Evaluation of microbial diversity present in herbal supplements as revealed by PCR-based 16S sequence analysis

Stone, Stephen (2014) Evaluation of microbial diversity present in herbal supplements as revealed by PCR-based 16S sequence analysis. Undergraduate thesis, under the direction of Colin Jackson from Biology, University of Mississippi.


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Over the last few decades people have become more aware of their general wellness and have turned towards alternative measures to ensure good health. One of these alternative measures, the herbal supplement market, has risen significantly in recent years, even though there is no conclusive research that points to the effectiveness of herbal supplements. Also, because of sparse regulation from the FDA, there are many questions related to the efficacy, composition, processing methods, and, consequently, safety of these supplements. The aim of this study was to determine the microbial composition of herbal supplements in an attempt to identify potential targets for both effectiveness and dangers. Five out of six herbal supplements tested contained evidence of bacterial DNA, with Gingko Biloba being the only exception. Dominant bacterial species or groups detected in multiple samples were Salmonella enterica, Lactobacillus spp, Shigella sonnei, Salmonella paratyphi a, Escherichia_Shigella spp, and Clostridium spp., although 27 different species or species groups were identified. S. enterica and Lactobacillus spp. were the most proportionally abundant species in most samples, representing a potential pathogen (S. enterica) and a potentially beneficial bacterium (Lactobacillus spp.), although neither of these species, or the others detected, could explain the variability in efficacy of supplements. The presence of DNA from potential pathogens in herbal supplements, along with that from bacterial cells that should only present in humans or animals, suggests that further regulation and/or moderation is needed so that herbal supplements will be adequately monitored to ensure their efficacy and safety.

Item Type: Thesis (Undergraduate)
Creators: Stone, Stephen
Student's Degree Program(s): B.A. Biology
Thesis Advisor: Colin Jackson
Thesis Advisor's Department: Biology
Institution: University of Mississippi
Subjects: Q Science > Q Science (General)
Q Science > QR Microbiology
R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine
R Medicine > RV Botanic, Thomsonian, and eclectic medicine
Depositing User: Mr. Stephen Stone
Date Deposited: 09 May 2014 14:13
Last Modified: 09 May 2014 14:13
URI: http://thesis.honors.olemiss.edu/id/eprint/121

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