The genus Cinnamomum

Pharmacology and Toxicology of Cinnamon and Cassia 267
inhibitory effect on IgE-dependent hisstamine release from RBL 2 H 3-cells. The result
indicates that the extract contains active compounds that inhibit mast cell granulation.
Anticancer activity
Investigations have also been carried out on the anticancer activity of cinnamon. Several
groups of workers studied the problem in in vivo and in vitro models. The results
obtained were encouraging. Konoshima et al. (1994) and others studied the effect of
cinnamon bark extract on skin and pulmonary tumours in vivo in animal models. They
investigated EBV-EA early antigen activation, a tumour-initiating factor, and found that
the extract strongly inhibited the activation of the antigen. The study on polynuclear
carbon induced skin tumour on mouse also has shown inhibition of skin change
with that of the control group. In another study Jin Won et al. (1994) using gastric and
colon cancer cell lines, reported that the extract inhibited growth. 2-Hydroxycinnamaldehyde
extracted from the stem bark of cinnamon was studied for its activity on
Farnesyl-protein-transferase, an enzyme involved in the initiation of tumour formation,
and Byoung Mog et al. (1996) reported that the enzyme activity was completely inhibited
at a concentration of 22g/ml. A cinnamon containing multiherbal formulation shows
antimetastatic potential to experimental liver and lung metastasis (Onishi et al., 1998).
Juzen-taiho-to, a Kampo Japanese herbal medicine, was administered orally seven days
prior to tumour inoculation, and it significantly decreased the number of liver metastatic
colonies of colon 26-L5 carcinoma cells and attenuated the increase of liver weight
at a dose range 4–40 mg/day. Oral administration of the medicine also inhibited
lung metastasis of B16-BL6 melanoma cells. 2-Hydroxycinnamaldehyde and
2-benzoyloxycinnamaldehyde, constituents of cinnamon which showed other useful
pharmacological activities, are also active as anticancer agents. These compounds
inhibited the growth of 29 human cancer cell lines in vitro. Both compounds are active
in vivo also. They inhibited the growth of SW-20 human tumour xenograft without loss
in body weight in nude mice (Chang Woo et al., 1999). Hyun et al. (1994) studied the
effect of the extracts of several medicinal herbs and found that Chinese cassia extracts
possessed an antineoplastic effect against human gastric and colon carcinoma cell lines.
The effect was produced at a dose of 250 g/ml concentration. Mukherjee et al. (1994)
isolated two monoacylglycerols and 2-flavanols from the methanol extract of C. camphora
and tested these compounds in vitro against L1210 cell lines and found cytotoxic activity
at an ED 50 value of 209 g/ml.
Metabolic studies
Samuelson et al. (1986) studied the metabolism of o-methoxycinnamaldehyde in rats.
A major pathway was found to be the oxidation to the corresponding cinnamic acid and
phenylpropanoic acid, which were largely excreted as glycine conjugate. No evidence of
conjugation to glutathione was obtained. Peters and Cadwell (1994) investigated
the metabolism of trans-cinnamaldehyde in rats and mice. They reported that over 90% of
the cinnamaldehyde administered was recovered from the excreta 72 hours after administration,
most of which (75–81%) was present in the urine produced over the first 24 hours.
Less than 2% of the dose was found in the carcasses 72 h after administration. The major
urinary metabolite was hippuric acid. The metabolic profiles of cinnamaldehyde in rats and
mice were not systematically affected by sex, dose size or route of administration.