Pharmacokinetics and Biodistribution of Thymoquinone-loaded Nanostructured Lipid Carrier After Oral and Intravenous Administration into Rats

Pharmacological modes of plant-derived compounds for targeting inflammation in rheumatoid arthritis: A comprehensive review on immunomodulatory perspective

BACKGROUND

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune, chronic, inflammatory disease characterized by joint inflammation, synovial swelling, loss of articular structures, swelling, and pain. RA is a major cause of discomfort and disability worldwide, associated with infectious agents, genetic determinants, epigenetic factors, advancing age, obesity, and smoking. Although conventional therapies for RA alleviate the symptoms, but their long-term use is associated with significant side effects. This necessitates the urge to discover complementary and alternative medicine from natural products with minimum side effects.

PURPOSE

In this review, natural product's potential mechanism of action against RA has been documented in the setting of in-vivo, in-vitro and pre-clinical trials, which provides new treatment opportunities for RA patients. The bioefficacy of these natural product's bioactive compounds must be further studied to discover novel natural medications for RA with high selectivity, improved effectiveness, and economic replacement with minimum side effects.

STUDY DESIGN AND METHODS

The current review article was designed systematically in chronological order. Plants and their phytochemicals are discussed in an order concerning their mode of action. All the mechanisms of action are depicted in diagrams which are thoroughly generated by the Chembiodraw to maintain the integrity of the work. Moreover, by incorporating the recent data with simple language which is not incorporated previously, we tried to provide a molecular insight to the readers of every level and ethnicity. Moreover, Google Scholar, PubMed, ResearchGate, and Science Direct databases were used to collect the data.

SOLUTION

Traditionally, various plant extracts and bioactive compounds are effectively used against RA, but their comprehensive pharmacological mechanistic actions are rarely discussed. Therefore, the objective of this study is to systematically review the efficacy and proposed mechanisms of action of different plants and their bioactive compounds including Tripterygium wilfordii Hook F (celastrol and triptolide), Nigella sativa (thymoquinone), Zingiber officinale (shogaols, zingerone), Boswellia serrata (boswellic acids), Curcuma longa (curcumin), and Syzygium aromaticum (eugenol) against rheumatoid arthritis.

CONCLUSION

These plants have strong anti-inflammatory, anti-oxidant, and anti-arthritic effects in different study designs of rheumatoid arthritis with negligible side effects. Phytomedicines could revolutionize pharmacology as they act through alternative pathways hence seeming biocompatible.

Deciphering the anticancer potential of thymoquinone: in-depth exploration of the potent flavonoid from Nigella sativa

Since its first written description around 3000 BC until the present day, cancer has stood as a leading global cause of death, claiming the lives of 1 in 6 individuals. Due to its widespread impact and lethality, it remains one of the most explored yet most challenging disease for the global scientific community. Throughout history, various plant extracts have been used in treating numerous diseases, including cancer. These natural extracts are regaining attention due to their therapeutic benefits and lesser side effects. Thymoquinone, chemically 2-isopropyl-5-methylbenzo-1,4-quinone, constitutes the primary bioactive component of the plant Nigella sativa. Extensive research across in vivo, in vitro models, and clinical trials has revealed Thymoquinone's noteworthy therapeutic potential against cancer. Thymoquinone has shown promising anti-cancer activity in various cancers including breast cancer, lung cancer, prostate cancer, colorectal cancer, cervical cancer, pancreatic cancer, gastric cancer and blood cancers. However, there are challenges such as limited clinical trials, low bioavailability, and the need for more research to understand its long-term safety and effectiveness. This article provides a comprehensive and thorough review of thymoquinone, covering its effectiveness across various malignancies, the molecular signalling pathways it influences, and its role in triggering apoptosis and inhibiting inflammation, angiogenesis, and metastasis. Additionally, the review includes a thorough examination of thymoquinone's pharmacokinetics and safety, making it the first of its kind in its comprehensiveness.

Development and Evaluation of Aloperine-Loaded Nanostructured Lipid Carriers for the Treatment of Pulmonary Arterial Hypertension

Objective

This study focuses on the development and evaluation of nanostructured lipid carriers (NLCs) loaded with aloperine as a potential therapeutic approach for the treatment of pulmonary arterial hypertension.

Methods

The NLCs were designed to enhance the solubility, stability, and bioavailability of aloperine, a compound with vasodilatory and anti-inflammatory properties. Through a series of experiments including single-factor experimentation, transmission electron microscopy, high-performance liquid chromatography, in vivo pharmacokinetics, and tissue distribution studies, we assessed the physicochemical properties, drug release profiles, and in vitro and in vivo performance of this novel nanocarrier.

Results

The prepared aloperine-loaded NLCs exhibited a milky white and translucent suspension appearance, presenting a quasi-spherical shape under a transmission electron microscope, with an average particle size of (509.48±30.04) nm and an entrapment efficiency of (64.18±1.14)%. The drug release profile demonstrated good sustained-release characteristics in vitro, and the formulation remained stable for up to 15 days when stored at 4°C. Compared to the aloperine solution group, the t1/2, AUC(0→t), AUC(0→∞), MRT(0→t), and clearance rate of the aloperine-loaded NLCs were 2.3, 2.96, 3.06, 3.03, and 0.22 times higher, respectively. This indicates that formulating aloperine into NLCs can prolong its circulation time in the body. Furthermore, the concentrations of aloperine in the lungs of the NLCs group were 1.79, 3.78, and 2.30 times higher than those in the solution group at three time points (0.25 h, 1.5 h, 4 h), suggesting that NLCs can increase the accumulation of aloperine in the lungs.

Conclusion

Our findings suggest that NLCs loaded with aloperine could offer a promising strategy for the treatment of pulmonary arterial hypertension.

Nigella sativa: A Comprehensive Review of Its Therapeutic Potential, Pharmacological Properties, and Clinical Applications

Nigella sativa (NS) is an annual herb belonging to the Ranunculaceae family, also known as black cumin or black seed. This plant has been used since ancient times due to its therapeutic properties and has proven effective in gastrointestinal, respiratory, cardiovascular, infectious, and inflammatory conditions. In this review, the aim is to highlight the therapeutic effects of the plant known in Arab countries as "the plant that cures any disease", which are provided by the phytochemical compounds in its composition, such as thymoquinone, p-cymene, α-thujene, longifolene, β-pinene, α-pinene, and carvacrol. These compounds confer an antioxidant effect to the seeds, leading to a significant decrease in ROS and a potent anti-inflammatory effect. Also, in this review, the aim is to highlight that NS seeds may have a synergistic effect with other drugs, such as chemotherapeutic agents or antibiotics, which may lead to a reduction in the therapeutic dose, may have an improved effect, and could lead to overcoming obstacles such as drug resistance. The studies provided in this review showed that NS has the potential to be a therapeutic agent both as a monotherapy and as an adjuvant. Although there are studies demonstrating the therapeutic properties of NS, there is a need for much more extensive research and more clinical trials with clearly established objectives so that the mechanism of action of the active substances in NS is much better understood. With the data provided so far, NS can be used in food and drug production in small quantities and can be administered for short periods. Further investigations may lead to an understanding of the therapeutic profile and the most effective mode of administration, as well as a clearer perspective on the toxicological profile of NS.

Efficacy of Nigella sativa seed oil against psychophysical stress induced irritable bowel syndrome and anxiety-like symptoms in Wistar rats

RATIONALE

Stressors play a critical role in the progression of irritable bowel syndrome (IBS). Heterogenous stress causes alterations in our bowel movements which can further cause anxiety and depression-like symptoms, decreasing the ability of individuals worldwide to function in social, academic, and employment settings.

OBJECTIVES

This study was aimed to investigate the effect of orally administered Nigella sativa (0.2 mL/kg b.wt.) seed oil (NSSO) on stress-induced IBS, anxiety, and depression-like symptoms in Wistar rats.

METHODS

In the present study, modelling IBS induced anxiety and depression-like symptoms in rodents have been employed to correlate the pathophysiological mechanisms behind this disorder. Moreover, evaluation of ameliorative potential of traditionally used NSSO in IBS was also carried out.

RESULTS

Present investigation indicated that acute stress of 1.5 h daily for 20 days induced hyper cortisol, gastrointestinal (GI) hypermotility, diarrhoea, altered levels of short chain fatty acids (SCFAs), and inflammation which are common symptoms of IBS. Furthermore, depression and anxiety-like symptoms were validated in test groups by various behavioral tests and decreased levels of 5-HT-Transporter mRNA gene expression, which are clear indicators of cognitive impairment.

CONCLUSIONS

It is possible that these IBS-like symptoms may have contributed to the pathogenesis of cognitive deficits and depression. However, the anti-oxidative, anti-inflammatory, anti-spasmodic, and possibly the anti-anxiolytic properties of NSSO helped in the mitigation of altered gut-brain axis. Because the concurrent treatment of NSSO alleviated the symptoms of modified GI function and consequently, the anxious & depressive behavior of the animals. Overall, this research explored the protective efficacy of NSSO against stress-induced IBS and depression-like symptoms, shedding light on the potential of this natural compound as a therapeutic option in the field of gastroenterology and psychiatry.

Thymoquinone' potent impairment of multidrug-resistant Staphylococcus aureus NorA efflux pump activity

The drug efflux pump is a crucial mechanism implicated in resistance to multiple antimicrobials. Thymoquinone (TQ) has evidently demonstrated multiple activities, antibacterial being the most effective. Knowledge about TQ activity against multidrug-resistant Staphylococcus aureus is very scarce. Therefore, the present study was conducted to investigate TQ resistance modulation in ciprofloxacin (CIP) and doxycycline (DO) multidrug-resistant S. aureus. Forty-seven samples were collected from different sources, and S. aureus was isolated and identified. Then, S. aureus resistance profiles to antimicrobials, N. sativa essential oil, and TQ; the correlation between TQ-MIC readings and disc diffusion; cartwheel and ethidium bromide (EtBr) accumulation assays; and norA gene expression were all described within silico molecular docking for TQ interactions with norA efflux pump protein. TQ-MICs ranged from 5-320 µg/ml. TQ down-regulated norA gene expression, resulting in a drop in efflux pump activity of 77.5-90.6% in the examined strains, comparable to that observed with verapamil. Exposure of S. aureus strains to CIP and DO raises the initial basal efflux pumping expression to 34.2 and 22.9 times, respectively. This induced efflux pumping overexpression was substantially reduced by 97.7% when TQ was combined with CIP or DO. There was a significant reduction of MICs of CIP and DO MICs by 2-15 and 2-4 folds, respectively, after treatment with 0.5XMIC-TQ in resistance modulation assays. These results refer to TQ ligand inhibitory interactions with NorA protein in molecular docking. Interpretations of inhibition zone diameters (IZDs) of disc diffusion and TQ-MICs exhibit independence of MICs from IZDs, as indicated by invalid linear regression analysis. TQ significantly reduced efflux pumping S. aureus induced by CIP and DO, but further investigations are needed to improve TQ-pharmacokinetics to restore CIP and DO activity and suppress fluoroquinolone and doxycycline-resistant S. aureus selection in clinical and animal settings.

Fabrication and optimization of chitosan-g-m-PEG-NH2 copolymer for advanced glioblastoma therapy using surface engineered lentinan loaded nanovesicles for nasal delivery

Glioblastoma multiforme (GBM) exhibits a high mortality with an incidence rate of 3-5 per 100,000 each year, which demands existence of newer approach for its treatment. The current study focuses on synthesis of novel lipidic nanovesicles (LNs) loaded with highly potent macromolecule Lentinan (LNT) and surface modified with methoxy poly (ethylene glycol; PEG) amine (m-PEG-NH2)-grafted-chitosan (CS) for intranasal delivery. The grafting procedure was optimized using Box Behnken design (BBD) to limit the use of organic solvents. The fabricated polymer showed enhanced aqueous solubility, biodegradability and mucoadhesion, resulting in higher nasal mucosa permeation (z = 53.52 μm). The presence of PEG enabled the sustained release of LNT till 48 h and assisted in achieving higher accumulation of LNT in CSF (41.7 ± 3.1 μg/mL) and a higher brain targeting potential of 96.3 ± 2.31 % (p < 0.05). In-vitro cellular studies showed the enhanced anti-GBM effect of LNT on U87 MG cells by reducing the cell viability (~2 times reduction in IC50 value) accompanied with large number of cells undergoing late apoptosis and death (p < 0.05) because of the higher cellular uptake (63.22 ± 3.01 ng/100 cells) of novel formulation. The copolymer comprising LNs were biocompatible, stable and can be used as an effective tool in the management of GBM.

Oral targeted drug delivery to post-gastrointestinal sites

As an essential branch of targeted drug delivery, oral targeted delivery is attracting growing attention in recent years. In addition to site-specific delivery for the treatment of locoregional diseases in the gastrointestinal tract (GIT), oral targeted delivery to remote sites beyond the GIT emerges as a cutting-edge research topic. This review aims to provide an overview of the fundamental concepts and most recent advances in this field. Owing to the physiological barriers existing in the GIT, carrier systems should be transported across the enteric epithelia to target remote sites. Recently, pioneer investigations have validated the transport of intact micro- or nanocarriers across gastrointestinal barriers and subsequently to various distal organs and tissues. The microfold (M) cell pathway is the leading mechanism underlying the oral absorption of particulates, but the contribution of the transcellular and paracellular pathways should not be neglected either. In addition to well-acknowledged physicochemical and biological factors, the formation of a protein corona may also influence the biological fate of carrier systems. Although in an early stage of conceptualization, oral targeted delivery to remote diseases has demonstrated promising potential for the treatment of inflammation, tumors, and diseases inflicting the lymphatic and mononuclear phagocytosis systems.

A comparative study on the protective effects of cuminaldehyde, thymoquinone, and gallic acid against carbon tetrachloride-induced pulmonary and renal toxicity in rats by affecting ROS and NF-κB signaling

CCl4 toxicity is a fatal condition that can cause numerous organ dysfunctions. We evaluated and compared the protective effects of cuminaldehyde (CuA), thymoquinone (TQ), and gallic acid (GA) on CCl4-induced pulmonary and renal toxicity in rats. The impacts of these compounds on CCl4-induced oxidative stress, inflammation, and morphological alterations were examined. The results showed that the compounds under investigation prevented CCl4 from significantly increasing pulmonary and renal lipid peroxidation and NO levels, as well as massively depleting GSH levels and GPX and SOD activities. Moreover, they suppressed the CCl4-induced increase in mucus secretion in the lung and upregulated the gene expression of pulmonary and renal NF-ҡB, iNOS, TNF-α, and COX-2. The heatmap cluster plots showed that GA and TQ had better protective potencies than CuA. The external organ morphology, histopathological results, and chest X-ray analysis confirmed the toxicity of CCl4 and the protective influences of the tested compounds in both the lungs and kidneys of rats. These compounds displayed predicted competitive inhibitory effects on iNOS activity and may block the IL-13α2 receptor, as revealed by molecular docking analysis. Thus, CuA, TQ, and GA, particularly the latter two, are prospective protective compounds against the pulmonary and renal toxicity caused by CCl4.

A bioanalytical assay for estimation of thymoquinone in rats cerebrospinal fluid and brain tissues of nasally administrated thymoquinone loaded lipo-polymeric nanoshells and its pharmacokinetic profiling

Thymoquinone (TH) has been one of the major phytochemical used in the treatment of cancers since long time, especially in the management of glioblastoma multiforme (GBM). The formulation of lipo-polymeric nanoshells (LPNs) and their nasal delivery are fascinating approaches for overcoming the drawbacks of low solubility and poor bioavailability of TH. Hence targeting LPNs to the brain requires a validated bioanalytical method for the assessment of TH concentration in Cerebrospinal fluid (CSF) and brain tissue homogenates (BTH). Therefore, the current work focuses on the development and validation of high-performance liquid chromatography (HPLC) method in CSF by employing nasal simulated fluid (NSF) as one of the major components of the mobile phase. The developed method was checked for linearity in the range of 0.05 to 1.6 μg/mL, having an r2 value of 0.999 with mean % recovery >95% and % RSD values below <2.0%. The developed method gave a clear separation of TH at 6.021 ± 0.17 min with an internal standard at 4.102 ± 0.09 min and a CSF spike at 2.170 ± 0.12 min. The developed method assisted in determining the in-vitro and in-vivo drug release study of LPNs, pharmacokinetic profiling, qualitative in-vivo brain uptake study, in-vitro cellular uptake, and generating stability data of formulated LPNs proposed for intranasal administration in rats.

Gas Chromatography-Mass Spectrometry Detection of Thymoquinone in Oil and Serum for Clinical Pharmacokinetic Studies

Thymoquinone (TQ) is the primary component of Nigella sativa L. (NS) oil, which is renowned for its potent hepatoprotective effects attributed to its antioxidant, anti-fibrotic, anti-inflammatory, anti-carcinogenic, and both anti- and pro-apoptotic properties. The aim of this work was to establish a method of measuring TQ in serum in order to investigate the pharmacokinetics of TQ prior to a targeted therapeutic application. In the first step, a gas chromatography-mass spectrometry method for the detection and quantification of TQ in an oily matrix was established and validated according to European Medicines Agency (EMA) criteria. For the assessment of the clinical application, TQ concentrations in 19 oil preparations were determined. Second, two serum samples were spiked with TQ to determine the TQ concentration after deproteinization using toluene. Third, one healthy volunteer ingested 1 g and another one 3 g of a highly concentrated NS oil 30 and 60 min prior to blood sampling for the determination of serum TQ level. After the successful establishment and validation of the measurement method, the highest concentration of TQ (36.56 g/L) was found for a bottled NS oil product (No. 1). Since a capsule is more suitable for oral administration, the product with the third highest TQ concentration (No. 3: 24.39 g/L) was used for all further tests. In the serum samples spiked with TQ, the TQ concentration was reliably detectable in a range between 5 and 10 µg/mL. After oral intake of NS oil (No. 3), however, TQ and/or its derivatives were not detectable in human serum. This discrepancy in detecting TQ after spiking serum or following oral ingestion may be attributed to the instability of TQ in biomatrices as well as its strong protein binding properties. A pharmacokinetics study was therefore not viable. Studies on isotopically labeled TQ in an animal model are necessary to study the pharmacokinetics of TQ using alternative modalities.

Thymoquinone-loaded lipid nanocapsules with promising anticancer activity for colorectal cancer

Colorectal cancer (CRC) is the third most common worldwide. Depending on its stage, chemotherapy is usually given after surgery when CRC has already metastasized to other organs like the liver or lungs. Unfortunately, the current antineoplastics used for CRC therapies involve toxicity and side effects due to their lack of site-specificity. To overcome the drawbacks of heavy chemotherapy, this study proposes to assess the efficacy of thymoquinone (TQ), a bioactive constituent of black seeds (Nigella sativa), as an antiproliferative and pro-apoptotic agent on an experimental CRC model in mice. TQ was encapsulated in lipid nanocapsules (LNCs), used as nanocarriers, in order to increase its specificity and cell absorption. TQ-loaded LNCs (TQ-LNCs) have a diameter of 58.3 ± 3.7 nm and 87.7 ± 4.5% TQ encapsulation efficiency. In turn, in vivo studies showed that the intratumoral administration of TQ-LNCs decreased the tumor size in colorectal cancer bearing mice compared to the control group. TQ-LNCs were more effective than free TQ for inducing tumor cell death. These results highlight the potential of TQ entrapped in LNCs as an anticancer agent for CRC treatment.

Impact of nanotechnology on the oral delivery of phyto-bioactive compounds

Nanotechnology is an advanced field that has remarkable nutraceutical and food applications. Phyto-bioactive compounds (PBCs) play critical roles in promoting health and disease treatment. However, PBCs generally encounter several limitations that delay their widespread application. For example, most PBCs have low aqueous solubility, poor biostability, poor bioavailability, and a lack of target specificity. Moreover, the high concentrations of effective PBC doses also limit their application. As a result, encapsulating PBCs into an appropriate nanocarrier may increase their solubility and biostability and protect them from premature degradation. Moreover, nanoencapsulation could improve absorption and prolong circulation with a high opportunity for targeted delivery that may decrease unwanted toxicity. This review addresses the main parameters, variables, and barriers that control and affect oral PBC delivery. Moreover, this review discusses the potential role of biocompatible and biodegradable nanocarriers in improving the water solubility, chemical stability, bioavailability, and specificity/selectivity of PBCs.

Pharmacokinetics and tumor delivery of nanoparticles

Nanoparticles (NPs) have been widely used in different areas, including consumer products and medicine. In terms of biomedical applications, NPs or NP-based drug formulations have been extensively investigated for cancer diagnostics and therapy in preclinical studies, but the clinical translation rate is low. Therefore, a thorough and comprehensive understanding of the pharmacokinetics of NPs, especially in drug delivery efficiency to the target therapeutic tissue tumor, is important to design more effective nanomedicines and for proper assessment of the safety and risk of NPs. This review article focuses on the pharmacokinetics of both organic and inorganic NPs and their tumor delivery efficiencies, as well as the associated mechanisms involved. We discuss the absorption, distribution, metabolism, and excretion (ADME) processes following different routes of exposure and the mechanisms involved. Many physicochemical properties and experimental factors, including particle type, size, surface charge, zeta potential, surface coating, protein binding, dose, exposure route, species, cancer type, and tumor size can affect NP pharmacokinetics and tumor delivery efficiency. NPs can be absorbed with varying degrees following different exposure routes and mainly accumulate in liver and spleen, but also distribute to other tissues such as heart, lung, kidney and tumor tissues; and subsequently get metabolized and/or excreted mainly through hepatobiliary and renal elimination. Passive and active targeting strategies are the two major mechanisms of tumor delivery, while active targeting tends to have less toxicity and higher delivery efficiency through direct interaction between ligands and receptors. We also discuss challenges and perspectives remaining in the field of pharmacokinetics and tumor delivery efficiency of NPs.

Nigella sativa L. and Its Active Compound Thymoquinone in the Clinical Management of Diabetes: A Systematic Review

Despite existing conventional hypoglycemic drugs to manage diabetes, their non-availability and cost in low-income countries coupled with the associated side effects remain a major concern. Consequently, exploring for alternative treatments to manage diabetes has been a continuous priority. Nigella sativa L. (NS) (Family: Ranunculaceae) is regarded as a valuable traditional remedy in diabetes management and extensively studied for its biological properties. This systematic review provides a comprehensive and critical analysis of clinical studies on the efficacy, safety, and mechanism of action of NS and its compound thymoquinone (TQ) in diabetes management. The main scientific databases which were scrutinised were Scopus, PubMed, Google Scholar, and Web of Science. Data search was conducted from inception to January 2022. A total of 17 clinical studies were obtained; 16 studies on Nigella sativa L. and 1 study on its compound TQ. N. sativa was found to be highly potent in terms of its hypoglycemic activity when compared to placebo based on improvement in parameters including fasting blood glucose (FBG), postprandial blood glucose (PPBG), Hemoglobin A1C (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), and homeostatic model assessment for assessment of beta-cell functionality (HOMA-β). The compound TQ in combination with a daily dose of metformin demonstrated a greater reduction in the levels of HbA1c and blood glucose compared to metformin alone. The bioavailability of TQ can be enhanced by using nanoparticulate drug delivery systems. Considering the findings of the clinical studies along with negligible adverse effects, NS has strong potential application in bioproduct development for the management of diabetes. Further investigations should explore the detailed mechanism of actions by which TQ exerts its therapeutic antidiabetic effects to provide more insights into its clinical use in the management of diabetes.

Thymoquinone in Ocular Neurodegeneration: Modulation of Pathological Mechanisms via Multiple Pathways

Thymoquinone is a naturally occurring compound and is the major component of Nigella sativa, also known as black seed or black cumin. For centuries thymoquinone has been used especially in the Middle East traditionally to treat wounds, asthma, allergies, fever, headache, cough, hypertension, and diabetes. Studies have suggested beneficial effects of thymoquinone to be attributed to its antioxidant, antibacterial, anti-oxidative stress, anti-inflammatory, and neuroprotective properties. Recently, there has been a surge of interest in thymoquinone as a treatment for neurodegeneration in the brain, such as that seen in Alzheimer’s (AD) and Parkinson’s diseases (PD). In vitro and in vivo studies on animal models of AD and PD suggest the main neuroprotective mechanisms are based on the anti-inflammatory and anti-oxidative properties of thymoquinone. Neurodegenerative conditions of the eye, such as Age-related Macular Degeneration (AMD) and glaucoma share at least in part similar mechanisms of neuronal cell death with those occurring in AD and PD. This review aims to summarize and critically analyze the evidence to date of the effects and potential neuroprotective actions of thymoquinone in the eye and ocular neurodegenerations.

Effect of thymoquinone on pharmacokinetics of 5-fluorouracil in rats and its effect on human cell line in vitro

Thymoquinone (TQ) is one of the components extracted from Nigella sativa seeds and has antioxidant, anti-inflammatory, and anticancer effects. We evaluated the effect of TQ on 5-fluorouracil (5-FU) pharmacokinetics (PK) in vivo and in vitro on human colorectal cancer cell line. Ten Adult male Wistar rats were assigned to two groups. TQ treated group received intraperitoneal TQ once daily for 14 consecutive days (5 mg/kg). Both groups received intraperitoneal 5-FU (50 mg/kg) on day 15 and blood samples were collected from retro-orbital plexus. The pharmacokinetics parameters were analyzed using high-performance liquid chromatography (HPLC). Moreover, various concentrations of 5-FU, TQ, and combination of 5-FU and TQ were added to the HT-29 cell line and cell viability was measured using 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay. The maximum serum concentration (C_max), area under the curve (AUC), and time of maximum concentration (T_max) of 5-FU in TQ treated group were significantly increased approximately by 61, 60, and 24% compared to the control group, respectively. The combination of 5-FU with TQ (0.284 mM) showed a greater inhibitory effect on HT-29 cell growth compared to the alone 5-FU (0.027 and 0.055 mM) administration. TQ increases the AUC, C_max, and T_max of 5-FU and has a synergistic effect on the PK of 5-FU. Moreover, low concentration of TQ enhances the inhibitory effects of 5-FU on cell growth in colorectal cancer cell line. This synergistic effect might enhance the anticancer effects of low concentration of 5-FU, leading to drug dose reduction and reduced systemic toxicity of this chemotherapeutic agent.

Biodistribution of Mesoporous Carbon Nanoparticles via Technetium-99m Radiolabelling after Oral Administration to Mice

The use of ordered mesoporous matrices, and in particular carbon-based mesoporous nanoparticles has shown great potential towards enhancing the bioavailability of orally administered drugs. Nevertheless, elucidation of the in vivo absorption, distribution, and excretion of such carriers is essential for understanding their behaviour, and radiolabelling provides a very useful way to track their occurrence inside the body. In this work, uniform spherical CMK-1-type ordered mesoporous carbon nanoparticles have been radiolabelled with Technetium-99m (99mTc) and traced after oral administration to mice. Ex vivo biodistribution studies showed that the radiolabelled nanoparticles accumulated almost exclusively in the gastrointestinal tract; complete elimination of the radiotracer was observed within 24 h after administration, with practically no uptake into other main organs. These findings along with the results from in vitro stability studies indicate that the spherical carbon nanoparticles examined could be safely used as drug carriers with minimal side effects, but also support the great value of radiolabelling methods for monitoring the particles' behaviour in vivo.