Co-administration of nuciferine reduces the concentration of metformin in liver via differential inhibition of hepatic drug transporter OCT1 and MATE1.

Nuciferine (NF), one of the main and effective components in Nelumbo nucifera Gaertn. leaf extracts, is a promising drug candidate for the treatment of obesity-related diseases, while metformin is a first line therapeutic drug for type 2 diabetes mellitus. Since nuciferine and metformin are likely to be co-administered, the aim of the present study was to evaluate whether co-administration of nuciferine would influence the liver (target tissue) distribution and the anti-diabetic effect of metformin by inhibiting hepatic organic cation transporter 1 (OCT1) and multidrug and toxin extrusion 1 (MATE1). The data demonstrated that nuciferine significantly reduced metformin accumulation in MDCK cells stably expressing human OCT1 (MDCK-hOCT1) or hMATE1 (MDCK-hMATE1), and primary cultured mouse hepatocytes. Furthermore, the presence of nuciferine in the basal compartment caused a concentration-dependent reduction of intracellular metformin accumulation in MDCK-hOCT1/hMATE1 cell monolayers. Compared with the metformin treatment-alone group, co-administration of nuciferine (40 mg/kg) markedly reduced the metformin concentration in mouse livers at 30 and 60 min after a single oral dose of metformin (200 mg/kg), and subsequently impaired the glucose-lowering effect of metformin (200 mg/kg), but the glucose-lowering effect became no different at 90 and 120 min. Therefore, nuciferine influenced the liver concentration and glucose-lowering effect of metformin only for a period of time after dose, administration of nuciferine and metformin with an interval might prevent the drug-drug interaction mediated by OCT1 and MATE1.

Comparison of Drug Concentrations in Human Aqueous Humor after the Administration of 0.3% Gatifloxacin Ophthalmic Gel, 0.3% Gatifloxacin and 0.5% Levofloxacin Ophthalmic Solutions.

PURPOSE: To investigate the penetration of 0.3% gatifloxacin ophthalmic gel, 0.3% gatifloxacin ophthalmic solution and 0.5% levofloxacin ophthalmic solution into aqueous humor after topical application. MATERIALS AND METHODS: Age-related cataract patients (150 eyes in 150 cases) receiving phacoemulsification were randomly divided into three groups: a 0.3% gatifloxacin gel group (n=50), a 0.3% gatifloxacin solution group (n=50), and a 0.5% levofloxacin solution group (n=50). Each group was administered one drop of gel or solution every 15 minutes for four doses. Aqueous samples were collected at different time points after the last drop. High pressure liquid chromatography (HPLC) was applied to determine the concentrations. The one-way ANOVA analysis was performed. RESULTS: Our data indicated that the concentration of the gatifloxacin gel group was higher than that of the gatifloxacin solution group at all time points (P <0.05); moreover, the gatifloxacin gel group exhibited higher levels than the levofloxacin solution group at 120.0 min and 180.0 min (P<0.05). Furthermore, the gatifloxacin gel produced the highest concentration at 120.0 min, and the gatifloxacin and levofloxacin solutions reached their peak values at 60.0 min. CONCLUSIONS: 0.3% gatifloxacin ophthalmic gel application produced highest aqueous humor drug concentration, maintained the longest time, had the best penetration and bioavailability.

Utilizing X-ray diffraction in conjunction with competitive adaptive reweighted sampling (CARS) and principal component analysis for the discrimination of medicinal pearl powder and nacre powder.

Nacre powder, often utilized to counterfeit medicinal pearl powder due to their similar chemical composition and appearance, poses a challenge in product authentication. This study introduces a rapid and efficient method for distinguishing between medicinal pearl powder and nacre powder using X-ray diffraction in conjunction with principal component analysis (PCA). The X-ray diffraction pattern underwent preprocessing techniques including smoothing denoising (Savitzky-Golay filter, 5-point) and second-order derivative analysis. Subsequently, PCA was employed for dimensionality reduction modeling. The CARS method was applied to select optimal variables for model refinement, determining the data preprocessing approach and key modeling variables. This method demonstrates the capability to accurately differentiate between pearl powder, nacre powder, and even counterfeit samples containing up to 90% pearl powder. With a high accuracy rate, swift operational speed, and potential for automation, this approach shows promise for practical implementation in the realm of pearl powder quality control.

Role of Drosophila alkaline ceramidase (Dacer) in Drosophila development and longevity.

Ceramidases catalyze the hydrolysis of ceramides to generate sphingosine (SPH) and fatty acids, and ceramide metabolism is implicated in various biological responses in Drosophila melanogaster. Here we report the cloning, biochemical characterization, and functional analysis of a Drosophila alkaline ceramidase (Dacer). Dacer, a membrane-bound protein of 284 amino acids, shares homology with yeast and mammalian alkaline ceramidases. Overexpression of Dacer in High Five insect cells increases ceramidase activity in the alkaline pH range, indicating that Dacer is a bona fide alkaline ceramidase. Dacer mRNA is highly expressed in the midgut and at the pupal stage. An inactivation of Dacer by insertional mutagenesis increases the levels of ceramides in both Drosophila pupae and adult flies. Dacer inactivation increases Drosophila pre-adult development time, lifespan, and anti-oxidative stress capacity. Collectively, these results suggest that Dacer plays an important role in the Drosophila development and longevity by controlling the metabolism of ceramides.

L-tetrahydropalmatine attenuates cisplatin-induced nephrotoxicity via selective inhibition of organic cation transporter 2 without impairing its antitumor efficacy.

Cisplatin is a first-line chemotherapeutic agent that is widely used for treatment of various solid tumors. However, cisplatin-induced adverse effects, particularly severe nephrotoxicity, preclude its application. In this study, we showed that L-tetrahydropalmatine (L-THP) could selectively inhibit organic cation transporter 2 (OCT2), which plays a crucial role in renal cisplatin uptake from the circulation. Additionally, we demonstrated that L-THP attenuated cisplatin-induced toxicity in mouse primary renal tubular cells. Subsequently, we verified that L-THP reduced the renal accumulation of cisplatin and alleviated cisplatin-induced renal injury in healthy and tumor-bearing nude mice. In healthy mice, co-treatment of L-THP at 5-40 mg/kg reduced cisplatin renal accumulation to 75.0%-49.9% of that in cisplatin alone group (10 mg/kg), and alleviated cisplatin-induced nephrotoxicity. Additionally, it did not alter Pt concentration in the tumor tissue and did not impair its antitumor efficacy in tumor bearing nude mice. The tumor inhibitory rates of cisplatin (10 mg/kg) co-treated with L-THP at 10, 20 and 40 mg/kg were 71.4%, 70.4% and 69.4%, respectively, in H460 tumor bearing nude mice, higher than that of in cisplatin alone group (60.6%), while in HCT116 tumor bearing nude mice, the tumor inhibitory rates in co-treated with 20 mg/kg L-THP was 34.7% (vs 26.3% in cisplatin alone group). Moreover, L-THP reduced cisplatin accumulation and alleviated cisplatin-induced cytotoxicity in human primary renal tubular cells. Therefore, our findings suggested that concomitant administration of L-THP could attenuate cisplatin-induced renal injury via selective inhibition of OCT2 without impairing its antitumor efficacy.

[Human aqueous humor levels of levofloxacin 0.5%, gatifloxacin 0.3% and levofloxacin 0.3% ophthalmic solution after topical dosing].

OBJECTIVE: To compare the aqueous humor concentration of levofloxacin 0.5%, gatifloxacin 0.3% and levofloxacin 0.3% ophthalmic solution after topical dosing in human eyes. METHODS: A randomized, double-blind and parallel study was conducted. Senile cataract patients (150 eyes in 150 cases) receiving phacoemulsification in eye center affiliated second hospital of Zhejiang university were randomized into three groups: levofloxacin 0.5%, 50 eyes;gatifloxacin 0.3%, 50 eyes and levofloxacin 0.3%, 50 eyes. Each group was randomized into five sub-groups, with 10 eyes in each sub-group. Each group received either levofloxacin 0.5% or topical gatifloxacin 0.3% or levofloxacin 0.3% preoperatively. One drop of antibiotic was administered every 15 minutes for 4 doses. More than 100 microl aqueous samples were obtained from different sub-groups during surgery, 15.0, 30.0, 60.0, 120.0 and 180.0 min after the last drop, respectively. Then 100 microl aqueous samples were put into test tube by sample injector accurately. Concentration of the antimicrobial agents was determined by the HPLC (high pressure liquid chromatography). Variance analysis was performed to detect differences among the antibiotic treatment groups. The differences between two groups were assumed by t-test. RESULTS: Humor concentration of levofloxacin 0.5% (1.61 +/- 0.48), (2.41 +/- 0.80), (2.93 +/- 0.50), (2.56 +/- 0.63), (1.87 +/- 0.88) mg/L was significantly higher than that of gatifloxacin 0.3% (0.70 +/- 0.18), (1.29 +/- 0.54), (1.59 +/- 0.67), (1.41 +/- 0.50), (1.13 +/- 0.28) mg/L and levofloxacin 0.3% (0.55 +/- 0.39), (1.15 +/- 0.42), (1.38 +/- 0.49), (1.02 +/- 0.33), (0.55 +/- 0.31) mg/L at the same period after the last drop (F = 23.64, 12.82, 21.13, 25.00, 12.22;P < 0.05). CONCLUSION: Topically applied levofloxacin 0.5% had the higher aqueous humor drug level than gatifloxacin 0.3% and levofloxacin 0.3%.

[Investigation on release model of insoluble drug in hydroxypropyl methycellulose matrix tablets].

OBJECTIVE: To investigate the release model of insoluble drug carbamazepine (CBM) based on HPMC matrix tablets. METHODS: CBM release profile from matrices and HPMC erosion rate were determined. RESULT: The mathematical model by matrix erosion rate and drug release from HPMC K15M were established for the fractional HPMC and CBM released as M(P(t))/M(P(infinity))=-[0.8095ln((t))+1.2775]Meq((-0.0622t-0.305)) and M(d(t))/M(d(infinity))=-[0.1891t-0.1294]Meq(-0.9326). In comparison with the data of HPMC K4M matrix erosion and CBM release from HPMC K4M matrices, theoretical value agreed well with experimental data. CONCLUSION: The two mathematical models can be satisfactorily applied to insoluble drug release, which is governed by matrix erosion.

Molecular cloning and characterization of neutral ceramidase homologue from the red flour beetle, Tribolium castaneum.

Ceramidase plays an important role in regulating the metabolism of sphingolipids, such as ceramide, sphingosine (SPH), and sphingosine-1-phosphate (S1P), by controlling the hydrolysis of ceramide. Here we report the cloning and biochemical characterization of a neutral ceramidase from the red flour beetle Tribolium castaneum which is an important storage pest. The Tribolium castaneum neutral ceramidase (Tncer) is a protein of 696 amino acids. It shares a high degree of similarity in protein sequence to neutral ceramidases from various species. Tncer mRNA levels are higher in the adult stage than in pre-adult stages, and they are higher in the reproductive organs than in head, thorax, and midgut. The mature ovary has higher mRNA levels than the immature ovary. Tncer is localized to the plasma membrane. It uses various ceramides (D-erythro-C(6), C(12), C(16), C(18:1), and C(24:1)-ceramide) as substrates and has an abroad pH optimum for its in vitro activity. Tncer has an optimal temperature of 37 °C for its in vitro activity. Its activity is inhibited by Fe(2+). These results suggest that Tncer has distinct biochemical properties from neutral ceramidases from other species.

Punicic acid from Trichosanthes kirilowii seed oil is rapidly metabolized to conjugated linoleic acid in rats.

The incorporation and metabolism of orally administered punicic acid (PA), one isomer of conjugated linolenic acid (CLNA), in rat tissues and plasma were studied over a 24-hour period. The punic acid was derived from Trichosanthes kirilowii Maxim seed oil, a unique PA-containing material, and identified and analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. The results show that PA was incorporated and metabolized to 9c,11t-conjugated linoleic acid (CLA) in rat plasma, liver, kidney, heart, brain, and adipose tissue. The level of PA and CLA in liver and plasma was higher than in brain, heart, kidney, and adipose tissue, and the lowest accumulation occurred in the brain. The observation that PA can be converted into 9c,11t-CLA has gained increased importance since it has been demonstrated that 9c,11t-CLA exerts many biological activities. Therefore natural resources containing CLNA, especially edible T. kirilowii seed, could be a potential dietary source of CLA, following PA metabolism. PA is expected to be used as a functional food and nutraceutical.