Exploring The Antioxidant Properties Of Ginseng

Overview

Oxidation is a harmful process that occurs daily, induced mainly by external factors such as pollution, UV rays, and chemicals. Over time, the stress caused by these elements can damage tissues and organs and develop ailments. This is why it is important to rely on antioxidants that can counteract this by neutralising oxidative stress (whereby there is an imbalance between free radical levels and antioxidants). 

Antioxidants can be endogenous (internal cause or origin) or exogenous (external cause or origin). A plant-based diet represents a great option to introduce natural antioxidants into our diet to protect ourselves against oxidation. Ginseng, a root discovered in Asia and historically used in traditional medicine for thousands of years is a potential source of antioxidants that has already shown promising results in animals. In this article, we are going to investigate the antioxidant properties of ginseng and its related health benefits.

What is oxidative stress?

Oxidative stress is an imbalance between the quantity of free radicals and antioxidants that can contrast the activity of these reactive species. 

Free radicals are molecules without a full set of electrons. In order to complete their set they obtain the remaining electron from a different molecule, which makes them highly reactive and unstable. Free radicals can be generated by our body as a result of biochemical reactions, or in response to factors, such as pollution.

When the levels of free radicals are too high and the antioxidants cannot balance the oxidative activity, this leads to structural and functional tissue and cell damage. In the long run, this can cause several pathological (disease-related) conditions.

Antioxidants are substances of high importance for our health, as they can stop oxidative reactions from happening. They seek and block free radicals from reacting with molecules, such as proteins, lipids and DNA, that would otherwise be affected and damaged.¹ 

Plant-based foods such as fruit, vegetables, and roots are natural sources of antioxidants that can be integrated into the daily diet for a balanced and healthy lifestyle. Among roots, ginseng has been shown in animal studies to contain substances with a protective activity against oxidative stress.²

The substances in ginseng thought to provide the antioxidant properties are called ginsenosides. Ginsenosides can enhance homeostasis (a balanced physiological state in our body associated with a healthy status) as they can optimise and boost cellular functions.

What are antioxidants?

Oxidative stress occurs when free radicals interact with cells, DNA, and other molecules causing damage. On the other hand, antioxidants are compounds that counteract the effects of oxidative stress and provide protection against oxidation. Antioxidants achieve this by giving free radicals one of their electrons to complete their full set. In doing so, this neutralises the free radicals, turning them into harmless and unreactive elements.³

Antioxidants can be endogenous, if produced by our body, or exogenous if introduced into our body through food or supplements. 

Endogenous antioxidants can be enzymes that participate in biochemical reactions, such as superoxide dismutase, glutathione peroxidase, and glutathione reductase. 

Antioxidants from external sources (exogenous) can be classified into four main categories:

• Vitamins (e.g., vitamin C, vitamin A, vitamin E)
• Minerals (e.g., selenium, manganese, iron)
• Carotenoids 
• Polyphenols 

Balancing the levels of free radicals with antioxidants is fundamental for a healthy lifestyle, as the neutralisation of oxidative reactions can prevent cell and tissue damage. If left untreated, pathological conditions may develop in some cases. Antioxidants are now considered co-factors alongside conventional therapies to combat oxidative stress and enhance the treatments available to alleviate disease-related symptoms.^2,4

Ginseng: an overview

Ginseng (or Panax ginseng) is a slow-growing plant found mainly in Asia but also in North America. Ginseng plants are commonly found in Japan, Korea, China, and Siberia. There are eleven existing species of ginseng, but not all of them contain the characteristic active ingredient, ginsenoside.

The content of ginsenoside can be influenced by several factors, such as the:

• Age of the plant
• Fertility of the area where the plant is growing
• Light exposure
• How much the dry roots weigh

The healthy benefits associated with ginseng stems are primarily provided by ginsenosides. However, it is important to note, that ginseng will only contain 1-2% of ginsenosides once it has been harvested after at least 5 years.⁵ This quantity of ginsenoside is deemed necessary for a substantial pharmacological effect. Ginseng grown for less time has no pharmacological benefits and is usually used in cooking only.

Ginseng used as a medicinal plant can be differentiated into two types:⁵

• White ginseng: Produced when a 4-6-year-old root is peeled and then sun-dried
• Red ginseng: Root harvested for more than 6 years steamed at around 100°C for 2-3 hours. It is then dried until it contains a very low moisture content. The red type exhibits a higher pharmacological activity than the white ginseng

Ginsenosides is the main component of ginseng that offers the most significant medicinal value. However, ginseng has a rich chemical content. It also consists of:

• Proteins
• Carbohydrates
• Essential oils
• Amino acids
• Vitamins

What is ginseng indicated for?

Ginseng is a superfood that is good for our overall health. Discovered 5000 years ago, it has been and is still used in traditional Chinese medicine. Recently, ginseng has also gained popularity in Western countries. Here are a few of its health benefits:⁵

Counteracts oxidative stress

Ginseng can potentially slow down the ageing process. Its antioxidant properties help to protect organs and tissues from damage caused by oxidative stress.

Anti-diabetic action

Research in rats has suggested ginseng can reduce glucose in the circulatory system and increase insulin sensitivity.

Protects the cardiovascular system

Studies have shown ginseng may be effective in treating cardiovascular conditions such as atherosclerosis and coronary heart disease. Ginseng improves cardiac function by regulating blood glucose and lipid levels and reducing blood pressure and oxidative stress.

Anti-cancer properties

Ginseng promotes antimetastatic mechanisms and induces cell death in cancer cells. 

Improves neurological functions

Ginseng has been shown to improve attention and reaction time.

Antioxidant properties of ginseng

There are several types of ginseng that are classified under the two main medicinal categories of red and white. The antioxidant activity can vary among the types of ginseng. 

As mentioned before, ginsenosides are responsible for the antioxidant properties in ginseng and can be classified into two categories: protopanaxadiol and protopanaxatriol. However, other compounds found in ginseng also have the same properties. For instance, maltol, found in red ginseng only, and vitamins and minerals contained in the root can also boost antioxidant activity.⁶

In addition to acting as an antioxidant, ginsenosides can help regulate pathways that are positively involved with:⁵

• Inflammatory responses
• Tumour cell suppression
• Endothelial growth
• Apoptosis (cell death)

Chinese ginseng

• Only 0.05% of extract has been demonstrated to be able to stop free radicals from propagating oxidative reactions⁵
• 30 mg/mL of extract is able to suppress lipoprotein oxidation in the human body when in the presence of Cu²⁺⁵
• 30 mg/mL of extract can also suppress the DNA breakage by scavenging free radicals produced in biochemical reactions⁵

Even though ginsenosides were shown to have antioxidant properties, in vivo (inside the living body of a plant or animal) studies did not provide a clear result and therefore our knowledge of the same effects on humans is limited. For instance, a study conducted on smokers and healthy participants showed a more significant reduction of oxidation in lipids in healthy people, whereby it would be expected that a more significant effect would be seen in smokers to balance the oxidative stress from smoking.⁵

American ginseng 

The American ginseng (Panax quinquefolius) is grown in the north of the country, mainly in Canada, and it can boast similar properties to that of Asian ginseng. American ginseng has been shown to have a scavenging action against free radicals which contributes to its antioxidant activity.⁷

Korean red ginseng

Korean ginseng (KRG) has undergone several studies which analysed the antioxidant activities of animals, comparing healthy ones to those exposed to oxidative stress.

KRG tested on healthy animals 

• Mice were administered ginsenosides belonging to the protopanaxadiol group, and the results showed a reduction in oxygen-related free radicals and lipid alteration induced by oxidative stress⁸
• Another study also demonstrated a reduction of lipid peroxidation in the liver and brain of rats that took KRG for 3 days²
• Injection of ginsenosides in mice for 5 days was associated with a big drop in the number of free radicals²

KRG tested on animals exposed to oxidative stress

• When KRG was administered to rats induced with diabetes for about 2 weeks, it was observed that the rats had lower levels of blood glucose and lipid oxidation, but higher levels of enzymes that have antioxidant activity, increasing their endogenous protection against oxidative stress⁹
• Mice injected with a herbicide to mimic neurological dysfunction were administered KRG extract and consequently had an increase in enzymatic antioxidants and a decrease in lipids peroxidation²
• Giving 100mg/kg of extract from Korean ginseng to rats with cardiovascular conditions resulted in a higher concentration of antioxidant protection and reduction in oxidative stress¹⁰

Summary

Ginseng is celebrated for its potent antioxidant capabilities, thanks to the active ingredient ginsenoside. Widely used in traditional Asian medicine, ginseng has gained attention also in Western culture for its potential to counteract oxidative stress and related medical conditions.

Animal studies suggest that ginseng consumption may prevent and mitigate conditions and related symptoms by reducing the action of free radicals and enhancing endogenous antioxidant enzymatic response. However, while promising, further research is essential to fully demonstrate ginseng's antioxidant effects on human health.