Stability of Caffeic Acid Phenethyl Amide (CAPA) in Rat Plasma

CAPE derivatives: Multifaceted agents for chronic wound healing

Chronic wounds significantly impact the patients' quality of life, creating an urgent interdisciplinary clinical challenge. The development of novel agents capable of accelerating the healing process is essential. Caffeic acid phenethyl ester (CAPE) has demonstrated positive effects on skin regeneration. However, its susceptibility to degradation limits its pharmaceutical application. Chemical modification of the structure improves the pharmacokinetics of this bioactive phenol. Hence, two novel series of CAPE hybrids were designed, synthesized, and investigated as potential skin regenerative agents. To enhance the stability and therapeutic efficacy, a caffeic acid frame was combined with quinolines or isoquinolines by an ester (1a-f) or an amide linkage (2a-f). The effects on cell viability of human gingival fibroblasts (HGFs) and HaCaT cells were evaluated at different concentrations; they are not cytotoxic, and some proved to stimulate cell proliferation. The most promising compounds underwent a wound-healing assay in HGFs and HaCaT at the lowest concentrations. Antimicrobial antioxidant properties were also explored. The chemical and thermal stabilities of the best compounds were assessed. In silico predictions were employed to anticipate skin penetration capabilities. Our findings highlight the therapeutic potential of caffeic acid phenethyl ester (CAPE) derivatives 1a and 1d as skin regenerative agents, being able to stimulate cell proliferation, control bacterial growth, regulate ROS levels, and being thermally and chemically stable. An interesting structure-activity relationship was discussed to suggest a promising multitargeted approach for enhanced wound healing.

Synthesis and Dopaminergic Neuroprotective Activity of the Proposed Structure of Bassiamide A, a Caffeamide Alkaloid Derived from Bassia Indica Wight

Herein, we describe the synthesis of the proposed structure of the caffeamide alkaloid bassiamide A. The amide moiety of bassiamide A was readily formed via an amide coupling reaction between caffeic acid and the known N-(3-aminopropyl)-3-methylbutanamide. However, the spectral data of the synthesized bassiamide A did not agree with that of a previous study. The structure of the synthesized bassiamide A was confirmed using combined two-dimensional NMR analysis. Extended analyses of the bioactivity of the synthesized bassiamide A revealed its efficacy in protecting dopaminergic neurons from MPP+-induced neurotoxicity in Caenorhabditis elegans. Additionally, treatment with bassiamide A notably ameliorated the impaired food-sensing ability and locomotion of Caenorhabditis elegans, suggesting a protective effect on the functionality of dopaminergic neurons.

Yeast Metabolic Engineering for Biosynthesis of Caffeic Acid-Derived Phenethyl Ester and Phenethyl Amide

Caffeic acid (CA)-derived phenethyl ester (CAPE) and phenethyl amide (CAPA) are extensively investigated bioactive compounds with therapeutic applications such as antioxidant, anti-inflammatory, and anticarcinogenic properties. To construct microbial cell factories for production of CAPE or CAPA is a promising option given the limitation of natural sources for product extraction and the environmental toxicity of the agents used in chemical synthesis. We reported the successful biosynthesis of caffeic acid in yeast previously. Here in this work, we further constructed the downstream synthetic pathways in yeast for biosynthesis of CAPE and CAPA. After combinatorial engineering of yeast chassis based on the rational pathway engineering method and library-based SCRaMbLE method, we finally obtained the optimal strains that respectively produced 417 μg/L CAPE and 1081 μg/L CAPA. Two screened gene targets of ΔHAM1 and ΔYJL028W were discovered to help improve the product synthesis capacity. This is the first report of the de novo synthesis of CAPA from glucose in an engineered yeast chassis. Future work on enzyme and chassis engineering will further support improving the microbial cell factories for the production of CA derivatives.

Caffeic Acid Phenethyl Ester Loaded in Skim Milk Microcapsules: Physicochemical Properties and Enhanced In Vitro Bioaccessibility and Bioactivity against Colon Cancer Cells

Caffeic acid phenethyl ester (CAPE) has various biological activities but low water solubility and poor bioavailability. In this study, CAPE was encapsulated in skim milk powder (SMP) by spray drying warm aqueous ethanol solutions with different mass ratios of SMP and CAPE. The loading capacity and encapsulation efficiency were up to 10.1 and 41.7%, respectively. Differential scanning calorimetry and X-ray diffraction results confirmed the loss of crystallinity of CAPE after encapsulation. Fourier-transform infrared and fluorescence spectroscopy results indicated the hydrophobic binding between CAPE and caseins. Scanning electron microscopy and static light scattering results showed spherical capsules with an average diameter of around 26 μm. The CAPE loaded in SMP microcapsules showed significantly improved in vitro bioaccessibility and antiproliferation activity against human colon cancer cells compared to free CAPE. The simple, scalable, and low-cost approach in the present study may be significant for industrial encapsulation of CAPE and other lipophilic bioactive compounds.

Cardiovascular Effects of Caffeic Acid and Its Derivatives: A Comprehensive Review

Caffeic acid (CA) and its phenethyl ester (CAPE) are naturally occurring hydroxycinnamic acids with an interesting array of biological activities; e.g., antioxidant, anti-inflammatory, antimicrobial and cytostatic. More recently, several synthetic analogs have also shown similar properties, and some with the advantage of added stability. The actions of these compounds on the cardiovascular system have not been thoroughly explored despite presenting an interesting potential. Indeed the mechanisms underlying the vascular effects of these compounds particularly need clarifying. The aim of this paper is to provide a comprehensive and up-to-date review on current knowledge about CA and its derivatives in the cardiovascular system. Caffeic acid, CAPE and the synthetic caffeic acid phenethyl amide (CAPA) exhibit vasorelaxant activity by acting on the endothelial and vascular smooth muscle cells. Vasorelaxant mechanisms include the increased endothelial NO secretion, modulation of calcium and potassium channels, and modulation of adrenergic receptors. Together with a negative chronotropic effect, vasorelaxant activity contributes to lower blood pressure, as several preclinical studies show. Their antioxidant, anti-inflammatory and anti-angiogenic properties contribute to an important anti-atherosclerotic effect, and protect tissues against ischemia/reperfusion injuries and the cellular dysfunction caused by different physico-chemical agents. There is an obvious shortage of in vivo studies to further explore these compounds' potential in vascular physiology. Nevertheless, their favorable pharmacokinetic profile and overall lack of toxicity make these compounds suitable for clinical studies.

Caffeic amide derivatives inhibit allergen-induced bone marrow-derived dendritic cell maturation

BACKGROUND

Caffeic amides are derivatives of caffeic acid, which have antioxidant and anti-inflammatory properties, and high in vivo stability. The therapeutic effect of caffeic amides on allergic diseases, and especially on the maturation of bone marrow-derived dendritic cells (BM-DCs), remains unclear. In this study, we investigated the therapeutic potential of caffeic amides on allergic diseases by evaluating the maturation of DCs and evaluated their potential in inducing the differentiation of T_H2 cells.

METHODS

BM-DCs isolated from BALB/c mice were treated with different caffeic amide derivatives for 48 h and the expression of surface markers was analyzed by flow cytometry. The differentiation of CD4⁺ T cells was detected by the 5-bromo-2-deoxyuridine (BrdU) incorporation assay and cytokine production was analyzed by ELISA.

RESULTS

Our results showed that among the six caffeic amides tested herein, only 36 M significantly inhibited the antigen-induced maturation of DCs associated with the expression of CD80, CD86, and major histocompatibility complex II (VC ovalbumin (OVA)+ thymic stromal lymphopoietin (TSLP) vs. 36 M OVA + TSLP). Additionally, the isolation and co-culture of antigen-specific CD4⁺ T cells with 36 M-treated BM-DCs suppressed the antigen-specific differentiation of T_H2 cells.

CONCLUSION

Among the six caffeic amides tested herein, 36 M (N-octyl caffeamide) might possess therapeutic potential for allergic diseases.

Engineering a bacterial platform for total biosynthesis of caffeic acid derived phenethyl esters and amides

Caffeic acid has been widely recognized as a versatile pharmacophore for synthesis of new chemical entities, among which caffeic acid derived phenethyl esters and amides are the most extensively-investigated bioactive compounds with potential therapeutical applications. However, the natural biosynthetic routes for caffeic acid derived phenethyl esters or amides remain enigmatic, limiting their bio-based production. Herein, product-directed design of biosynthetic schemes allowed the development of thermodynamically favorable pathways for these compounds via acyltransferase (ATF) mediated trans-esterification. Production based screening identified a microbial O-ATF from Saccharomyces cerevisiae and a plant N-ATF from Capsicum annuum capable of forming caffeic acid derived esters and amides, respectively. Subsequent combinatorial incorporation of caffeic acid with various aromatic alcohol or amine biosynthetic pathways permitted the de novo bacterial production of a panel of caffeic acid derived phenethyl esters or amides in Escherichia coli for the first time. Particularly, host strain engineering via systematic knocking out endogenous caffeoyl-CoA degrading thioesterase and pathway optimization via titrating co-substrates enabled production enhancement of five caffeic acid derived phenethyl esters and amides, with titers ranging from 9.2 to 369.1mg/L. This platform expanded the capabilities of bacterial production of high-value natural aromatic esters and amides from renewable carbon source via tailoring non-natural biosynthetic pathways.

Protective Effect of Caffeic Acid Derivatives on tert-Butyl Hydroperoxide-Induced Oxidative Hepato-Toxicity and Mitochondrial Dysfunction in HepG2 Cells

Oxidative stress results in structural and functional abnormalities in the liver and is thought to be a crucial factor in liver diseases. The aim of this study was to investigate the cytoprotective and antioxidant effects of caffeic acid (CA) derivatives on tert-butyl hydroperoxide (t-BHP)-induced oxidative stress in HepG2 cells. Nine CA derivatives were synthesized, including N-phenylethyl caffeamide (PECA), N-(3-florophen)methyl caffeamide (FMCA), N-(4-methoxy-phen)methyl caffeamide (MPMCA), N-heptyl caffeamide (HCA), N-octyl caffeamide (OCA), octyl caffeate (CAOE), phenpropyl caffeate (CAPPE), phenethyl caffeate (CAPE), and phenmethyl caffeate (CAPME). The results showed that CA and its derivatives significantly inhibited t-BHP-induced cell death of HepG2 cells. The rank order of potency of the CA derivatives for cytoprotection was CAOE > HCA > OCA > FMCA > CAPPE > CAPME > CAPE > PECA > MPMCA > CA. Their cytoprotective activity was associated with lipophilicity. The antioxidant effect of these compounds was supported by the reduction in the levels of thiobarbituric acid reactive substrates, a biomarker of lipid peroxidation, in HepG2 cells. Pre-treatment of CA derivatives significantly prevented the depletion of glutathione, the most important water-soluble antioxidant in hepatocytes. Pre-treatment of CA derivatives before t-BHP exposure maintained mitochondrial oxygen consumption rate and ATP content in the injured HepG2 cells. CA derivatives except OCA and HCA significantly suppressed t-BHP-induced hypoxia-inducible factor-1α (HIF-1α) protein level. In addition, all of these CA derivatives markedly increased the nuclear factor erythroid 2-related factor 2 (Nrf2) accumulation in the nucleus, indicating that their cytoprotection may be mediated by the activation of Nrf2. Our results suggest that CA derivatives might be a hepatoprotective agent against oxidative stress.

Derivatives of caffeic acid, a natural antioxidant, as the basis for the discovery of novel nonpeptidic neurotrophic agents

Neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, threaten the lives of millions of people and the number of affected patients is constantly growing with the increase of the aging population. Small molecule neurotrophic agents represent promising therapeutics for the pharmacological management of neurodegenerative diseases. In this study, a series of caffeic acid amide analogues with variable alkyl chain lengths, including ACAF3 (C3), ACAF4 (C4), ACAF6 (C6), ACAF8 (C8) and ACAF12 (C12) were synthesized and their neurotrophic activity was examined by different methods in PC12 neuronal cells. We found that all caffeic acid amide derivatives significantly increased survival in PC12 neuronal cells in serum-deprived conditions at 25μM, as measured by the MTT assay. ACAF4, ACAF6 and ACAF8 at 5µM also significantly enhanced the effect of nerve growth factor (NGF) in inducing neurite outgrowth, a sign of neuronal differentiation. The neurotrophic effects of amide derivatives did not seem to be mediated by direct activation of tropomyosin receptor kinase A (TrkA) receptor, since K252a, a potent TrkA antagonist, did not block the neuronal survival enhancement effect. Similarly, the active compounds did not activate TrkA as measured by immunoblotting with anti-phosphoTrkA antibody. We also examined the effect of amide derivatives on signaling pathways involved in survival and differentiation by immunoblotting. ACAF4 and ACAF12 induced ERK1/2 phosphorylation in PC12 cells at 5 and 25µM, while ACAF12 was also able to significantly increase AKT phosphorylation at 5 and 25µM. Molecular docking studies indicated that compared to the parental compound caffeic acid, ACAF12 exhibited higher binding energy with phosphoinositide 3-kinase (PI3K) as a putative molecular target. Based on Lipinski's rule of five, all of the compounds obeyed three molecular descriptors (HBD, HBA and MM) in drug-likeness test. Taken together, these findings show for the first time that caffeic amides possess strong neurotrophic effects exerted via modulation of ERK1/2 and AKT signaling pathways presumably by activation of PI3K and thus represent promising agents for the discovery of neurotrophic compounds for management of neurodegenerative diseases.

Synthesis, Characterization, and In Vitro and In Vivo Evaluations of 4-(N)-Docosahexaenoyl 2', 2'-Difluorodeoxycytidine with Potent and Broad-Spectrum Antitumor Activity

In this study, a new compound, 4-(N)-docosahexaenoyl 2′, 2′-difluorodeoxycytidine (DHA-dFdC), was synthesized and characterized. Its antitumor activity was evaluated in cell culture and in mouse models of pancreatic cancer. DHA-dFdC is a poorly soluble, pale yellow waxy solid, with a molecular mass of 573.3 Da and a melting point of about 96°C. The activation energy for the degradation of DHA-dFdC in an aqueous Tween 80–based solution is 12.86 kcal/mol, whereas its stability is significantly higher in the presence of vitamin E. NCI-60 DTP Human Tumor Cell Line Screening revealed that DHA-dFdC has potent and broad-spectrum antitumor activity, especially in leukemia, renal, and central nervous system cancer cell lines. In human and murine pancreatic cancer cell lines, the IC₅₀ value of DHA-dFdC was up to 10⁵-fold lower than that of dFdC. The elimination of DHA-dFdC in mouse plasma appeared to follow a biexponential model, with a terminal phase t_1/2 of about 58 minutes. DHA-dFdC significantly extended the survival of genetically engineered mice that spontaneously develop pancreatic ductal adenocarcinoma. In nude mice with subcutaneously implanted human Panc-1 pancreatic tumors, the antitumor activity of DHA-dFdC was significantly stronger than the molar equivalent of dFdC alone, DHA alone, or the physical mixture of them (1:1, molar ratio). DHA-dFdC also significantly inhibited the growth of Panc-1 tumors orthotopically implanted in the pancreas of nude mice, whereas the molar equivalent dose of dFdC alone did not show any significant activity. DHA-dFdC is a promising compound for the potential treatment of cancers in organs such as the pancreas.

Molecular Characterization and Enhancement of Anticancer Activity of Caffeic Acid Phenethyl Ester by γ Cyclodextrin

Caffeic Acid Phenethyl Ester (CAPE) is a key component in New Zealand propolis, known for a variety of health promoting and therapeutic potentials. We investigated the molecular mechanism of anticancer and anti-metastasis activities of CAPE. cDNA array performed on the control and CAPE-treated breast cancer cells revealed activation of DNA damage signaling involving upregulation of GADD45α and p53 tumor suppressor proteins. Molecular docking analysis revealed that CAPE is capable of disrupting mortalin-p53 complexes. We provide experimental evidence and demonstrate that CAPE induced disruption of mortalin-p53 complexes led to nuclear translocation and activation of p53 resulting in growth arrest in cancer cells. Furthermore, CAPE-treated cells exhibited downregulation of mortalin and several other key regulators of cell migration accountable for its anti-metastasis activity. Of note, we found that whereas CAPE was unstable in the culture medium (as it gets degraded into caffeic acid by secreted esterases), its complex with gamma cyclodextrin (γCD) showed high efficacy in anti-tumor and anti-metastasis assays in vitro and in vivo (when administered through either intraperitoneal or oral route). The data proposes that CAPE-γCD complex is a potent anti-cancer and anti-metastasis reagent.

Modification of Caffeic Acid with Pyrrolidine Enhances Antioxidant Ability by Activating AKT/HO-1 Pathway in Heart

Overproduction of free radicals during ischemia/reperfusion (I/R) injury leads to an interest in using antioxidant therapy. Activating an endogenous antioxidant signaling pathway is more important due to the fact that the free radical scavenging behavior in vitro does not always correlate with a cytoprotection effect in vivo. Caffeic acid (CA), an antioxidant, is a major phenolic constituent in nature. Pyrrolidinyl caffeamide (PLCA), a derivative of CA, was compared with CA for their antioxidant and cytoprotective effects. Our results indicate that CA and PLCA exert the same ability to scavenge DPPH in vitro. In response to myocardial I/R stress, PLCA was shown to attenuate lipid peroxydation and troponin release more than CA. These responses were accompanied with a prominent elevation in AKT and HO-1 expression and a preservation of mnSOD expression and catalase activity. PLCA also improved cell viability and alleviated the intracellular ROS level more than CA in cardiomyocytes exposed to H₂O₂. When inhibiting the AKT or HO-1 pathways, PLCA lost its ability to recover mnSOD expression and catalase activity to counteract with oxidative stress, suggesting AKT/HO-1 pathway activation by PLCA plays an important role. In addition, inhibition of AKT signaling further abolished HO-1 activity, while inhibition of HO-1 signaling attenuated AKT expression, indicating cross-talk between the AKT and HO-1 pathways. These protective effects may contribute to the cardiac function improvement by PLCA. These findings provide new insight into therapeutic approaches using a modified natural compound against oxidative stress from myocardial injuries.

N-Phenethyl caffeamide and photodamage: protecting skin by inhibiting type I procollagen degradation and stimulating collagen synthesis

Skin is mainly damaged by genetic and environmental factors such as ultraviolet (UV) light and pollutants. UV light is a well-known factor that causes various types of skin damage and premature aging. Reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases that break down type I collagen. This study investigated the antioxidant and antiphotodamage activity and mechanisms of N-phenethyl caffeamide (K36) in human skin fibroblasts. The results indicated that K36 demonstrated strong 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, which dose-dependently reduced the production of UVB-induced intracellular ROS in human dermal fibroblasts. K36 prevented UVB-irradiation-induced type I collagen degradation by inhibiting the expression of matrix metalloproteins-1, -3, and -9 and the phosphorylation of mitogen-activated protein (MAP) kinases. Furthermore, K36 elevated collagen synthesis in skin fibroblasts by inhibiting UVB-induced Smad7 overexpression. K36 downregulated the expression of the transcription factor, activator protein-1 (AP-1). Our results indicated that K36 exhibited antioxidant properties and prevented skin collagen degradation caused by UV exposure and the stimulation of collagen synthesis, which suggests the potential use of K36 in preventing photodamage.

Caffeic acid phenethyl amide ameliorates ischemia/reperfusion injury and cardiac dysfunction in streptozotocin-induced diabetic rats

BACKGROUND

Caffeic acid phenethyl ester (CAPE) has been shown to protect the heart against ischemia/reperfusion (I/R) injury by various mechanisms including its antioxidant effect. In this study, we evaluated the protective effects of a CAPE analog with more structural stability in plasma, caffeic acid phenethyl amide (CAPA), on I/R injury in streptozotocin (STZ)-induced type 1 diabetic rats.

METHODS

Type 1 diabetes mellitus was induced in Sprague-Dawley rats by a single intravenous injection of 60 mg/kg STZ. To produce the I/R injury, the left anterior descending coronary artery was occluded for 45 minutes, followed by 2 hours of reperfusion. CAPA was pretreated intraperitoneally 30 minutes before reperfusion. An analog devoid of the antioxidant property of CAPA, dimethoxyl CAPA (dmCAPA), and a nitric oxide synthase (NOS) inhibitor (Nω-nitro-l-arginine methyl ester [l-NAME]) were used to evaluate the mechanism involved in the reduction of the infarct size following CAPA-treatment. Finally, the cardioprotective effect of chronic treatment of CAPA was analyzed in diabetic rats.

RESULTS

Compared to the control group, CAPA administration (3 and 15 mg/kg) significantly reduced the myocardial infarct size after I/R, while dmCAPA (15 mg/kg) had no cardioprotective effect. Interestingly, pretreatment with a NOS inhibitor, (L-NAME, 3 mg/kg) eliminated the effect of CAPA on myocardial infarction. Additionally, a 4-week CAPA treatment (1 mg/kg, orally, once daily) started 4 weeks after STZ-induction could effectively decrease the infarct size and ameliorate the cardiac dysfunction by pressure-volume loop analysis in STZ-induced diabetic animals.

CONCLUSIONS

CAPA, which is structurally similar to CAPE, exerts cardioprotective activity in I/R injury through its antioxidant property and by preserving nitric oxide levels. On the other hand, chronic CAPA treatment could also ameliorate cardiac dysfunction in diabetic animals.

Development and validation of an LCMS method to determine the pharmacokinetic profiles of caffeic acid phenethyl amide and caffeic acid phenethyl ester in male Sprague-Dawley rats

A validated LCMS method was developed for the quantitative determination of caffeic acid phenethyl amide (CAPA) and caffeic acid phenethyl ester (CAPE) from rat plasma. Separation was achieved using a reverse-phase C12 HPLC column (150 × 2.00 mm, 4 µm) with gradient elution running water (A) and acetonitrile (B). Mass spectrometry was performed with electrospray ionization in negative mode. This method was used to determine the pharmacokinetic profiles of CAPA and CAPE in male Sprague-Dawley rats following intravenous bolus administration of 5, 10 and 20 mg/kg of CAPA and 20 mg/kg of CAPE. The pharmacokinetic analysis suggests the lack of dose proportionality in the dose range of 5-20 mg/kg of CAPA. Total clearance values for CAPA ranged from 45 to 156 mL/min and decreased with increasing dose of CAPA. The volume of distribution for CAPA ranged from 17,750 to 52,420 mL, decreasing with increasing dose. The elimination half-life for CAPA ranged from 243.1 to 295.8 min and no statistically significant differences were observed between dose groups in the range of 5-20 mg/kg (p > 0.05). The elimination half-life for CAPE was found to be 92.26 min.

Caffeic acid phenethyl amide improves glucose homeostasis and attenuates the progression of vascular dysfunction in Streptozotocin-induced diabetic rats

BACKGROUND

Glucose intolerance and cardiovascular complications are major symptoms in patients with diabetes. Many therapies have proven beneficial in treating diabetes in animals by protecting the cardiovascular system and increasing glucose utilization. In this study, we evaluated the effects of caffeic acid phenethyl amide (CAPA) on glucose homeostasis and vascular function in streptozotocin (STZ)-induced type 1 diabetic rats.

METHODS

Diabetes (blood glucose levels > 350 mg/dL), was induced in Wistar rats by a single intravenous injection of 60 mg/kg STZ. Hypoglycemic effects were then assessed in normal and type 1 diabetic rats. In addition, coronary blood flow in Langendorff-perfused hearts was evaluated in the presence or absence of nitric oxide synthase (NOS) inhibitor. The thoracic aorta was used to measure vascular response to phenylephrine. Finally, the effect of chronic treatment of CAPA and insulin on coronary artery flow and vascular response to phenylephrine were analyzed in diabetic rats.

RESULTS

Oral administration of 0.1 mg/kg CAPA decreased plasma glucose in normal (32.9 ± 2.3% decrease, P < 0.05) and diabetic rats (11.8 ± 5.5% decrease, P < 0.05). In normal and diabetic rat hearts, 1-10 μM CAPA increased coronary flow rate, and this increase was abolished by 10 μM NOS inhibitor. In the thoracic aorta, the concentration/response curve of phenylephrine was right-shifted by administration of 100 μM CAPA. Coronary flow rate was reduced to 7.2 ± 0.2 mL/min at 8 weeks after STZ-induction. However, 4 weeks of treatment with CAPA (3 mg/kg, intraperitoneal, twice daily) started at 4 weeks after STZ induction increased flow rate to 11.2 ± 0.5 mL/min (P < 0.05). In addition, the contractile response induced by 1 μM phenylephrine increased from 6.8 ± 0.6 mN to 11.4 ± 0.4 mN (P < 0.05) and 14.9 ± 1.4 mN (P < 0.05) by insulin (1 IU/kg, intraperitoneal) or CAPA treatment, respectively.

CONCLUSIONS

CAPA induced hypoglycemic activity, increased coronary blood flow and vascular response to phenylephrine in type 1 diabetic rats. The increase in coronary blood flow may result from endothelial NOS activation. However, the detailed cellular mechanisms need to be further evaluated.