Introduction
Azo dyes – a fatal threat or a new generation of drugs?
In 1858 Griss developed the azo coupling reaction and obtained
first azo dye – Aniline Yellow. Nowadays, around 10 thousands
of these compounds are described and more than 2 thousands
are applied to color various materials. Azo dyes are characterized
by the presence of the azo moiety (–N=N–) in their structure,
conjugated with two, distinct or identical, mono- or polycyclic
aromatic systems. Because of their specific physico-chemical
properties and biological activities, they have found a broad
application in pharmaceutical, cosmetic, food, dyeing/textile
industry and analytical chemistry. However, the most typical and
popular field of utility remains their coloring function. Azo dyes are
the largest and the most versatile class of dyes. They possess intense
bright colors, in particular oranges, reds and yellows. In addition,
azo dyes exhibit a variety of interesting biological activities. Medical
importance of these compounds is well known for their antibiotic,
antifungal and anti-HIV properties. On the other hand they bring
a certain danger for health and environment because of canceroand
mutagenicity. In this review, selected synthetic strategies and
biological activities of azo dyes are presented, the latter in the
context of a therapeutic potential and a hazard connected with
their production and application.