Antimicrobial Activity of Syzygium aromaticum and Zanthoxylum xanthoxyloides Essential Oils Against Phytophthora megakarya

Abstract

The aim of this study was to assess the chemical composition and the antimicrobial activity of essential oils of dried fruits and buds of Zanthoxylum xanthoxyloides (Z. xanthoxyloides) and Syzygium aromaticum (S. aromaticum or clove), respectively, against Phytophthora megakarya (P. megakarya). Essential oils were extracted by hydrodistillation, and their composition was determined by gas chromatography and by gas chromatography coupled with Mass Spectrometry. The minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) of the essential oils against P. megakarya were assessed by the Agar dilution method. The in vivo efficacy study consisted of spraying the essential oil emulsions on cocoa pod husk pieces (CPHP), followed by the inoculation with P. megakarya zoospores. The hydrodistillation yielded 10.54 and 1.89% of essential oils for S. aromaticum and Z. xanthoxyloides, respectively. Both oils were mainly made up of oxygenated monoterpenes (89.58 and 88.2%, respectively). Eugenol (83.02%) and eugenyl acetate (9.15%) were the main components of clove oil while α‐citronelol (25.83%) and trans‐geraniol (16.49%) were mostly found in the Z. xanthoxyloides oil. Clove oil exhibited stronger antimicrobial activity with a MIC of 250 μl/l than Z. xanthoxyloides with MIC of 350 μl/l. The symptoms were totally suppressed on pod husk treated with clove oil at 2000 μl/l. The decrease in the growth rate of the necrosis (GRN) and the sporulation of P. megakarya (PS) on cocoa husk after the successful infection was significant after the treatment with essential oils. These results are promising and indicate that the studied essential oils might be further investigated as natural alternatives to synthetic fungicides for the control of cocoa black pod diseases.

Evaluation of Clove Essential Oil as a Mycobiocide Against Rhizopus stolonifer and Fusarium solani, Tuber Rot Causing Fungi in Yam (Dioscorea rotundata Poir.)

“…Moreover, Nana et al. () also showed the in vivo effectiveness of clove oil to protect cocoa pod against black pod disease. In addition, the lipophilic property of the essential oil that readily diffuses into plant tissues across membranes and acts on mycelia and conidia could justify the reduction of the necrosis rate (Xing et al.…”

“…Essential oils extracted from clove have been previously investigated for chemical composition and biological activities. Nana et al (2015) steamed distillated clove oil from another locality of Cameroon and obtained a yield of 10.54%. In this study, we obtained a significantly lower yield (6.34%), supporting the fact that the rate of secretion of secondary metabolites by plants can vary depending on the site.…”

Chemical Composition and Anti-bacterial Effects of Clove (Syzygium aromaticum) Flowers

“…By the last technology, many spots were observed and the spots were scratched and the chemical components were extracted by ethanol. Finally, it was gained the alcoholic extraction of clove that used in further experiments (9). Several previous studies focused on the extraction of different compounds from clove (Syzygium aromaticum) flowers and used in different fields of medicine.…”

“…Both of isolates were cultured into Muller Hinton broth prior to experiment (9). The disc diffusion method was used to assessment the antibacterial activity of the extract against Bacillus and Serratia marcescens.…”

Chemical Composition of Essential Oils from SixZanthoxylumSpecies and Their Repellent Activities against Two Stored-Product Insects

“…Also, Zanthoxylum species have a folklore history in the treatment of various diseases, such as inflammation [15], toothache, lumbago [16], ascarid infection [17], sickle-cell anaemia, and malaria. Literatures have also shown that Zanthoxylum species possess a potential antiinsect [7,18,19], antimicrobial [20], antibacterial [21], and antifungal [22] activities.…”