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.
Lactococcus lactis ; Colorectal Neoplasms ; Caco-2 Cells

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.
Caco-2 Cells ; Drugs, Chinese Herbal ; Emulsions ; Humans ; Isoflavones ; Nanoparticles

OBJECTIVETo establish and assess the Caco-2 cell in vitro absorption model.

METHODSCaco-2 cells were cultured on the millipore filters fixed in Snapwell transport chamber. The cell morphology, transepithelial electrical resistance, mannitol efflux rate and alkaline phosphatase activities were monitored during culture.

RESULTSAfter 21 days of in vitro culture, formation of tight junction was observed between the cells. The transepithelial electrical resistance reach a relatively stable value of 620-/+47 Omega.cm(2), the mannitol efflux rate was lower than 0.3%.h(-1).cm(-2), and the alkaline phosphatase activity in the apical side was significantly higher than that in the basolateral side.

CONCLUSIONThe established Caco-2 cell model shows similar morphology to intestinal epithelial cells with formation of polarity, and can be used as an in vitro model for absorption studies.

Caco-2 Cells ; Cell Culture Techniques ; methods ; Epithelial Cells ; cytology ; metabolism ; Humans ; Intestinal Absorption ; Intestines ; cytology

Although the essential oil of Xiangfu Siwu decoction (XFSWD) has strong pharmacological activity, its special physical and chemical properties restrict the clinical application and curative effect. In this paper, Xiangfu Siwu decoction essential oil (XFS-WO) was prepared by forming inclusion complex with β-cyclodextrin (β-CD). The present study is to investigate the effect of β-CD inclusion complex on the transport of major components of XFSWO using Caco-2 cell monolayer model, thus to research the effect of this formation on the absorption of drugs with low solubility and high permeability, which belong to class 2 in biopharmaceutics classification system. A sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of senkyunolide A, 3-n-butylphthalide, Z-ligustilide, dehydrocostus lactone and α-cyperone, which are active compounds in XFSWO. The transport parameters were analyzed and compared in free oil and its β-CD inclusion complex. The result revealed that the formation of XFSWO/β-CD inclusion complex has significantly increased the transportation and absorption of major active ingredients than free oil. Accordingly, it can be speculated that cyclodextrin inclusion complex can improve bioavailability of poorly water-soluble drugs. Above all these mentioned researches, it provided foundation and basis for physiological disposition and pharmaceutical study of XFSWD.
Biological Transport ; Caco-2 Cells ; Drugs, Chinese Herbal ; analysis ; Humans ; Oils, Volatile ; analysis ; beta-Cyclodextrins ; pharmacology

OBJECTIVETo investigate the role of cyclic adenosine monophosphate(cAMP) in the regulation of intestinal epithelial barrier function under hypoxia.

METHODSIntestinal epithelial barrier was established by Caco-2 monolayers. Cells were divided into four groups: normoxia (Nx), normoxia plus Forskolin(Nx+FSK), hypoxia(Hx), hypoxia plus SQ22536(Hx+SQ22536). cAMP concentrations of different groups were assessed by cAMP enzyme immunoassay kit. RT-PCR and Western blotting were used to detect the mRNA and protein expressions of claudin-1 and occludin under normoxic and hypoxic condition. Caco-2 monolayers were grown on Millicell filters, and transepithelial electrical resistance(TER) was measured using a Millipore electric resistance system.

RESULTSThe concentration of cAMP under hypoxic conditions(Hx group) was higher compared with Nx group [(6.30±0.50) pmol/L vs. (2.38±0.18) pmol/L, P<0.01]. At the same time, both mRNA and protein expressions of claudin-1 and occluding were lower in Hx group than those in Nx group(all P<0.05). TER decreased by 76.30±0.64(P<0.01). When the monolayers were exposed to hypoxia plus SQ22536 (Hx+SQ22536 group), the concentration of cAMP was(2.12±0.23) pmol/L, which was lower than that under hypoxic conditions(Hx group, P<0.01). Both mRNA and protein expressions of claudin-1 and occludin were higher compared to Hx group (all P<0.01). TER increased by 32.96±2.16 (P<0.05).

CONCLUSIONWhen Caco-2 cells are exposed to hypoxia, barrier function, claudin-1 and occludin expression are diminished in parallel with a high level of intracellular cAMP compared with the normoxic condition. Inhibition of the intracellular cAMP level under hypoxia can maintain the intestinal epithelial function through regulating the claudin-1 and occludin expression and attenuate the permeability of intestinal mucosa.

Adenosine Monophosphate ; Caco-2 Cells ; Claudin-1 ; metabolism ; Humans ; Intestinal Mucosa ; metabolism ; Intestines ; Occludin ; metabolism

OBJECTIVETo investigate the intestinal absorption mechanism of swertiamain metabolite {(Z)-5-ethylidene-8-hydroxy-3,4,5,6,7,8-hexahydro-1H-pyrano [3,4-c]pyridine-1-one, EHPO}.

METHODThe time depended hi-directional transport of EHPO in Caco-2 monolayer model was investigated with the factors of concentration, pH and verapamil. EHPO concentration was measured by HPLC assay and the apparent permeability coefficients (Papp) were calculated.

RESULTIn the this cell model, EHPO could be absorbed through Caco-2 soon. The P(app AP-BL) was equal to the P(app BL-AP), and Papp keep almost constant with the selected concentration investigated. But the Papp could be influenced by pH and verapamil (100 mg x L(-1)).

CONCLUSIONThe absorption of EHPO in Caco-2 cell model is a passive one. And absorption of EHPO in the intestines is quite good.

Biological Transport ; Caco-2 Cells ; Cell Membrane Permeability ; Drugs, Chinese Herbal ; chemistry ; pharmacokinetics ; Humans ; Models, Biological

OBJECTIVETo study the absorption mechanism of icariin by using Caco-2 monolayer model.

METHODCaco-2 cell monolayer model was used to study the bi-direction transport of icariin. The effects of time, drug concentration and inhibitor on the absorption of icariin were studied. The concentration of icariin in cell culture medium was measured by UPLC and the apparent permeability coefficients (Papp) was calculated.

RESULTThe amount of icariin which was transported increased linearly with the time (14 hr). The ratio of PBA/PAB was larger than 4. Verapamil, the P-glycoprotein inhibitor, could cause significantly effect on transport of icariin, PAB increased, the ratio of PBA/PAB decreased.

CONCLUSIONThe reason for low absorption of icariin in Caco-2 cell model may be the secretion of the P-gp transporter.

Absorption ; Caco-2 Cells ; Epimedium ; chemistry ; Flavonoids ; pharmacokinetics ; Humans ; Models, Biological

OBJECTIVETo determine the concentration of ginsenoside Rb(2) and study the absorption characteristics of ginsenoside Rb(2) in Caco-2 cell monolayer.

METHODSLC-MS-MS was used to determine the concentration of ginsenoside Rb(2), and the apparent permeability coefficient (P(app)) of ginsenoside Rb(2) was calculated.

RESULTSP(app(AP-BL)) was 3.27 x 10(-7) cm.s(-1), P(app(BL-AP)) was 3.16 x 10(-6) cm.s(-1), and the efflux ratio (P(app(BL-AP))/P(app(AP-BL))) was 9.63.

CONCLUSIONThe absorption characteristics of ginsenoside Rb(2) in Caco-2 cell model have been demonstrated.

Caco-2 Cells ; Gas Chromatography-Mass Spectrometry ; methods ; Ginsenosides ; pharmacokinetics ; Humans ; Intestinal Absorption

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.
Angelica ; Caco-2 Cells ; Coumarins ; Drugs, Chinese Herbal ; Humans ; Intestinal Absorption ; Plant Roots

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.
Alkaloids ; Biological Products ; Caco-2 Cells ; Drugs, Chinese Herbal ; Herbal Medicine ; Humans ; Sophora