungal properties against 8 superficial fungal strains in vitro.

MATERIALS AND METHODS

Plant preparations were followed the theory of TCM by using sterile water boiled with plant material at 100°C to produce water decoction of the tested sample. The minimum inhibitory concentration (MIC) of each plant for each fungus was determined. For the compatibility investigation, both invariable (same amounts of each tested TCM) and variable (different amounts of each tested TCM) combinations were evaluated.

RESULTS

All the tested TCMs demonstrated varying degrees of antifungal activities against one or more of the tested superficial fungi, and 16 of which were effective on all of the fungi. Strong antifungal activities were exhibited by water decoction of 7 TCMs with MIC at about 100μg/ml, and among these effective antifungal extracts, 4 TCMs including Melaphis chinensis, Polygonum cuspidatum, Punica granatum and Schisandra chinensis showed the significantly inhibitory activities against all of the fungi with MICs among 50μg/ml. Most of the invariable combinations of the above-mentioned 4 TCMs showed synergic effects against 4 of the least susceptible fungi strains, especially the invariable combination of Punica granatum, Melaphis chinensis and Schisandra chinensis, with the MIC at 23.4μg/ml. However, their further variable combinations investigation demonstrated that only the combination of 7.5g Punica granatum with 10g Melaphis chinensis and 7.5g Schisandra chinensis showed synergic effect with the MIC at19.5μg/ml.

CONCLUSIONS

The present study aimed the discovery of therapeutically useful agents for treatment of superficial fungal infections. Findings suggested that the combination of 3 TCMs including Punica granatum, Melaphis chinensis and Schisandra chinensis showed potential antifungal activity and thus appeared to be promising agents in preventing superficial fungal skin infectious in a natural way through herbal resources. The synergic effects of invariable and variable combinations of the tested TCMs threw a light on our further animal model and clinical practice as well as the bio-guided isolation and identification of the antifungal compounds.