Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Bradley C. Bennett

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Suzanne Koptur

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Jennifer Richards

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

J. Martin Quirke

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Maria Fadiman

Fifth Advisor's Committee Title

Committee Member


Ethnobotany, medicinal plants, diabetes, social network analysis, phenolic, alpha-glucosidase, Ethnomedicine

Date of Defense



Diabetes mellitus (DM) is a group of non-infectious diseases that cause hyperglycemia. DM symptoms were first clinically described by ancient Greek physicians whose prescriptions included plant-based remedies. Today, DM affects >400 million people globally and prevalence rates are rapidly increasing in developing countries where basic healthcare relies on local knowledge of botanical remedies. Many developing countries are home to diverse peoples and plants—providing fodder for varied plant-selection strategies and unique botanical pharmacopoeias.

I addressed the plant-selection strategies used in a multi-ethnic, developing country, Trinidad and Tobago (T&T), to ascertain their role in shaping the local antidiabetic pharmacopoeia and to assess their benefits and risks in identifying safe and useful remedies. Using literature reviews, field surveys, and laboratory bioassays, I completed three categories of analysis.

Ethnobotanical analyses showed that T&T’s antidiabetic pharmacopoeia is primarily of recent origin as >50% of the 48 historical DM remedies were Neotropical natives, including congenerics of well-known medicinal Paleotropical genera. Nevertheless, conservative knowledge transmission was also evident as several Paleotropical species of T&T’s pharmacopoeia, including Momordica charantia and Catharanthus roseus were also used in Africa, India and across the Caribbean. Paleotropical natives with a long history of use are likely to be safer remedies.

Ethno-medicinal analyses of the pre- and post-2000 DM remedies of T&T, totaling 99 species, suggest that the centuries-old hot/cold folk disease-model was the model predominantly used in plant-selection. Parallels found between T&T folk concepts and biomedical mechanisms of DM provide probable bases for efficacy but the chronic use of purgatives and bitter-tasting plants is likely to be risky.

Phytochemical analyses revealed that 69% of the tested plant extracts contained phenolic compounds, with more than half producing >80% alpha-glucosidase inhibition. Phenolic content and alpha-glucosidase inhibition were strongly correlated among food plants used as medicines, suggesting higher probability of selection as a result of non-target effects. The medicinal use of food plants may provide the best margins of safety and efficacy in identifying antidiabetic remedies.

Together, these analyses showed how culture-specific plant-selection strategies can identify safe, useful remedies for developing countries to address their increasing DM prevalence in a cost-effective and sustainable manner.




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