Vet World Vol.17 December-2024 Article - 28
Research Article
Veterinary World, 17(12): 2975-2984
https://doi.org/10.14202/vetworld.2024.2975-2984
Phytochemical composition and antimicrobial potential of Stevia rebaudiana Bertoni extract and its topical spray formulation against animal skin pathogens
2. Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand.
3. Division of Physiology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand.
4. Department of Pharmacology, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok, Thailand.
Background and Aim: The rise of antimicrobial resistance in veterinary medicine is a significant concern, particularly for pathogens responsible for skin infections. Although Stevia rebaudiana Bertoni (stevia) has demonstrated effective antimicrobial properties, there is limited research on its efficacy against animal skin pathogens. This study aimed to identify natural compounds in stevia extract, develop a topical spray formulation, and assess its effectiveness against six common bacterial and fungal pathogens associated with animal skin infections.
Materials and Methods: The aerial parts of stevia plants were extracted using hexane in a Soxhlet apparatus. Total phenolic and flavonoid contents were quantified using colorimetric assays. The volatile oil content was analyzed using gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of stevia extract against Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes was evaluated using broth microdilution and time-kill tests. Environmental scanning electron microscopy (E-SEM) and leakage studies were conducted to assess the extract’s impact on microbial morphology and cell membrane integrity. The antimicrobial efficacy and stability of a topical spray formulation containing stevia extract were evaluated using time-kill and freeze-thaw testing.
Results: The stevia extract yield was 3.59% of the dry plant weight with 259.96 ± 23.66 mg gallic acid equivalent (GAE)/g extract of total phenolics and 247.41 ± 19.92 mg quercetin equivalent (QE)/g extract of total flavonoids. GC-MS analysis identified major volatile components, including N-acetyl-14, 15, 16-trinorlabd-8(17)-en-13-amine (37.70% of peak area), phytol (11.02% of peak area), (-)-spathulenol (9.46% of peak area), n-hexadecanoic acid (8.01% of peak area), and (diphenylphosphinoyloxymethyl) dimethylsilane (7.59% of peak area). The minimum inhibitory concentration of the extract against the tested microorganisms ranged from 0.25 to 128.00 mg/mL. Time-kill kinetics exhibited time- and concentration-dependent germicidal effects. E-SEM and cell leakage analyses indicated that stevia extract compromised microbial cell membrane integrity. A spray formulation containing 10% w/w stevia extract displayed excellent eradication efficacy, achieving a 99.9999% reduction of S. pseudintermedius and a 99.999% reduction of M. pachydermatis and dermatophytes, with good stability after six freeze-thaw cycles.
Conclusion: Stevia extract is an effective antimicrobial against S. pseudintermedius, M. pachydermatis, Mi. canis, Mi. gypseum, Mi. gallinae, and T. mentagrophytes in vitro. Future research will investigate the pharmaceutical properties and toxicity profiles of purified compounds and determine appropriate dosages and clinical efficacy.
Keywords: animal skin infection, antimicrobial activity, Stevia rebaudiana, topical formulation.
How to cite this article: Singh R, Borlace GN, Sringam P, Thongkham E, and Aiemsaard J (2024) Phytochemical composition and antimicrobial potential of Stevia rebaudiana Bertoni extract and its topical spray formulation against animal skin pathogens, Veterinary World, 17(12): 2975-2984.
Received: 2024-09-05 Accepted: 2024-11-26 Published online: 2024-12-30
Corresponding author: E-mail:
DOI: 10.14202/vetworld.2024.2975-2984
Copyright: Singh, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
