In Vitro Antifungal Effect of Crude Extracts and Solvent Fractions of Vernonia amygdalina Delile and Croton macrostachyus Hochst. ex Del. against Fungi Isolated from Formalin Fixed Cadavers
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Date
2018-07
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Addis Ababa Universty
Abstract
Cadavers are an excellent tool for medical students to learn the correct anatomic structures, landmarks and relationships. A successful embalming procedure is necessary for better preservation of cadaver for anatomical study. Embalming fluids contain fixatives and disinfectants like formalin and phenol. These chemicals are proven to have diverse toxic effects for embalmers, researchers, students and instructors. Beyond their health and environmental hazard, embalming chemicals are not adequately effective in inhibiting the growth of fungi, bacteria and maggots. The most prevalent problem that anatomists face during handling of cadavers is the growth of fungi on the cadavers. In Ethiopia, no studies have been carried out to find solutions for these problems.
The objective of this study was to isolate fungi grown on formalin-fixed cadavers and test their susceptibilities to the aqueous and 80% methanol extracts as well as solvent fractions of Vernonia amygdalina Del. and Croton macrostachyus hochst. ex Del. with the aim of finding natural products that improve the preservative capacity of the currently used embalming solutions.
The studied plants were selected based on their ethnomedicinal profiles and reported antifungal effects. Suspected colonies were collected by the swab technique from the surface of formalin-fixed cadavers obtained from the School of Medicine, College of Health Sciences, Addis Ababa University, St. Paul‟s Millennium Medical College and Africa Medical College and cultured in Sabouraud Dextrose Agar (SDA). Morphological identification confirmed that the fungi belong to the genera Acremonium, Aspergillus, Geomyces, Madurella, Microsporum, Neosartorya, Penicillium, Scopulariopsis, Talaromyces and Trichophyton with Penicillium genus identified with the highest frequency of occurrence followed by Aspergillus. Furthermore, some of the fungi were identified up to species level by biolog and used for plant extract activity evaluation. The identified species were Aspergillus avenaceus, Aspergillus carneus, Aspergillus restrictus Geomyces pulvereus, Neosartorya fischeri, Penicillium pinophilum, Penicillium restrictum, Penicillium roqueforti, Scopulariopsis brumptii and Talaromyces bacillisporus. The concentrations of aqueous and 80% methanol extracts used for the agar well diffusion method were 25, 50, 100 and 200 mg/mL, whilst 12.5, 25, 50 and 100 mg/mL concentrations were employed for the hexane, chloroform, acetone and methanol fractions. For the determination of minimum inhibitory concentrations (MICs) in the agar dilution assay, concentrations of 1, 2, 4 and 8 mg/mL were utilized for all the experiments involving the total extracts and solvent fractions. The results of the study revealed that the 80% methanol extract of V. amygdalina showed activity towards A. avenaceus, N. fischeri and S. brumptii, whilst all the tested fungi were resistant to the aqueous extract of the same plant. On the contrary, the aqueous extract of C. macrostchyus was active against A. restrictus, P. restrictum, S. brumptii and T. bacillisporus, whereas its 80% methanol extract was effective against P. pinophilum only. Solvent fractions of both plants were not active against the tested fungi in agar well diffusion method.
In conclusion, the findings of the present study have established the susceptibilities of some of the isolated fungal species to the extracts of V. amygdalina and C. macrostachyus, demonstrating the usefulness of the studied medicinal plants at least for the modification of the present embalming solution by mixing it with the plant extracts. The study further provides scientific evidence for the use of the leaves of V. amygdalina for preservation of corpse by people in southern Ethiopia.
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Keywords
Cadaver, Embalming, Antifungal, Medicinal plants, Inhibition zone