[6]-Gingerol impedes 7,12-dimethylbenz(a)anthracene-induced inflammation and cell proliferation-associated hamster buccal pouch carcinogenesis through modulating Nrf2 signaling events

The "root" causes behind the anti-inflammatory actions of ginger compounds in immune cells

Ginger (Zingiber officinale) is one of the most well-known spices and medicinal plants worldwide that has been used since ancient times to treat a plethora of diseases including cold, gastrointestinal complaints, nausea, and migraine. Beyond that, a growing body of literature demonstrates that ginger exhibits anti-inflammatory, antioxidant, anti-cancer and neuroprotective actions as well. The beneficial effects of ginger can be attributed to the biologically active compounds of its rhizome such as gingerols, shogaols, zingerone and paradols. Among these compounds, gingerols are the most abundant in fresh roots, and shogaols are the major phenolic compounds of dried ginger. Over the last two decades numerous in vitro and in vivo studies demonstrated that the major ginger phenolics are able to influence the function of various immune cells including macrophages, neutrophils, dendritic cells and T cells. Although the mechanism of action of these compounds is not fully elucidated yet, some studies provide a mechanistic insight into their anti-inflammatory effects by showing that ginger constituents are able to target multiple signaling pathways. In the first part of this review, we summarized the current literature about the immunomodulatory actions of the major ginger compounds, and in the second part, we focused on the possible molecular mechanisms that may underlie their anti-inflammatory effects.

Intra-peritoneal lavage of Zingiber officinale rhizome and its active constituent gingerol impede inflammation, angiogenesis, and fibrosis following post-operative peritoneal adhesion in male rats

Post-operative peritoneal adhesions (PA) are a common and important clinical problem. In this study, we focused on the ameliorative efficacy of ginger and gingerol compounds on surgical-induced peritoneal adhesion, and their strategies that disrupted the PA formation pathways to suppress their incidence. First, liquid chromatography-mass spectrometry (LC-MS) was established to separate and identify several chemical groups of ginger rhizome extract. In the next steps, male Wistar albino rats were randomly selected and divided into various groups, namely sham, control, ginger extract (0.6, 1.8, 5 %w/v), and gingerol (0.05, 0.1, 0.3, and 1 %w/v). Finally, we investigated the macroscopic parameters such as wound healing, body weight as well as spleen height and weight. In addition, visual peritoneal adhesion assessment was performed via Nair et al and Adhesion Scoring Scheme. Moreover, the microscopic parameters and biological assessment was performed via and immunoassays. The present findings revealed significant improvement in wound healing and reduction of the adhesion range, as Nair et al. and Adhesion Scoring Scheme scoring, in both the ginger and gingerol groups compared to the PA group (P < 0.05). Whereas, gingerol (0.3 % w/v) was able to increase the body weight in rats (P < 0.0001) at end stage of experiment. Also, inflammation, angiogenesis, and fibrosis were significantly decreased due to the downregulation of interleukin (IL)-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF), respectively, in the ginger and gingerol groups compared to the PA group (P < 0.05). In contrast, the levels of IL-10 were increased in the ginger and gingerol groups compared to the control group (P < 0.01). Our results proved that ginger rhizome and gingerol, as novel therapeutic compounds, could be used to prevent PA for their beneficial anti-inflammatory as well as anti-fibrosis properties in clinical trials. However, further clinical studies are required to approve the effectiveness of ginger and gingerol.

Modulation of carcinogenesis with selected GRAS nutraceuticals via Keap1-Nrf2 signaling pathway

Keap1-Nrf2 is a fundamental signaling cascade known to promote or prevent carcinogenesis. Extensive studies identify the key target of modulatory aspects of Keap1-Nrf2 signaling against cancer. Nutraceuticals are those dietary agents with many health benefits that have immense potential for cancer chemoprevention. The nutritional supplements known as nutraceuticals are found to be one of the most promising chemoprevention agents. Upon investigating the dual nature of Nrf2, it became clear that, in addition to shielding normal cells from numerous stresses, Nrf2 may also promote the growth of tumors. In the present review, we performed a systematic analysis of the role of 12 different nutraceuticals like curcumin, sulforaphane, resveratrol, polyunsaturated fatty acids (PUFA) from fish oil, lycopene, soybean, kaempferol, allicin, thymoquinone, quercetin, gingerol, and piperine in modulating the Nrf2/Keap1 signaling mechanism. Among these, 12 Generally Recognized As Safe (GRAS) certified nutraceuticals, sulforaphane is the most extensively studied compound in modulating Keap1-Nrf signaling. Even though there is much evidence at preclinical levels, further high-quality research is still required to validate the potential role of these nutraceuticals in Keap1-Nrf2 modulation.

Nanoencapsulation of Ru(p-cymene) Complex Bearing Ginger-based Natural Product into Liposomal Nanoformulation to Improve Its Cellular Uptake and Antiproliferative Activity

The organometallic compounds are prospective candidates in the row of developing metallochemotherapeutics with the aim of overcoming the limitations of platinum drugs. In order to explore the anticancer properties of organometallic compounds with the natural medicines, two Ru(II)-p-cymene complexes containing the natural products, viz., 6-gingerol (6G) and benzylated-6-gingerdione (B-6GD) have been synthesized and characterized well. The phenolic group of the Ru(6G) complex facilitates its higher cell-free antioxidant activity than its analogue complex. Also, the same complex shows higher cytotoxicity toward A549 lung and HeLa-S3 cervical cancer cells than the Ru(B-6GD) complex but lower cytotoxicity toward A2058 metastatic melanoma cancer cells. Both complexes are shown to easily accumulate in melanoma cancer cells, and their degree of cytotoxicity in the same cells is found to be positively correlated with cell uptake. The cytotoxicity of complexes arises from their intracellular activity, mainly due to the induction of singlet oxygen production in cancer cells. The subcellular fractionation study shows that mitochondria and ER-Golgi membranes might be their predominant targets. Also, the mechanistic investigation revealed that Ru(B-6GD) induces caspase-dependent non-apoptotic cell death whereas Ru(6G) can induce caspase-independent non-apoptotic cell death. Furthermore, both complexes are found to moderately alter the adhesion properties of cancer cells, which is beneficial for antimetastatic treatment. Despite the potential pharmacological activity, Ru(6G) is encapsulated into polymer-supported liposomes to reduce its toxicity and further improve its anticancer potency. The π-conjugated yne-ene chain of polydiacetylene aids in the development of a stable nanoformulation, which achieved a slow release of the complex. Most importantly, the cancer cell uptake of the liposome-encapsulated Ru(6G) complex is 20 times enhanced and the total ROS formation in cancer cells is significantly increased compared to the non-encapsulated complex. However, the nanoformulation does not alter the antimetastatic potency of the encapsulated complex.

Cancer Chemoprevention: A Strategic Approach Using Phytochemicals

Cancer chemoprevention approaches are aimed at preventing, delaying, or suppressing tumor incidence using synthetic or natural bioactive agents. Mechanistically, chemopreventive agents also aid in mitigating cancer development, either by impeding DNA damage or by blocking the division of premalignant cells with DNA damage. Several pre-clinical studies have substantiated the benefits of using various dietary components as chemopreventives in cancer therapy. The incessant rise in the number of cancer cases globally is an issue of major concern. The excessive toxicity and chemoresistance associated with conventional chemotherapies decrease the success rates of the existent chemotherapeutic regimen, which warrants the need for an efficient and safer alternative therapeutic approach. In this scenario, chemopreventive agents have been proven to be successful in protecting the high-risk populations from cancer, which further validates chemoprevention strategy as rational and promising. Clinical studies have shown the effectiveness of this approach in managing cancers of different origins. Phytochemicals, which constitute an appreciable proportion of currently used chemotherapeutic drugs, have been tested for their chemopreventive efficacy. This review primarily aims to highlight the efficacy of phytochemicals, currently being investigated globally as chemopreventives. The clinical relevance of chemoprevention, with special emphasis on the phytochemicals, curcumin, resveratrol, tryptanthrin, kaempferol, gingerol, emodin, quercetin genistein and epigallocatechingallate, which are potential candidates due to their ability to regulate multiple survival pathways without inducing toxicity, forms the crux of this review. The majority of these phytochemicals are polyphenols and flavanoids. We have analyzed how the key molecular targets of these chemopreventives potentially counteract the key drivers of chemoresistance, causing minimum toxicity to the body. An overview of the underlying mechanism of action of these phytochemicals in regulating the key players of cancer progression and tumor suppression is discussed in this review. A summary of the clinical trials on the important phytochemicals that emerge as chemopreventives is also incorporated. We elaborate on the pre-clinical and clinical observations, pharmacokinetics, mechanism of action, and molecular targets of some of these natural products. To summarize, the scope of this review comprises of the current status, limitations, and future directions of cancer chemoprevention, emphasizing the potency of phytochemicals as effective chemopreventives.

6-Gingerol Alleviates Neonatal Hypoxic-Ischemic Cerebral and White Matter Injury and Contributes to Functional Recovery

Hypoxic-ischemic encephalopathy (HIE) is one main cause of neonatal death and disability, causing substantial injury to white and gray matter, which can lead to severe neurobehavioral dysfunction, including intellectual disability and dyskinesia. Inflammation, nerve cell death, and white matter injury are important factors in the pathological process of HIE. 6-Gingerol is a ginger extract, which reduces inflammatory response and cell death. However, the role of 6-Gingerol in neonatal hypoxic-ischemic brain injury (HIBI) remains unknown. In this study, we constructed a mouse HIBI model and analyzed the protective effect of 6-Gingerol on HIBI by using behavioral tests, histological staining, qPCR and western blot. Here, we found that 6-Gingerol treatment could alleviate HIBI and improve short-term reflex performance, which is closely related to cell death and neuroinflammation. Additionally, 6-Gingerol reduced neuronal apoptosis, pro-inflammatory factor release, as well as microglial activation. Furthermore, 6-Gingerol significantly improved motor disability, which is associated with white matter damage. Thus, our results showed that 6-Gingerol could reduce the loss of myelin sheaths, alleviate cell death of oligodendrocytes, and stimulate the maturation of oligodendrocytes. In terms of mechanism, we found that 6-Gingerol decreased histone H3K27me3 levels, activated AKT pathway and inhibited the activation of ERK and NF-κB pathway at 3 days post-HIBI. Taken together, our data clearly indicate that 6-Gingerol plays a neuroprotective role against HIBI by epigenetic modification and regulation of AKT, ERK, and NF-κB pathways, inhibiting inflammatory responses and reducing cell death.

Plant-Based Antioxidant Extracts and Compounds in the Management of Oral Cancer

Oral cancer continues to be a leading cause of death worldwide, and its prevalence is particularly high in developing countries, where people chew tobacco and betel nut on a regular basis. Radiation-, chemo-, targeted-, immuno-, and hormone-based therapies along with surgery are commonly used as part of a treatment plan. However, these treatments frequently result in various unwanted short- to long-term side effects. As a result, there is an urgent need to develop treatment options for oral cancer that have little or no adverse effects. Numerous bioactive compounds derived from various plants have recently attracted attention as therapeutic options for cancer treatment. Antioxidants found in medicinal plants, such as vitamins E, C, and A, reduce damage to the mucosa by neutralizing free radicals found in various oral mucosal lesions. Phytochemicals found in medicinal plants have the potential to modulate cellular signalling pathways that alter the cellular defence mechanisms to protect normal cells from reactive oxygen species (ROS) and induce apoptosis in cancer cells. This review aims to provide a comprehensive overview of various medicinal plants and phytoconstituents that have shown the potential to be used as oral cancer therapeutics.

Medicinal chemistry inspired by ginger: exploring the chemical space around 6-gingerol

Ginger (Zingiber officinale Roscoe) has been used as a spice and as a traditional remedy since ancient times, especially in traditional Chinese medicine. It has been applied as a treatment for many diseases either alone or in combination with other remedies. Many studies were conducted on ginger and its constituents and a wide array of bioactivities were reported, e.g., antioxidant, anti-inflammatory, antiemetic, and anticancer activity. Most of these had been correlated to gingerols and shogaols, the most abundant secondary metabolites in ginger. This inspired several research groups to explore the biomedical value of the chemical space around these compounds, and many of their synthetic or semi-synthetic analogues have been prepared and studied for various bioactivities. Thanks to this, many valuable structure activity relationships have been revealed for such compounds. Herein, we provide a brief summary on the synthetic derivatization efforts that had so far been implemented on 6-gingerol, the main constituent of fresh ginger. This review covers 160 natural, semisynthetic, or synthetic 6-gingerol derivatives and their reported bioactivities.

Structure and reported bioactivities of semi-synthetic and synthetic 6-gingerol derivatives.