Nanotechnology is an important field of the modern research dealing with synthesis and manipulation of the structure of matter ranging from approximately 1 to 100 nm in size, commonly called nanomaterials. Nanoparticles can be prepared through a variety of physical and chemical processes which are costly and affect the environment. Phytonanotechnology emerges as a method of green synthesis in which plants are used for the synthesis of nanoparticles, as a technology that respects the environment. The noble metal nanoparticles show unique and considerably different physical and chemical properties compared to their macro scaled counterparts. Silver is one of the noble metals with antimicrobial activity and lower toxicity for animal cells. Due to their potential application in human and animal medicine for treating skins fungal infections, interest in silver nanoparticles (AgNP) have been increased in the last years. Yeasts of Malassezia genus are considered etiological agent of pityriasis versicolor and Malassezia folliculitis, associated agents in seborrheic dermatitis/dandruff and a contributory factors to exacerbate other skin disorders.
Objectives of this work were to obtain AgNP by chemical and green synthesis and to study its in vitro antifungal activity against clinical isolates of Malassezia furfur.
Chemical synthesis of nanoparticles (AgNP-CS) was performed by chemical reduction of AgNO3 in ethanol according to Roldán et al., (2008). An aqueous leaf extract of Acanthospermum australe (Loefl.) Kuntze, was used for the green synthesis (AgNP-GS), according to Song et al., (2009) with modifications.
In order to evaluate the inhibitory activity of both AgNP synthesized, the minimum inhibitory concentrations (MIC) against 22 clinical isolates and a reference strain of M. furfur were determined by broth microdilution method in accordance with CLSI M27-A3 with the modifications proposed by Rojas et al., (2014). Range, arithmetic mean, mode, MIC50 and MIC90 values defined as the lowest concentration at which 90 and 50% of the isolates were inhibited, were also obtained.
AgNP-CS against M. furfur showed values ranged 0.12-2 μg/mL; arithmetic mean: 0.70 μg/mL; mode: 1 μg/mL; MIC50: 0.50 μg/mL; MIC90: 1 μg/mL. In contrast, AgNP-GS showed range 0.25-8 μg/mL; arithmetic mean: 6.00 μg/mL; mode: 8 μg/mL; MIC50: 8 μg/mL and MIC90: 8 μg/mL.
M. furfur showed a diverse susceptibility profiles against AgNP obtained by chemical and green synthesis. AgNP-CS was more active than AgNP-GS, showing lower variability among different isolates. However, it should be taken into account that the green synthesis of nanoparticles is a less expensive method with the important advantage related to the care of the environment.

Chemical and green synthesis of silver nanoparticles and its antifungal activity against Malassezia furfur