Herbs, spices and gut health 165
and diglycosyl esters of a polyene dicarboxylic acid, named crocetin). The digentiobiosyl
ester of crocetins a-crocin is the major component of saffron. (b) Picrocrocin is the
main substance responsible of the bitter taste in saffron. (c) Safranal is the volatile oil
responsible of the characteristic saffron odour and aroma (Abdoullaev, 1993; Rios et
al., 1996). Many mechanisms of action have been proposed for the antitumour and
anticarcinogenic activity of saffron and its components (Abdoullaev, 2002). Some of
the mechanisms involve inhibitory effects on cellular DNA and RNA synthesis,
inhibitory effects on free radical chain reactions acting as free-radical scavengers or
it has been proposed that the antitumour activity is mediated via lectins or via apoptosis.
All the extracts of Bolivian plants that possessed cytoprotective effects contained
saponins, flavonoids and tannins; coumarins appeared in some of them (B. genistelloides
and S. boliviana). Several references report that polyphenolic compounds (mainly
flavonoids and tannins) have gastroprotective activity (Martin et al., 1988; Rainova
and Nakov, 1988; Alarcon de la Lastra et al., 1992, 1994; Montilva et al., 1992,
1993), and some of them present anti-inflammatory activity (Galvez et al., 1997; Rao
et al., 1997).
A crude aqueous extract of G. lucidum was effective in enhancing the recovery of
leucocyte counts, splenic blastogenic responses and splenic CD4 and CD8 T cells
subsets in mice subjected to g-irradiation (Cheng et al., 1995). The percentage of
natural killer cells in blood mononuclear cells increased in human subjects orally
administered hot-water extracts from the fruiting body of G. lucidum (Cheng et al.,
1985). The cytotoxic activity of splenic natural killer cells increased in normal and
tumour-bearing mice subjected to i.p. injection with an alcohol-insoluble fraction of
G. lucidum extracts (Won et al., 1989). An inhibitory effect of G. lucidum on immunity
has also been reported. Mice injected intraperitoneally with a protein isolated from
G. lucidum mycelium exhibited low systemic antibody production against the hepatitis
B surface antigen (Kino et al., 1991). In addition, methanolic extracts of G. lucidum
reduced the phytohemaglutinin and 12-O-tetradecanoylphorbol 13-acetate induced
cell proliferation in human peripheral blood mononuclear cells exposed to the extracts
in vitro (Kim et al., 1997). Thus, both stimulatory and inhibitory activities of G.
lucidum on immunity are reported in diverse systems. On the other hand G. lucidum
mycelium appears to depress mucosal IgA responses in mice when taken by the oral
route (Ha, 2003).
10.7 Adverse effects...............................................................................
Many herb and spice extracts are used widely in the food, health and personal care
industries and are classified as GRAS substances or are permitted food additives
(Kabara, 1991). Herbal remedies are the single most used type of complementary and
alternative medicine (Moody et al., 1998; Hilsden et al., 1998; Langmead et al.,
2000). Usage is particularly common in patients with irritable bowel syndrome and
inflammatory bowel disease (Rawsthorne et al., 1999; Smart et al., 1986; Moser et
al., 1996). This may be related to the chronic and refractory nature of these disorders
as well as physiological factors (Hilsden et al., 1998; Langmead et al., 2000; Moser
et al., 1996). However, the use of a herbal remedy for several thousand years does not
guarantee either its efficacy or safety. Contrary to the widespread popular view that
because it is natural it is safe, herbal therapy probably carries more risks and produces
more serious side-effects than any other form of alternative therapy (Vickers and