Research and Development Story: Inspired by the efficacy of traditional medicinal plants in Japan A plant extract for personal care products, “Ai-LurosTM”

Ai’, an indigo plant, has been used in Japan and other parts of the world since ancient times as a dye with a distinctive deep blue color. It is also known as a medicinal plant with detoxifying, antifebrile, and anti-inflammatory effects.
Ai-Luros™ is a personal care ingredient with skin brightening properties extracted from the leaves and stems of Japanese indigo plants (Polygonum tinctorium), which was launched in 2005. This product emerged from our rich history of research, spanning from work in glycoscience and saccharide, which started at the foundation of the company, to the subsequent exploration of pharmaceutical research as another key area of focus. Research on Ai-Luros™ began in the pharmaceuticals field and has since evolved to encompass applications in the personal care industry. Here is the story of our development, made possible through the accumulation of research expertise across various fields.

Efficacy of indigo plants discovered by the ancients

Japanese indigo plant (Polygonum tinctorium); flowers (left) and leaves (right)
The history of indigo plants dates back to around 2000 B.C. when indigo dyeing was already prevalent in ancient Egypt. The utilization of indigo plants for medicinal purposes can be traced back to their earliest documented use in the ancient Chinese medical text, the Shennong Bencaojing (Divine Farmer's Classic of Materia Medica), written approximately 2,000 years ago. Even before the development of science, our ancestors must have known the medicinal benefits of indigo plants and utilized them in their daily lives.

In fact, ‘indigo’ does not refer to a specific plant called indigo, but rather to all plants (collectively referred to as ‘indigo-containing plants’), including indican, the source of blue dye.

Kanso Iwaki, who was a leader of the research members of Japanese indigo, says,
“The Japanese indigo is the indigo plant of the Polygonaceae, but there are dozens of species of indigo-containing plants around the world. For example, the Indian indigo (Indigofera tinctoria) of the Fabaceae and the European woad (Isatis tinctoria) of the Brassicaceae, are all used as dyes and for medicinal purposes. It is very interesting to know that our ancestors discovered the effectiveness of indigo-containing plants in their own regions and used them in their daily lives."

Medicinal effects of Japanese indigo in folklore revealed by the modern technology

We started research on Japanese indigo in 1995.
During that time, the pharmaceutical research team was studying various natural substances, including propolis, aspiring to support people’s health by harnessing the power of nature. Japanese indigo was one of the research subjects, that has some folklores such as “Samurai (Japanese warriors) who wear indigo-dyed clothes heal quickly without festering wounds” and “Indigo-dyed clothes keep insects and snakes away.”

Although the medicinal properties of Japanese indigo have been acknowledged for some time, limited numbers of scientific reports prompted them to initiate their own research endeavors, beginning with fundamental exploration. They examined the effects of indigo extracts by boiling indigo leaves in water and extracting their components using organic solvents, and confirmed various biological activities such as antioxidant, anti-inflammatory, antibacterial, and antiviral activities.
Among these, antioxidant and anti-inflammatory effects were the key functions linked to the skin care benefits of Ai-Luros™, which will be covered later in this story.

Which components in the indigo extract are specifically responsible for these effects? To answer this question, research was conducted to isolate and identify the components in the extract that cause the respective activities.

“There are numerous substances in the extract and extracting only the active target is a big challenge", Iwaki says. Without knowing the properties of the substances to be extracted, the team had to go through a time-consuming process of purification over and over again, using adsorption and filtration techniques. Despite the numerous processes involved, research progressed with a commitment to finding novel active substances for the development of life-altering pharmaceutical ingredients.

After about five years of research, a substance called Tryptanthrin was revealed to be the prominent component of the medicinal benefits of Japanese indigo. However, Tryptanthrin had already been reported and known to be found particularly in indigo-containing plants. Although they decided not to introduce it as a new active pharmaceutical ingredient, they could not give up the dream of harnessing the properties and insights of Tryptanthrin.

Pharmaceutical research leads to success in personal care ingredients

Research team for personal care in the 1990’s

A few years after Tryptanthrin was identified, a research team specialized for personal care ingredients was set up following the launch of our flagship product ‘AA2G™’, a stabilized Vitamin C derivative.

The team was searching for a promising substance that can be utilized for personal care applications among the internal findings from various research fields. They hypothesized that the antioxidant and anti-inflammatory effects of indigo extract could be beneficial in personal care products, thus started to develop it as a new ingredient.

Manami Sawatani, who was a member of the team, recalls those days.
“We were passionate about developing a novel ingredient for cosmetics, which was a new field to most of us. Although we were a team of only 10 people, all of us had great expectations for Japanese indigo and worked diligently on the project, each bringing our own expertise to the table."

Launch of Ai-Luros™ through collaboration with the pharmaceutical team

Manami Sawatani (left) and Kanso Iwaki (right)

In developing indigo as a material for cosmetics, a number of experiments were conducted to explore the functions of indigo. In addition to confirming previously discovered antioxidant and anti-inflammatory properties, a range of aesthetic benefits - including skin brightening, moisturizing, and promotion of collagen production—were revealed.

However, it was not a smooth path to commercialization. The first challenge they encountered was that plant extracts using raw materials derived from natural products tend to precipitate easily. They collaborated with the team in charge of purification of Tryptanthrin in indigo research and improved the manufacturing process to minimize precipitation as much as possible. The second challenge was scaling production, because knowledge of manufacturing technology and specialized expertise are necessary to take the ingredient from the research phase to the industrial level. However, there were no such expertise in the team at the time, therefore, they worked with the pharmaceutical research team to scale up mass production. Finally, they were successfully able to commercialize the product, Ai-Luros™, mainly composed of an extract of Japanese indigo (Polygonum tinctorium) in 2005.

The name ‘Ai-Luros™’ reflects the thoughts of the cosmetic research team. They were initially inspired by the cat's eye effect (a phenomenon in which white light shines in a line like a cat's eye) that occurs when gemstones are illuminated by light. The name ‘Ai-Luros™’ was created by combining the Greek word ‘ailouros’, meaning ‘cat’, and the Japanese word ‘ai’ meaning ‘indigo’, with the wish that people who use Ai-Luros™ would glow just as brightly as the light.

Ai-Luros™ is currently used in a wide range of personal care products, including lotions, cleansers, brightening essences, and oral care products. As cosmetic ingredients are applied directly to the skin, what we selected as the raw material was indigo leaves grown under highly controlled conditions* in specific regions of Japan.

Sawatani proudly states, “These days, there is a greater demand for environmentally friendly, plant-derived raw materials. We have been ahead of the times for over 20 years, researching and commercializing indigo, a naturally occurring ingredient."
*Cultivated without the use of pesticides and has been awarded the Certificate of Excellence under the “Tokushima An2 Agricultural Products Certification Scheme”. It is an agricultural product certification system in which Tokushima Prefecture incorporates the concept of GAP (Good Agricultural Practices: a set of management activities of agricultural production process) and Farm Management Methods, considering 'food safety', 'environmental conservation', and 'worker safety' to ensure sustainability in agriculture.

Accomplishment consolidated by long-standing research

Above: Fujisaki Institute for pharmaceutical and saccharide research established in 1981.Below: Corridors of the institute where autographs and messages from renowned researchers are showcased (as of Jan. 2024.)

The development of Ai-Luros™ was by no means an overnight process. Through years of basic research and collaboration with pharmaceutical research teams, they overcame various challenges to bring this product to market.
We have been devoted many years not only to research on saccharides as represented by trehalose, but also to pharmaceutical research, and possess a high level of technological expertise. Known as one of the leading research companies in Japan, we attract enthusiastic researchers from both Japan and abroad. This positive and active research environment has led to the successful development of a variety of materials, beyond saccharides.

Iwaki recalls those days.
“The indigo used in the experiment was grown without agricultural chemicals by a contract farmer in Yasugi City, Shimane Prefecture. We left it to the farmer until the indigo was grown, but our employees went to the site and did the reaping themselves. We were told that the best quality indigo is harvested before sunrise, so we gathered at the office late at night with sickles and other tools and drove. It was tough, but I have fond memories of it.”

“In the world of basic research, the hurdles for research results to be commercialized are very high. As a person involved in basic research, I was delighted to see Ai-Luros™ was launched as a new material for personal care products, emerged from our pharmaceutical research. Although it did not reach commercialization as a pharmaceutical material, our efforts were never in vain, and the baton was passed on to other research teams, leading to the successful commercialization of the product.”

Our commitment to cross-disciplinary collaboration among multiple research teams remains unchanged today. We will continue to incorporate our research insights and produce new materials that are useful and bring greater values to people’s lives.