Hovenia dulcis (H. dulcis, more commonly known as the Japanese raisin tree) is a fruit tree of the Rhamnaceae family that has long been valued by practitioners of Eastern medicine.
The ripe fruits are edible raw or cooked and have a pear-like flavor. When dried, they look just like raisins. The fruit is sweet and can be used in candies or to make a honey substitute. It can also be made into juice or fermented to make wine and vinegar.
H. dulcis is native to Japan, China, North Korea, and South Korea and is also found growing naturally in the forests of Thailand and North Vietnam. Today it’s cultivated worldwide.
How is it used?
H. dulcis can be eaten fresh, dried, or as a tea. You can find it in a powder or in capsules. The active ingredient can also be found as an extract.
There are currently no dosing guidelines available because there have been few clinical trials done with human subjects.
Traditional uses include:
- treating hangovers
- managing liver diseases
- fighting parasitic infections
- stabilizing blood sugar levels
H. dulcis has long been used in Korean and Chinese traditional medicine to relieve intoxication after excessive drinking. A detailed study, published in 1999, found that it lowers the blood alcohol level of mice. This suggests that H. dulcis could help people metabolize alcohol more quickly and efficiently, which could potentially relieve both drunkenness and hangovers.
Another study, published in 1997 in a Japanese medical journal, found that H. dulcis prevents alcohol-induced muscle relaxation in rats. This suggests that it could be used to combat the lack of coordination commonly associated with drunkenness.
There are no studies of these effects of H. dulcis on humans, but eating the fruit seems to be safe.
Studies suggest it prevents alcohol-related liver damage
H. dulcis and other herbal medicines have been used for hundreds of years in Chinese medicine to treat diseases of the liver. Research provides scientific proof that it really works, in mice:
- Research in 2012 found that juice and fermented vinegar made from H. dulcis significantly reduced alcohol-related liver damage in mice. This suggests that adding H. dulcis to your diet could help protect your liver.
- A 2010 study also found that a dose of H. dulcis could protect mice from alcohol-related liver damage. Researchers also noted an increase in antioxidant enzymes assisting in alcohol metabolism.
Taking herbs to protect the liver from toxic substances isn’t an invitation to drink more alcohol; if you or your health care provider have concerns about your liver health, avoid alcohol.
Treats hepatitis C
A 2007 study published in the American Journal of Chinese Medicine found that H. dulcis can prevent liver damage from hepatitis C. The study looked at the effects of H. dulcis in mice infected with hepatitis C and found reduced levels of fibrosis and necrosis of the liver.
However, with the new hepatitis C drugs, you and your doctor may want to consider other more evidence-based and possibly safer ways to treat hepatitis C.
Many people have hangovers after they drink to the point of intoxication. The exact cause of hangovers is unknown, although there are most likely several contributing factors.
Typically, hangovers begin when the alcohol concentration in your blood begins to fall. Your hangover peaks when your blood alcohol level reaches zero. For many people, this hangover peak happens at right about the time they wake up in the morning.
Two enzymes — alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) — help your body break down alcohol. A 1999 study suggests that H. dulcis increases the activity of these enzymes, which means it could help you metabolize alcohol faster. Theoretically, the sooner your blood alcohol level reaches zero, the more quickly your hangover can pass.
A 2017 study found that people who ingested an extract of H. dulcis experienced less headache, dizziness, nausea, and weakness in their hangover than did others who did not take the extract.
However, there are many factors that contribute to a hangover that wouldn’t be affected by H. dulcis. This includes low blood sugar, dehydration, and gastrointestinal upset.
Drink fluids, rest, and consider having a couple of glasses of water between drinks next time.
Treats alcohol withdrawal syndrome
Some people believe that hangovers are partially caused by a sort of mini-withdrawal from alcohol. For people with alcoholism, however, alcohol withdrawal syndrome is a serious, even life-threatening condition. There are currently no prescription medications without significant side effects that can be used to treat alcohol withdrawal.
Research published in 2012 suggests that dihydromyricetin, a derivative of H. dulcis, has the potential to treat alcohol withdrawal syndrome. Research conducted with rats found a reduction in withdrawal symptoms including anxiety, tolerance, and seizures. Rats taking dihydromyricetin were also less likely to voluntarily consume alcohol, suggesting that it may also reduce alcohol cravings.
Risks and side
There appear to be few, if any, risks associated with H. dulcis.
A 2017 study in Pharmacognosy Magazine evaluated the possibility that H. dulcis might interact with other drugs. The researchers found no potential for drug interactions with H. dulcis, which means that it should be safe for people taking prescription and over-the-counter medications. However, these tests were done using lab equipment, not by testing human or animal subjects.
A 2010 study of H. dulcis in mice found that over the course of a 14-day observation, no mice showed symptoms of toxic side effects from their dose of H. dulcis.
Humans have been using this fruit tree for medicinal purposes for thousands of years, so it’s unlikely that you’ll have a negative reaction. However, the FDA doesn’t monitor supplements or herbs, so avoid processed supplements or herbal remedies made from this whole food. Instead, try eating the fruit.
The research suggests that H. dulcis could lower your blood alcohol level and protect your liver from damage and disease. If you’re curious about it, discuss H. dulcis with your doctor.