About
56
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Introduction
My research passion centers on the discovery of bioactive natural products, nutraceuticals and their role in supporting human health. As a multidisciplinary researcher, I focus on ethnobotanical leads, and fungi from multiple ecological sources. I combine field screening, analytical metabolomics, and detailed structural and biological analysis to characterize active constituents as well as elucidate the mechanistic pathways of efficacy against infectious and chronic human diseases.
Additional affiliations
August 2019 - present
January 2015 - December 2016
Position
- Instructor
Description
- I teach organic chemistry and general chemistry (for majors and non-majors) with class sizes 20-150 students.
January 2015 - July 2018
South Univeristy
Position
- Professor (Associate)
Description
- I teach general chemistry, and nutritional foundations.
Education
January 2010 - December 2014
August 2007 - December 2009
June 2006
ACS Synthetic Organic Chemistry: Modern Methods and Strategies
Field of study
Publications
Publications (56)
A central challenge of natural products research is assigning bioactive compounds from complex mixtures. The gold standard approach to address this challenge, bioassay-guided fractionation, is often biased toward abundant, rather than bioactive, mixture components. This study evaluated the combination of bioassay-guided fractionation with untargete...
Endolichenic fungi are diverse groups of predominantly filamentous fungi that reside asymptomatically
in the interior of lichen thalli. Natural products from endolichenic fungi, isolated from a
variety of different lichen species, have been attracting increased attention for their potential to produce
bioactive metabolites possessing new structures...
A challenge that must be addressed when conducting studies with complex natural products is how to evaluate their complexity and variability. Traditional methods of quantifying a single or a small range of metabolites may not capture the full chemical complexity of multiple samples. Different metabolomics approaches were evaluated to discern how th...
Covering: up to the end of 2018 Dietary supplements, which include botanical (plant-based) natural products, constitute a multi-billion-dollar industry in the US. Regulation and quality control for this industry is an ongoing challenge. While there is general agreement that rigorous scientific studies are needed to evaluate the safety and efficacy...
Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is a deadly and debilitating disease globally affecting millions annually. Emerging drug-resistant Mtb strains endanger the efficacy of the current combination therapies employed to treat tuberculosis; therefore, there is an urgent need to develop novel drugs to combat this disease. Artemisi...
Introduction:
Selection of marker compounds for targeted chemical analysis is complicated when considering varying instrumentation and closely related plant species. High-resolution gas chromatography-mass spectrometry (GC-MS), via orbitrap detection, has yet to be evaluated for improved marker compound selection.
Objective:
This study directly...
Diet-derived aryl hydrocarbon receptor (AHR) ligands have potential to maintain gut health. However, among the myriad bioactive compounds from foods, identifying novel functional ligands which would significantly impact gastrointestinal health is a challenge. In this study, a novel AHR modulator is predicted, identified, and characterized in the wh...
Mass spectrometry metabolomics has become increasingly popular as an integral aspect of studies to identify active compounds from natural product mixtures. Classical metabolomics data analysis approaches do not consider the possibility that interactions (such as synergy) could occur between mixture components. With this study, we developed "interac...
Cannabis is a complex biosynthetic plant, with a long history of medicinal use. While cannabinoids have received the majority of the attention for their psychoactive and pharmacological activities, cannabis produces a diverse array of phytochemicals, such as terpenes. These compounds are known to play a role in the aroma and flavor of cannabis but...
Natural products, including plants, have played a remarkable role in the development of antiinfective therapeutics. However, in their unrefined form, natural products consist of complex mixtures of many structurally diverse components, the identities of which are often not known, and incredibly varied due to variations in taxonomy, environment, and...
Botanical supplements with broad traditional and medicinal uses represent an area of growing importance for American health management; 25% of U.S. adults use dietary supplements daily and collectively spent over $9. 5 billion in 2019 in herbal and botanical supplements alone. To understand how natural products benefit human health and determine po...
Despite the value of mass spectrometry in modern natural products discovery workflows, it remains very difficult to compare data sets between laboratories. In this study we compared mass spectrometry data for the same sample set from two different laboratories (quadrupole time-of-flight and quadrupole-Orbitrap) and evaluated the similarity between...
The botanical natural product goldenseal can precipitate clinical drug interactions by inhibiting cytochrome P450 (CYP) 3A and CYP2D6. Besides P‐glycoprotein, effects of goldenseal on other clinically relevant transporters remain unknown. Established transporter‐expressing cell systems were used to determine the inhibitory effects of a goldenseal e...
The safety and efficacy of kratom (Mitragyna speciosa) for treatment of pain is highly controversial. Kratom produces more than 40 structurally related alkaloids, but most studies have focused on just two of these, mitragynine and 7-hydroxymitragynine. Here, we profiled 53 commercial kratom products using untargeted LC-MS metabolomics, revealing tw...
Hydrastis canadensis, commonly known as goldenseal, is a botanical native to the southeastern United States that has been used for the treatment of infection. The activity of goldenseal is often attributed to the presence of alkaloids (cyclic, nitrogen-containing compounds) present within its roots. Chemical components of botanical supplements like...
Two separate commercial products of kratom [Mitragyna speciosa (Korth.) Havil. Rubiaceae] were used to generate reference standards of its indole and oxindole alkaloids. While kratom has been studied for over a century, the characterization data in the literature for many of the alkaloids are either incomplete or inconsistent with modern standards....
Efforts to meet the steadily increasing global need for plant products without continuously expanding the environmental footprint of crop production face several convoluted challenges. One challenge is minimizing crop loss due to diseases and pests without heavily relying on synthetic pesticides. Microorganisms secrete diverse molecules to influenc...
Adulteration remains an issue in the dietary supplement industry, including botanical supplements. While it is common to employ a targeted analysis to detect known adulterants, this is difficult when little is known about the sample set. With this study, untargeted metabolomics using liquid chromatography coupled to ultraviolet-visible spectroscopy...
Non-targeted and suspect analyses with liquid chromatography/electrospray/high-resolution mass spectrometry (LC/ESI/HRMS) are gaining importance as they enable identification of hundreds or even thousands of compounds in a single sample. Here, we present an approach to address the challenge to quantify compounds identified from LC/HRMS data without...
Here we introduce a novel implementation of weighted quantile sum (WQS) regression, a modeling strategy for mixtures analyses, which integrates a random subset algorithm in the estimation of mixture effects. We demonstrate the application of this method (WQS RS) in three case examples, with mixtures varying in size from 34 to 472 variables. In eval...
Compounds derived from natural sources represent the majority of small-molecule drugs utilized today. Plants, owing to their complex biosynthetic pathways, are poised to synthesize diverse secondary metabolites that selectively target biological macromolecules. Despite the vast chemical landscape of botanicals, drug discovery programs from these so...
Current estimates report that approximately 25% of U.S. adults use dietary supplements for medicinal purposes. Yet, regulation and transparency within the dietary supplement industry remains a challenge, and economic incentives encourage adulteration or augmentation of botanical dietary supplement products. Undisclosed changes to the dietary supple...
Botanical medicines have been utilized for centuries, but it remains challenging to identify bioactive constituents from complex botanical extracts. Bioassay-guided fractionation is often biased toward abundant or easily isolatable compounds. To comprehensively evaluate active botanical mixtures, methods that allow for the prioritization of active...
Green tea (Camellia sinensis) is a popular beverage worldwide, raising concern for adverse interactions when co-consumed with conventional drugs. Like many botanical natural products, green tea contains numerous polyphenolic constituents that undergo extensive glucuronidation. As such, the UDP-glucuronosyltransferases (UGTs), particularly intestina...
A critical challenge in the study of botanical natural products is the difficulty of identifying multiple compounds that may contribute additively, synergistically, or antagonistically to biological activity. Herein, it is demonstrated how combining untargeted metabolomics with synergy-directed fractionation can be effective toward accomplishing th...
This chapter focuses on Native American ethnobotany, with a smaller amount of information on the European Diaspora that dominates the Americas today. The Americas can be separated into the following regions: North, Central, and South America, and the Caribbean islands. Many farming tribes were known for cultivating the “three sisters” companion cro...
Metabolomics has emerged as an important analytical technique for multiple applications. The value of information obtained from metabolomics analysis depends on the degree to which the entire metabolome is present and the reliability of sample treatment to ensure reproducibility across the study. The purpose of this study was to compare methods of...
The potential of fungal endophytes to alter or contribute to plant chemistry and biology has been the topic of a great deal of recent interest. For plants that are used medicinally, it has been proposed that endophytes might play an important role in biological activity. With this study, we sought to identify antimicrobial fungal endophytes from th...
American Indian and Alaska Native (AI/AN) students can experience a disconnect between their indigenous culture and the Eurocentric focus of U.S. science, technology, engineering, and mathematics (STEM) classrooms. As a result, some AI/AN students are less motivated to participate in educational activities that seem irrelevant or detached from thei...
##Assembly-Data-START## Assembly Method :: Sequencher v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
##Assembly-Data-START## Assembly Method :: Sequencher v. 5.3 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
Global incidence of type 2 diabetes has escalated over the past few decades, necessitating a continued search for natural sources of enzyme inhibitors to offset postprandial hyperglycemia. The objective of this study was to evaluate coastal Alaskan seaweed inhibition of α-glucosidase and α-amylase, two carbolytic enzymes involved in serum glucose r...
Inflammation of adipose tissue and increased metabolism of carbohydrates are two dominant factors underlying the development of insulin resistance and metabolic syndrome, a condition that disproportionately impacts Alaska Native populations. However, traditional dietary foods, like seaweeds, are a rich source of polyphenols with potential to counte...
A dominant factor underlying the development of metabolic syndrome is abdominal obesity, which is associated with chronic inflammation in adipose tissue. Alaska Native populations, who suffer disproportionately high rates of obesity, have shifted away from traditional dietary foods, like seaweeds, that are a rich source of polyphenols with potentia...
In the harsh, unprotected wilds, environmental or climatic stressors (elicitors) provoke the deposition of health-protective secondary phytochemicals in plants that will help them adapt and thrive. For berries endemic to the wind-battered open plains of the Dakotas, the arctic tundra of Alaska, exposed elevations in the Andean Mountains or the nutr...
Alaska Native (AN) communities have utilized tidal plants and marine seaweeds as food and medicine for generations, yet the bioactive potential of these resources has not been widely examined. This study screened six species of Alaskan seaweed (Fucus distichus, Saccharina latissima, Saccharina groenlandica, Alaria marginata, Pyropia fallax, and Ulv...
People draw upon multiple forms of environmental knowledge, from scientific to highly contextual local or traditional forms of knowledge, to interpret problems and gauge risks in complex socio-ecological systems. In collaboration with three remote Alaska Native communities, and using an interdisciplinary, participatory, and mixed methods research a...
The emerging research evidence regarding functional food health benefits, coupled with the modern rise in degenerative and lifestyle-related health conditions, has created a growing market in the United States: the super-fruit. Wild berries, which contain bioactive phytochemicals with demonstrated efficacy against metabolic syndrome, have fulfilled...
The emerging research evidence regarding functional food health benefits, coupled with the modern rise in degenerative and lifestyle-related health conditions, has created a growing market in the United States: the super-fruit. Wild berries, which contain bioactive phytochemicals with demonstrated efficacy against metabolic syndrome, have fulfilled...
Wild berries are fundamental components of traditional diet and medicine for Native American and Alaska Native tribes and contain a diverse array of phytochemicals, including anthocyanins and proanthocyanidins, with known efficacy against metabolic disorders. Bioexploration represents a new paradigm under which bioactive preparations are screened i...
Science teachers continuously struggle to develop hands-on, stimulating pedagological tools
that capture the enthusiasm of their students, while simultaneously grappling with issues of cost-
effectiveness and relevance to real-world situations. These constraints are particularly pronounced when
educating indigenous students, who navigate daily b...
Wild berries are integral dietary components for Alaska Native people and a rich source of polyphenolic metabolites that can ameliorate metabolic disorders such as obesity and diabetes. In this study, five species of wild Alaskan berries (Vaccinium ovalifolium , Vaccinium uliginosum , Rubus chamaemorus , Rubus spectabilis , and Empetrum nigrum) wer...
Wild indigenous berries including Vaccinium uliginosum, V. ovalifolium, Empetrum nigrum, Rubus chamaemorus , and R. spectabilis , traditional subsistence foods in American Indian and Alaskan Native (AI/AN) populations, are a rich source of anthocyanins (AC) and proanthocyanidins (PAC), with known efficacy against metabolic disorders. In recent year...
Questions
Questions (11)
Good afternoon brilliant minds!
I am looking to try to score two different MS2 scans to get a sense of their similarity. I know about Tanimoto or Jaccard similarities, but how can I easily input the scan data to do the calculation? I know there is GNPS, but I'm not looking to associate the whole run, just a couple of individual scans.
Thanks!
In starting up a new lab, I'm trying to be proactive and think constructively about how to handle the eventual multitude of samples that we generate, and tying the data together. It seems like developing a barcode system for extracts/fractions, and tracking their information in a database of some sort would be relatively straight forward.
So, my thought is: make an extract/fraction set from plant X. A database will have all the information about X (taxonomy, source, acquired date, storage location in the lab, link to extraction protocol, etc.), and I will put a barcode on X that ties back to that database, and so that I can put the barcode number into a lab notebook page when I use it in an assay (or do further fractionation/isolation). A scannable barcode would be put on the storage vial itself to make life easier.
However, this is something I've never done before, so I am curious what other researchers/labs out there use to track samples. This is not for purchased chemicals, but rather for extracts/molecules generated in house. And if it ties into an ELN, all the better.
I'd prefer something open source or free (I usually prefer to do-it-myself), but I am not an expert in SQL or other databasing software. I am willing to pay for the right service if it is truly that much better.
Thank you in advance for your insight and help!!
As part of a new script we're working on, I need the scan-by-scan data exported out of our mass spec data files (obtained on a Thermo Q-Exactive orbitrap instrument), with m/z and intensity (counts) for each scan. I can do it manually, but that'll take forever!! Does anyone know of way to export it, or if there's another way to do it (through MSConvert, or R, or MZMine, etc.)? Thanks in advance!!
We recently purchased two Eppendorf 5000uL adjustable Research plus pipettes, and have had no end of trouble with them. The piston keeps getting stuck in the barrel, preventing the piston from re-setting after delivering the liquid. We have to disassemble it to get it reset. We use the pipette filters all the time, and filtered pipette tips to prevent solvent from getting up into the barrel, and this problem was happening right away as soon as we purchased them.
Has anyone else seen this issue before? Is it something simple, like re-greasing the piston (though they're brand new, I had hoped we wouldn't have to do maintenance on them for a while). Or do we need to think about replacing parts?
TIA for your advice!
In looking at systems that can go from analytical to semi-prep (or full prep), are there any systems you have used that you like? I was taking a peek at the Gilson system (http://www.gilson.com/en/AI/Products/52.69/Default.aspx#.WhWe6xN-qRv), and we've used the Varian modular system in the past (but not sure if those are still available). Any reviews or recommendations would be greatly appreciated!! Thank you!
I'm looking to do statistics and modeling of metabolomics data, then go further with some data manipulations and calculations using the model's matrices, and have it be implemented in an easy-to-use manner. But I'm not a computer scientist or programmer by trade, so something user-friendly would be helpful. Thanks!
We've started a project looking at some OTC botanical tinctures, which are already dissolved in either glycerol/water or glycerol/ethanol. I need to get them dried down for our analysis, and that is proving to be difficult. Does anyone have experience removing glycerol from a sample? Either rotovapping, or lyophilizing, or some other method? Thanks for your help!!
I am in the process of reviewing a manuscript, which cites several MS and PhD theses as deposited in the university's library. However, multiple searches, including PubMed, Google Scholar, and the university's own library portal, fail to bring these manuscripts up. I am wondering the following...
If a student does not wish to publish publicly his or her dissertation or thesis, that is perfectly ok. But is it then acceptable to cite it as a reference, when no one can verify or refer back to the original research?
If it is not ok to cite the research like this, can it be brought up in a different way?
Thanks for your input in helping me shape my review!
I am venturing into the arena of multivariate analysis, PLS and PCA for complex data sets. The lab I am in uses PRS's software Sirius, but I am having trouble navigating the menus and options. Does anyone out there use this software already? Or know of any tutorial material to help get me up and running?
Thank you!
I've been searching for commercial sources of some of the more common phlorotannins, like eckol, fuhalol, etc., that could be used for HPLC quantification and cell culture studies. I've looked at some of the usual companies (ChromaDex, Sigma), but so far to no avail. Any suggestions?
My current research focus is on a couple species of marine microalgae. However, I'm tryng to find a way to rapidly quantify the percentage or raw amount of viable algae cells, in order to ascertain the effect of treatments on the algae. I've tried staining them using either Trypan blue (to identify dead cells) or MTS/MTT (to identify live cells), yet neither has produced a noticeable color change in the control samples.
From the literature, it seems this has happened before; Li and Song's 2007 article in Phycologia(doi: http://dx.doi.org/10.2216/07-11.1) mentioned several species of algae that were not able to be stained by MTT/MTS.
Does anyone here have experience using organic dyes to measure viability? If so, have you run into similar problems with certain dyes/stains? Are there any suggestions of other chemicals that might be more effective, or other methods that could easily measure the viable cells in a sample?
