Publications by authors named "Larry Walker"

Since its establishment in 1994, the National Center for Natural Products Research (NCNPR) at the University of Mississippi has made notable contributions to the field of natural product research, coinciding with the passage of the Dietary Supplement Health and Education Act. Over the past three decades, the Center has focused on studying plants, herbs, and other natural materials for applications in medicine, agriculture, and nutraceuticals, particularly in the area of botanical dietary supplements. NCNPR scientists have been actively engaged in developing and improving quality control measures to help ensure the safety of dietary supplements in response to a growing market.

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Cannabidiol (CBD) is a major phytocannabinoid from . It is currently widely available and widely used in the USA, but despite its rapid progress to market, the pharmacology and toxicology of both CBD and cannabidiol-rich cannabis extracts (CRCE) remain largely unknown. The goals of this study were to investigate the potential of a novel human microphysiological system to emulate CRCE-induced hepatotoxicity and pharmacological properties demonstrated in animal models.

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Cannabidiol (CBD) has gained widespread popularity; however, its pharmacological and toxicological profiles in the context of human genetic diversity remain largely unexplored. Here, we investigated the variability in metabolism and toxicity of CBD-rich cannabis extract (CRCE) in genetically diverse mouse models: C57BL/6J, B6C3F/J, and NZO/HlLtJ strains. Mice received a single dose of CRCE containing 57.

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Article Synopsis
  • Primaquine and Tafenoquine are the only drugs that can cure malaria completely, but they pose risks for individuals with G6PD deficiency, potentially causing severe blood cell damage.
  • The study introduces a new mouse model replicating a specific human G6PD variant, allowing researchers to observe how a metabolite called 5,6-POQ affects red blood cells.
  • The research indicates that 5,6-POQ is not just a harmless byproduct of drug metabolism but actively contributes to the destruction of older red blood cells in G6PD-deficient individuals, challenging previous assumptions about its role.
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Article Synopsis
  • Primaquine (PQ) is an anti-malarial drug recommended by WHO, but it can have harmful effects in individuals with G6PD deficiency, a condition affecting red blood cells.
  • This study involved administering a low dose of PQ to African males while monitoring drug levels and hemoglobin changes, finding that the drug's pharmacokinetics followed a simple one-compartment model and that body weight influenced clearance and volume.
  • Importantly, the results showed no significant decrease in hemoglobin levels post-treatment, suggesting that a single low dose of PQ is safe for G6PD-deficient patients.
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The berries of have been traditionally used for therapeutic purposes. They have been reported to possess various pharmacological effects such as anti-inflammatory, hypoglycemic and hypolipidemic activities. In this study, a methanolic extract of berries (JB) was evaluated for its effects on peroxisome proliferator-activated receptors alpha and gamma (PPAR and PPAR), liver X receptor (LXR), glucose uptake and lipid accumulation using various cellular systems.

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Primaquine (PQ) is an 8-aminoquinoline antimalarial, active against dormant hypnozoites and mature gametocytes. PQ is currently used for radical cure and prevention of malaria transmission. PQ is a racemic drug and since the metabolism and pharmacology of PQ's enantiomers have been shown to be divergent, the objectives of this study were to evaluate the comparative tolerability and metabolism of PQ with respect to its two enantiomers in human volunteers in a 7 days' treatment schedule.

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Undetectables Atlanta (UA), a peer support network for Black gay men living with HIV, conducted an exploratory evaluation to begin identifying outcomes of UA membership. Th is initial evaluation suggested decreased HIV stigma and increased comfort with disclosure, treatment adherence, and other areas of well-being that warrant prospective evaluation.

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Primaquine (PQ), a prototype 8-aminoquinoline (8-AQ) drug used to treat malaria, is rapidly metabolized into different inactive and active metabolites. Due to the hemolytic toxicity, the uses of PQ have been confined. To understand its overall metabolism and its relation to drug efficacy and toxicity, profiling of urine for the parent drug and its metabolites is important.

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Primaquine (PQ) is a racemic drug used in treatment of malaria for six decades. Recent studies suggest that the two enantiomers of PQ are differentially metabolized in animals, and this results in different pharmacological and toxicological profiles. The current study characterizes the pharmacokinetic (PK) properties, metabolism and tolerability of the individual enantiomers of PQ in healthy human volunteers with normal glucose-6-phosphate dehydrogenase (G6PD) activity.

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Primaquine (PQ) and Tafenoquine (TQ) are clinically important 8-aminoquinolines (8-AQ) used for radical cure treatment of P. vivax infection, known to target hepatic hypnozoites. 8-AQs can trigger haemolytic anaemia in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd), yet the mechanisms of haemolytic toxicity remain unknown.

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Background: Primaquine (PQ) has been used for the radical cure of relapsing Plasmodium vivax malaria for more than 60 years. PQ is also recommended for prophylaxis and prevention of transmission of Plasmodium falciparum. However, clinical utility of PQ has been limited due to toxicity in individuals with genetic deficiencies in glucose 6-phosphate dehydrogenase (G6PD).

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Modulation of the endocannabinoid system (ECS) is of great interest for its therapeutic relevance in several pathophysiological processes. The CB2 subtype is largely localized to immune effectors, including microglia within the central nervous system, where it promotes anti-inflammation. Recently, a rational drug design toward precise modulation of the CB2 active site revealed the novelty of Pyrrolo[2,1-c][1,4]benzodiazepines tricyclic chemotype with a high conformational similarity in comparison to the existing leads.

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8-Aminoquinolines (8-AQs) are an important class of anti-infective therapeutics. The monoamine oxidases (MAOs) play a key role in metabolism of 8-AQs. A major role for MAO-A in metabolism of primaquine (PQ), the prototypical 8-AQ antimalarial, has been demonstrated.

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Newly designed pyrrolo[2,1-c][1,4]benzodiazepines tricyclic skeleton has shown potential clusters of cannabinoid receptors CB1/CB2 selective ligands. CB2 plays a critical role in microglial-derived neuroinflammation, where it modulates cell proliferation, migration, and differentiation into M1 or M2 phenotypes. Beginning with computer-based docking studies accounting the recently discovered X-ray crystal structure of CB2, we designed a series of PBD analogs as potential ligands of CB2 and tested their binding affinities.

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To date very few promising leads from natural products (NP) secondary metabolites with antiviral and immunomodulatory properties have been identified for promising/potential intervention for COVID-19. Using in-silico docking studies and genome based various molecular targets, and their in vitro anti-SARS CoV-2 activities against whole cell and/or selected protein targets, we select a few compounds of interest, which can be used as potential leads to counteract effects of uncontrolled innate immune responses, in particular those related to the cytokine storm. A critical factor for prevention and treatment of SARS-CoV-2 infection relates to factors independent of viral infection or host response.

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The antimalarial drug primaquine (PQ) causes methemoglobinemia and hemolysis in individuals with a genetic deficiency of glucose 6-phosphate dehydrogenase. Reactive oxygen species (ROS) generated by redox cycling of the metabolite primaquine-5,6-orthoquinone (POQ) in erythrocytes has been attributed to be responsible for the toxicity of PQ. Carboxyprimaquine (CPQ), the major human plasma metabolite of PQ, can also form the analogous carboxyprimaquine-5,6-orthoquinone (CPOQ) metabolite, which can also generate ROS in erythrocytes by redox cycling, thus contributing to the hematotoxicity of this drug.

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Cannabidiol (CBD) is a biologically active, non-psychotropic component of whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model.

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Hemp products are readily available and are aggressively marketed for their health and medicinal benefits. Most consumers of these products are interested because of cannabidiol (CBD), which has taken the natural products industry by storm. The CBD and Δ-tetrahydrocannabinol (Δ-THC) concentrations in these products are often absent, and even where labeled, the accuracy of the label amounts is often questionable.

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The proliferation in the last few years of cannabidiol (CBD)-containing products in the U.S. markets has been greatly accelerated by changes in the regulatory environment, and by perceptions of their health benefits and presumed safety.

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Products containing cannabidiol (CBD) are now available throughout the United States, but their quality is oftentimes questionable. The CBD and Δ-tetrahydrocannabinol (THC) content of 25 commercially available hemp oil products, obtained throughout the state of Mississippi, was determined gas chromatography/flame ionization detection (GC/FID). These products were also analyzed for the presence of synthetic cannabinoids using full scan gas chromatography/mass spectrometry (GC/MS).

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Cannabidiol (CBD) is the major non-psychotropic phytocannabinoid present in . In 2018, Congress designated certain plant material as "hemp," thus removing it from the DEA's list of controlled substances. As a result, CBD-containing hemp extracts and other CBD products are now widely available and heavily marketed, yet their FDA regulatory status is still hotly debated.

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Methylene blue (MB) with a 10-N-carbamoyl linkage was discovered and developed as a multifunctional far-red (660 nm) photocleavable ligand capable of rendering a series of MB-conjugated compounds with off-to-on fluorescence switch properties through the controlled release of MB.

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Current clinical antidiabetic drugs, like rosiglitazone , have been implicated in some serious side effects like edema, weight gain, and heart failure, making it necessary to find alternative agents. Partial agonists of peroxisome-proliferator activated receptor-gamma (PPARγ) were determined to possess improved insulin sensitivity without undeseirable side-effects when compared to full agonists of PPARγ, like rosiglitazone . The traditional Chinese medicine (TCM) plants, Goji ( and ) are widely used for treating symptoms related to various diseases including diabetes and hypertension.

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