The genus Cinnamomum

274 K.K. Vijayan and R.V. Ajithan Thampuran
species of fungi and aflatoxin production by them are inhibited by cinnamon bark or
cinnamon oil. Studies carried out in recent years have proved the advantages of using
cinnamon as a fungistatic agent in stored cereals, pulses and other type of food
articles including processed foods (see 13.2). It can be used as a preservative in fruit
juice and fruit products at a wide range of pH conditions. Masimango et al. (1978)
reported that cinnamon inhibited Aspergillus flavus growth and aflatoxin production.
Aspergillus species of fungi are usually grown on storage cereals and pulses and
produces toxins like aflatoxin, which are highly poisonous and carcinogenic.
Valearcel et al. (1986) in an in vitro study observed that cinnamon inhibited the
growth of A. parasiticus at 1 mg/ml concentration. Misra et al. (1987) observed that
cinnamon leaf oil exerted the fungitoxic effect on A. flavus and A. parasiticus at
3000 ppm and 1000 ppm, respectively, and was not affected by temperature, autoclaving
or storage. They attributed this activity to euginol, a minor constituent of
cinnamon. Mishra et al. (1991) reported that the mycostatic effect was produced at a
concentration of 4000 ppm and was as effective as many synthetic antifungal agents
commonly employed, such as dithane M-45, thiovic, etc. Tiwari and Dixit (1994)
studied the effect of cinnamon bark oil on the storage fungi A. flavus and A. niger and
found that it was effective in inhibiting the mycelial growth at a MIC of 400 ppm.
Tiwari et al. (1994) found that at the concentration of 400 ppm, cinnamon oil
completely inhibited the mycelial growth of Alternaria spp., Aspergillus spp., Bipolaris
oryzae, Chaetomium hispanicum, Cladosporium spp., Curvularia spp., Fusarium spp.,
Mucor spp., Penicillium spp., Phoma spp., Rhizopus arrhizus., Thelavia terricola, and
Trichoderma spp. Mukherjee and Nandi (1994) investigated the fungistatic effect of
cinnamon oil on poultry feed. Poultry feed starter mash was treated with 0.1 and
0.2% w/v of cinnamon oil and stored for 30 days. In treated feeds the fungal population
decreased with the length of storage compared to untreated feeds. The fungal
contamination was due mainly to A. flavus, A. niger, A. candidus, A. fumigatus and
Rhizopus nigricans. The optimal quality of cinnamon oil to protect stored maize from
fungal growth was assessed by Montes-Belmont and Carvajal (1998) who found that
3 to 8% of the oil gave protection. No phytotoxic effect on germination and corn
growth was observed.
Studies on the wood-destroying fungi Gloeophyllum trabeum, Coriolus versicolor, and
Botryodiploidea theobromeae by agar diffusion technique by Jantan et al. (1994)
indicated that cinnamon was very effective, exhibiting an ED 50 of 60.3 g/ml for
C. versicolor, 58.8 g/ml for G. trabeum and 48.0 g/ml for B. theobromeae. Baruah
et al. (1996) investigated the antifungal action against Fusarium moniliforme, a postharvest
fungal pathogen of cereal crops, and observed that it completely inhibited
the fungal growth. Wilson et al. (1997) tested cinnamon on Botrytis cinerea and
observed that cinnamon oil was very effective against this plant pathogen. The bark
extract of C. loureirii was investigated for antifungal activity against Alternaria
alternata, a plant pathogen. The ether fraction of the extract was found to be highly
active. A visible inhibition zone was caused by a 1000-fold dilution of the extract
and the activity was comparable to polyoxin. Further investigation revealed that
cinnamaldehyde was the most active component (Ho et al., 1996). Cinnamon
bark oil is a potent fungitoxicant against fungi causing respiratory tract mycoses.
Singh et al. (1995) studied in vitro the effect of the oil on A. niger, A. fumigatus,
A. nidulans, A. flavus, Candida albicans, C. tropicalis, C. pseudotropicalis and
Histoplasma capsulatum and determined the minimal inhibiting concentration (MIC),