Herbs, spices and gut health 159
pylori to immobilized human mucus, erythrocytes and cultured gastric epithelial
cells. They suggested that cranberry juice may also inhibit adhesion of bacteria to the
stomach in vivo, and may be useful for the prevention of stomach ulcers caused by
H. pylori.
Gram positive bacteria are more susceptible to essential oils than gram negatives
(Dabbah et al., 1970; Farag et al., 1989; Shelef, 1983; Tassou and Nychas, 1995b,c;
Smith-Palmer et al., 1998). The tolerance of Gram negative bacteria to oils from
spices has been ascribed to the presence of a hydrophilic outer membrane that blocked
the penetration of hydrophobic essential oils to the target cell membrane (Mann et
al., 2000).
Generally, essential oils of herbs and spices damage the structural and functional
properties of membranes and this is reflected in the dissipation of the two components
of the proton motive force: the pH gradient (DpH) and the electrical potential (Dy)
(Sikkema et al., 1995; Davidson, 1997; Ultee et al., 1999, 2000, 2002). Thymol and
carvacrol, active components of many essential oils, disrupt the membrane integrity,
which further affects pH homeostasis and equilibrium of inorganic ions (Helander et
al., 1998; Lambert et al., 2001). Disruption of membrane causes leakage of ions,
ATP, nucleic acids, and amino acids (Tranter et al., 1993; Cox et al., 1998; Ultee et
al., 1999; Tassou et al., 2000). Nutrient uptake, nucleic acid synthesis and ATPase
activity may also be affected, leading to further damage of the cell (Denyer and
Hugo, 1991).
10.4 Herbs and spices as growth promoters in animal studies.............
The combination of the properties described above of herbs and spices (effects on
digestibility and antimicrobial activity) has found application also in the feeding of
animals such as pigs, chickens, sows as growth promoters and antibiotic replacements.
Indeed, herbs, spices and various plant extracts have received increased attention as
possible antibiotic growth promoter replacements (Table 10.4). Plant extract
supplementation (essential oil extract from oregano, cinnamon, pepper and extract
from sage, thyme, rosemary) has been shown to improve apparent whole-tract and
ileal digestibility of the feeds for broilers (Hernandez et al., 2004). The above plant
extracts fed to broilers showed little growth promoter effect and live performance
levels similar to an antibiotic growth promoter (Hernandez et al., 2004). Jamroz
and Kamel (2002) observed improvements of 8.1% in daily gain and 7.7% in feed
Table 10.4 Herbs, spices and their constituents used as growth promoters and antibiotic replacements
in the feeding of animals
Oregano (carvacrol)3,5,6,7,9
Cinnamon (cinnamaldehyde)5,6,7,9
Pepper (capsaicin, capsicum oleoresin)5,6,7
Sage^5
Thyme5,9
Rosemary (rosmarinic acid, flavones, monoterpenes)4,5
blends of essential oils1,2,8
1: Alcicek et al. (2003), 2: Alcicek et al. (2004); 3: Botsoglou et al. (2002); 4: Debersac et al. (2001);
5: Hernandez et al. (2004); 6: Jamroz and Kamel (2002); 7: Manzanilla et al. (2004); 8: Mitsch et al. (2004);
9: Namkung et al. (2004).