Antifungal activity of Myrtaceae essential oils and their components against three phytopathogenic fungi

Abstract

Commercial plant essential oils obtained from 11 Myrtaceae plant species were tested for their antifungal activity against Phytophthora cactorum, Cryponectria parasitica and Fusarium circinatum. Good antifungal activity against Phytophthora cactorum was achieved with the essential oil derived from Leptospermum petersonii at 28 × 10 −3 mg/ml air concentration. Inhibition rates of Eucalyptus citriodora and Melaleuca quinquenervia were 35.4% and 33.6% at 28 × 10 −3 mg/ml air concentration, respectively. In a test with C. parasitica, inhibition rates of E. citriodora and L. petersonii were 29.4% and 38.5%, respectively. Only L. petersonii essential oil showed antifungal activity against F. circinatum. Analysis by gas chromatography-mass spectrometry led to identification of 16, 15 and 12 compounds, respectively, in the oils of L. petersonii, M. quinquenervia and E. citriodora. The antifungal activity of the identified compounds was tested individually using standard or synthesized compounds. The inhibition rates of citronellol, neral, geraniol and geranial were 100% against P. cactorum at 28 × 10 −3 mg/ml air concentration. In a test with C. parasitica, the inhibition rates of neral and geranial were 61.7% and 68.9% at 28 × 10 −3 mg/ml air concentration.

Antibacterial and antifungal activities of essential oils from medicinal plants found in the South Pacific

“…The present study showed a dose-dependent relationship between the tested fungi and the essential oil concentrations as similarly reported in literature (Mishra et al, 2015;Silva et al, 2008). The GC-MS analysis showed the presence of linalool (0.21%), citronellal (45.09%) and citronellol (19.11%) as the main contributors toward the broad antifungal activities (Chand et al, 2016;Lee et al, 2008;Olorunnisola et al, 2014;Pauli and Knobloch, 1987).…”

Fumigant antifungal activity of plant essential oils and components from West Indian bay (Pimenta racemosa) and thyme (Thymus vulgaris) oils against two phytopathogenic fungi

“…The antifungal activities of α-pinene, β-pinene, myrcene, p-cymene, 1,8-cineole, limonene, γ-terpinene, linalool, terpinen-4-ol, α-terpineol, geraniol and β-caryophyllene against two phytopathogens tested in this study have been reported in an earlier study. 16 Two phenols (thymol and carvacrol) showed very strong antifungal activity against P. cactorum and C. parasitica at 28 × 10 -3 mg/ml air concentration, but there was a signi¼cant difference in antifungal activity at lower concentrations. The position of the hydroxyl group (-OH) is the only difference in the chemical structures of the two phenols.…”

“…Jointly or independently, they contribute to antifungal, insecticidal or nematicidal activities. [5][6]16 We analysed 17 and 20 volatile compounds from bay and red thyme oils, respectively, by GC-MS. Chemical components of red thyme and bay oils have been well studied. [7][8] Similar results were obtained in our analysis, although there was some difference in the ratios of chemicals.…”

“…The structure-activity relationships of certain plant compounds against fungi have been well studied. Lee et al 16 investigated antifungal activities of compounds identi¼ed in Myrtaceae essential oils, and reported the primary alcohol to be more active than secondary or tertiary alcohols. In aldehyde groups, α,β-unsaturated carbonyl compounds were more toxic.…”

Effect of essential oils of medicinal plants on leaf blotch in Tanzania grass

“…However, the continued and indiscriminate use of pesticides causes a host of environmental and humanhealth problems, such as the interruption of natural biological control (SOYLU; KURT;SOYLU, 2010), resistance by pathogens causing outbreaks of disease (LEE et al, 2008) and contamination of ground and surface water (FERNANDES NETO;SARCINELLI, 2009). …”