The antifungal activity and bioanalysis of fractions from Tulbaghia violacea (leaf and root) acetone extracts.
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Date
2022-12
Authors
Makgati, Mogau Mafise Brian
Journal Title
Journal ISSN
Volume Title
Publisher
Vaal University of Technology
Abstract
Infectious diseases represent a critical problem to health and cause morbidity and mortality worldwide. Despite the significant progress in human medicine, infectious diseases caused by microorganisms such as fungi are still a major threat to public health. Tulbaghia violacea is one medicinal plant that has been used traditionally to manage fungal infections. The present study aimed to determine the antifungal activity and perform bioanalysis of acetone fractions from T. violacea extracts. Tulbaghia violacea crude leaf and root acetone extracts and their fractions were tested against seven fungal species for antifungal activity. The plant extracts were prepared using the maceration method, and column chromatography was utilized to obtain fractions.
The plant extract’s total phenolic and flavonoid contents were determined using the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activity was evaluated using the free radical scavenging methods 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS•+) assays. The antimicrobial activity of T. violacea crude leaf and root extracts and their fractions was determined using the well diffusion, microtiter, and time-kill assay. The compounds present in the T. violacea leaf and root extracts and their fractions were determined using GC-MS. The results indicated that the total phenolic content (TPC) of all four samples of T. violacea leaf extracts ranged from 0.597-5.003 mg of Gallic acid equivalent/g, whereas total flavonoid content (TFC) varied between 5.324- 15.844 mg of Quercetin/g. The TPC and TFC of all root extracts ranged between 3.19-8.41 mg of GAE/g and 10.28-12.40 844 mg of QE/g, respectively. DPPH leaf fractions ranged from 48-50% and 60-61% for root extracts at 0.5 mg/mL. The ABTS assay also showed a dose-dependent radical scavenging activity. The scavenging activity ranged between 92-95% (crude leaf extract and fractions) and 77-84% (crude root extract and fractions). The investigations using GC-MS revealed a total of 21 metabolites with varied phytochemical activity.
For antimicrobial activity, all T. violacea leaf and root acetone extracts and their fractions suppressed the growth of all fungal strains with leaf extracts zones of inhibition ranging between 3-18 mm whereas the root extracts ranged between 3.3-21 mm. The MIC of leaf and root acetone extracts and their fractions ranged between 0.78-12.5 mg/mL and 0.39-12.5 mg/mL, respectively whereas the MFC values of the plant leaf and root acetone extracts and their fractions ranged between 0.78- ˃ 50 mg/mL and 0.39-25 mg/mL, respectively. The time-kill curve assay demonstrated that most of the leaf extract and their fractions at 2 MIC demonstrated fungistatic activity averaging 3-6.23 log10 kill against C. albicans whereas, almost all root extract and their fractions demonstrated fungicidal activity, averaging 0.04-3 log10 kill.
The membrane permeability assay indicated membrane damage in a dose-dependent manner for all extracts. In conclusion, T. violacea possesses phytocomponents with good potential as antifungals.
Description
M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology.
Keywords
Phytochemicals, Immunocompromised individuals, Fungal pathogens, Antifungal activity, Antimicrobial activity, Tulbaghia violacea, Time-kill assay, Membrane permeability assay, GC-MS, Apoptosis, AO/EB, Fungistatic, Fungicidal, Necrotic cells