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

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.

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.

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.