Thymoquinone sensitizes human hepatocarcinoma cells to TRAIL-induced apoptosis via oxidative DNA damage

The effect of plant growth regulators, FeO3-CTs nanoparticles and LEDs light on the growth and biochemical compounds of black seed (Nigella sativa L.) callus in vitro

BACKGROUND

black seed (Nigella sativa L.) has long been utilized in traditional medicine and as a food ingredient due to its potential therapeutic properties including its effectiveness against cancer, coronaviruses, and bacterial infections. Recently, it has garnered significant attention for its rich reservoir of beneficial secondary metabolites. In vitro culture of black seeds presents an efficient and modern approach for the large-scale production of these valuable compounds, offering advantages such as space efficiency, reduced time, and lower costs. This study aimed to develop and optimize a protocol for callus induction and the identification of key secondary metabolites, including thymoquinone (TQ), phenolic compounds, and flavonoids. To induce callus formation in seed explants, two plant growth regulators (PGRs) were applied individually or in combination and incorporated into Murashige and Skoog (MS) culture medium.

RESULTS

The combination of Auxin, 2,4-dichlorophenoxyacetic acid (2,4-D) and cytokinin, 6-benzylaminopurine (BAP), effectively induced callus formation in most explants, with the response varying based on concentration. The highest callus fresh weight (7.02 g) was obtained on Red(R) LED lighting with FeO3-CTs nanoparticles (100 mg/L- 1), which also resulted in the highest dry weight (1.307 g) after 40 days of cultivation. Similarly, the highest levels of phenols, flavonoids and amino acids were observed under R LED with FeO3-CTs nanoparticles (100 mg L- 1), while FeO3-CTs nanoparticles at 100 and 200 mg/L- 1) exhibited significant effects on metabolite production. In contrast, the antioxidant activity against DPPH free radicals and total carbohydrate accumulation were enhanced in callus cultures treated with FeO3-CTs nanoparticles (200 mg/L- 1) under dark conditions. Additionally, GC-MS analysis revealed that FeO3-CTs nanoparticles (100 mg/L- 1) yielded the most effective enhancement of secondary metabolites under blue (B) LED light at a concentration of 295 mg/L- 1.

CONCLUSION

The finding of this study highlights the potential of the proposed method for the large-scale production of secondary metabolites, total carbohydrates, amino acids, phenolic compounds, and flavonoids from black seed callus cultures in a controlled environment. This optimized approach offers a cost-effective and space-efficient strategy for enhancing bioactive compound synthesis, with potential applications in pharmaceutical and nutraceutical industries.

The Role of Thymoquinone in Inflammatory Response in Chronic Diseases

Anti-inflammatory therapies have been shown to be effective in the prevention of various cardiovascular diseases, tumors, and cancer complications. Thymoquinone (TQ), the main active constituent of Nigella sativa, has shown promising therapeutic properties in many in vivo and in vitro models. However, TQ has poor bioavailability and is hydrophobic, prohibiting clinical trials with TQ alone. Studies have explored the combination of TQ with biological nanomaterials to improve its bioavailability. The TQ nanoparticle formulation shows better bioavailability than free TQ, and these formulations are ready for clinical trials to determine their potential as therapeutic agents. In this paper, we review current knowledge about the interaction between TQ and the inflammatory response and summarize the research prospects in Korea and abroad. We discuss the different biological activities of TQ and various combination therapies of TQ and nanomaterials in clinical trials.

Anticancer and Anti-Metastatic Role of Thymoquinone: Regulation of Oncogenic Signaling Cascades by Thymoquinone

Cancer is a life-threatening and multifaceted disease. Pioneering research works in the past three decades have mechanistically disentangled intertwined signaling networks which play contributory roles in carcinogenesis and metastasis. Phenomenal strides have been made in leveraging our scientific knowledge altogether to a new level of maturity. Rapidly accumulating wealth of information has underlined a myriad of transduction cascades which can be pharmaceutically exploited for cancer prevention/inhibition. Natural products serve as a treasure trove and compel interdisciplinary researchers to study the cancer chemopreventive roles of wide-ranging natural products in cell culture and preclinical studies. Experimental research related to thymoquinone has gradually gained momentum because of the extra-ordinary cancer chemopreventive multifunctionalities of thymoquinone. In this mini-review, we provide an overview of different cell signaling cascades reported to be regulated by thymoquinone for cancer chemoprevention. Essentially, thymoquinone efficacy has also been notably studied in animal models, which advocates for a rationale-based transition of thymoquinone from the pre-clinical pipeline to clinical trials.

Cytotoxic, apoptotic, and genetic evaluations of Nigella sativa essential oil nanoemulsion against human hepatocellular carcinoma cell lines

Background

Phytochemicals and plant extracts are showing promising anticancer potentials. In the current study, the volatile faction (essential oil) of Nigella sativa seeds was evaluated against some hepatocellular carcinoma (HCC). The essential oil was extracted and characterized by chromatographic techniques to reveal its chemical composition, especially thymoquinone. Then, the oil was fabricated in two nanoemulsion formulations (F1 and F2), which differ in their composition of surfactants. The cytotoxicity and apoptotic activities of the essential oil and its nanoemulsions were evaluated in vitro against HepG2 and Huh-7 cell lines. Normal WI-38 cell line was also included in that evaluation to study the selectivity and safety of the different formulations on normal cells.

Results

Gas chromatographic analysis indicated that the essential oil is composed mainly of p-cymene (40.0%), thymoquinone (31.2%) and trans-α-thujene (12.8%). Particle size of the nanoemulsions ranged between 9.4 and 119.7 nm depending on the type of surfactant used in the formulation process. The pure essential oil and its two nanoemulsions (F1 and F2) showed dose-dependent antiproliferative activity against both HCC cells. This activity reached its highest cell inhibition in the case of nanoemulsion (F2) where the proliferation percentage was only 21.9% and 9.2% against HepG2 and Huh-7 cells, respectively. The same nanoemulsion (F2) also showed the lowest IC50 values (55.7 and 35.5 µg/ml) against both HepG2 and Huh-7 cells, respectively, compared to 100 µg/ml for the reference drug Doxorubicin. Flow cytometric analysis also confirmed that nanoemulsion (F2) has the highest apoptotic activity compared to nanoemulsion (F1) and the pure unformulated essential oil. Genetic expressions of pro-apoptotic (Bax) and the anti-apoptotic (Bcl-2) gene markers evaluation revealed that nanoemulsion (F2) has better activity in upregulating (Bax) and down-regulate (Bcl-2) with the highest Bax/Bcl-2 ratio (69) was found against Huh-7 cells. All N. sativa nanoemulsions showed minimal cytotoxicity on the normal WI-38 cell, indicating wide safety margins due to selective properties.

Conclusion

Overall, the study revealed the potentials of N. sativa essential oil, after formulation in specially tailored nanoemulsion for application as potential adjuvant liver anticancer agent.

Graphical Abstract