Post-Harvest Fungi of Vitellaria Paradoxa and Parkia Biglosa in Chad Republic and Bioactivity of Natural Products against some Pathogenic Fungi

Abstract

In Chad Republic, kernels/grains of Shea butter Nuts butter tree (Vitellaria paradoxa) and locust bean (Parkia biglobosa) are two Non-Timber Forest Products (NTFP) which offers important revenues to the growers in the production, processing and marketing chain. However, un-identified post-harvest fungi that affect their sanitary quality, marketability and nutritional value are responsible for high post-harvest losses. The objective of the study was to contribute to the management of the post-harvest diseases of Shea butter nuts and locust bean. To achieve this, fungi were isolated from infected grains and their pathogenicity tested. Then, antifungal activity of essential oil (EO) of Thymus vulgaris (obtained by hydro distillation) and crude extract of Panax africana (obtained from a naturopath) was carry out by the dispersion method on the agar medium on four pathogenic fungi isolated from the two infected NTFP. Results showed that fungal species frequently associated with Shea nuts and locust bean grains were: Aspergillus niger (46%), Rhizopus nigricans (17%), Oidium sp (22%) and Cercospora sp (8%); and Oidium sp (55%), A. niger (18%), A. flavus (18%) and Cercospora sp (6%) in V. paradoxa and P. biglobosa respectively. Pathogenicity test was positive with all species of the genus Aspergillus and the species Oidium sp. Growth inhibition of the four fungal species tested with essential oil of T. vulgaris at 1.5 µl/ml and with crude extract of Panax africana at 120 µg/ml and this was significantly comparable (p<0.05) to the reference fungicide (Terazeb). Biological control of post-harvest diseases of V. paradoxa and P. biglosa grains with EO of T. vulgaris and Panax africana is envisaged for further studies.

Recent advances in the implementation of ultrasound technology for the extraction of essential oils from terrestrial plant materials: A comprehensive review

“…EOs antifungal activity is similar to its antibacterial activity described before [63] . He et al [64] explained that EOs of Perilla frutescens rhizome destroyed cell walls and interfered with the morphology of the fungus Aspergillus flavus , leading to a notable reduction in its growth.…”

“…However, two primary physical phenomena commonly observed in the extraction process of EOs are diffusion in cell membranes and walls and cell wall destruction through the cavitation process. It leads to the rinsing of cell contents, resulting in increased mass transfer and enhancing the overall extraction process [63] , [79] , [80] , as shown in Fig. 4 .…”