Anti-Inflammatory and Antioxidant Activities of Ginger

Abstract

Ginger (Zingiber officinale Rosc.), a member of the Zingiberaceae family, is a medicinal herb utilized for its anti-inflammatory and antioxidant qualities. Ginger’s influence on health was discovered due to its high phytochemical content, which includes compounds that eliminate free radicals created by biological systems. Gingerol, shogaol, and other related ginger chemicals limit the body’s production of prostaglandins and leukotrienes. They can also suppress the production of pro-inflammatory cytokines, such as IL-1, TNF-, NF-B, and IL-8. According to our knowledge, NF-B activation is associated with a number of inflammatory disorders, including cancer, kidney injury, and Alzheimer’s disease.

1. Introduction

Ginger (Zingiber officinale Rosc.) is a member of the Zingiberaceae family. Ginger is native to Southeast Asia and is used in many nations as a spice and condiment to give flavor to cuisine. In addition, ginger rhizome has been utilized in traditional herbal medicine [1]. The pharmacological potential of ginger is ascribed to its rich phytochemistry [2]. Jolad et al. classify fresh ginger into two broad categories: volatiles and non-volatiles. Sesquiterpene and monoterpenoid hydrocarbons are volatiles that give ginger its distinctive scent and flavor. In contrast, non-volatile pungent chemicals include gingerols, shogaols, paradols, and zingerone [3]. The health advantages of ginger are attributed primarily to its phenolic components, such as gingerols and shogaols. Ginger offers many biological actions, including antioxidant, anti-inflammatory, anticancer, renoprotective impact, antinausea, and antiemetic properties, according to accumulated research.

2. Pharmacological activities of ginger (Zingiber officinale Rosc.)

2.1 Ginger’s antioxidant activity

Overproduction of free radicals, such as reactive oxygen species (ROS), has been shown to play a significant role in the development of numerous chronic diseases [4].

Ginger’s antioxidant activity was assessed in vitro using the ferric-reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azinobis-(3-ethylbenzothiazole-6-sulfonic acid) (ABTS) techniques. The number of phenolic compounds in dried ginger was 5,2 times, 1,1 times, and 2,4 times greater than in fresh, stir-fried, and carbonized ginger, respectively. The antioxidant activity of various gingers tended to exhibit the following characteristics: dried ginger > stir-fried ginger > carbonized ginger > and fresh ginger [5].

Moreover, data from FRAP, oxygen radical absorbance capacity, and cellular antioxidant activity experiments revealed that a polyphenol-rich fraction of the dried ginger powder exhibited strong antioxidant activity [6].

Additionally, the kind of extraction solvent may influence the antioxidant activity of ginger. An ethanolic extract of ginger revealed a significant antioxidant capacity and ferric-reducing ability, whereas an aqueous extract exhibited potent free radical scavenging activity and chelating capacity [6]. In human chondrocyte cells, ginger extract exhibited antioxidant properties, with oxidative stress mediated by interleukin-1 [7]. It increased the production of antioxidant enzymes and decreased the production of reactive oxygen species and lipid peroxidation. Ginger extract lowered the level of malondialdehyde (MDA), which is connected to lipid peroxidation, in stressed rat heart homogenates [8].

Via the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, ginger and its bioactive components (such as 6-Shogaol) displayed antioxidant action [9]. Nrf2 is a redox-sensitive transcription factor that is mostly expressed in metabolic and detoxifying renal organs and protects against oxidative stress in cells. In addition, ginger phenylpropanoids improved Nrf2 activity and increased the levels of glutathione S-transferase P1 (GSTP1) and the Nrf2 antioxidant response element's downstream effector in foreskin fibroblast cells [10]. In a human mesenchymal stem cell model, the effects of ginger oleoresin on ionizing radiation-induced damage were examined. By translocating Nrf2 to the cell nucleus and stimulating the gene expression of HO-1 and NQO1 (nicotinamide adenine dinucleotide phosphate (NADPH) quinone dehydrogenase 1), oleoresin could reduce the level of reactive oxygen species (ROS). In rats with chlorpyrifos-induced oxidative damage, the 6-gingerol-rich fraction from ginger reduced H2O2 and MDA levels, enhanced antioxidant enzyme activity, and increased glutathione [11].

In addition, ginger extract treatment increased serum levels of antioxidants and testosterone and protected rat testes from cyclophosphamide-induced damage.

2.2 Ginger’s anti-inflammatory activity

Several studies have demonstrated that ginger and its active ingredients exhibit anti-inflammatory properties that may protect against inflammation-related disorders [12]. Phoshatidylinositol-3-kinase (PI3K), protein kinase B (Akt), and nuclear factor kappa light chain-enhancer of activated B cells (NF-B) were primarily responsible for the anti-inflammatory effects. In human intestinal cell models, 6-Shogaol also showed protective properties against tumor necrosis factor (TNF-)-induced intestinal barrier disruption. It also blocked the overexpression of Claudin-2 and the disassembly of Claudin-1 by inhibiting the PI3K/Akt and NF-B signaling pathways [13]. Moreover, a 6-gingerol-rich fraction reduced an increase in inflammatory markers such as myeloperoxidase, NO, and TNF- in the brain, ovaries, and uterus of chlorpyrifos-treated rats [11].

2.3 Renoprotective effect of ginger

Many studies revealed the effect of ginger on kidney dysfunction. From these studies, it was found ginger significantly protects the renal cells and reduces the severity of tubular damage caused by gentamicin. Ginger was effective as a prophylaxis agent, but it has no curative activity [14]. Interestingly the presence of polyphenols and flavonoids in the Z. officinale extract might be responsible for the antioxidant and nephroprotective activities [15]. Furthermore, it was found that injecting ginger (200 mg/kg) in rats induces a considerable decrease in the concentration of urea and creatinine in rat model, improved, restored, and recovered the affected kidney tissue after inducing kidney injury by azathioprine [16].

2.4 Ginger’s kidney protective effect

Numerous research has demonstrated ginger’s efficacy on renal impairment. Ginger greatly protects renal cells and lowers the severity of tubular damage produced by gentamicin, according to these investigations. Ginger was useful as a preventative, but it lacks curative properties [14]. Intriguingly, the antioxidant and nephroprotective properties of the Z. officinale extract may be due to the presence of polyphenols and flavonoids [15]. Moreover, it was discovered that 200 mg/kg of ginger generates a significant drop in the levels of urea and creatinine in rat models, and improves, restores, and recovers damaged kidney tissue induced by azathioprine [16].

2.5 Ginger’s anticancer effect

The method by which ginger acts as a cytotoxin against cancer cells is still a matter of debate among scientists. Ginger contains anti-inflammatory and anti-tumorigenic substances, including [6]-gingerol, [6]-shogaol, [6]-paradol, and zerumbone. Ginger and its bioactive compounds inhibit the progression of colorectal, gastric, ovarian, liver, skin, breast, and prostate cancers [17].

2.6 Ginger’s antiemetic effect

Ginger (and its compounds) exert its antiemetic effects peripherally, within the gastrointestinal system, by boosting gastric tone and motility via anticholinergic and antiserotonergic activities [18]. Additionally, it is said to enhance gastric emptying. This combination of roles explains ginger’s well-known capacity to alleviate symptoms of functional gastrointestinal diseases, such as dyspepsia, abdominal pain, and nausea, which are frequently associated with impaired gastric motility. Three recent studies have explored the effect of ginger on serotonin (5-hydroxytryptamine, 5-HT3, and 5-HT4) and cholinergic (M3) receptor activity; however, the precise mechanism of action of ginger concerning its antiemetic qualities is yet unknown [19].

2.7 Ginger’s effect on liver

In a mouse model, dried ginger (Zingiber officinale) suppresses inflammation, improves pathological alterations, and lowers INF and IL6 levels. It may potentially cause liver damage. NF-B activation is inhibited to reduce proinflammatory responses, TNF, IL-6, and other inflammatory cytokines levels [20].

2.8 Ginger’s effect on diabetes

The consumption of ginger has an impact on lipid profiles, insulin sensitivity, glycemic status, and other metabolic abnormalities in people with type 2 diabetes mellitus (T2DM). Reducing inflammatory substances, such as CRP, IL6, TNF, and others, improves them [21].

It reveals an antagonistic effect against serotonin receptors. Notably, it decreases intestine glucosidase and amylase activity, which reduces glucose absorption [22]. Ginger’s neuroprotective effects on the brains of streptozotocin-induced diabetic rats may also result from changes in astrocyte function. Damage response, decreasing the expression of acetylcholinesterase (AchE), and improving the construction of neurons [23].

2.9 Ginger effect on neurological degenerative diseases

Ginger’s active component, 6-Shogaol, reduces neuroinflammation and cognitive impairments in animal dementia models. Therefore, it plays a significant role in the amelioration of symptoms in Alzheimer’s and other neurological illness patients. It enhances memory in animal models of dementia by suppressing the activity of glial cells and by minimizing memory corruption [24].

In addition, ginger inhibits NF-B,16,17 iNOS, and cyclooxygenase2 activity (COX2) [25]. It protects C57BL/6 mice from inflammation caused by ultraviolet B [26]. Ginger has an inhibitory effect on melanogenesis in B16F10 melanoma cells and can therefore prevent the darkening of the skin (Figure 1) [27].

Figure 1.

Multiple health benefits of ginger [28].

3. Conclusion

Ginger’s pharmacological effects are generally known. Anti-oxidant and anti-inflammatory responses allow it to cure a wide variety of disorders. Ginger’s anticancer effect is well-documented, and its functional components, gingerols, shogaol, and paradols, are useful chemicals that can prevent various malignancies, metastasis, and prevention of cell-cycle development. Additionally, it enhances the condition of the kidneys and digestive tract.