Are the plant extracts in cosmetics all "IQ taxes"?

Many people think that plant extracts in cosmetics are just conceptual additions and have no effect, but many big brands will add some patented plant active ingredients. Are these ingredients useful? Are they all "IQ taxes"? Let's talk about this issue with you today.

01. Are plant ingredients a waste of money?

As a treasure trove of natural compounds, plants have now become the focus of many research and development institutions, and isolating and purifying relevant components from plants and conducting scientific verification is also a basic scientific research model. Many classic ingredients that we are familiar with today, such as vitamin C and salicylic acid, were originally derived from plants, so it is definitely incorrect to say that plant ingredients are IQ taxes.

In fact, there are many similar ingredients. For example, the "new whitening ingredient" that has appeared in the past two years - glycyrrhizin is also a typical example. I believe that friends who are interested in the whitening field have heard of this ingredient. Glycyrrhizin is a flavonoid extracted from the plant licorice, and studies have confirmed that glycyrrhizin is of great significance in the field of whitening. It can significantly inhibit the activity of tyrosinase, which is the rate-limiting enzyme for the production of melanin. In this way, glycyrrhizin ultimately inhibits the production of melanin, thereby achieving a whitening effect.

Separating and purifying relevant components from plants and conducting scientific verification is also a basic scientific research model. We will use the research on glabridin to introduce how to find and obtain active ingredients from plants. However, before we start, we must first talk about the demand: whitening.

02. Why do Chinese people love whitening more?

Our cultural tradition seems to have always favored fair skin, for example, Song Yu of the Chu State mentioned "eyebrows like emerald feathers, skin like white snow" in "Dengtu Zi's Lustful Fu", "hands like tender catkins, skin like solidified fat" in "Shuo Ren" from the pre-Qin period, or Bai Juyi's "skin is as white as ice and snow, clothes are as bright as clouds", and there are also a series of idioms, such as "flawless white jade", "powdered and jade-carved", etc.

Even, not only the Chinese, for example, in Japanese literature, the Heian period poet Seishonagon once wrote: "雪の下にぬれせしまろがねのゆふすめし时の心ぞしられる" also describes white skin.

Why do people in China and even many parts of East Asia prefer fair skin? The answer may be hidden deep inside our skin: Chinese people are more prone to pigmentation.

Melanin is an important component of the human body's response to light. When ultraviolet rays in the sun reach the skin, they stimulate the skin receptors and transmit signals to melanocytes. Melanocytes then produce melanin and secrete it into other cells, giving the skin a better ability to resist light. [1]

From this we can see that melanin is actually a protective ingredient itself, but when this protective ingredient affects our appearance, it tends to make the skin darker, which affects the appearance.

In terms of melanin deposition, our skin has higher melanin levels than the European population, both in photoprotected and photoexposed areas [2].

More melanin gives us superior natural light protection, but because of this, we Chinese are more prone to melanin deposition and dull skin, which also leads to our stronger demand for whitening.

Traditional skin care strategies often use strong drugs to whiten the skin, such as nicotinamide, which is an amide compound of nicotinic acid and can reduce melanin in the skin and make the skin look whiter by transporting melanin.

However, this also determines that niacinamide is essentially a transfer strategy rather than an eradication strategy for whitening. Transferring melanin cannot eradicate melanin. Once you stop using it, melanin will immediately accumulate, resulting in the problem of easy re-darkening that many people encounter.

Not only that, niacinamide itself is highly irritating and its effective concentration is also high, which can easily irritate the skin. This is even more obvious for us Chinese people because our skin generally has a thin stratum corneum, is more sensitive, and is easily affected by external stimuli.

In addition, the study also found that substances like niacin stay in the skin of Asians for a shorter time, so we need to use larger amounts, which further aggravates skin irritation.

Because of this, when strong whitening ingredients such as niacinamide are used in large quantities, it is also easy to cause other health problems on the skin, such as skin problems such as allergies and inflammation, and these skin problems often lead to pigmentation. In other words, for Chinese people, niacinamide, an irritating whitening ingredient, does have a little whitening effect, but its strong irritation will cause more pigmentation, resulting in no whitening effect.

Because of this, in the face of the special whitening needs of Chinese people, how to find a more efficient and gentle whitening ingredient has become a necessity. The discovery of a better whitening ingredient from plants - glabridin has also become a classic case. Let's talk about how the ingredient glabridin was discovered, which will also help our future research and development progress.

03. Licorice: A gift from licorice

In order to find a more gentle and effective whitening ingredient suitable for Chinese people, researchers turned to natural organic treasures - plants, which are also an important source of many classic active ingredients. They found a substance in ancient books that is believed to be able to whiten skin: licorice.

The book "Medical Introduction" in the Ming Dynasty records that "Sanbai Soup" made from licorice and other medicinal materials has the effect of nourishing the skin and whitening the skin. Of course, ancient medical books are also uneven, and the contents in them may not all be correct records and effects. These records are mainly used to screen and narrow the selection range to reduce the randomness of the research as much as possible. Therefore, its whitening effect must be tested first.

Therefore, the researchers directly extracted the Glycyrrhiza glabra from the Glycyrrhiza genus, and then tested the extract's ability to inhibit tyrosinase activity, which can directly reflect its whitening effect. The results showed that the Glycyrrhiza glabra extract did have the ability to inhibit tyrosinase activity. In vitro experiments showed that its inhibition rate for tyrosinase was close to 70%, and inhibiting tyrosinase is an important way to whiten skin [1]. This means that Glycyrrhiza glabra does have a whitening effect as recorded in ancient books.

Of course, this step is not enough. Modern technology has entered the molecular component stage. We need to determine the active ingredients in Glycyrrhiza glabra so that we can better apply it.

The next step was to analyze the various components in Glycyrrhiza glabra and conduct corresponding experiments one by one to find the real active ingredients [4].

(HPLC chart of chemical components in licorice)

After repeated research and testing, the researchers finally found the key ingredient in licorice: glycyrrhizin.

Glabridin is a unique flavonoid component in Glycyrrhiza glabra. Studies have found that it has a strong ability to relieve melanin.

The researchers first tested the activity of glabridin on mushroom tyrosinase, which is also a classic strategy for detecting tyrosinase activity. The results showed that different concentrations of glabridin (0.5, 2.5, 5.0, 15.0 and 25.0 μmol/L) had a significant inhibitory effect on tyrosinase [5].

The activity of tyrosinase is inhibited, so the ability of melanocytes to produce melanin is reduced accordingly, so the skin becomes whiter.

The researchers also found the binding site of glabridin (GLU) and tyrosinase (TYR), which further revealed the molecular mechanism of glabridin's whitening effect.

After years of research, scientists have revealed the whitening mechanism of glabridin. That is, glabridin extracted from Glycyrrhiza glabra can bind to a-MSH on skin cells. The signal then contacts the MC1R on the cell membrane and further passes through AC→c-AMP→PKA→CREB→MITF, etc., ultimately acting on tyrosinase and its receptors, thereby affecting the production of melanin, and finally inhibiting melanin to achieve a skin whitening effect.

04. How does glabridin compare to the traditional whitening ingredient niacinamide?

Then you must be curious, how does glabridin compare to the traditional whitening ingredient niacinamide?

The researchers compared the effects of different concentrations of glycyrrhizin and nicotinamide on tyrosinase activity. The results are shown in the table below [6].

We can clearly see that under the same concentration, the inhibitory efficiency of glabridin on tyrosinase is significantly higher than that of niacinamide. For example, at the same concentration of 3.125 mg/L, the inhibition rate of glabridin on tyrosinase is 140 times that of niacinamide (43.52±1.62 vs. 0.31±2.91). This inhibition efficiency is as high as hundreds of times, which also means that to achieve the same whitening effect, the content of glabridin used should be much less than that of niacinamide, which naturally reduces the irritation to the skin.

And we can see that glabridin can be effective at very low concentrations (3.125mg/L), but niacinamide is different. It is almost ineffective (0.31±2.91) at low concentrations (3.125mg/L), and even at a high concentration of 50mg/L, its inhibition rate on tyrosinase is not as good as that of low-concentration glabridin. This means that in order for niacinamide to achieve a whitening effect, a very high concentration must be used, and the production process of niacinamide itself has niacin residues. High concentration means high irritation, which is not good for the skin. Glabridin is much better. It is effective at low concentrations and has the effect of soothing, repairing and fading redness, so it is safer and gentler.

Through the above series of research experiments, we can clearly see that glabridin is a more powerful whitening ingredient, and its whitening effect is nearly 100 times stronger than that of traditional niacinamide. In terms of safety, glabridin can be effective at a lower dose, which effectively reduces irritation to the skin, and it also has its own soothing and redness-removing properties, while niacinamide needs to be effective at a higher concentration. High concentrations of niacinamide themselves are highly irritating, reflecting the milder characteristics of glabridin. This means that glabridin is a better whitening ingredient that is more suitable for Chinese people.

From the discovery process of glabridin, we can see a very clear and definite idea of ​​obtaining excellent skin care ingredients from plants, which is: discover needs → find potential plants → isolate plant ingredients → scientifically verify effective ingredients.

The discovery path of glycyrrhizin follows this basic process, and ultimately a powerful yet gentle whitening ingredient more suitable for Chinese people was found, which also provides a good reference for other explorations.

1. Obaid, Rami J., Ehsan Ullah Mughal, Nafeesa Naeem, Amina Sadiq, Reem I. Alsantali, Rabab S. Jassas, Ziad Moussa, and Saleh A. Ahmed. "Natural and synthetic flavonoid derivatives as new potential tyrosinase inhibitors: A systematic review." RSC advances 11, no. 36 (2021): 22159-22198.

2. Alaluf, Simon, Derek Atkins, Karen Barrett, Margaret Blount, Nik Carter, and Alan Heath. "Ethnic differences in epidermal melanin content and composition between photoexposed and photoprotected areas." Proceedings of the 2002 China Cosmetics Symposium (2002).

3. Han Lijun, Huang Lili, Sui Minghui. Preparation of whitening lotion containing Glycyrrhiza glabra extract[J]. Fermentation Science and Technology Newsletter, 2019, 48(02): 106-110. DOI: 10.16774/j.cnki.issn.1674-2214.2019.02.008.

4. Simmler, Charlotte, Guido F. Pauli, and Shao-Nong Chen. "Phytochemistry and biological properties of glabridin." Fitoterapia 90 (2013): 160-184.

5. Pan, Chunxing, Xiaoying Liu, Yating Zheng, Zejun Zhang, Yongliang Li, Biao Che, Guangrong Liu et al. "The mechanisms of melanogenesis inhibition by glabridin: molecular docking, PKA/MITF and MAPK/MITF pathways." Food Science and Human Wellness 12, no. 1 (2023): 212-222.

6. Wang Ruixue, Zhao Zhen, Zhong Yan, Li Xiaodi, and Wang Zhiyong. "Study on the synergistic effect of several commonly used whitening agents." Journal of Surfactant Chemical Industry 44, no. 10 (2019): 572-576.