1. Introduction
Conventional wisdom leads to the belief that natural dyes
are friendlier to the environment than their synthetic counterparts.
Natural dyes can exhibit better biodegradability and
generally have a higher compatibility with the environment.
Recently, the potentiality of using natural dyes in textile colouration
as anti-UV and anti-microbial has been reported
[1e3]. Reviews on the use of natural dyes in food and in textile
colouration have been published [4,5]. Lac dye (C.I. Natural
Red 25; C.I. 75450) [6] is obtained from the dried bodies
of an insect, Coccus laccae (Laccifer lacca Kerr), found growing
on the twigs of certain tree native to southeast Asia. The
use of lac dye in the dyeing of silk and leather seems to
have been known to the Chinese some 4000 years ago. Lac
is a mixture of at least five closely related lacciac acids
(Fig. 1), which are water-soluble red dyes of anthraquinoid
type structure [7,8].