A Colon-Targeted Prodrug, 4-Phenylbutyric Acid-Glutamic Acid Conjugate, Ameliorates 2,4-Dinitrobenzenesulfonic Acid-Induced Colitis in Rats

An elevated level of endoplasmic reticulum (ER) stress is considered an aggravating factor for inflammatory bowel disease (IBD). To develop an ER-stress attenuator that is effective against colitis, 4-phenylbutyric acid (4-PBA), a chemical chaperone that alleviates ER stress, was conjugated with acidic amino acids to yield 4-PBA-glutamic acid (PBA-GA) and 4-PBA-aspartic acid (PBA-AA) conjugates. The PBA derivatives were converted to 4-PBA in the cecal contents, and the conversion was greater with PBA-GA than that with PBA-AA. After oral administration of PBA-GA (oral PBA-GA), up to 2.7 mM PBA was detected in the cecum, whereas 4-PBA was not detected in the blood, indicating that PBA-GA predominantly targeted the large intestine. In 2,4-dinitrobenzenesulfonic acid-induced colitis in rats, oral PBA-GA alleviated the damage and inflammation in the colon and substantially reduced the elevated levels of ER stress marker proteins in the inflamed colon. Moreover, PBA-GA was found to be as effective as the currently used anti-IBD drug, sulfasalazine. In conclusion, PBA-GA is a colon-targeted prodrug of 4-PBA and is effective against rat colitis probably via the attenuation of ER stress in the inflamed colon.

A Tumor-Immune Interaction Model for Synergistic Combinations of Anti PD-L1 and Ionizing Irradiation Treatment

Combination therapy with immune checkpoint blockade and ionizing irradiation therapy (IR) generates a synergistic effect to inhibit tumor growth better than either therapy does alone. We modeled the tumor-immune interactions occurring during combined IT and IR based on the published data from Deng et al. The mathematical model considered programmed cell death protein 1 and programmed death ligand 1, to quantify data fitting and global sensitivity of critical parameters. Fitting of data from control, IR and IT samples was conducted to verify the synergistic effect of a combination therapy consisting of IR and IT. Our approach using the model showed that an increase in the expression level of PD-1 and PD-L1 was proportional to tumor growth before therapy, but not after initiating therapy. The high expression level of PD-L1 in T cells may inhibit IT efficacy. After combination therapy begins, the tumor size was also influenced by the ratio of PD-1 to PD-L1. These results highlight that the ratio of PD-1 to PD-L1 in T cells could be considered in combination therapy.

In Vitro and In Vivo Assessment of Metabolic Drug Interaction Potential of Dutasteride with Ketoconazole

Dutasteride (DUT) is a selective, potent, competitive, and irreversible inhibitor of both type-1 and type-2 5α-reductase (5AR) commonly used in the treatment of benign prostatic hyperplasia and androgenetic alopecia. In the present study, we developed a simple and sensitive high-performance liquid chromatography with fluorescence detection (HPLC-FL) method for simultaneous determination of DUT and its major active metabolite, 6β-hydroxydutasteride (H-DUT). Next, the pharmacokinetic interactions of DUT with ketoconazole (KET), a potent CYP3A inhibitor, were comprehensively investigated. In vivo rat intravenous and oral studies revealed that the pharmacokinetics of DUT and H-DUT were significantly altered by the co-administration of KET. Furthermore, the in vitro microsomal metabolism, blood distribution, and protein-binding studies suggest that the altered pharmacokinetics of DUT could be attributed primarily to the inhibition of the DUT metabolism by KET. To the best of our knowledge, this is the first study to show the drug interaction potential of DUT with azole antifungal drugs including KET, together with a newly developed HPLC-FL method for the simultaneous quantification of DUT and H-DUT.

Conjugation of Amisulpride, an Anti-Psychotic Agent, with 5-Aminosalicylic Acid via an Azo Bond Yields an Orally Active Mutual Prodrug against Rat Colitis

Amisulpride (ASP), an anti-psychotic agent, is a pharmacologically equivalent to sulpiride (SP). Because SP demonstrates anti-ulcer and anti-colitic activities, ASP with an aniline moiety was azo-coupled to salicylic acid to generate 5-(aminoethanoylsulfamoyl)-N-[(1-ethylpyrrolidin-2-yl)methyl]-2-methoxybenzamide (ASP-azo-ASA), with the expectation that it would act as a colon-specific mutual prodrug against colitis. Following a 24 h incubation, approximately 80% of ASP-azo-ASA was cleaved to form ASP and 5-aminosalicylic acid (5-ASA) in the cecal contents, whereas it remained stable in the small intestinal contents. Oral gavage of ASP-azo-ASA (oral ASP-azo-ASA) delivered 5-ASA to the cecum to levels comparable with those observed for sulfasalazine (SSZ; clinical colon-specific prodrug of 5-ASA) and without detectable concentrations of ASP in the blood, indicating efficient colonic delivery. Oral ASP-azo-ASA ameliorated 2, 4-dinitrobenzenesulfonic acid hydrate (DNBS)-induced colitis in rats more effectively than oral SSZ. Additionally, oral ASP-azo-ASA lowered the levels of inflammatory mediators in the inflamed distal colon more effectively than oral SSZ. Combined treatment with 5-ASA and ASP via the rectal route more effectively reversed colonic damage and inflammation than treatment with 5-ASA or ASP alone, confirming the mutual anti-colitic actions of 5-ASA and ASP. In conclusion, ASP-azo-ASA is an orally active mutual prodrug against rat colitis with limited systemic absorption of ASP.

Blood component ridable and CD44 receptor targetable nanoparticles based on a maleimide-functionalized chondroitin sulfate derivative

Chondroitin sulfate A-deoxycholic acid-polyethylene glycol-maleimide (CSA-DOCA-PEG-MAL; CDPM) nanostructures were designed for the transient binding of MAL with thiol in blood components and cell membranes, in addition to the CD44 receptor targeting, for the therapy of breast cancer. The spontaneous binding of free thiol groups in plasma proteins and blood cells with the MAL group of CDPM was significantly higher than that of CSA-DOCA-PEG (CDP). Enhanced cellular uptake and the in vitro antiproliferation efficacy of docetaxel (D)-loaded CDPM (CDPM/D) nanoparticles (NPs) in MCF-7 cells indicated dual-targeting effects based on MAL-thiol reactions and CSA-CD44 receptor interactions. Following intravenous injection in rats, reduced clearance and an elevated half-life of the drug was observed in the CDPM/D NPs compared to the CDP/D NPs. Taken together, MAL modification of CDP NPs could be a promising approach not only to enhance tumor targeting and penetration but also to extend the blood circulation time of anticancer drugs.

Effects of Harvest Time on Phytochemical Constituents and Biological Activities of Panax ginseng Berry Extracts

Ginseng (Panax ginseng) has long been used as a traditional medicine for the prevention and treatment of various diseases. Generally, the harvest time and age of ginseng have been regarded as important factors determining the efficacy of ginseng. However, most studies have mainly focused on the root of ginseng, while studies on other parts of ginseng such as its berry have been relatively limited. Thus, the aim of this study iss to determine effects of harvest time on yields, phenolics/ginsenosides contents, and the antioxidant/anti-elastase activities of ethanol extracts of three- and four-year-old ginseng berry. In both three- and fourfour-year-old ginseng berry extracts, antioxidant and anti-elastase activities tended to increase as berries ripen from the first week to the last week of July. Liquid chromatography-tandem mass spectrometry analysis has revealed that contents of ginsenosides except Rg1 tend to be the highest in fourfour-year-old ginseng berries harvested in early July. These results indicate that biological activities and ginsenoside profiles of ginseng berry extracts depend on their age and harvest time in July, suggesting the importance of harvest time in the development of functional foods and medicinal products containing ginseng berry extracts. To the best of our knowledge, this is the first report on the influence of harvest time on the biological activity and ginsenoside contents of ginseng berry extracts.

Tyrosinase Inhibition Antioxidant Effect and Cytotoxicity Studies of the Extracts of Cudrania tricuspidata Fruit Standardized in Chlorogenic Acid

In the present study, various extracts of C. tricuspidata fruit were prepared with varying ethanol contents and evaluated for their biomarker and biological properties. The 80% ethanolic extract showed the best tyrosinase inhibitory activity, while the 100% ethanolic extract showed the best total phenolics and flavonoids contents. The HPLC method was applied to analyze the chlorogenic acid in C. tricuspidata fruit extracts. The results suggest that the observed antioxidant and tyrosinase inhibitory activity of C. tricuspidata fruit extract could partially be attributed to the presence of marker compounds in the extract. In this study, we present an analytical method for standardization and optimization of C. tricuspidata fruit preparations. Further investigations are warranted to confirm the in vivo pharmacological activity of C. tricuspidata fruit extract and its active constituents and assess the safe use of the plant for the potential development of the extract as a skin depigmentation agent.

A Simple HPLC Method for the Quantitative Determination of Silybin in Rat Plasma: Application to a Comparative Pharmacokinetic Study on Commercial Silymarin Products

Silybin (SBN) is a major active constituent of silymarin, a mixture of flavonoids found in fruits and seeds of milk thistle. The aim of this study was to describe a simple bioanalytical method for quantifying SBN in rat plasma. A simple protein deproteinization procedure with acetonitrile (ACN) was employed for plasma sample preparation. A reversed column and gradient elution of a mobile phase (mixture of phosphate buffer (pH 5.0) and ACN) were used for chromatographic separation. The selectivity, linearity (50–5000 ng/mL), precision, accuracy, recovery, matrix effect, and stability for this method were validated as per the current Food and Drug Administration (FDA) guidelines. Our method for SBN was applied to a comparative pharmacokinetic study on four different commercial silymarin products. This in vivo rat study demonstrated that product #4 significantly enhanced the relative oral bioavailability of SBN, as compared to product #1–3. Therefore, the bioanalytical method proposed herein could serve as a promising alternative for preclinical pharmacokinetic studies on silymarin products and, by extension, clinical use after partial modification and validation.

Effects of lobetyolin on xanthine oxidase activity in vitro and in vivo: weak and mixed inhibition

Lobetyolin (LBT), a general marker compound mainly found in Codonopsis plants including C. pilosula, C. tubulosa, and C. lanceolata, exhibits antitumor, antiviral, anti-inflammatory, mucosal protective, and antioxidant activities. Xanthine oxidase (XO) catalyzes the formation of uric acid from xanthine, a critical metabolic pathway related to hyperuricemia and gout. The aim of this study was to investigate the effect of LBT on XO activity and its mechanism using in vitro enzyme assay system and in vivo potassium oxonate-induced hyperuricemic mice. LBT was found to weakly inhibit XO activity via a mixed type mechanism. Consistently, the impact of 1-week oral LBT treatment on serum XO activity in vivo is limited in hyperuricemic mice. However, oral LBT at 50 mg/kg significantly reduced hepatic XO activity in vivo. To the best of our knowledge, this is the first study to report effects of LBT on XO activity and its inhibition mechanism.

A novel high-performance liquid chromatographic method combined with fluorescence detection for determination of ertugliflozin in rat plasma: Assessment of pharmacokinetic drug interaction potential of ertugliflozin with mefenamic acid and ketoconazole

Ertugliflozin (ERTU) is a novel, potent, and highly selective sodium glucose cotransporter 2 inhibitor that has been recently approved for the treatment of type 2 diabetes mellitus. We describe a novel bioanalytical method using high-performance liquid chromatography (HPLC) coupled with fluorescence detection for quantitative determination of ERTU in rat plasma. Acetonitrile-based protein precipitation method was used for sample preparation, and chromatographic separation was performed on a Kinetex® C18 column with an isocratic mobile phase comprising acetonitrile and 10 mM potassium phosphate buffer (pH 6.0). The eluent was monitored by a fluorescence detector at an optimized excitation/emission wavelength pair of 277/320 nm. The method was validated to demonstrate the selectivity, linearity (ranging from 4 to 2000 ng/mL), precision, accuracy, recovery, matrix effect, and stability in line with the current FDA guidelines. The newly developed method was successfully applied to investigate the pharmacokinetic interactions of ERTU with mefenamic acid (MEF) and ketoconazole (KET). The findings of the present study revealed that the pharmacokinetics of ERTU may be altered by concurrent administration of MEF and KET in rats. To our knowledge, the present study is the first to develop a validated bioanalytical method for quantification of ERTU using HPLC coupled with fluorescence detection and to assess the drug interaction potential of ERTU with non-steroidal anti-inflammatory (MEF) and azole antifungal (KET) drugs.

Metabolic interactions of rosmarinic acid with human cytochrome P450 monooxygenases and uridine diphosphate glucuronosyltransferases

In light of the widespread use of herbal medicines containing rosmarinic acid (RA) and limited literature available thereon, we investigated the metabolic interactions of RA with human cytochrome P450 monooxygenases (CYPs) and uridine diphosphate glucuronosyltransferases (UGTs). The involvement of selected enzymes (CYP1A2, CYP2C19, CYP2E1, CYP3 A4, UGT1A1, UGT1A6, and UGT2B7) in the metabolism of RA and the inhibitory effect of RA on the enzyme activity were comprehensively evaluated using human recombinant isozyme system. Additionally, concentration-dependent RA metabolism mediated by phase I enzymes (including CYPs) or UGT was investigated in human liver microsome (HLM) system. A significant disappearance of RA was observed in the seven CYP and UGT isoforms studied, indicating their possible involvement in the metabolism of RA. Based on Michaelis-Menten kinetics, the metabolism study using HLM suggests that the UGT system may have a higher capacity and lower affinity for the metabolism of RA than phase I enzyme (including CYP) systems. Moreover, RA weakly inhibited CYP2C9 and 2E1 activities with IC50 values of 39.6 and 61.0 μM, respectively, while moderately inhibiting UGT1A1, 1A6, and 2B7 with IC50 values of 9.24, 19.1, and 23.4 μM, respectively. By constructing Line weaver-Burk plots, the type of inhibition exhibited by RA on CYP and UGT activities was determined as follows: CYP2C19, mixed inhibition; CYP2E1, UGT1A1, UGT1A6, and UGT2B7, competitive inhibition. Based on the comparison of the IC50 and Ki values obtained in the current study with the previously reported plasma concentrations of RA after oral dosing in humans, it is suggested that RA may significantly inhibit the activities of the tested UGTs, rather than CYPs, in clinical settings. Thus, the present study could provide a basis for further studies on clinically significant interactions between UGT substrate drugs and herbal medicines containing RA.

Differential regulation of intestinal and hepatic CYP3A by 1α,25-dihydroxyvitamin D3 : Effects on in vivo oral absorption and disposition of buspirone in rats

1α,25-Dihydroxyvitamin D₃ (also called 1,25(OH)₂ D₃ or calcitriol) is the biologically active form of vitamin D, which functions as a ligand to the vitamin D receptor (VDR). It was previously reported that intestinal cytochrome P450 3A (CYP3A) expression was altered by 1,25(OH)₂ D₃ -mediated VDR activation. However, to clarify whether the change in CYP3A subfamily expression by VDR activation can affect metabolic function, further evidence is needed to prove the effect of 1,25(OH)₂ D₃ treatment on CYP3A-mediated drug metabolism and pharmacokinetics. Here, we report the effects of 1,25(OH)₂ D₃ on CYP3A activity and in vivo pharmacokinetics of buspirone in Sprague-Dawley rats. CYP3A mRNA expression and CYP3A-mediated testosterone metabolism were enhanced in the intestine but were unaffected in the livers of rats treated with 1,25(OH)₂ D₃ . Notably, the oral pharmacokinetic profile of buspirone (CYP3A substrate drug) and 6'-hydroxybuspirone (major active metabolite of buspirone formed via CYP3A-mediated metabolism) was significantly altered, while its intravenous pharmacokinetic profile was not affected by 1,25(OH)₂ D₃ treatment. To the best of our knowledge, this study provides the first reported data regarding the effects of 1,25(OH)₂ D₃ treatment on the in vivo pharmacokinetics of intravenous and oral buspirone in rats, by the differential modulation of hepatic and intestinal CYP3A activity. Our present results could lead to further studies in clinically significant CYP3A-mediated drug-nutrient interactions with 1,25(OH)₂ D₃ , including 1,25(OH)₂ D₃ -buspirone interaction. Preclinical Research & Development.

Microemulsion-based hydrogels for enhancing epidermal/dermal deposition of topically administered 20(S)-protopanaxadiol: in vitro and in vivo evaluation studies

BACKGROUND

20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD.

METHODS

MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model.

RESULTS

A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient r 2 = 0.929‒0.947).

CONCLUSION

The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.

Modulation of Rat Hepatic CYP1A and 2C Activity by Honokiol and Magnolol: Differential Effects on Phenacetin and Diclofenac Pharmacokinetics In Vivo

Honokiol (2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol) and magnolol (4-Allyl-2-(5-allyl-2-hydroxy-phenyl)phenol) are the major active polyphenol constituents of Magnolia officinalis (Magnoliaceae) bark, which has been widely used in traditional Chinese medicine (Houpu Tang) for the treatment of various diseases, including anxiety, stress, gastrointestinal disorders, infection, and asthma. The aim of this study was to investigate the direct effects of honokiol and magnolol on hepatic CYP1A and 2C-mediated metabolism in vitro using rat liver microsomes and in vivo using the Sprague-Dawley rat model. Honokiol and magnolol inhibited in vitro CYP1A activity (probe substrate: phenacetin) more potently than CYP2C activity (probe substrate: diclofenac): The mean IC₅₀ values of honokiol for the metabolism of phenacetin and diclofenac were 8.59 μM and 44.7 μM, while those of magnolol were 19.0 μM and 47.3 μM, respectively. Notably, the systemic exposure (AUC and C_max) of phenacetin, but not of diclofenac, was markedly enhanced by the concurrent administration of intravenous honokiol or magnolol. The differential effects of the two phytochemicals on phenacetin and diclofenac in vivo pharmacokinetics could at least be partly attributed to their lower IC₅₀ values for the inhibition of phenacetin metabolism than for diclofenac metabolism. In addition, the systemic exposure, CL, and V_ss of honokiol and magnolol tended to be similar between the rat groups receiving phenacetin and diclofenac. These findings improve our understanding of CYP-mediated drug interactions with M. officinalis and its active constituents.

Hot-water extract of the branches of Hovenia dulcis Thunb. (Rhamnaceae) ameliorates low-fiber diet-induced constipation in rats

Hovenia dulcis Thunb. (Rhamnaceae), also known as oriental raisin tree, is used in traditional herbal medicine. Its extracts have been reported to show various pharmacological effects such as hepatoprotection, antitumor, antiatopic dermatitis, antilipid peroxidation, anti-steatotic, anti-inflammatory, and antiallergic activities. However, there have been no reports on the effect of H. dulcis extracts in relieving constipation so far. The aim of this study was to investigate the effects of a hot-water extract of the branches of H. dulcis (WEHD) on low-fiber diet-induced constipation in Sprague Dawley rats. The in vivo laxative activity of WEHD was assessed by measuring the intestinal transit of charcoal meal and stool parameters. Furthermore, the in vitro spasmogenic activity of WEHD was evaluated by monitoring the temporal profiles of contraction of rat colon in the absence or presence of WEHD. In addition, constituent profiling was conducted using high-performance liquid chromatography analysis. Pretreatment with WEHD significantly enhanced the intestinal transit of charcoal meal and increased the frequency and weight of stools in rats. In addition, the frequency and amplitude of contractile responses of isolated rat colon were markedly enhanced by WEHD. Two organic phenolic acids, ferulic and vanillic acids, were identified in WEHD, of which vanillic acid exhibited spasmogenic activity. To the best of our knowledge, this is the first study to report the laxative and spasmogenic activities of H. dulcis and its constituents, suggesting that WEHD can serve as a complementary and/or alternative laxative in alleviating chronic constipation.

Novel reverse electrodialysis-driven iontophoretic system for topical and transdermal delivery of poorly permeable therapeutic agents

Topical and transdermal drug delivery has great potential in non-invasive and non-oral administration of poorly bioavailable therapeutic agents. However, due to the barrier function of the stratum corneum, the drugs that can be clinically feasible candidates for topical and transdermal delivery have been limited to small-sized lipophilic molecules. Previously, we fabricated a novel iontophoretic system using reverse electrodialysis (RED) technology (RED system). However, no study has demonstrated its utility in topical and/or transdermal delivery of poorly permeable therapeutic agents. In this study, we report the topical delivery of fluorescein isothiocyanate (FITC)-hyaluronic acid (FITC-HA) and vitamin C and the transdermal delivery of lopinavir using our newly developed RED system in the in vitro hairless mouse skin and in vivo Sprague-Dawley rat models. The RED system significantly enhanced the efficiency of topical HA and vitamin C and transdermal lopinavir delivery. Moreover, the efficiency and safety of transdermal delivery using the RED system were comparable with those of a commercial ketoprofen patch formulation. Thus, the RED system can be a potential topical and transdermal delivery system for various poorly bioavailable pharmaceuticals including HA, vitamin C, and lopinavir.

Quantitative Analysis, Extraction Optimization, and Biological Evaluation of Cudrania tricuspidata Leaf and Fruit Extracts

Cudrania tricuspidata Bureau (Moraceae) shows numerous pharmacological effects and has been used in traditional herbal remedies for inflammation, gastritis, tumors, and liver diseases. However, no validated analytical method for the standardization and optimization of the biological properties of C. tricuspidata preparations has been reported. We developed and validated a reverse-phase high-performance liquid chromatography (HPLC) method for the separation and quantification of active markers. Ethanolic extracts of C. tricuspidata leaves were prepared and evaluated for chemical profiles and biological activities. The 80% ethanolic extract demonstrated the greatest antioxidant activity and phenolic content, while the 100% ethanolic extract had the greatest total flavonoid content and xanthine oxidase (XO) inhibitory activity. The validated HPLC method confirmed that chlorogenic acid, rutin, and kaempferol were present in C. tricuspidata leaf extracts. We postulated that the antioxidant and anti-hyperuricemic/gout effects of C. tricuspidata extract could be attributed to these marker compounds. Our results suggested that the flavonoid-rich fraction of the leaf extract may be utilized for the treatment and prevention of hyperuricemia-related diseases, and the validated method and marker compounds could be applied for the quality control of C. tricuspidata preparations.

Fabrication of polymer matrix-free nanocomposites based on Angelica gigas Nakai extract and their application to breast cancer therapy

Nanocomposites (NCs) based on the ethanol extract of Angelica gigas Nakai (AGN EtOH ext) were developed for breast cancer therapy. Polymer matrix-free nano-sized particles based on the extract of natural product were fabricated using a modified emulsification-solvent evaporation method. Without the use of polymer matrix, toxicity can be minimized and the clinical application may be assured. AGN NCs with approximately 200nm mean diameter, narrow size distribution, and negative zeta potential were prepared in this study. Sustained release of decursin (D) and decursinol angelate (DA) (as major components of AGN) from AGN NCs was observed at pH 7.4. Cellular accumulation efficiency and intracellular distribution of AGN NCs were evaluated in MCF-7 (human breast adenocarcinoma) cells. According to the results of antiproliferation assay in MCF-7 cells, IC₅₀ value of AGN NCs group (27.4±4.0μg/mL) was lower than that of AGN EtOH ext group (75.3±13.7μg/mL) (p<0.05). Also, the percentage of apoptotic events of AGN NCs group was significantly higher than that of AGN EtOH ext group (p<0.05). All these findings suggest that developed AGN NCs can be used as one of promising nanosystems for the therapy of breast cancers.

Advanced Growth Factor Delivery Systems in Wound Management and Skin Regeneration

Growth factors are endogenous signaling molecules that regulate cellular responses required for wound healing processes such as migration, proliferation, and differentiation. However, exogenous application of growth factors has limited effectiveness in clinical settings due to their low in vivo stability, restricted absorption through skin around wound lesions, elimination by exudation prior to reaching the wound area, and other unwanted side effects. Sophisticated systems to control the spatio-temporal delivery of growth factors are required for the effective and safe use of growth factors as regenerative treatments in clinical practice, such as biomaterial-based drug delivery systems (DDSs). The current review describes the roles of growth factors in wound healing, their clinical applications for the treatment of chronic wounds, and advances in growth factor-loaded DDSs for enhanced wound healing, focusing on micro- and nano-particulate systems, scaffolds, hydrogels, and other miscellaneous systems.

Preparation and in vivo evaluation of cationic elastic liposomes comprising highly skin-permeable growth factors combined with hyaluronic acid for enhanced diabetic wound-healing therapy

To enhance the therapeutic effects of exogenous administration of growth factors (GFs) in the treatment of chronic wounds, we constructed GF combinations of highly skin-permeable epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and platelet-derived growth factor-A (PDGF-A). We genetically conjugated a low-molecular-weight protamine (LMWP) to the N-termini of these GFs to form LMWP-EGF, LMWP-IGF-I, and LMWP-PDGF-A. Subsequently, these molecules were complexed with hyaluronic acid (HA). Combinations of native or LMWP-fused GFs significantly promoted fibroblast proliferation and the synthesis of procollagen, with a magnification of these results observed after the GFs were complexed with HA. The optimal proportions of LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, and HA were 1, 1, 0.02, and 200, respectively. After confirming the presence of a synergistic effect, we incorporated the LMWP-fused GFs-HA complex into cationic elastic liposomes (ELs) of 107±0.757nm in diameter and a zeta potential of 56.5±1.13mV. The LMWP-fused GFs had significantly improved skin permeation compared with native GFs. The in vitro wound recovery rate of the LMWP-fused GFs-HA complex was 23% higher than that of cationic ELs composed of LMWP-fused GFs alone. Moreover, the cationic ELs containing the LMWP-fused GFs-HA complex significantly accelerated the wound closure rate in a diabetic mouse model and the wound size was maximally decreased by 65% and 58% compared to cationic ELs loaded with vehicle or native GFs-HA complex, respectively. Thus, topical treatment with cationic ELs loaded with the LMWP-fused GFs-HA complex synergistically enhanced the healing of chronic wounds, exerting both rapid and prolonged effects.

STATEMENT OF SIGNIFICANCE

We believe that our study makes a significant contribution to the literature, because it demonstrated the potential application of cationic elastic liposomes as topical delivery systems for growth factors (GFs) that have certain limitations in their therapeutic effects (e.g., low percutaneous absorption of GFs at the lesion site and the requirement for various GFs at different healing stages). Topical treatment with cationic elastic liposomes loaded with highly skin-permeable low-molecular-weight protamine (LMWP)-fused GFs-hyaluronic acid (HA) complex synergistically enhanced the healing of diabetic wounds, exerting both rapid and prolonged effects.

Identification of the biologically active constituents of Camellia japonica leaf and anti-hyperuricemic effect in vitro and in vivo

Camellia japonica L. is a plant of which the seeds are used as a folk medicine, and it is native to South Korea, Japan and China. In previous study, triterpenes, flavonoids, tannins and fatty acids which have antiviral, antioxidant and anti inflammatory activity were reported from C. japonica leaf and flower. In Korea, the seed from this plant is used as a traditional medicine and in folk remedies for the treatment of bleeding and inflammation. However, the major issue associated with the use of the seed as a medicinal and/or functional food ingredient is its application to the pharmaceutical and food industry. First, the productivity of seed extract is very much less than that of the leaf. Second, the beneficial usage of the seed extract as an alternative medicine and functional source is not yet clear. Thus, in this study, we focused on another part of the plant, the leaf, and found that the extract of Camellia japonica leaf has a high concentration of vitamin E, rutin and other biologically active compounds related to hyperuricemia. We aimed to investigate the biological activities, namely the antioxidant activities, xanthine oxidase (XO) inhibitory activity and anti‑hyperuricemic effects of extract from C. japonica leaf and the phytochemicals contained therein. Ethanol extracts of C. japonica leaf (ECJL) were prepared, and the extract was used with respect to antioxidant activities, total phenolic contents and XO inhibitory activity. The in vivo XO inhibitory activity and anti‑hyperuricemic effects of the extract were evaluated in mice with potassium oxonate‑induced hyperuricemia. To clarify the marker compounds that are responsible for the anti‑hyperuricemic effects, several key constituents were identified using gas chromatography‑mass spectrometry (GC‑MS) and and liquid chromatography-mass spectrometry (LC-MS). ECJL was found to have strong antioxidant activities, and in vitro XO inhibitory activity. The results of the in vivo experiments using mice demonstrated that ECJL at the doses of 100 and 300 mg/kg inhibited hepatic XO activity and significantly attenuated hyperuricemia. To the best of our knowledge, the present study is the first report on the XO inhibitory and anti-hyperuricemic effects of ECJL, which can be therapeutically applied in the treatment of hyperuricemia and gout.

Antimicrobial and Anti-Inflammatory Effects of Ethanol Extract of Corylopsis coreana Uyeki Flos

Background:

Corylopsis coreana Uyeki (Hamamelidaceae) is a medicinal plant cultivated in Northeast Asia. Previously, we have reported that an ethanol extract of Corylopsis coreana Uyeki flos (ECCF) contains four active compounds with antioxidant activity.

Objective:

The aim of this study was to investigate the antimicrobial spectrum against infectious bacteria and anti-inflammatory effect of ECCF in a mouse model of acute local inflammation.

Materials and Methods:

In vitro antimicrobial susceptibility was evaluated using standard plate assay technique. Antimicrobial activities (minimum inhibitory concentration, MIC; μg/mL) were determined with the serial dilution method. In vivo anti-inflammatory activity was studied using a mouse model of carrageenan-induced air pouch inflammation.

Results:

The ECCF showed antimicrobial activities against general bacteria and drug-resistant bacteria including Staphylococcus aureus, Micrococcus luteus ATCC 9341, Mycrobacterium smegmatis ATCC 9341, Mycrobacterium smegmatis ATCC 9341, Salmonella typhimrium KCTC 1925, and nine methicillin-resistant Staphylococcus aureus strains, with MIC values ranging from 250 to 1000 μg/mL. In in vivo mouse model, inflammatory morphologic changes observed in the air pouch membrane were restored to its normal condition by the ECCF treatment. Moreover, the ECCF significantly reduced exudate volumes, protein contents, inflammatory cell counts, and pro-inflammatory cytokine levels in the exudates recovered from air pouches of the mouse model. Flavonoids in the ECCF were found to contain bergenin, quercitrin, and quercetin with reported anti-inflammatory activity via suppressing tumor necrosis factor-α production.

Conclusion:

To the best of our knowledge, this is the first report to demonstrate the antimicrobial and anti-inflammatory activities of ECCF. Our results suggest that the ECCF might potentially serve as an alternative or complementary medicine for treating inflammatory diseases caused by microbial infection.

SUMMARY

ECCF showed antimicrobial activity against infectious bacteria and multidrug-resistant strains.

ECCF exhibited anti-inflammatory activity in a carrageenan-induced air pouch mouse model.

ECCF contained several active constituents such as bergenin, quercitrin, and quercetin.

Abbreviations used:Corylopsis coreana CCF: Uyeki flos, ECCF: ethanol extract of CCF

Capmul MCM/Solutol HS15-Based Microemulsion for Enhanced Oral Bioavailability of Rebamipide

Rebamipide (RBP) is a potent anti-ulcer and anti-oxidative agent, which is a BCS class IV drug with a low oral bioavailability of less than 10%. Thus, the systemic absorption of RBP into the blood circulation is an essential prerequisite for exerting its pharmacological activities after oral dosing. Herein, we report on microemulsion (ME) systems for the enhancement of oral RBP bioavailability. In this study, MEs consisting of Capmul MCM (oil), Solutol HS15 (surfactant), and ethanol (co-surfactant) were prepared by the construction of pseudo-ternary phase diagram. The RBP-loaded MEs had spherical nano-sized droplets with narrow size distribution and neutral zeta potential. Moreover, the prepared MEs significantly enhanced the dissolution and oral bioavailability of RBP with no discernible intestinal toxicity. These results suggest that the present ME system could be further developed as an alternative oral formulation for RBP.