Effect of combination treatment of protocatechuic acid with 5-fluorouracil and oxaliplatin on colon cancer Caco-2 cell line

Among the most common antitumor drugs used in the treatment of colon cancer are 5-fluorouracil and oxaliplatin (5-FU and OXA). However, both these drugs have many side effects, and hence there is a need for new treatment\approach to reduce the side effects aas well as drug concentration. In this context, here, we investigated the effect of addition of protocatechuic acid (PCA) onto either monotherapies or combination therapies of 5-FU and OXA on the human colon cancer (Caco-2) cell line. In addition, we did evaluate the synergistic effect of PCA with 5-FU and OXA. Further, we determined the suppressive effects of different doses of PCA alone or in combination with 5-FU/OXA on cell proliferation after 24 and 48 hours. We identified a suppressive effect of PCA on cell viability at 48 h starting from the dose of 50 µM Matrix metalloproteinase-2 (MMP-2) and MMP-9 gene expression levels and apoptotic effects showed significant increases and decreases depending on the dose and time applied in the experimental groups. The highest synergistic activity was seen at 2:1 concentration of 5-FU+ PCA. Our findings indicate the presence of the cytotoxic and apoptotic effects of PCA in Caco-2 cells at 48 h, increasing with a dose- and time-dependent manner.

Anti-oxidative Stress Effect and Mechanism of Huangqintang on Caco-2 Cells Through Nrf2 Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo verify the anti-oxidative stress effect of Huangqintang based on the nuclear factor E2-related factor 2 （Nrf2） signaling pathway by using Caco-2 cells as a carrier and RNA interference （RNAi） technology with in vitro experiments. MethodThe Caco-2 cells in the logarithmic growth phase were transfected with siRNA to construct siRNA Caco-2 cells. After normal Caco-2 cells and siRNA Caco-2 cells were incubated with Huangqintang of different doses， RNA and protein were extracted. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were used to detect the mRNA and protein expression of heme oxygenase-1 （HO-1）， NAD（P）H quinone oxidoreductase 1 （NQO1）， glutathione S-transferase （GST）， Kelch-like ECH-associated protein 1 （Keap1）， and Nrf2. Meanwhile， the activities of superoxide dismutase （SOD） and GSH-Px， as well as the expression levels of malondialdehyde （MDA） and reactive oxygen species （ROS）， were detected by the colorimetric method and the probe method. ResultCompared with the results in the normal group， only the 400 mg·L-1 Huangqintang group and the sulforaphane （SFN） group could reduce the content of ROS and MDA in Caco-2 cells （P<0.01）， while the activities of SOD and GSH-Px in the cells of the Huangqintang groups and the SFN group showed an upward trend. Furthermore， there were significant differences in the 400 mg·L-1 Huangqintang group/the SFN group and the normal group （P<0.01）. Meanwhile， the protein and mRNA expression levels of HO-1， GST， Keap1， NQO1， and Nrf2 showed an upward trend in all groups （P<0.05， P<0.01）. After transfection， compared with the normal group， the model group showed increased content of MDA and ROS， blunted activities of GSH-Px and SOD， and reduced protein and mRNA expression of HO-1， GST， Keap1， and NQO1 （P<0.05， P<0.01）. After drug incubation， compared with the model group， the SFN group showed potentiated SOD activity， and the SFN group and the Huangqintang groups showed enhanced GSH-Px activity （P<0.01）. Moreover， the activities of SOD and GSH-Px in the 400 and 200 mg·L-1 Huangqintang groups and the SFN group showed an upward trend （P<0.01）， and the content of MDA in the 400 mg·L-1 Huangqintang group and the SFN group showed a downward trend. ROS decreased in all groups with drug intervention （P<0.01）， and the protein and mRNA expression of HO-1， GST， Keap1， NQO1， and Nrf2 increased to varying degrees （P<0.05， P<0.01）. ConclusionHuangqintang can play an anti-oxidative stress role by regulating the Nrf2 pathway.

Effects of hypoxia on the expression and function of P-gp in Caco-2 cells / 中南大学学报(医学版)

OBJECTIVES@#Hypoxia can alter the oral bioavailability of drugs, including various substrates (drugs) of P-glycoprotein (P-gp), suggesting that hypoxia may affect the function of P-gp in intestinal epithelial cells. Currently, Caco-2 monolayer model is the classic model for studying the function of intestinal epithelial P-gp. This study combines the Caco-2 monolayer model with hypoxia to investigate the effects of hypoxia on the expression and function of P-gp in Caco-2 cells, which helps to elucidate the mechanism of changes in drug transport on intestinal epithelial cells in high-altitude hypoxia environment.@*METHODS@#Normally cultured Caco-2 cells were cultured in 1% oxygen concentration for 24, 48, and 72 h, respectively. After the extraction of the membrane proteins, the levels of P-gp were measured by Western blotting. The hypoxia time, with the most significant change of P-gp expression, was selected as the subsequent study condition. After culturing Caco-2 cells in transwell cells for 21 days and establishing a Caco-2 monolayer model, they were divided into a normoxic control group and a hypoxic group. The normoxic control group was continuously cultured in normal condition for 72 h, while the hypoxic group was incubated for 72 h in 1% oxygen concentration. The integrity and polarability of Caco-2 cells monolayer were evaluated by transepithelial electrical resistance (TEER), apparent permeability (Papp) of lucifer yellow, the activity of alkaline phosphatase (AKP), and microvilli morphology and tight junction structure under transmission electron microscope. Then, the Papp of rhodamine 123 (Rh123), a kind of P-gp specific substrate, was detected and the efflux rate was calculated. The Caco-2 cell monolayer, culturing at plastic flasks, was incubated for 72 h in 1% oxygen concentration, the expression level of P-gp was detected.@*RESULTS@#P-gp was decreased in Caco-2 cells with 1% oxygen concentration, especially the duration of 72 h (P<0.01). In hypoxic group, the TEER of monolayer was more than 400 Ω·cm2, the Papp of lucifer yellow was less than 5×10-7 cm/s, and the ratio of AKP activity between apical side and basal side was greater than 3. The establishment of Caco-2 monolayer model was successful, and hypoxia treatment did not affect the integrity and polarization state of the model. Compared with the normoxic control group, the efflux rate of Rh123 was significantly reduced in Caco-2 cell monolayer of the hypoxic group (P<0.01). Hypoxia reduced the expression of P-gp in Caco-2 cell monolayer (P<0.01).@*CONCLUSIONS@#Hypoxia inhibits P-gp function in Caco-2 cells, which may be related to the decreased P-gp level.

Analysis of the of Pb, Cd and As in decoction of Lindera aggregata (Sims) Kosterm. by PBET digestion in vitro/Caco-2 cell model and their cumulative risk assessment / 药学学报

Inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the concentrations of lead (Pb), cadmium (Cd) and arsenic (As) in Lindera aggregata (Sims) Kosterm. The physiologically based extraction test (PBET) digestion in vitro/Caco-2 cell model was established to investigate the bioaccessible contents of Pb, Cd and As in decoction of Lindera aggregata (Sims) Kosterm. The target-organ toxicity dose modification of HI method (TTD) was used to evaluate the cumulative risk caused by the combined exposure of the total levels of Pb, Cd and As in Lindera aggregata (Sims) Kosterm. and the bioaccessible contents in the decoction. The results showed that the total contents of Pb, Cd and As in 4 batches of samples were in the range of 2.901-3.872, 1.299-1.800 and 0.062-0.216 mg·kg-1, respectively. After transportation by Cacco-2 cells, the bioaccessible contents of Pb, Cd, and As in the decoction were in the range of 0.045-0.080, 0.070-0.112 and 0.004-0.018 mg·kg-1. The results of risk assessment showed that calculated by the total amounts of heavy metals in the Lindera aggregata (Sims) Kosterm., for the end points of nervous system, the cumulative risks of co-exposure of heavy metals in 3 batches of samples were of concern. After decoction and transportation by Caco-2 cells, for the end points of cardiovascular system, blood, nervous system, kidney and testis, the TTD modification of HI values of all batches of samples were less than 1, and the health risks were acceptable. The study provided methodology basis for a more objective assessment of the health risks of heavy metals and harmful elements in traditional Chinese medicine and for a more scientific limit standard of heavy metals and harmful elements.

Intestinal absorption mechanism of saikosaponin d in vitro and in vivo / 中国药科大学学报

@#In order to reveal the intestinal absorption mechanism of saikosaponin d (SSd) in vitro and in vivo, the current research investigated the effects of different experimental conditions (time, concentration, temperature, pH, intestinal segments), transporter inhibitors, paracellular pathway enhancer, metabolic enzyme inhibitors on the intestinal absorption of SSd, in Caco-2 monolayers and a single pass perfusion model in rats.The results showed that the apparent permeability coefficient (Papp) and effective permeability coefficient (Peff) of SSd were 4.75 × 10-7 - 6.38 × 10-7 cm/s and 0.19 × 10-4- 0.27 × 10-4 cm/s, respectively, indicating that it was a low permeability compound, and that the transmembrane transport of SSd was concentration-dependent (0.5-5 μmol/L) and time-dependent (0-180 min).Ileum was the main absorption site for SSd. Experimental results based on Caco-2 monolayers showed that the P-gp inhibitor and paracellular permeability enhancer significantly increased the absorption of SSd (P < 0.05), which was consistent with the results obtained in rats. Inhibitors of OATPs and OCTs showed different results in vitro and in vivo, which may be related to the lower expression of them in jejunum.In summary, the intestinal absorption of SSd occurs through a carrier-mediated and energy-dependent transport, as well as passive diffusion, and P-glycoprotein plays an important role in the active transport of SSd.

Effect of bile on intestinal alkaline phosphatase in intestinal mucosa / 中华肝胆外科杂志

Objective:To investigate the expression of intestinal alkaline phosphatase (IAP) in intestinal mucosa with bile deficiency and the effect of bile on the expression of IAP in intestinal epithelial Caco-2 cell model.Methods:Thirty healthy male SD rats were randomly divided into control group (Ctrl, n=10), external drainage group (ED, n=10) and obstructive jaundice group (OJ, n=10). Ileum specimens were collected on the 7th day after modeling. Western blot and immunohistochemical staining were used to determine the expression of IAP in rat intestinal mucosa. Different concentrations of human bile were used to treat on Caco-2 cells, and Western blot was used to detect the changes in IAP expression in Caco-2 cells. Results:Rat models were successfully established. The expression level of IAP in the intestinal mucosa of ED group [(9.19±1.67)%] was significantly lower than that of the Ctrl group [(15.09±0.61)%, P<0.05]; the expression of IAP in the intestinal mucosa of OJ group [(6.86±1.07)%] was significantly lower than that of the Ctrl group ( P<0.05). Through in vitro cell experiments, expression of IAP in Caco-2 cells was increased in a time and dose-dependent manner when treated with human bile. Conclusions:Bile deficiency in the intestine can cause inhibition of IAP in the intestinal mucosa. Bile can promote the expression of IAP in intestinal mucosal epithelial cells.

Comparative permeability of three saikosaponins and corresponding saikogenins in Caco-2 model by a validated UHPLC-MS/MS method / 药物分析学报

Saikosaponins (SSs) are the main active components extracted from Bupleuri Radix (BR) which has been used as an important herbal drug in Asian countries for thousands of years.It has been reported that the intestinal bacteria plays an important role in the in vivo disposal of oral SSs.Although the deglycosylated derivatives (saikogenins,SGs) of SSs metabolized by the intestinal bacteria are speculated to be the main components absorbed into the blood after oral administration of SSs,no studies have been reported on the characteristics of SGs for their intestinal absorption,and those for SSs are also limited.Therefore,a rapid UHPLC-MS/MS method was developed to investigate and compare the apparent permeability of three common SSs (SSa,SSd,SSb2) and their corresponding SGs (SGF,SGG,SGD) through a bidirectional transport experiment on Caco-2 cell monolayer model.The method was validated according to the latest FDA guidelines and applied to quantify the six analytes in transport medium samples extracted via liquid-liquid extraction (LLE).The apparent permeability coefficient (Papp) determined in this study indicated that the permeability of SGs improved to the moderate class compared to the corresponding parent compounds,predicting a higher in vivo absorption.Moreover,the efflux ratio (ER) value demonstrated an active uptake of SSd and the three SGs,while a passive diffusion of SSa and SSb2.

Adherence and internalisation of Lactococcus lactis M4 towards human colorectal cancer cell line, Caco-2

Aims@#Lactococcus lactis is a non-colonizing, generally-regarded as safe (GRAS) lactic acid bacteria that has been frequently studied as a potential vector for bactofection. To mediate bactofection, a series of interaction between the bacteria and the host cell needs to occur. This study aims to investigate the in vitro bacterial-cell interaction between a locally-isolated L. lactis M4 strain with human colorectal cancer line, Caco-2.@*Methodology and results@#Bacterial interaction was evaluated via adherence and internalisation assays. A 250:1 ratio of bacteria to cancer cell was selected as the optimum multiplicity of infection for all assays. After 2 h, L. lactis M4 was able to adhere to and internalise into Caco-2 cells at comparable rates to commercial strains L. lactis NZ9000 and MG1363. @*Conclusion, significance and impact of study@#Findings from this study showed that this strain has similar interaction properties with the commercial strains and would make a promising candidate for future bactofection studies and development of bacteria-mediated DNA vaccination against various diseases.

Biopharmaceutical classification and transport mechanism of 4 alkaloids in Mongolian herbal medicine Sophorae Flavescentis Radix / 中国中药杂志

In this study, we studied the solubility and permeability of matrine, oxymatrine, sophoridine, and oxysophocarpine, four alkaloids in the Mongolian herbal medicine Sophorae Flavescentis Radix, and evaluated the absorption mechanism with the Caco-2 cell model, so as to provide a basis for the new drug development and efficacy evaluation of Sophorae Flavescentis Radix. The results showed that all the four alkaloids had high solubility and high permeability and can be well absorbed, belonging to the class-I drugs of Biopharmaceutical Classification System(BCS). The absorption(AP→BL) and excretion(BL→AP) of matrine and oxymatrine were not affected by the concentration while the absorption depended on P-gp protein. The absorption(AP→BL) and excretion(BL→AP) of sophoridine and oxysophocarpine were positively related to the concentration and time, and the absorption process was independent from P-gp protein. The results provide scientific reference and an experimental basis for the development of Mongolian medical prescriptions containing Sophorae Flavescentis Radix.

Assessment strategies for drug permeability during drug discovery and development / 药学学报

Permeability is a key factor in the bioavailability of oral drugs. Therefore, in the early stage of drug discovery, accurate and efficient evaluation of drug permeability is essential. The parallel artificial membrane permeability assay (PAMPA) with Caco-2 cells model was used by the industry as early evaluation methods. At present, the Ussing chamber rat model is also widely used. This review summarizes the human data for the in vivo single-pass perfusion technique (Loc-I-Gut) – the gold standard, and then focuses on the basic principles, experimental operation, and efficiency of the three in vitro methods, with correlation to the effective permeability coefficient (Peff) and fractional absorbed (Fa) in man. We provide recommendations for the use of proper permeability methods at different stages in drug discovery and development.

Studies on absorption and transportation of coumarins in Angelica dahurica 'Yubaizhi' across human intestinal epithelial by using human Caco-2 cell monolayers / 中国中药杂志

The absorption is the key to the resulted efficacy of orally administered drugs and the small intestine is the main site to absorb the orally administered drug. In this paper, internationally recognized human colon adenocarcinoma cell line(Caco-2) monola-yer model which can simulate small intestinal epithelial cell was used to comparatively study the absorption and transportation diffe-rences of total coumarins and main individual coumarin in Angelica dahurica 'Yubaizhi' by separately using 6-and 12-well plates. It was found that apparent permeability coefficient(P_(app)) values of oxypeucedanin hydrate, byakangelicin and phellopterin were at the quantitative degree of 1 × 10~(-5) cm·s~(-1) when the individual administration was conducted independently, indicating that they were well-absorbed compounds. P_(app) ratio of their bi-directional transportation was close to 1, indicating that they can be absorbed across Caco-2 monolayer by passive diffusion mechanism without carrier mediation during the transportation. The similar trend of transportation was also observed for imperatorin, isoimperatorin and bergapten. The P_(app) values of oxypeucedanin hydrate, byakangelicin and bergapten were at quantitative degree of 1 × 10~(-5) cm·s~(-1) when the administration of total coumarins in Angelica dahurica 'Yubaizhi' was conducted, indicating that they were well-absorbed compounds. The results were consistent with those of independent administration of individual coumarins. Whereas, the P_(app) values of imperatorin, phellopterin and isoimperatorin in the total coumarins decreased, indicating that the interaction between compounds may exist although the P_(app) value ratio of bi-directional transportation was between 0.5 and 1.5. The results laid the foundation for intestinal absorption study of Angelica dahurica 'Yubaizhi' coumarins in compound Chinese medicine.

Study on oral absorption mechanisms of puerarin in nanocrystals self-stabilized pickering emulsion / 中国中药杂志

Nanocrystals self-stabilized Pickering emulsion(NSSPE) is a new kind of emulsion where only nanocrystals of poorly soluble drugs are used as stabilizers. Our previous study showed that NSSPE with Ligusticum chuanxiong oil as the main oil phase can significantly promote oral absorption of puerarin. The present study aimed to explore its absorption mechanism in oral administration. The in vitro dissolution test was carried out to study the effect of NSSPE on release of puerarin. The effects and mechanism of NSSPE on uptake and transport of puerarin across Caco-2 cell were investigated. The results showed that the drug release rate of NSSPE was similar to that of nanocrystals, with their cumulative dissolution of puerarin not affected by pH of releasing mediums, both significantly higher than that of crude material. The uptake of puerarin in NSSPE was concentration-dependent and significantly higher than that of solution or surfactant stabilized emulsion. Genistein and indomethacin, inhibitors of lipid rafts/caveolin, could significantly reduce the uptake of puerarin in NSSPE. Compared with solution, NSSPE and surfactants stabilized emulsion obviously increased transport rate K_a and apparent permeability coefficient P_(app) of puerarin in AP → BL direction, but there was no significant difference in BL → AP direction. It could be inferred that there were both passive and active transport mechanisms, as well as lipid raft/caveolin mediated endocytosis for absorption of NSSPE. The promoted oral absorption of puerarin in NSSPE was mainly related to the existing nanocrystal form which could promote dissolution, puerarin as well as Ligusticum chuanxiong oil which could promote drug transmembrane transport and inhibit drug efflux. It is the unique structure and composition of the compound NSSPE that promoted the oral absorption of puerarin.

Effects of HPMCAS MF on absorption of silybin from supersaturable self-nanoemulsifying drug delivery system / 中国中药杂志

To evaluate the effects of Hydroxypropyl methylcellulose acetate succinate(HPMCAS MF) on absorption of silybin(SLB) from supersaturable self-nanoemulsifying drug delivery system which was pre-prepared at the early stage experiment. The cell toxicity of self-emulsifying preparation was evaluated by the MTT method, and the in vitro membrane permeability and absorption promoting effect of the self-emulsifying preparation were evaluated by establishing a Caco-2 cell monolayer model. The in vivo and in vitro supersaturation correlation was evaluated via the blood concentration of SLB. The results of MTT showed that the concentration of the preparation below 2 mg·mL~(-1)(C_(SLB) 100 μg·mL~(-1)) was not toxic to Caco-2 cells, and the addition of polymer had no significant effect on Caco-2 cells viability. As compared with the solution group, the transport results showed that the P_(app)(AP→BL) of the self-emulsifying preparation had a very significant increase; the transport rate of silybin can be reduced by polymer in 0-30 min; however, there was no difference in supersaturated transport between supersaturated SLB self-nanoemulsion drug delivery system(SLB-SSNEDDS) and SLB self-nanoemulsion drug delivery system(SLB-SNEDDS) within 2 hours. As compared with SLB suspension, pharmacokinetic parameters showed that the blood concentration of both SLB-SNEDDS and SLB-SSNEDDS groups were significantly increased, and C_(max) was 5.25 times and 9.69 times respectively of that in SLB suspension group, with a relative bioavailability of 578.45% and 1 139.44% respectively. C_(max) and relative bioavailability of SLB-SSNEDDS were 1.85 times and 197% of those of SLB-SNEDDS, respectively. Therefore, on the one hand, SSNEDDS can increase the solubility of SLB in gastrointestinal tract by maintaining stability of SLB supersaturation state; on the other hand, the osmotic transport process of SLB was regulated through the composition of its preparations, and both of them could jointly promote the transport and absorption of SLB to improve the oral bioavailability of SLB.

Gastrointestinal lipolysis and trans-epithelial transport of SMEDDS

Self-microemulsifying drug delivery systems (SMEDDSs) have recently returned to the limelight of academia and industry due to their enormous potential in oral delivery of biomacromolecules. However, information on gastrointestinal lipolysis and trans-epithelial transport of SMEDDS is rare. Aggregation-caused quenching (ACQ) fluorescent probes are utilized to visualize the

Cytotoxicity Studies Of An Ethnobotanically Selected Solanum Pubescens Willd. Against Selected Human Cancer Cell Lines

Objective: The present study was aimed to determine the cytotoxicity concentration (CTC50) of different extracts made from the leaf and stem bark of an ethno botanically selected S. pubescens against Human liver carcinoma (Hep G2), Human colon carcinoma (CaCo2) and Human breast cancer (T-47 D) cell lines. Methods: Ethnobotanical survey was done through interviewing traditional medicinal practitioners then a potential herbal plant was selected after a thorough literature survey and its identity was confirmed. The soxhlet extraction method was adopted using five different solvents from leaf and stem bark powders of the study plant and the CTC50 of all the extracts were determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay method. Results: Among the different extracts, CTC50 values were significant for stem bark extracts made from methanol (24.51±0.08 µg/ml) against Hep G2, while leaf chloroform extract was promising (57.15±1.75 µg/ml) against CaCo2 and n-hexane extract of leaf exhibited significant value (20.27±1.52 µg/ml) against T-47 D cancer cell lines. Conclusion: The major findings of the present study clearly provides evidence that the leaf and stem bark of S. pubescens possesses the potential anticancer bioactive compound solasodine.

Transport of Lipoamide and Lipoic Acid in Caco-2 Cell Monolayer Model / 中国药学杂志

OBJECTIVE: To study the transport of lipoamide (LAM) and lipoic acid (LA) in Caco-2 cell monolayer model in vitro. METHODS: Effects of LAM and LA on the survival rate of Caco-2 cells were investigated by MTS, the bi-directional transport of lipoamide and lipoic acid from the intestinal cavity side (apical side, AP) to the basal side (basolateral side,BL) was investigated. The cumulative transport volume, apparent permeability coefficient (Papp) and transport percentage were calculated,and the relationships between transport volume and concentration and time were further studied. RESULTS: The transport amounts of LAM and LA were increased in time-and concentration-dependent manners, the Papps of LAM and LA (AP→BL) were 2.443 44×10-5-2.392 91×10-5 and 8.179 78×10-6-7.897 25×10-6 cm•s-1, and the Papps(BL→AP) were 2.258 13×10-5-2.214 3×10-5 and 8.267 98×10-6-7.926 73×10-6 cm•s-1, respectively. CONCLUSION: In the transport test of Caco-2 cells, LAM is superior to LA, suggesting that it is well absorbed orally and has high bioavailability. But it is still necessary to verify the pharmacokinetic data in vivo.

Effects of low molecular weight chitosan and its nanoparticles on intestinal permeability of Panax notoginseng saponins / 中草药

Objective: To evaluate the effect of low molecular weight chitosan (LMW-CTS) and its nanoparticles (LMW-CTS-NPs) on the intestinal permeability of Panax notoginseng saponins (PNS) by using Caco-2 cell model. Methods: LMW-CTS was prepared by combining chitosanase hydrolysis combined with ultrafiltration separation technology, and molecular weight of LMW-CTS was determined by using permeation gel chromatography (GPC). LMW-CTS-NPs were prepared by ionic gel method, and characterized by scanning electron microscopy, nano particle sizer, and flourier transformation infrared spectroscopy. Caco-2 cell model was established and validated to evaluate the effects of LMW-CTS and LMW-CTS-NPs on the intestinal permeability of PNS. Results: LMW-CTS has a molecular weight of 5 760 and a polydispersity coefficient of 1.42. LMW-CTS-NPs have a round shape and narrow particle size distribution, with an average particle size of 115.5 nm and zeta potential of +37.1 mV. The apparent permeability coefficients (Papp, AB→BL) of PNS was less than 1 × 10-6 cm/s, indicating a poor permeability. In LMW-CTS group, the Papp of R1 and Rg1 was increased by 17.83% and 20.29%, respectively, but no significant effect of promotion was observed on other components. However, the Papp of R1, Rg1, Re, Rb1, and Rd in LMW-CTS-NPs group was increased by 35.66%, 23.28%, 29.41%, 37.99%, and 36.00%, respectively, compared tothe control group. Conclusion: LMW-CTS can significantly promote the intestinal mucosal permeability of R1 and Rg1 in PNS, but has no significant effect on Re, Rb1, and Rd. LMW-CTS-NPs significantly increased the permeability of the major monomer saponin components in PNS. Namely, the intestinal permeability of PNS can be further improved by transforming LMW-CTS into LMW-CTS-NPs.

Study on oil-water distribution of taxifolin and its absorption and transport mechanism in Caco-2 cell model / 中草药

Objective: To prepare the taxifolin and determine its apparent oil-water partition coefficient in different media, and to study the mechanism of absorption and transport of taxifolin in Caco-2 cell model. Methods: Taxifolin was prepared by enzymolysis. HPLC was used to determine the saturated solubility of taxifolin in 37 ℃, different pH buffer solution and water, apparent oil-water distribution coefficient of taxifolin obtained by calculation formula of oil-water distribution coefficient; CCK-8 experiment was used to investigate the safe concentration range of taxifolin in Caco-2 cells, and then the single-layer model of Caco-2 cells was used to study the mechanism of bilateral transmembrane absorption and transport. CCK-8 experiment was used to investigate the safe concentration range of taxifolin in HDMEC cells. The inflammatory model of HDMEC cells induced by lipopolysaccharide was established, and the activity of lactic dehydrogenase was detected by the intervention of floxacin. The activity of lactic dehydrogenase was detected by lactic dehydrogenase kit. Results: The lgP values of taxifolin in the following solvents were 0.29 (0.1 mol/L hydrochloric acid), 0.48 (pH 2.0), 0.46 (pH 5.8), 0.34 (pH 6.8), 0.26 (pH 7.4), and 0.38 (water), respectively; There was no significant toxic effect on Caco-2 cells in the range of 50-500 μg/mL; There was no significant difference in Papp value of bilateral transport between different concentrations of taxifolin in Caco-2 monolayer cell model, and it was less than 1 × 10-6 cm/s and ER was less than 2. There was no significant toxic effect on HDMEC cells in the range of 50-300 μg/mL; After treatment with taxifolin, compared with LPS stimulation group, the activity of LDH in each treatment group was decreased significantly (P < 0.05), and the activity of LDH was decreased significantly in the range of 50-100 μg/mL, and tended to be stable in the range of 100-250 μg/mL. Conclusion: Taxifolin is a kind of drug which is difficult to absorb in the intestine. The mechanism of transmembrane transport is passive transport. It can inhibit the inflammation of hdmec cells induced by LPS and has anti-inflammatory activity.

Preparation of silybin self-nanomicroemulsion containing functional oil and its in vitro evaluation / 中草药

Objective: In order to improve the bioavailability of the insoluble drug silybin, silybin supersaturated self- nanoemulsifying drug delivery systems (SLB-S-SNEDDS) containing functional oil were prepared, its characterization and in vitro evaluation were also performed. Methods: Functional oils were screened by performing potassium ferrohydride reduction and 1,1- diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging experiments. The pseudo-ternary phase diagram was drawn to investigate the emulsifying ability of emulsifier. The proportion of mixed oil phase and drug loading capacity were explored by analyzing particle size, polydispersity index (PDI), zeta potential, etc. The type and concentration of supersaturated substance in SLB-S-SNEDDS were obtained by conducting the compatibility and dissolution experiments. SLB-S-SNEDDS was characterized with appearance, particle size distribution, self-emulsification efficiency, and morphology, and its in vitro dissolution, antioxidant capacity, and cytotoxicity were also evaluated. Results: The prescriptions of SLB-S-SNEDDS were as follows: (1) wheatgerm oil/Capryol 90- Cremophor ELP-Transcutol HP; (2) seabuckthorn seed oil/Capryol 90-Cremophor ELP-Transcutol HP. One g S-SNEDDS matrix contained 0.043 g of wheatgerm oil or sea-buckthorn seed oil, 0.387 g of Capryol 90, 0.380 g of Cremophor ELP, and 0.190 g of Transcutol HP. The adding amount of silybin in S-SNEDDS prescription was 20% of the sum of the equilibrium solubility of silybin in each component, and the adding amount of Soluplus was 0.1% of the total mass described above. The two obtained SLB-S-SNEDDS were transparent homogeneous liquid with light yellow (wheat germ oil) and bright yellow (seabuckthorn seed oil) color, respectively. After being dispersed, SLB-S-SNEDDS turned into subspherical white flat emulsion droplets with the particle size of about 50 nm, and the emulsification time was 65 s. Compared with raw materials and SLB-SNEDDS, the cumulative dissolution of silybin in SLB-S-SNEDDS was maintained between 85% and 110% within 8 h, indicating that the two systems can significantly improve the dissolution of silybin. The absorbance of SLB-S-SNEDDS after reaction with potassium ferricyanide (0.452-0.782, 0.488-0.765) and the DPPH free radical clearance of SLB-S-SNEDDS (39.09%-96.02%, 30.54%-89.20%) were all higher than those of raw silybin (0.411-0.760, 22.89%-63.21%), which suggested that the two systems can enhance the antioxidant capacity of silybin. Cytotoxicity test results showed that the cell survival rate in silybin raw material group, combination of silybin and S-SNEDDS group, and blank S-SNEDDS group were greater than 90% at 5 µmol/L and 10 µmol/L drug concentration, indicating that SLB-S-SNEDDS and its auxiliary materials were safe and less toxic to human cloned colorectal adenocarcinoma cell line (Caco-2). Conclusion: The SLB-S-SNEDDS containing functional oil prepared in this paper can not only increase the cumulative dissolution of silybin, but also enhance its antioxidant capacity, which provides a useful reference for supersaturated self-nanoemulsifying drug delivery systems (S-SNEDDS) to improve the water-solubility and bioactivity of insoluble drugs.

Biopharmaceutics classification evaluation for paris saponin VII / 中国天然药物

To study the biopharmaceutics characteristics of paris saponin VII (PSVII). The solubility of PSVII was evaluated by measurement of the equilibrium solubility in different solvents and media. The permeability of PSVII was evaluated by measuring the oil/water partition coefficient (lgP) and determining the apparent permeability coefficient (PC) on a mono-layer Caco-2 cell model. The effects of p-glycoprotein and multidrug resistance related protein 2 on PSVII transport in mono-layer Caco-2 cell model were further investigated. Finally, the small intestinal absorption of PSVII was investigated in rat. In solvents of different pH, the equilibrium solubility of PSVII was quite low, and the dose number of PSVII was larger than 1. The lgP of PSVII was less than 0. The apparent permeability coefficient [PC] of PSVII in mono-layer Caco-2 cell model was less than 14.96 × 10 cm·s, and the efflux ratio of PSVII in mono-layer Caco-2 cell model was less than 1. The transport rate of PSVII in mono-layer Caco-2 cell model was not affected by the inhibitors of p-glycoprotein and multidrug resistance related protein 2. After oral administration, PSVII could be detected in rat intestinal contents, but could not be detected in the small intestinal mucosa. PSVII showed low solubility and permeability, which would result in low oral bioavailability in clinic. PSVII belonged to Class IV compound in biopharmaceutics classification system.