Every year from September to November is water caltrop season in Taiwan, China. In the water caltrop fields covered with leaves, if you turn the leaves over, you can see the water caltrops popping out between the stems. In fact, the cultivation history of water caltrop is recorded as having lasted more than 2,000 years, and it is also a quite representative product of Guantian, Tainan, Taiwan, China. Now, through the efforts of a research team at Taipei Medical University, research on extracts and purified substances from water caltrop shells will turn discarded water caltrop shells into black treasure, bringing greater value to health care applications.

Whenever the crisp autumn wind arrives, the peak production season of water caltrop begins. Guantian, Tainan has long ranked first nationwide in water caltrop cultivation output, and every autumn it presents a lively pastoral scene of busy farming, making the scenery of "water caltrop fragrance and boat shadows" one of the New Nanying Eight Scenes.

With technological progress, farmers have used advanced freezing technology to preserve the fresh sweetness of in-season water caltrops. No matter when you come to Guantian, you can taste authentic and delicious water caltrop health meals. Although water caltrops are delicious, peeling off the shells produces nearly 3,700 metric tons of discarded water caltrop shells each year. To solve the problem of where to put water caltrop shells, Guantian currently reuses water caltrop shell waste, turning it into water caltrop shell biochar, which is used to improve soil and purify farmland water quality. Because the production process of water caltrop biochar can also produce value-added products such as bamboo vinegar or wood vinegar, it can be used for agricultural purposes such as pest and disease control, soil improvement and composting. It can even extract polyphenolic compounds and isoflavones from water caltrop shells to produce beauty and skincare products.... This allows water caltrops to realize value from the outside in.

The tsunami of advanced aging arrives   Water caltrop shell extracts reveal a dawn of anti-aging hope

Taiwan, China entered an aged society in 2018. According to a survey by the National Development Council, negative population growth is expected to occur in the next 3 to 10 years (the total population growth rate turning negative in 2021-2028). Furthermore, according to estimates by the Taiwan Alzheimer's Disease Association, in December 2017 the population with dementia in Taiwan, China exceeded 270,000, and about half of older adults aged 85 and above have broad-sense dementia.

The longer people live, the more inevitably they will be accompanied by such degenerative cognitive and behavioral diseases that affect quality of life, such as the common Alzheimer's disease and Parkinson's disease. Apart from age and familial genetic causes, "in order to improve the problem of degenerative diseases brought by advanced age, we tried to find a solution from water caltrop shell extracts," said Hou Wen-Chi, professor at the Graduate Institute of Pharmacognosy at Taipei Medical University.

The research team formed by Professor Hou Wen-Chi, Professor Wang Jing-Chiung of Taipei Medical University and Professor Chen Li-Keng of National Chiayi University has participated since January last year (2017) in the "Key Technology Enhancement Program for Key Industries of the Council of Agriculture's Bioeconomy." The team used discarded water caltrop shells from Guantian as raw material, obtained extracts and other fractions through different extraction methods, and then carried out activity screening with enzymes and in vitro cell tests. "As is well known, free radicals are the killers that cause aging. For various chronic diseases such as cancer, heart disease, diabetes, stroke, arthritis, senile dementia, immune system disorders... and so on, about nearly 100 diseases are associated with free radicals damaging normal human cells. As for acetylcholinesterase inhibitors, they are currently clinical drugs for Alzheimer's disease, and the results of in vitro tests show that each extract of water caltrop shells has concentration-related acetylcholinesterase inhibitory activity and ORAC antioxidant activity for free radical scavenging. In addition, each extract has strong activity in inhibiting the glycation reaction in the galactose/bovine serum albumin model. In other words, based on the in vitro test results of water caltrop shell extracts, we can continue to conduct in vivo animal model evaluations for improving degenerative cognitive and behavioral diseases."

The team also conducted animal tests on water caltrop shell extracts. Through the experimental results, it was found that using discarded water caltrop shells as raw material, mice with scopolamine-induced Alzheimer's-like disease were given feeding tests, and the Morris water maze or passive avoidance test was used to evaluate the efficacy in improving learning and memory. "The results show that, compared with the non-intervention induced group, the intervention group significantly prolonged the time spent in the bright room by scopolamine-induced Alzheimer's-like mice, or significantly increased the time spent in the platform quadrant and the number of entries and exits to the platform quadrant by scopolamine-induced Alzheimer's-like mice. In other words, water caltrop shell extracts can effectively improve learning and memory efficacy in scopolamine-induced Alzheimer's-like mice," Hou Wen-Chi explained.

Inviting enterprises to participate  Through technology transfer, making water caltrop a health care black gold

Regarding the research results, Hou Wen-Chi said that the Compendium of Materia Medica mentions that water caltrop shell can be used to treat diarrhea and dysentery, while the Supplement to the Compendium of Materia Medica mentions that water caltrop shell burned to ash (or subjected to charring while preserving its nature) mixed with sesame oil or sesame oil can be applied externally to treat swelling and toxins or yellow water sores on the head and face. This shows that water caltrop shells have effects for both internal and external use. The Chinese Materia Medica published in the mainland region explains that water caltrop shell can be decocted in soup for internal use (dosage 15-30 grams, with a large dose up to 60 grams). However, our country's current regulations do not clearly specify whether water caltrop shells are an edible raw material. If the raw material standards and safety of water caltrop shells can be further confirmed in the future, it will be possible to enhance the large-scale reuse of water caltrop by-products and the value-added nature of products, thereby increasing the income of regional farmers. "Water caltrop shell powder can also be used in food additives, such as water caltrop shell powder egg rolls, water caltrop shell powder cakes, water caltrop shell powder added to egg yolk pastries, and so on. We very much welcome interested enterprises to participate together. Whether in the field of food or health foods, in the future technology transfer can be used to further develop health foods that improve degenerative cognitive and behavioral diseases, doing our part to prevent and address an aged society!"

In the past, when farmers harvested water caltrops and removed the kernels, they either discarded the water caltrop shells at the field edge and burned them in the open, or entrusted garbage trucks to clear and transport them. By borrowing the concept of the circular economy to reuse water caltrop shells, not only can the impression of water caltrop shells as agricultural waste be further overturned, but water caltrop can also become farmland black gold with development potential.

Related information

To further understand the details of this project's research and development results, please contact Mr. He of the Agricultural Technology Research Institute, telephone: 03-5185049, email: [email protected]