Effects of <i>Cymbopogon nardus</i> (L.) W. Watson essential oil on the growth and morphogenesis of <i>Aspergillus niger</i>

Abstract

The growth inhibitory effect of Cymbopogon nardus (L.) W. Watson var. nurdus essential oil on Aspergillus niger (Van Tieghem) mycelium was determined on agar medium. The mycelium growth was completely inhibited at 800 mg/L. This concentration was found to be lethal under the test conditions. Essential oil at 400 mg/L caused growth inhibition of 80% after 4 days of incubation, and a delay in conidiation of 4 days compared with the control. Microscopic observations were carried out to determine the ultrastructural modifications of A. niger hyphae after treatment with C. nardus essential oil. The main change observed by transmission electron microscopy concerned the hyphal diameter and the hyphal wall, which appeared markedly thinner. These modifications in cytological structure might be caused by the interference of the essential oil with the enzymes responsible for wall synthesis which disturb normal growth. Moreover, the essential oil caused plasma membrane disruption and mitochondrial structure disorganization. The findings thus indicate the possibility of exploiting Cymbopogon nardus essential oil as an effective inhibitor of biodegrading and storage-contaminating fungi.

Fungitoxicity of the essential oil of Citrus sinensis on post-harvest pathogens

“…Our observations find support from the findings of the surface modifications in SEM study as observed by de Billerbeck et al (2001) using Cymbopogon nardus essential oil against A. niger. Zambonelli et al (1996) reported similar findings in Pythium ultimum and Colletotrichum lindemuthianum treated with thyme and lavender oil.…”

“…There have been some studies on the effects of essential oils on post-harvest pathogens (Bishop & Thornton 1997). Some of the essential oils have been reported to inhibit post-harvest fungi in in vitro conditions (Bishop & Reagan 1998;Sharma 1998;de Billerbeck et al 2001;Hidalgo et al 2002;Sharma & Verma 2004). There are also some reports on essential oils enhancing the storage life of fruits and vegetables by controlling their fungal rotting (Dubey & Kishore 1988).…”

In vitro efficacy of Hyptis suaveolens L. (Poit.) essential oil on growth and morphogenesis of Fusarium oxysporum f.sp. gladioli (Massey) Snyder & Hansen

“…Similar types of results were also reported by Sharma and Tripathi (2008) against Aspergillus niger with treatment of Citrus sinensis oil. Cymbopogon nardus oil was also used previously to investigate the growth, conidiation and ultrastructure of A. niger (de Billerbeck et al 2001). Our observations can also be compared to the results presented by Cymbopogon nardus oil, but we found that H. suaveolens essential oil caused severe damage and alterations to vegetative hyphae leading to complete loss of cytoplasm from the hyphae.…”

Use of some essential oils as post-harvest botanical fungicides in the management of grey mould of grapes caused by Botrytis cinerea

“…Most of the essential oils have been reported to inhibit post-harvest fungi in in vitro conditions (Bishop and Reagon 1998;Singh and Tripathi 1999;Bellerbeck et al 2001;Hidalgo et al 2002). In vitro antifungal activity of the essential oils from Monarda citridora and Melaleuca alternifolia was evaluated against various post-harvest pathogens.…”