The genus Cinnamomum

Pharmacology and Toxicology of Cinnamon and Cassia 263
hyperlipidaemic rats. The chloroform fraction exhibited remarkable inhibitory effects
on HMG-CoA reductase, an enzyme that catalyses cholesterol biosynthesis.
Antioxidant action
The use of spices and their constituent essential oils as additives for the prevention of
food deterioration is an ancient practice. The basis of action involves antioxidant and/or
antimicrobial activity. Antioxidants scavenge free radicals and control lipid peroxidation
in mammalian systems. Lipid peroxidation is a chain reaction, providing a continuous
supply of free radicals that initiate further peroxidation. This cycle causes the deterioration
of food. In vivo it causes tissue damage, which can lead to inflammatory diseases,
aging, atherosclerosis, cancer, etc. Within the cell free radicals can cause peroxidation of
polyunsaturated fatty acids in the phospholipid membranes, the formation of cytotoxic
peroxides, the oxidation of proteins and the denaturation of DNA. These phenomena
contribute to death, true death and aging.
Investigations on the antioxidative potential were carried out by several groups of
workers and their results indicated that cinnamon has a very high potential in countering
the phenomena listed above. In a study conducted to ascertain the antioxidant
effect of spices, Reddy and Lokesh (1992) observed that cinnamon at high doses
(600 g/ml) inhibited lipid peroxidation of rat microsomes. The antiperoxidative
ability of cinnamon extract was studied by Yokozawa et al. (1977) in a screening test
carried out on traditional Chinese prescriptions and they obtained promising results. In
yet another study to explore the ability of crude drugs on free radical scavenging activity
on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), Yokozawa et al. (1998) reported
strong free radical scavenging activity for cinnamon cortex. Trombetta et al. (1998)
correlated the antioxidant effect of cinnamon with that of the phenolic concentration
(hydroxycinnamaldehyde, hydroxycinnamic acid, etc.) of the extract. The antioxidant
activity of cinnamon is attributed to its ability to activate the hepatic and cardiac
antioxidation enzymes. Dhuleep (1999) studied the hepatic and cardiac antioxidant
enzyme (GSH) content and lipid conjugated dienes in rats fed a high fat diet along with
spices. The result of the study showed that cinnamon and cardamom counteracted
increases in lipid conjugates, the primary product of lipid peroxidation. Hence they
concluded that the spice significantly activates the production of antioxidant enzymes.
DPPH free radical trapping activity has also been reported by the methanol extract
of C. cassia (Kim et al., 1999). Stoltz (1998) indicated that the cinnamon powder
containing cream epicontrol A5 (cinnamon powder ligated to a lipoaminoacid, such as
lipoglycine) has high free radical scavenging action, which is attributed to the cinnamon
component. Its activity is much greater than known free radical scavengers such
as phenoxypropanol and zinc gluconate, but less effective than vitamin C.
Recently Hsiao et al. (2001) reported a new antiperoxidative cytoprotectant and free
radical scavenger, cinnamophilin, from Cinnamomum philippinense. The antioxidant
properties of cinnamophilin (a natural compound isolated from Cinnamomum
philippinense) were evaluated for its ability to react with relevant reactive oxygen
species. Its protective effect on cultured cells and biomacromolecules under
oxiditive stress was also studied. Cinnamophilin suppressed non-enzymatic
iron-induced lipid peroxidation in rat brain homogenates, with an IC 50 value
of 8.0 0.7M and an iron ion/ADP/ascorbate-initiated rat liver mitochondrial
lipid peroxidation, with an IC 50 value of 17.7 0.2M. It also exerted an