Antifungal Potency of Essential Oil Components of African Ginger - Zingiber officinale (Roscoe)

Abstract

The antifungal potency of essential oil of zingiber officinale (Roscoe) (African Ginger) was investigated using the hyphal extension bioassay. The essential oil (vacuum distillate) was obtained through vacuum distillation. Gas chromatography-mass spectrometry analysis of the oil revealed 27 compounds with six compounds (1.8-Cineole, α-Pinene, Camphene, ( E,E )-α-Fanesene, Geranial and Zingiberene) showing major biological activity. Results of antifungal screening of the bioactive blend from these compounds and vacuum distillate in comparison with four synthetic fungicides revealed that the bioactive blend was more effective against the test pathogen – Botryodiplodia theobromae (Pat.) in culture allowing the shortest hyphal lengths of 1.12cm, 0.28cm and 0.18cm at 50, 75 and 100μg/ml concentration compared with 3.39cm, 0.77cm and 0.28cm respectively obtained for forcelet (the best fungicide tested). Vacuum distillate was comparable (P<0.05) in performance to the bioactive blend. These two plant-based chemicals were persistent in their action against B. theobromae at all levels of concentration throughout the course of the experiment.