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Papers by Kaleb Lund

Cardiovascular Toxicology, 2004

Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to re... more Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to reflect mitochondrial targets of drug toxicity. The prevailing hypothesis is that, through structural mimicry, the NRTIs are mistaken as substrates for DNA polymerase and incorporated into replicating DNA, where they cause truncation of the elongating strand. Although there exist five forms of nuclear DNA polymerase, mitochondria possess solely DNA polymerase-g (pol-g), which is a preferred target for most NRTIs. Consequently, mitochondria are particularly susceptible to inhibition of DNA replication by the NRTIs, which is consistent with the phenotype of mitochondrial depletion and metabolic failure in affected patients. However, the DNA pol-g hypothesis by itself fails to explain the entire array of metabolic deficiencies associated with NRTI-induced disorders. In this article, we review the published literature regarding the direct effects of NRTIs on various mitochondrial targets and suggest the possibility that the initiating event in NRTIinduced cardiomyopathy is a direct mitochondrial toxicity rather than inhibition of mitochondrial DNA pol-g. The goal of this review is to encourage a discussion of the cause of NRTI-induced mitochondrial cardiomyopathy to include a fresh consideration of all possible targets and integrating pathways that are involved in establishing mitochondrial bioenergetic fidelity and metabolic capacity in the affected myocardium.

Mitochondrion, Jul 1, 2004

In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NR... more In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NRTIs) and their corresponding nucleotides can cause a direct, DNA polymerase-g-independent, inhibition of respiration, membrane potential, and calcium loading capacity in isolated rat heart mitochondria in vitro. Both AZT and d4T also increased total adenine phosphate energy charge in H9c2 rat cardiac myocytes in cell culture. These results demonstrate that the various NRTI nucleosides and nucleotides are capable, at sufficiently high concentrations, of directly affecting mitochondrial bioenergetics in vitro, which may enhance the toxicity observed in vivo previously attributed to inhibition of DNA polymerase-g.

Journal of restorative medicine, Apr 1, 2014

Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidl... more Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidly gaining popularity as supplements for a wide assortment of conditions including cardiovascular disease, cancer, asthma, diabetes, neurodegeneration, aging and stress. Unfortunately the therapeutic potential of these compounds is limited by their poor intestinal and intracellular bioavailability. Therefore this study sought to examine how combinations of quercetin, resveratrol, and curcumin, with and without piperine, 200 nM, affected an in vitro permeability model using apical-to-basal permeability across intact caco-2 monolayers. Quercetin, resveratrol and curcumin were applied apically alone or in combination at 50 ?M and measured in the basal chamber at 30 min. Results: Resveratrol received the greatest enhancement in permeability when combined with other agents: quercetin (310%), curcumin (300%), quercetin and curcumin (323%, 350% with piperine). Curcumin also demonstrated increased permeability when combined with quercetin alone (147%) and both quercetin and resveratrol (188%), addition of piperine resulted in a 229% increase in permeability. Quercetin permeability was not significantly affected using any combination, but showed maximal permeability when combined with resveratrol and the lowest permeability when combined with resveratrol, curcumin and piperine together. Conclusion: Combination of quercetin, resveratrol and curcumin may improve intestinal absorption of resveratrol and curcumin without affecting quercetin absorption. These data highlight the need for further research and suggest that developing combination therapies may improve intestinal absorption of these constituents. Our study also demonstrates that the apical-to-basal permeability across intact caco-2 monolayer model is a viable model to investigate absorption of natural compounds.

Antimicrobial Agents and Chemotherapy, Jul 1, 2007

Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming incre... more Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming increasingly difficult to accommodate these differences solely in the context of DNA polymerase gamma inhibition. Therefore, we examined the toxicities of zidovudine (AZT) (10 and 50 M; 2.7 and 13.4 g/ml), didanosine (ddI) (10 and 50 M; 2.4 and 11.8 g/ml), and zalcitabine (ddC) (1 and 5 M; 0.21 and 1.1 g/ml) in HepG2 and H9c2 cells without the presumption of mitochondrial DNA (mtDNA) depletion. Ethidium bromide (EtBr) (0.5 g/ml; 1.3 M) was used as a positive control. AZT treatment resulted in metabolic disruption (increased lactate and superoxide) and increased cell mortality with decreased proliferation, while mtDNA remained unchanged or increased (HepG2 cells; 50 M AZT). ddC caused pronounced mtDNA depletion in HepG2 cells but not in H9c2 cells and increased mortality in HepG2 cells, but no significant metabolic disruption in either cell type. ddI caused a moderate depletion of mtDNA in both cell types but showed no other effects. EtBr exposure resulted in metabolic disruption, increased cell mortality with decreased cell proliferation, and mtDNA depletion in both cell types. We conclude that nucleoside analogs display unique toxicities within and between culture models, and therefore, care should be taken when generalizing about the mechanisms of nucleoside reverse transcriptase inhibitor toxicity. Additionally, mtDNA abundance does not necessarily correlate with metabolic disruption, especially in cell culture; careful discernment is recommended in this regard.

Planta Medica, Jul 14, 2014

Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was u... more Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

Biomedicine & Pharmacotherapy, May 1, 2022

INTRODUCTION Panax notoginseng (Burkill) F.H. commonly referred to as Sanqi, is a Chinese herb th... more INTRODUCTION Panax notoginseng (Burkill) F.H. commonly referred to as Sanqi, is a Chinese herb that has long been used to treat various conditions including blood disorders and cardiovascular diseases. While Panax notoginseng has been used as an anti-cancer medicinal herb in recent years, how it achieves this therapeutic effect has not been thoroughly elucidated. The purpose of this study was to reveal more about the mechanism of the cytotoxic effect of Panax notoginseng on prostate cancer (PCa) cells. METHODS Ethanol extract of Panax notoginseng root was authenticated using high-performance liquid chromatography (HPLC). The cytotoxic activity of this herb against PCa cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). RESULTS The assessment of cellular metabolic activity demonstrated that Panax notoginseng reduces the viability of LNCaP and 22Rv1 cells in a dose-dependent manner. Annexin-V binding flow cytometry assay showed that Panax notoginseng induces apoptosis in PCa cells. Cell cycle analysis by quantification of DNA content using flow cytometry showed that Panax notoginseng arrests the cell cycle at the G2/M phase in both LNCaP and 22Rv1 cells. Moreover, ELISA demonstrated that Panax notoginseng-treated PCa cells secrete significantly less tumor-promoting cytokine interleukin-4 (IL-4) to the supernatant compared with controls. CONCLUSIONS These results provide evidence for the cytotoxic effects of Panax notoginseng on PCa cell lines. This botanical is a promising candidate for the complementary and integrative medicine treatment of PCa and further studies are indicated to determine the anti-cancer mechanism of Panax notoginseng.

Toxicology and Applied Pharmacology, 2008

Nucleoside analog reverse transcriptase inhibitors (NRTI) are known to directly inhibit mitochond... more Nucleoside analog reverse transcriptase inhibitors (NRTI) are known to directly inhibit mitochondrial complex I activity as well as various mitochondrial kinases. Recent observations that complex I activity and superoxide production are modulated through cAMP-dependent phosphorylation suggests a mechanism through which NRTIs may affect mitochondrial respiration via kinasedependent protein phosphorylation. In the current study we examine the potential for NRTIs to inhibit the cAMP-dependent phosphorylation of complex I and the associated NADH:CoQ oxidoreductase activities and rates of superoxide production using HepG2 cells. Phosphoprotein staining of immunocaptured complex I revealed that 3′-azido-3′-deoxythymidine (AZT; 10 and 50 μM), AZT monophosphate (150 μM), and 2′,3′-dideoxycytidine (ddC; 1μM) prevented the phosphorylation of the NDUFB11 subunit of complex I. This was associated with a decrease in complex I activity with AZT and AZT monophosphate only. In the presence of succinate, superoxide production was increased with 2′,3′-dideoxyinosine (ddI; 10 μM) and ddC (1 μM). In the presence of succinate + cAMP AZT showed an inverse dose-dependent effect on superoxide production. None of the NRTIs examined inhibit PKA activity suggesting that the observed effects are due to a direct interaction with complex I. These data demonstrate a direct effect of NRTIs on cAMP-dependent regulation of mitochondrial bioenergetics independent of DNA polymerase-γ activity; in the case of AZT these observations may provide a mechanism for the observed long-term toxicity with this drug.

Planta Medica

Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was u... more Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

International Journal of Pharmacognosy and Phytochemical Research

Bignonia capreolata is a perennial semi-evergreen vine from the Southeast United States that was ... more Bignonia capreolata is a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid. http://www.ijppr.com/PDF%20all%20edtions%20IJPPR/Vol4/Issue3/IJPPR,Vol4,Issue3,Article3.pdf

Integrative Medicine Research, 2015

ABSTRACT Bignonia capreolata is a perennial semi-evergreen vine from the Eastern US that was used... more ABSTRACT Bignonia capreolata is a perennial semi-evergreen vine from the Eastern US that was used as a medicine by the Native Americans but has since fallen out of use. The aim of this analysis was to 1) verify (and quantitate) the presence of the indole alkaloid reserpine in B. capreolata using high performance liquid chromatography referenced with an analytical standard of reserpine; and 2) if verified, generate an alkaloid rich fraction of B. capreolata to more accurately identify reserpine by liquid chromatography and mass spectrometry. Initial HPLC analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

Journal of Restorative Medicine, 2014

Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidl... more Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidly gaining popularity as supplements for a wide assortment of conditions including cardiovascular disease, cancer, asthma, diabetes, neurodegeneration, aging and stress. Unfortunately the therapeutic potential of these compounds is limited by their poor intestinal and intracellular bioavailability. Therefore this study sought to examine how combinations of quercetin, resveratrol, and curcumin, with and without piperine, 200 nM, affected an in vitro permeability model using apical-to-basal permeability across intact caco-2 monolayers. Quercetin, resveratrol and curcumin were applied apically alone or in combination at 50 ?M and measured in the basal chamber at 30 min. Results: Resveratrol received the greatest enhancement in permeability when combined with other agents: quercetin (310%), curcumin (300%), quercetin and curcumin (323%, 350% with piperine). Curcumin also demonstrated increased permeability when combined with quercetin alone (147%) and both quercetin and resveratrol (188%), addition of piperine resulted in a 229% increase in permeability. Quercetin permeability was not significantly affected using any combination, but showed maximal permeability when combined with resveratrol and the lowest permeability when combined with resveratrol, curcumin and piperine together. Conclusion: Combination of quercetin, resveratrol and curcumin may improve intestinal absorption of resveratrol and curcumin without affecting quercetin absorption. These data highlight the need for further research and suggest that developing combination therapies may improve intestinal absorption of these constituents. Our study also demonstrates that the apical-to-basal permeability across intact caco-2 monolayer model is a viable model to investigate absorption of natural compounds.

The Journal of Immunology, 2001

IL-5 is implicated in the pathogenesis of asthma and is predominantly released from T lymphocytes... more IL-5 is implicated in the pathogenesis of asthma and is predominantly released from T lymphocytes of the Th2 phenotype. In anti-CD3 plus anti-CD28-stimulated PBMC, albuterol, isoproterenol, rolipram, PGE 2 , forskolin, cholera toxin, and the cAMP analog, 8-bromoadenosine cAMP (8-Br-cAMP) all inhibited the release of IL-5 and lymphocyte proliferation. Although all of the above compounds share the ability to increase intracellular cAMP levels and activate protein kinase (PK) A, the PKA inhibitor H-89 failed to ablate the inhibition of IL-5 production mediated by 8-Br-cAMP, rolipram, forskolin, or PGE 2. Similarly, H-89 had no effect on the cAMP-mediated inhibition of lymphocyte proliferation. Significantly, these observations occurred at a concentration of H-89 (3 M) that inhibited both PKA activity and CREB phosphorylation in intact cells. Additional studies showed that the PKA inhibitors H-8, 8-(4-chlorophenylthio) adenosine-3,5-cyclic monophosphorothioate Rp isomer, and a myristolated PKA inhibitor peptide also failed to block the 8-Br-cAMP-mediated inhibition of IL-5 release from PBMC. Likewise, a role for PKG was considered unlikely because both activators and inhibitors of this enzyme had no effect on IL-5 release. Western blotting identified Rap1, a downstream target of the cAMP-binding proteins, exchange protein directly activated by cAMP/cAMP-guanine nucleotide exchange factors 1 and 2, in PBMC. However, Rap1 activation assays revealed that this pathway is also unlikely to be involved in the cAMP-mediated inhibition of IL-5. Taken together, these results indicate that cAMP-elevating agents inhibit IL-5 release from PBMC by a novel cAMP-dependent mechanism that does not involve the activation of PKA.

Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to re... more Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to reflect mitochondrial targets of drug toxicity. The prevailing hypothesis is that, through structural mimicry, the NRTIs are mistaken as substrates for DNA polymerase and incorporated into replicating DNA, where they cause truncation of the elongating strand. Although there exist five forms of nuclear DNA polymerase, mitochondria possess solely DNA polymerase-g (pol-g), which is a preferred target for most NRTIs. Consequently, mitochondria are particularly susceptible to inhibition of DNA replication by the NRTIs, which is consistent with the phenotype of mitochondrial depletion and metabolic failure in affected patients. However, the DNA pol-g hypothesis by itself fails to explain the entire array of metabolic deficiencies associated with NRTI-induced disorders. In this article, we review the published literature regarding the direct effects of NRTIs on various mitochondrial targets and suggest the possibility that the initiating event in NRTIinduced cardiomyopathy is a direct mitochondrial toxicity rather than inhibition of mitochondrial DNA pol-g. The goal of this review is to encourage a discussion of the cause of NRTI-induced mitochondrial cardiomyopathy to include a fresh consideration of all possible targets and integrating pathways that are involved in establishing mitochondrial bioenergetic fidelity and metabolic capacity in the affected myocardium.

Antimicrobial agents and …, 2007

Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming incre... more Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming increasingly difficult to accommodate these differences solely in the context of DNA polymerase gamma inhibition. Therefore, we examined the toxicities of zidovudine (AZT) (10 and 50 M; 2.7 and 13.4 g/ml), didanosine (ddI) (10 and 50 M; 2.4 and 11.8 g/ml), and zalcitabine (ddC) (1 and 5 M; 0.21 and 1.1 g/ml) in HepG2 and H9c2 cells without the presumption of mitochondrial DNA (mtDNA) depletion. Ethidium bromide (EtBr) (0.5 g/ml; 1.3 M) was used as a positive control. AZT treatment resulted in metabolic disruption (increased lactate and superoxide) and increased cell mortality with decreased proliferation, while mtDNA remained unchanged or increased (HepG2 cells; 50 M AZT). ddC caused pronounced mtDNA depletion in HepG2 cells but not in H9c2 cells and increased mortality in HepG2 cells, but no significant metabolic disruption in either cell type. ddI caused a moderate depletion of mtDNA in both cell types but showed no other effects. EtBr exposure resulted in metabolic disruption, increased cell mortality with decreased cell proliferation, and mtDNA depletion in both cell types. We conclude that nucleoside analogs display unique toxicities within and between culture models, and therefore, care should be taken when generalizing about the mechanisms of nucleoside reverse transcriptase inhibitor toxicity. Additionally, mtDNA abundance does not necessarily correlate with metabolic disruption, especially in cell culture; careful discernment is recommended in this regard.

In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NR... more In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NRTIs) and their corresponding nucleotides can cause a direct, DNA polymerase-g-independent, inhibition of respiration, membrane potential, and calcium loading capacity in isolated rat heart mitochondria in vitro. Both AZT and d4T also increased total adenine phosphate energy charge in H9c2 rat cardiac myocytes in cell culture. These results demonstrate that the various NRTI nucleosides and nucleotides are capable, at sufficiently high concentrations, of directly affecting mitochondrial bioenergetics in vitro, which may enhance the toxicity observed in vivo previously attributed to inhibition of DNA polymerase-g.

Cardiovascular Toxicology, 2004

Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to re... more Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to reflect mitochondrial targets of drug toxicity. The prevailing hypothesis is that, through structural mimicry, the NRTIs are mistaken as substrates for DNA polymerase and incorporated into replicating DNA, where they cause truncation of the elongating strand. Although there exist five forms of nuclear DNA polymerase, mitochondria possess solely DNA polymerase-g (pol-g), which is a preferred target for most NRTIs. Consequently, mitochondria are particularly susceptible to inhibition of DNA replication by the NRTIs, which is consistent with the phenotype of mitochondrial depletion and metabolic failure in affected patients. However, the DNA pol-g hypothesis by itself fails to explain the entire array of metabolic deficiencies associated with NRTI-induced disorders. In this article, we review the published literature regarding the direct effects of NRTIs on various mitochondrial targets and suggest the possibility that the initiating event in NRTIinduced cardiomyopathy is a direct mitochondrial toxicity rather than inhibition of mitochondrial DNA pol-g. The goal of this review is to encourage a discussion of the cause of NRTI-induced mitochondrial cardiomyopathy to include a fresh consideration of all possible targets and integrating pathways that are involved in establishing mitochondrial bioenergetic fidelity and metabolic capacity in the affected myocardium.

Mitochondrion, Jul 1, 2004

In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NR... more In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NRTIs) and their corresponding nucleotides can cause a direct, DNA polymerase-g-independent, inhibition of respiration, membrane potential, and calcium loading capacity in isolated rat heart mitochondria in vitro. Both AZT and d4T also increased total adenine phosphate energy charge in H9c2 rat cardiac myocytes in cell culture. These results demonstrate that the various NRTI nucleosides and nucleotides are capable, at sufficiently high concentrations, of directly affecting mitochondrial bioenergetics in vitro, which may enhance the toxicity observed in vivo previously attributed to inhibition of DNA polymerase-g.

Journal of restorative medicine, Apr 1, 2014

Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidl... more Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidly gaining popularity as supplements for a wide assortment of conditions including cardiovascular disease, cancer, asthma, diabetes, neurodegeneration, aging and stress. Unfortunately the therapeutic potential of these compounds is limited by their poor intestinal and intracellular bioavailability. Therefore this study sought to examine how combinations of quercetin, resveratrol, and curcumin, with and without piperine, 200 nM, affected an in vitro permeability model using apical-to-basal permeability across intact caco-2 monolayers. Quercetin, resveratrol and curcumin were applied apically alone or in combination at 50 ?M and measured in the basal chamber at 30 min. Results: Resveratrol received the greatest enhancement in permeability when combined with other agents: quercetin (310%), curcumin (300%), quercetin and curcumin (323%, 350% with piperine). Curcumin also demonstrated increased permeability when combined with quercetin alone (147%) and both quercetin and resveratrol (188%), addition of piperine resulted in a 229% increase in permeability. Quercetin permeability was not significantly affected using any combination, but showed maximal permeability when combined with resveratrol and the lowest permeability when combined with resveratrol, curcumin and piperine together. Conclusion: Combination of quercetin, resveratrol and curcumin may improve intestinal absorption of resveratrol and curcumin without affecting quercetin absorption. These data highlight the need for further research and suggest that developing combination therapies may improve intestinal absorption of these constituents. Our study also demonstrates that the apical-to-basal permeability across intact caco-2 monolayer model is a viable model to investigate absorption of natural compounds.

Antimicrobial Agents and Chemotherapy, Jul 1, 2007

Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming incre... more Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming increasingly difficult to accommodate these differences solely in the context of DNA polymerase gamma inhibition. Therefore, we examined the toxicities of zidovudine (AZT) (10 and 50 M; 2.7 and 13.4 g/ml), didanosine (ddI) (10 and 50 M; 2.4 and 11.8 g/ml), and zalcitabine (ddC) (1 and 5 M; 0.21 and 1.1 g/ml) in HepG2 and H9c2 cells without the presumption of mitochondrial DNA (mtDNA) depletion. Ethidium bromide (EtBr) (0.5 g/ml; 1.3 M) was used as a positive control. AZT treatment resulted in metabolic disruption (increased lactate and superoxide) and increased cell mortality with decreased proliferation, while mtDNA remained unchanged or increased (HepG2 cells; 50 M AZT). ddC caused pronounced mtDNA depletion in HepG2 cells but not in H9c2 cells and increased mortality in HepG2 cells, but no significant metabolic disruption in either cell type. ddI caused a moderate depletion of mtDNA in both cell types but showed no other effects. EtBr exposure resulted in metabolic disruption, increased cell mortality with decreased cell proliferation, and mtDNA depletion in both cell types. We conclude that nucleoside analogs display unique toxicities within and between culture models, and therefore, care should be taken when generalizing about the mechanisms of nucleoside reverse transcriptase inhibitor toxicity. Additionally, mtDNA abundance does not necessarily correlate with metabolic disruption, especially in cell culture; careful discernment is recommended in this regard.

Planta Medica, Jul 14, 2014

Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was u... more Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

Biomedicine & Pharmacotherapy, May 1, 2022

INTRODUCTION Panax notoginseng (Burkill) F.H. commonly referred to as Sanqi, is a Chinese herb th... more INTRODUCTION Panax notoginseng (Burkill) F.H. commonly referred to as Sanqi, is a Chinese herb that has long been used to treat various conditions including blood disorders and cardiovascular diseases. While Panax notoginseng has been used as an anti-cancer medicinal herb in recent years, how it achieves this therapeutic effect has not been thoroughly elucidated. The purpose of this study was to reveal more about the mechanism of the cytotoxic effect of Panax notoginseng on prostate cancer (PCa) cells. METHODS Ethanol extract of Panax notoginseng root was authenticated using high-performance liquid chromatography (HPLC). The cytotoxic activity of this herb against PCa cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). RESULTS The assessment of cellular metabolic activity demonstrated that Panax notoginseng reduces the viability of LNCaP and 22Rv1 cells in a dose-dependent manner. Annexin-V binding flow cytometry assay showed that Panax notoginseng induces apoptosis in PCa cells. Cell cycle analysis by quantification of DNA content using flow cytometry showed that Panax notoginseng arrests the cell cycle at the G2/M phase in both LNCaP and 22Rv1 cells. Moreover, ELISA demonstrated that Panax notoginseng-treated PCa cells secrete significantly less tumor-promoting cytokine interleukin-4 (IL-4) to the supernatant compared with controls. CONCLUSIONS These results provide evidence for the cytotoxic effects of Panax notoginseng on PCa cell lines. This botanical is a promising candidate for the complementary and integrative medicine treatment of PCa and further studies are indicated to determine the anti-cancer mechanism of Panax notoginseng.

Toxicology and Applied Pharmacology, 2008

Nucleoside analog reverse transcriptase inhibitors (NRTI) are known to directly inhibit mitochond... more Nucleoside analog reverse transcriptase inhibitors (NRTI) are known to directly inhibit mitochondrial complex I activity as well as various mitochondrial kinases. Recent observations that complex I activity and superoxide production are modulated through cAMP-dependent phosphorylation suggests a mechanism through which NRTIs may affect mitochondrial respiration via kinasedependent protein phosphorylation. In the current study we examine the potential for NRTIs to inhibit the cAMP-dependent phosphorylation of complex I and the associated NADH:CoQ oxidoreductase activities and rates of superoxide production using HepG2 cells. Phosphoprotein staining of immunocaptured complex I revealed that 3′-azido-3′-deoxythymidine (AZT; 10 and 50 μM), AZT monophosphate (150 μM), and 2′,3′-dideoxycytidine (ddC; 1μM) prevented the phosphorylation of the NDUFB11 subunit of complex I. This was associated with a decrease in complex I activity with AZT and AZT monophosphate only. In the presence of succinate, superoxide production was increased with 2′,3′-dideoxyinosine (ddI; 10 μM) and ddC (1 μM). In the presence of succinate + cAMP AZT showed an inverse dose-dependent effect on superoxide production. None of the NRTIs examined inhibit PKA activity suggesting that the observed effects are due to a direct interaction with complex I. These data demonstrate a direct effect of NRTIs on cAMP-dependent regulation of mitochondrial bioenergetics independent of DNA polymerase-γ activity; in the case of AZT these observations may provide a mechanism for the observed long-term toxicity with this drug.

Planta Medica

Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was u... more Bignonia capreolatais a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

International Journal of Pharmacognosy and Phytochemical Research

Bignonia capreolata is a perennial semi-evergreen vine from the Southeast United States that was ... more Bignonia capreolata is a perennial semi-evergreen vine from the Southeast United States that was used as a medicine by the Native Americans but has since fallen out of use. A preliminary screen of B. capreolata suggested the presence of the indole alkaloid reserpine. This analysis was undertaken to 1) verify the presence reserpine using LC-MS referenced with an analytical standard of reserpine; and 2) if verified, quantitate the level of reserpine in B. capreolata leaf. LC-MS analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid. http://www.ijppr.com/PDF%20all%20edtions%20IJPPR/Vol4/Issue3/IJPPR,Vol4,Issue3,Article3.pdf

Integrative Medicine Research, 2015

ABSTRACT Bignonia capreolata is a perennial semi-evergreen vine from the Eastern US that was used... more ABSTRACT Bignonia capreolata is a perennial semi-evergreen vine from the Eastern US that was used as a medicine by the Native Americans but has since fallen out of use. The aim of this analysis was to 1) verify (and quantitate) the presence of the indole alkaloid reserpine in B. capreolata using high performance liquid chromatography referenced with an analytical standard of reserpine; and 2) if verified, generate an alkaloid rich fraction of B. capreolata to more accurately identify reserpine by liquid chromatography and mass spectrometry. Initial HPLC analysis has confirmed the presence of reserpine in B. capreolata, which makes this the only known plant outside the Apocynaceae family to contain this indole alkaloid.

Journal of Restorative Medicine, 2014

Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidl... more Objective: Quercetin, resveratrol and curcumin are plant derived natural products that are rapidly gaining popularity as supplements for a wide assortment of conditions including cardiovascular disease, cancer, asthma, diabetes, neurodegeneration, aging and stress. Unfortunately the therapeutic potential of these compounds is limited by their poor intestinal and intracellular bioavailability. Therefore this study sought to examine how combinations of quercetin, resveratrol, and curcumin, with and without piperine, 200 nM, affected an in vitro permeability model using apical-to-basal permeability across intact caco-2 monolayers. Quercetin, resveratrol and curcumin were applied apically alone or in combination at 50 ?M and measured in the basal chamber at 30 min. Results: Resveratrol received the greatest enhancement in permeability when combined with other agents: quercetin (310%), curcumin (300%), quercetin and curcumin (323%, 350% with piperine). Curcumin also demonstrated increased permeability when combined with quercetin alone (147%) and both quercetin and resveratrol (188%), addition of piperine resulted in a 229% increase in permeability. Quercetin permeability was not significantly affected using any combination, but showed maximal permeability when combined with resveratrol and the lowest permeability when combined with resveratrol, curcumin and piperine together. Conclusion: Combination of quercetin, resveratrol and curcumin may improve intestinal absorption of resveratrol and curcumin without affecting quercetin absorption. These data highlight the need for further research and suggest that developing combination therapies may improve intestinal absorption of these constituents. Our study also demonstrates that the apical-to-basal permeability across intact caco-2 monolayer model is a viable model to investigate absorption of natural compounds.

The Journal of Immunology, 2001

IL-5 is implicated in the pathogenesis of asthma and is predominantly released from T lymphocytes... more IL-5 is implicated in the pathogenesis of asthma and is predominantly released from T lymphocytes of the Th2 phenotype. In anti-CD3 plus anti-CD28-stimulated PBMC, albuterol, isoproterenol, rolipram, PGE 2 , forskolin, cholera toxin, and the cAMP analog, 8-bromoadenosine cAMP (8-Br-cAMP) all inhibited the release of IL-5 and lymphocyte proliferation. Although all of the above compounds share the ability to increase intracellular cAMP levels and activate protein kinase (PK) A, the PKA inhibitor H-89 failed to ablate the inhibition of IL-5 production mediated by 8-Br-cAMP, rolipram, forskolin, or PGE 2. Similarly, H-89 had no effect on the cAMP-mediated inhibition of lymphocyte proliferation. Significantly, these observations occurred at a concentration of H-89 (3 M) that inhibited both PKA activity and CREB phosphorylation in intact cells. Additional studies showed that the PKA inhibitors H-8, 8-(4-chlorophenylthio) adenosine-3,5-cyclic monophosphorothioate Rp isomer, and a myristolated PKA inhibitor peptide also failed to block the 8-Br-cAMP-mediated inhibition of IL-5 release from PBMC. Likewise, a role for PKG was considered unlikely because both activators and inhibitors of this enzyme had no effect on IL-5 release. Western blotting identified Rap1, a downstream target of the cAMP-binding proteins, exchange protein directly activated by cAMP/cAMP-guanine nucleotide exchange factors 1 and 2, in PBMC. However, Rap1 activation assays revealed that this pathway is also unlikely to be involved in the cAMP-mediated inhibition of IL-5. Taken together, these results indicate that cAMP-elevating agents inhibit IL-5 release from PBMC by a novel cAMP-dependent mechanism that does not involve the activation of PKA.

Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to re... more Nucleoside reverse transcriptase inhibitor (NRTI)-induced cardiomyopathy has been suggested to reflect mitochondrial targets of drug toxicity. The prevailing hypothesis is that, through structural mimicry, the NRTIs are mistaken as substrates for DNA polymerase and incorporated into replicating DNA, where they cause truncation of the elongating strand. Although there exist five forms of nuclear DNA polymerase, mitochondria possess solely DNA polymerase-g (pol-g), which is a preferred target for most NRTIs. Consequently, mitochondria are particularly susceptible to inhibition of DNA replication by the NRTIs, which is consistent with the phenotype of mitochondrial depletion and metabolic failure in affected patients. However, the DNA pol-g hypothesis by itself fails to explain the entire array of metabolic deficiencies associated with NRTI-induced disorders. In this article, we review the published literature regarding the direct effects of NRTIs on various mitochondrial targets and suggest the possibility that the initiating event in NRTIinduced cardiomyopathy is a direct mitochondrial toxicity rather than inhibition of mitochondrial DNA pol-g. The goal of this review is to encourage a discussion of the cause of NRTI-induced mitochondrial cardiomyopathy to include a fresh consideration of all possible targets and integrating pathways that are involved in establishing mitochondrial bioenergetic fidelity and metabolic capacity in the affected myocardium.

Antimicrobial agents and …, 2007

Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming incre... more Nucleoside analogs are associated with various mitochondrial toxicities, and it is becoming increasingly difficult to accommodate these differences solely in the context of DNA polymerase gamma inhibition. Therefore, we examined the toxicities of zidovudine (AZT) (10 and 50 M; 2.7 and 13.4 g/ml), didanosine (ddI) (10 and 50 M; 2.4 and 11.8 g/ml), and zalcitabine (ddC) (1 and 5 M; 0.21 and 1.1 g/ml) in HepG2 and H9c2 cells without the presumption of mitochondrial DNA (mtDNA) depletion. Ethidium bromide (EtBr) (0.5 g/ml; 1.3 M) was used as a positive control. AZT treatment resulted in metabolic disruption (increased lactate and superoxide) and increased cell mortality with decreased proliferation, while mtDNA remained unchanged or increased (HepG2 cells; 50 M AZT). ddC caused pronounced mtDNA depletion in HepG2 cells but not in H9c2 cells and increased mortality in HepG2 cells, but no significant metabolic disruption in either cell type. ddI caused a moderate depletion of mtDNA in both cell types but showed no other effects. EtBr exposure resulted in metabolic disruption, increased cell mortality with decreased cell proliferation, and mtDNA depletion in both cell types. We conclude that nucleoside analogs display unique toxicities within and between culture models, and therefore, care should be taken when generalizing about the mechanisms of nucleoside reverse transcriptase inhibitor toxicity. Additionally, mtDNA abundance does not necessarily correlate with metabolic disruption, especially in cell culture; careful discernment is recommended in this regard.

In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NR... more In this investigation we demonstrate that various nucleoside reverse transcriptase inhibitors (NRTIs) and their corresponding nucleotides can cause a direct, DNA polymerase-g-independent, inhibition of respiration, membrane potential, and calcium loading capacity in isolated rat heart mitochondria in vitro. Both AZT and d4T also increased total adenine phosphate energy charge in H9c2 rat cardiac myocytes in cell culture. These results demonstrate that the various NRTI nucleosides and nucleotides are capable, at sufficiently high concentrations, of directly affecting mitochondrial bioenergetics in vitro, which may enhance the toxicity observed in vivo previously attributed to inhibition of DNA polymerase-g.