Fungi are ubiquitous organisms able to colonize organic substrates such as paper, paintings, stone or even synthetic polymers giving rise to phenomena of biodeterioration or biofouling. The best approach to the conservation remains the prevention, controlling temperature and relative humidity and keeping the museums free of dust and dirt. However, sometimes these measures are not sufficient and biocidal products must be used to disinfect the contaminated object or environment. Unfortunately, often these products are toxic for the operator and/or pollutant for the environment. Essential oils (EOs) are the odorous, volatile products of the secondary metabolism of aromatic plants. The recent interest for natural solutions is leading to these substances, which can be used as a fumigant as alternative to conventional chemicals. Several studies have shown that some EOs have a strong antifungal, antiviral, insecticidal and anti-oxidant effect, while showing little harm to humans and warm-blooded animals. The inhibitory activities of vapour phase of essential oils of Eugenia caryophyllata, Cinnamomum cassia and Cinnamomum camphora, against fungi that usually attack and colonize library and archival materials were tested. The oils have been chosen on the basis of the main functional groups: alcohol for C.camphora, phenol for E. caryophyllata and aldehyde for C.cassia. Headspace GC-MS analysis showed that the main component concentration was superior to 75%. Aspergillus flavus, Aspergillus niger, Stachybotrys chartarum and Chaetomium globosum were grown in Petri dishes containing optimal grow medium. Different amounts of EOs (1, 5, 10, 20, 30, 40 or 50 ?l) were spread on paper or cellulose discs, placed in the centre of the Petri plate lids. The fungi diameter was measured after 7 and 14 days. Antifungal activity was documented for all the tested EOs and their action was more or less significant according to the substance and the concentration used A. flavus showed the smaller sensitivity to all the EOs tested, while C. globosum and S. chartarum and A. niger (particularly with C.Cassia) were more susceptible to essential oil treatments. E. caryophyllata and C. Cassia exhibited the strongest antifungal activity, showing significant results on C.globosum and S.chartarum at the lowest concentration (1 ?L) and on A. niger and A.flavus with lower concentration than the other EOs.
Antimicrobial activity of essential oils: a green alternative to treat cultural heritage.
C Sbrana;E Galli
2017
Abstract
Fungi are ubiquitous organisms able to colonize organic substrates such as paper, paintings, stone or even synthetic polymers giving rise to phenomena of biodeterioration or biofouling. The best approach to the conservation remains the prevention, controlling temperature and relative humidity and keeping the museums free of dust and dirt. However, sometimes these measures are not sufficient and biocidal products must be used to disinfect the contaminated object or environment. Unfortunately, often these products are toxic for the operator and/or pollutant for the environment. Essential oils (EOs) are the odorous, volatile products of the secondary metabolism of aromatic plants. The recent interest for natural solutions is leading to these substances, which can be used as a fumigant as alternative to conventional chemicals. Several studies have shown that some EOs have a strong antifungal, antiviral, insecticidal and anti-oxidant effect, while showing little harm to humans and warm-blooded animals. The inhibitory activities of vapour phase of essential oils of Eugenia caryophyllata, Cinnamomum cassia and Cinnamomum camphora, against fungi that usually attack and colonize library and archival materials were tested. The oils have been chosen on the basis of the main functional groups: alcohol for C.camphora, phenol for E. caryophyllata and aldehyde for C.cassia. Headspace GC-MS analysis showed that the main component concentration was superior to 75%. Aspergillus flavus, Aspergillus niger, Stachybotrys chartarum and Chaetomium globosum were grown in Petri dishes containing optimal grow medium. Different amounts of EOs (1, 5, 10, 20, 30, 40 or 50 ?l) were spread on paper or cellulose discs, placed in the centre of the Petri plate lids. The fungi diameter was measured after 7 and 14 days. Antifungal activity was documented for all the tested EOs and their action was more or less significant according to the substance and the concentration used A. flavus showed the smaller sensitivity to all the EOs tested, while C. globosum and S. chartarum and A. niger (particularly with C.Cassia) were more susceptible to essential oil treatments. E. caryophyllata and C. Cassia exhibited the strongest antifungal activity, showing significant results on C.globosum and S.chartarum at the lowest concentration (1 ?L) and on A. niger and A.flavus with lower concentration than the other EOs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
