Hovenia dulcis & Dihydromyricetin (DHM)

A Botanical and Biochemical Perspective on Liver Protection and Alcohol Metabolism

Dr. James Odell, ND, OMD, L.Ac.

An Ancient East Asian Tree with Modern Clinical Relevance

Hovenia dulcis (commonly known as the Japanese raisin tree; alternatively referred to as the Japanese cherry tree or Chinese raisin tree) belongs to a small genus within the Rhamnaceae family and is indigenous to East Asia. Its natural distribution ranges from Japan, Korea, and eastern China to the Himalayas, at altitudes of up to 2,000 m. It grows preferentially in sunny, moist, sandy, or loamy soils.

It is a glabrous tree with lenticulate branches and grows up to 10 meters in height. Hovenia dulcis is cultivated in plantations in China for its medicinal use. It has become invasive in South American rainforests (notably Brazil) as well as in Tanzania. It has also been introduced as an ornamental tree in several countries, including the United States, Australia, New Zealand, and parts of Central Africa.

Traditional Use and Historical Recognition in Liver Health

The tree is renowned for its numerous health benefits when consumed as a tea or extract, and it also produces edible fruit. It has been used for centuries in Traditional Chinese Medicine as a remedy for alcohol poisoning and hangover. Hovenia dulcis is listed among the premier liver herbs and anti-hangover remedies in the Chinese pharmacopoeia, including the Tang Materia Medica. It is effective for various liver diseases and alcohol intoxication, partly due to its active compound, dihydromyricetin (DHM).

Dihydromyricetin (DHM): A Bioactive Flavonoid from Hovenia dulcis

Dihydromyricetin (DHM), also known as ampelopsin, is a natural flavonoid compound found in high concentrations in Hovenia dulcis and other plants. This flavonoid may help the body metabolize alcohol (ethanol, EtOH) more efficiently by enhancing the activity of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH).

Ethanol catabolism is mediated by ADH and ALDH: ADH converts ethanol into acetaldehyde, which is then oxidized by ALDH into the nontoxic metabolite acetyl-CoA. Thus, potential mechanisms of Hovenia dulcis extracts involve direct or indirect regulation of the expression or activity of these enzymes. However, the full spectrum of active constituents and their exact mechanisms of action has not yet been completely elucidated.

Systemic Effects Beyond Alcohol Metabolism

Like other flavonoids, dihydromyricetin exhibits a range of biological effects. DHM demonstrates anti-inflammatory, cardioprotective, and dermaprotective properties. By influencing oxidized cholesterol metabolism, DHM may inhibit the development of atherosclerosis. Its positive effects on insulin resistance appear to be related to its ability to lower blood glucose levels, and dihydromyricetin has been shown to suppress diabetic cardiomyopathy.

DHM may act as a scavenger of reactive oxygen species (ROS), protecting tissues from oxidative stress, or alternatively may potentiate ROS generation selectively in cancer cells without affecting normal cells. Most notably, DHM has demonstrated significant hepatoprotective effects. Its beneficial influence on alcohol-induced and other liver diseases has been demonstrated in studies of acute liver injury.

Biochemical and Neuroregulatory Mechanisms of Action

The impact of DHM on ethanol consumption has been partially explained by its competitive inhibition at benzodiazepine binding sites on GABAA_AA​ receptors. Experimental studies have shown that ethanol intoxication in rats was reduced following DHM administration, and symptoms of alcohol withdrawal syndrome were mitigated.

The hepatoprotective effects of DHM are likely linked to its ability to protect liver cells from oxidative stress and inflammatory responses. Studies using human umbilical vein endothelial cells and the human hepatocellular carcinoma cell line HepG2 have demonstrated that DHM influences intracellular regulatory mechanisms that reduce ROS levels.

Experimental Models, Enzyme Modulation, and Remaining Questions

Available data suggest that DHM, when used as a dietary supplement, may reduce oxidative damage to hepatocytes. However, the precise mechanisms underlying its hepatoprotective effects against alcohol remain incompletely understood. Many studies rely on experimental models such as HepG2 cells, which lack fully functional enzymes for oxidative ethanol metabolism.

Additional research using hepatoblastoma cells has shown that DHM supplementation significantly increases both the activity and expression of alcohol dehydrogenase and aldehyde dehydrogenase. Notably, CYP2E1—an enzyme involved in ethanol metabolism, particularly during chronic alcohol exposure—was significantly downregulated by DHM in mouse models.

Although DHM’s health-promoting effects appear largely related to reductions in oxidative stress, its exact role in ethanol metabolism remains unclear. While several hypotheses have been proposed, a definitive mechanism has yet to be established.

Modern Use: Teas, Extracts, and Supplemental Formulations

DHM is commercially available as an extract and is often combined with other liver-supportive herbal extracts (such as milk thistle) and compounds (such as N-acetylcysteine [NAC]). These formulations are marketed for liver support and hangover relief. Typical daily doses of DHM range from 300 to 1,000 mg.

Limited short-term human studies have reported no significant adverse effects or evidence of toxicity to date. Some sources report mild side effects, including drowsiness, dizziness, and dry mouth.

This information is not intended as medical advice. Consultation with a qualified healthcare professional is recommended before using any new supplement.

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