Hydroxyurea-Lactose Interaction Study: In Silico and In Vitro Evaluation.

The Maillard reaction between hydroxyurea (a primary amine-containing drug) and lactose (used as an excipient) was explored. The adduct of these compounds was synthesized by heating hydroxyurea with lactose monohydrate at 60 °C in borate buffer (pH 9.2) for 12 h. Synthesis of the adduct was confirmed using UV-visible spectroscopy and Fourier transform infrared, differential scanning calorimetry, high-pressure liquid chromatography, and liquid chromatography-mass spectrometry studies. An in silico investigation of how the adduct formation affected the interactions of hydroxyurea with its biological target oxyhemoglobin, to which it binds to generate nitric oxide and regulates fetal hemoglobin synthesis, was carried out. The in silico evaluations were complemented by an in vitro assay of the anti-sickling activity. Co-incubation of hydroxyurea with deoxygenated blood samples reduced the percentage of sickled cells from 38% to 12 ± 1.6%, whereas the percentage of sickled cells in samples treated with the adduct was 17 ± 1.2%. This indicated loss of anti-sickling activity in the case of the adduct. This study confirmed that hydroxyurea can participate in a Maillard reaction if lactose is used as a diluent. Although an extended study at environmentally feasible temperatures was not carried out in the present investigation, the partial loss of the anti-sickling activity of hydroxyurea was investigated along with the in silico drug-target interactions. The results indicated that the use of lactose in hydroxyurea formulations needs urgent reconsideration and that lactose must be replaced by other diluents that do not form Maillard adducts.

Standardization of homeopathic mother tincture of Toxicodendron pubescens and correlation of its flavonoid markers with the biological activity.

BACKGROUND: Standardization and quality control of homeopathic drugs is very challenging. As mother tinctures are derived from complex natural resources, there is a need of systematic evaluation of chemical markers which correlate with the proposed biological activities of mother tinctures. METHODS: In present study, High-Performance Thin-Layer Chromatography (HPTLC) standardization method of homeopathic mother tinctures of Toxicodendron pubescens using quercitrin and rutin as chemical markers is validated and correlations of content of these markers with its anti-inflammatory effects are established. For HPTLC analysis, precoated silica gel plates were used as stationary phase. Two flavonoids, namely quercitrin and rutin were used as markers. Separation was achieved using methylene chloride:methanol:water:glacial acetic acid (15:1.5:1:8 v/v/v) as mobile phase. The developed plates were scanned at 365 nm. RESULTS: It was observed that quercitrin (Rf value 0.63) and Rutin (Rf value 0.41) are well resolved. The minimum detectable concentrations for quercitrin and rutin were 5 ng/spot. The linearity range was between 100 and 2000 ng/spot for both the markers. Subsequently, anti-inflammatory activity of these formulations was determined against carrageenan-induced paw edema in rats, pain threshold determined by electronic Von-Frey apparatus and paw withdrawal latency (PWL) on hot-plate. All the tested formulations of Rhus Tox showed anti-inflammatory and analgesic activity against carrageenan induced paw edema in rats. Quantitative correlation between the content of markers and anti-inflammatory activity of mother tinctures was established. RESULTS: Anti-inflammatory effect as well as effect on paw withdrawal and pain threshold, at third hour after carrageenan injection, correlated with quercitrin and rutin content in the respective formulations. CONCLUSIONS: This study validates a quantitative HPTLC method for standardization of homeopathic mother tincture of Rhus Tox and establishes quercitrin and rutin as markers corresponding its biological activity. Contents of quercitrin and rutin in T. pubescens mother tincture correlates with its anti-inflammatory and analgesic actions and the validated HPTLC method can be used in standardization of homeopathic mother tincture of T. pubescens.

Modification of pharmacological activity of nebivolol due to Maillard reaction.

Lactose is used as an excipient in solid dosage forms of nebivolol. Ultraviolet spectroscopy, Fourier-transform infrared spectroscopy and differential scanning calorimetry were used to study the interaction between nebivolol and lactose. The formation of a Maillard product was noted in aqueous mixtures of nebivolol and lactose heated at 60°C at unbuffered and buffered alkaline pH. A similar Maillard adduct formation was evident within 15 days in a dry physical mixture of nebivolol and lactose maintained at 40°C and 75% relative humidity in the dark. High-performance liquid chromatography and liquid chromatography-mass spectrometry analyses of the reaction mixtures confirmed the formation of a nebivolol-lactose adduct. The effects of intravenously administered nebivolol and the nebivolol-lactose adduct on the blood pressure and heart rate of anesthetized normotensive rats were investigated. The bradycardic effect of the adduct was significantly less than that of nebivolol. The present investigation reveals an incompatibility between nebivolol and lactose, leading to the loss of the pharmacological activity of nebivolol. Hence, the use of lactose as an excipient in dosage forms of nebivolol, a secondary amine, needs reconsideration.

Development and biological evaluation of protective effect of kidney targeted N-acetylated chitosan nanoparticles containing thymoquinone for the treatment of DNA damage in cyclophosphamide-induced haemorrhagic cystitis.

Thymoquinone (TQ), the most prominent constituent of Nigella sativa seeds, essential oil, is reported to possess an organ protective effect via Nrf2 expression and activation of Phase-II antioxidant enzymes. Haemorrhagic cystitis is the sudden onset of haematuria combined with bladder pain and irritable bladder symptoms are the known toxic effects of cyclophosphamide (CYP) chemotherapy. The objective of the present study was to investigate and compare the protective effect of thymoquinone (TQ) and thymoquinone nanoparticles (TQ-NP) in the kidney against CYP-induced haemorrhagic cystitis. Primarily, TQ-NP was fabricated by synthesis of N-acetylated chitosan and nanoparticle preparation by the ionic gelation technique. They were characterized by particle size, polydispersive index (PDI), zeta potential, entrapment efficiency (EE), SEM, and dynamic scattering calorimetry (DSC). Moreover, fluorescein isothiocyanate (FITC) labeled NPs were prepared for biodistribution studies. The protective mechanisms of TQ-NP included its anti-inflammatory activity, inhibitory effects on cytokine levels, and protection against the DNA damage in the bladder epithelium. The cystitis was induced in rats by orally administering 200 mg/kg of CYP. The dose-dependent protective effect of the TQ-NP was determined by intravenously administering 1, 2, and 5 mg/kg of the TQ-NP to CYP-treated rats. The present study revealed that the TQ-NP prepared by ionic gelation method provides kidney targeted delivery of TQ as compared to TQ solution. The mean particle size, PDI, and %EE of TQ-NP were 272.6 nm, 0.216, 70.81 ± 0.12% respectively. The zeta potential of thymoquinone-loaded nanoparticles was found to be -20.7 mV and - 22.6 mV respectively before and after lyophilization. SEM study also confirmed the small size and spherical shape. Pharmacokinetic studies revealed the improvement in half-life and prolonged action of the TQ-NP as compared to the TQ solution. Also, TQ-NP administration showed more protection against the characteristic histological alterations in the bladder in comparison to TQ solution. The present study indicates that TQ-NP exerts potent anti-oxidant, DNA protective and cytokine inhibitory activity at considerably lower concentrations as compared to plain TQ solution. The nano formulation of TQ using N-acetylated chitosan provides effective kidney targeted delivery of TQ, which in turn improves its retention and protective efficacy against CYP-induced haemorrhagic cystitis.

Aloin protects against arsenic trioxide-induced myocardial membrane damage and release of inflammatory cytokines.

Aloin exerts concentration-dependent pro-oxidant and antioxidant effects when tested in vitro. Such duality of effects has not been investigated through in vivo studies on aloin. We evaluated the effects of aloin at doses ranging between 1 and 125 mg/kg against the arsenic trioxide (As2O3)-induced cardiotoxicity in mice. As2O3 (5 mg/kg/day) was intraperitoneally administrated for 10 days. Aloin was administered through oral gavage at 1, 5, 25, and 125 mg/kg/day. As2O3 induced rise in ST height and QT interval in ECG, increased oxidative stress, and depleted the antioxidative defense. As2O3 increased inflammatory cytokine concentrations in the heart. Aloin dose dependently inhibited the As2O3-induced cardiotoxicity. There was no evidence of increased oxidative stress in the low-dose aloin-treated mice receiving As2O3. Our results indicate that aloin possesses cardioprotective potentials and its pro-oxidant effect is not evident in vivo at tested doses.

Chemomodulatory Potential of Bartogenic Acid Against DMBA/Croton Oil Induced Two-Step Skin Carcinogenesis in Mice.

Barringtonia racemosa fruits are believed to be useful in cancer treatment in Ayurveda, the Indian system of medicine. In present study, bartogenic acid (BA), a triterpenoid constituent of Barringtonia fruits was evaluated for its cytotoxicity property using the human skin carcinoma cell line (SCC-13) and human peripheral blood mononuclear cells (PBMC). The chemopreventive efficacy of BA was evaluated against the DMBA/Croton oil-induced skin carcinogenesis in mice.BA was orally administered at the doses of 1, 2 or 4 mg/kg/day or applied topically every day for 12 weeks following DMBA application. The in vitro data from cell lines revealed that BA induces cytotoxicity against the SCC-13 cells (IC50=7.5 µM). It was found 4.05 times more selective to exert cytotoxicity against SCC-13 as compared to the PBMC (IC50=30.4 µM). The in vivo datacollected from mice model of DMBA/Croton oil-induced skin carcinogenesis revealed that BA administered orally or applied topically, both reduced the precancerous skin lesions andthe incidence of tumor bearing. The oral doses of BA (2 and 4 mg/kg) and topical treatment significantly reduced the incidence and number of skin papillomas. At these doses, BA also increased the activities of catalase and superoxide dismutase and induced an increase in glutathionecontent and inhibited lipid peroxidation in the skin. These findings reveal the chemopreventive efficacy of BA and also demonstrate that it contributes to the cytotoxic and antioxidative effects of Barringtonia racemosa fruits. The study also validates the traditional claims of Barringtonia fruits and provides a scientific basis of its chemopreventive property.