Effects of Citrus sinensis (L.) Osbeck epicarp essential oil on growth and morphogenesis of Aspergillus niger (L.) Van Tieghem

Abstract

Essential oils from different plant parts are known for their antimicrobial activity but the antifungal effects of essential oil from Citrus sinensis (L.) Osbeck epicarp on growth and morphogenesis of Aspergillus niger has not been observed so far. The mycelial growth was inhibited at 2.5 and 3.0 microg/ml of oil in Potato Dextrose Broth and Agar medium, respectively. These concentrations were fungicidal under the test conditions. The fungitoxicity of oil did not change even at exposure to 100 degrees C and autoclaving. The main changes observed under light and scanning electron microscopy after oil treatment were loss of cytoplasm in fungal hyphae, and budding of hyphal tip. The hyphal wall and its diameter became markedly thinner, distorted and resulted in cell wall disruption. The flattened and empty hyphal tips bifurcated into bud like structures. GC-MS studies of the oil revealed the presence of 10 chemical constituents. Limonene has been found to be major component (84.2%).

Fusarium graminearum growth inhibition mechanism using phenolic compounds from Spirulina sp

“…The other metabolic activity indicators showed negligible changes. loss of rigidity, and integrity of the hypha resulting in the collapse and death of the mycelium, similar to that reported by Sharma and Tripathi (2006). Such possibility is suggested by the inhibition of amylase activity (95%) of the F. graminearum 702-01 stock isolated from wheat.…”

In vitro antifungal activity and cytotoxic effect of essential oils and extracts of medicinal and aromatic plants against Candida krusei and Aspergillus fumigatus

“…This difference in antifungal activity between essential oils from plants of the same species can be explained by the chemotype (chemical composition), geographical region of plant collection, age of plant, extraction method of oils, method used to assess the antifungal activity or by the intra or inter species differences (Samaranayake et al, 1995;Cruz et al, 2007;Maksimovic et al, 2008). Sharma & Tripathi (2008) have shown that the antifungal activity of essential oils is better evaluated in liquid than in solid media, since in the latter, the hydrophobic nature of the majority of essential oil components hamper uniform diffusion of these substances through the agar medium (de Cerqueira et al, 2007). We used the standard microdilution methods M38-A and AFST-EUCAST for the evaluation of antifungal susceptibility of filamentous fungi and yeasts, respectively.…”

Citral and carvone chemotypes from the essential oils of Colombian Lippia alba (Mill.) N.E. Brown: composition, cytotoxicity and antifungal activity

“…Sharma and Tripathi (2008) have shown that the antifungal activity of essential oils can be more effectively evaluated in liquid rather than in solid media, since in the latter, oil diffusion may not be appropriate. In this study, the standard methods of microdilution for the evaluation of antifungal susceptibility to drugs were used.…”

“…Hayes and Markovic (2002) showed that Backhousia citriodora essential oil, with a 92% composition of citral, was active against C. albicans and Aspergillus niger with MICs comparable to commercial citral. Recently, Sharma and Tripathi (2008) determined, through an agar diffusion method, a MIC value of 0.3 µg/mL against A. niger for a Citrus sinensis essential oil, which has a limonene concentration of 87%. Linalool and linalool-rich essential oils from Croton cajucara are active against C. albicans, with MIC values of 0.7 µg/mL and 13.4 µg/mL, respectively (Alviano et al 2005).…”