Hexahydroxydiphenoyl-Containing Tannins

Hexahydroxydiphenoyl-containing tannins are a group of complex plant polyphenols associated particularly with ellagitannins, a family of hydrolyzable tannins found in a variety of plants and foods.

The long name comes from the hexahydroxydiphenoyl (HHDP) group, an important structural feature of many ellagitannins. Ellagitannins are characterized by one or more HHDP groups attached to a sugar molecule, usually glucose.

When HHDP-containing tannins are broken down, the HHDP portion can form ellagic acid. Ellagic acid can then be further transformed by microorganisms living within the digestive system into compounds known as urolithins.

This makes HHDP-containing tannins particularly interesting for health and wellness because we are not simply looking at what exists in a plant. We are also looking at what happens to those compounds after the plant is eaten and how they may interact with digestion, the gut microbiome and the rest of the body.

Possible Health & Wellness Benefits

Antioxidant Activity

HHDP-containing tannins have complex structures containing numerous hydroxyl groups that can participate in antioxidant reactions.

This has led to considerable research into their ability to interact with free radicals and other reactive molecules.

Oxidative stress occurs when the production of reactive molecules exceeds the body's ability to manage them. Persistent oxidative stress can contribute to damage involving cellular membranes, proteins and DNA.

Plants containing HHDP tannins therefore provide another source of polyphenols that may contribute to the overall antioxidant activity of a varied plant-based diet.

Inflammation Research

Ellagitannins, ellagic acid and their metabolites are also being investigated for their possible effects on biological pathways associated with inflammation.

Inflammation is an essential part of the body's normal response to injury and infection. Problems can arise when inflammatory processes become excessive or remain active for extended periods.

Laboratory and experimental research has identified anti-inflammatory activities associated with several ellagitannins and their metabolites.

This does not mean that eating a particular plant will treat an inflammatory disease. Instead, it helps explain why researchers continue studying tannin-rich plants as part of the larger relationship between nutrition and long-term wellness.

Cellular Protection

Another area of research involves the potential effects of ellagitannins on cellular health.

Their antioxidant activity and interactions with cellular signalling pathways have led researchers to investigate their possible protective effects against oxidative cellular damage.

Ellagitannins and their metabolites have also been investigated experimentally in relation to abnormal cell proliferation.

These findings are areas of ongoing research and should not be interpreted as evidence that a particular HHDP-containing plant can prevent or treat cancer.

Cardiovascular Wellness

Polyphenols are widely investigated for their possible contributions to cardiovascular health.

HHDP-containing tannins and the compounds produced from them may influence several processes associated with cardiovascular wellness, including oxidative stress and inflammatory signalling.

The greatest value may come from consuming a diversity of plants rather than attempting to obtain large amounts of one particular tannin.

A plant containing HHDP tannins normally contains many other compounds as well, potentially providing a much broader phytochemical profile.

Digestive & Gut Microbiome Connection

One of the most fascinating areas of HHDP-tannin research involves the gut microbiome.

Ellagitannins can be broken down to produce ellagic acid.

Certain intestinal microorganisms can then transform ellagic acid into a family of compounds called urolithins.

Not everyone produces the same amounts or types of urolithins because everyone's intestinal microbiome is different.

This means two people can eat the same raspberry, strawberry or other ellagitannin-containing plant and potentially process some of its compounds differently.

It demonstrates why understanding plant compounds involves much more than simply identifying what is present in a plant.

There is a pathway:

Plant → HHDP-containing tannins → ellagic acid → gut microorganisms → urolithins

Each part of that pathway can influence what ultimately becomes available to the body.

Understanding HHDP-Containing Tannins

Not every tannin is an HHDP-containing tannin.

This distinction is important when identifying plants for this Wellness Profile.

Tannins are a large and chemically diverse family of plant polyphenols.

Within that larger family are hydrolyzable tannins.

Within hydrolyzable tannins are ellagitannins, many of which contain HHDP structural groups.

Examples of HHDP-containing or HHDP-derived ellagitannins include:

• Pedunculagin
• Casuarictin
• Potentillin
• Agrimoniin
• Sanguiin H-6
• Lambertianin C
• Castalagin
• Tellimagrandins

Some are relatively small molecules, while others are large oligomeric tannins constructed from several connected units.

This is why simply finding the word "tannins" in a plant's phytochemical profile is not enough to establish that it contains HHDP-containing tannins.

Whenever possible, we need to look deeper at which tannins researchers have actually identified.

Ontario & Locally Relevant Plants

Broadleaf Plantain — Plantago major

Broadleaf Plantain deserves particular attention within this Wellness Profile.

Research involving tannin preparations obtained from Plantago major leaves has reported hexahydroxydiphenoyl-containing tannin structures.

That makes Broadleaf Plantain important here for a very different reason than simply saying that Plantain contains tannins.

It provides a connection specifically to the HHDP family being explored in this profile.

Broadleaf Plantain is also especially relevant when looking at practical health and wellness.

Unlike berry shrubs, it does not require a large garden.

It can grow:

• outdoors in Ontario,
• in garden beds,
• in relatively small containers,
• on balconies,
• or indoors under suitable artificial lighting.

The young leaves are edible when correctly identified and gathered or grown under safe conditions.

Broadleaf Plantain also contains many compounds beyond tannins, including iridoid glycosides such as aucubin, phenolic compounds, flavonoids, polysaccharides and other phytochemicals.

This is exactly why looking at the complete plant profile can be more useful than focusing on one vitamin or one isolated compound.

A relatively small plant can provide access to numerous different plant compounds.

For people with limited growing space, Broadleaf Plantain therefore deserves consideration as a practical plant rather than simply being viewed as a common lawn weed.

Black Raspberry — Rubus occidentalis

Black Raspberry is another valuable locally relevant source of ellagitannins.

Black raspberries contain complex ellagitannins alongside the anthocyanins responsible for their dark colour.

Ellagitannins associated with Rubus fruits include compounds such as:

• Sanguiin H-6
• Lambertianin C
• Related HHDP-containing structures.

Black raspberry therefore provides several different polyphenol families within one edible fruit.

The berries can be consumed fresh, frozen or preserved, providing opportunities to extend their availability beyond their relatively short harvest season.

The limitation from a small-space perspective is size.

A raspberry plant requires considerably more room than Broadleaf Plantain or strawberries, so it may be better suited to outdoor growing where space is available.

Red Raspberry — Rubus idaeus

Red raspberries are among the best studied dietary sources of ellagitannins.

Two particularly important raspberry ellagitannins are:

Sanguiin H-6

and

Lambertianin C

Both are complex ellagitannins containing HHDP-derived structures.

Other HHDP-containing compounds and related structures have also been identified in raspberry preparations, including bis-HHDP-glucose compounds.

Raspberries therefore provide an excellent example of how complicated plant chemistry can exist inside a familiar food.

A raspberry is not simply providing Vitamin C, fibre or sugar.

It is providing a mixture that can include vitamins, minerals, anthocyanins, flavonoids, phenolic acids and complex ellagitannins.

Practical Small-Space Growing Options

For people living in apartments or other homes with limited growing space, simply identifying plants containing a compound is not enough.

We also need to ask:

Can I realistically grow this plant?

That changes which plants become most useful.

Broadleaf Plantain — Plantago major

Broadleaf Plantain stands out because it combines the HHDP connection with a plant that can realistically be grown in a relatively small space.

It does not require the large permanent growing area associated with raspberry or blackberry plants.

Leaves can also be harvested while allowing the plant to continue growing.

That gives Plantain another advantage for small-space wellness growing: repeated harvests from the same growing space.

For people interested in growing plants for their broader phytochemical profiles rather than simply maximum food weight, that can be particularly valuable.

Strawberry — Fragaria Species

Strawberries are another excellent small-space option.

Strawberries contain several ellagitannins, with agrimoniin being one of the most important.

Research on cultivated strawberries has also identified compounds including:

• Agrimoniin
• Pedunculagin
• Potentillin
• Casuarictin
• Sanguiin H-6
• Fragariin A

These compounds demonstrate that strawberries can provide a surprisingly diverse collection of ellagitannins from a relatively compact plant.

Strawberries can be grown in:

• small pots,
• hanging containers,
• vertical systems,
• shelves,
• hydroponic systems,
• indoor grow areas,
• balconies,
• or outdoor containers.

Indoor growing requires sufficient light, appropriate nutrition and pollination of the flowers, but the relatively small size of strawberry plants makes them much more practical than berry shrubs.

Day-neutral strawberries can be especially interesting for controlled growing because flowering and fruiting are less dependent on seasonal day-length changes than traditional June-bearing varieties.

Agrimony — Agrimonia Species

Agrimony is another plant worth understanding because its name is connected directly to agrimoniin, an important ellagitannin.

Agrimoniin has been identified as a major ellagitannin in studied Agrimonia species.

Agrimony has a long history of traditional herbal use and demonstrates that HHDP-containing tannins are not restricted to fruits and berries.

The plant can be container-grown, although it requires more vertical space than Plantain or strawberries.

For very restricted indoor growing areas, Broadleaf Plantain and strawberries may therefore be more practical choices.

Other Edible Sources

HHDP-containing ellagitannins occur in a much broader selection of foods.

Important dietary sources include:

• Raspberries
• Black raspberries
• Blackberries
• Strawberries
• Wild strawberries
• Cranberries
• Cloudberries
• Pomegranates
• Walnuts
• Almonds

Raspberries and blackberries are particularly associated with sanguiin H-6 and lambertianin C, while strawberries are strongly associated with agrimoniin.

This provides several ways of including these compounds through ordinary foods rather than relying on concentrated extracts or supplements.

Why Broadleaf Plantain Matters

Broadleaf Plantain helps demonstrate something important about practical health and wellness.

Some of the plants growing around us—or plants that can easily be grown in relatively small spaces—contain far more complex chemistry than their appearance suggests.

Plantain is often treated simply as a weed.

Looking at its phytochemistry changes that perspective.

The plant contains multiple families of compounds, and evidence for HHDP-containing tannin structures adds another piece to that profile.

That does not make Plantain a miracle plant.

It makes it a useful plant worth understanding.

For someone with limited space, the question is not necessarily whether a plant can produce kilograms of food.

Another useful question is:

How much nutritional and phytochemical diversity can I grow within the space available to me?

A small collection containing plants such as Broadleaf Plantain and strawberries can provide very different compounds while requiring far less room than conventional large vegetable plants or berry shrubs.

Outdoor growing can then complement those plants with seasonal foods such as raspberries and blackberries.

Growing for Plant Diversity

Learning about HHDP-containing tannins reinforces one of the larger ideas behind the Wellness Profiles:

Health and wellness cannot be reduced to one vitamin, one nutrient, one plant or one plant compound.

Plants contain mixtures of compounds.

A strawberry provides Vitamin C, fibre and minerals, but it also provides flavonoids, phenolic acids, anthocyanins and ellagitannins.

Broadleaf Plantain provides nutrients alongside iridoid glycosides, flavonoids, phenolic compounds, polysaccharides and tannins.

Raspberries provide yet another phytochemical mixture.

Growing several useful plants can therefore create greater nutritional and phytochemical diversity than concentrating all available growing space on a single crop.

This is especially important for people growing in apartments or other small spaces.

We can look at what grows naturally where we live.

We can look at what can be grown outdoors during Ontario's growing season.

And we can look at what can continue growing indoors throughout the year.

The goal is not to chase one compound.

It is to gain enough knowledge to make better use of the plants and growing space available to us.

Hexahydroxydiphenoyl-containing tannins are another piece of that much larger picture connecting plants, nutrition, accessibility, growing, the gut microbiome, health and wellness.

Disclaimer

This Wellness Profile is provided for educational and informational purposes only and is not medical advice.

Research into HHDP-containing tannins, ellagitannins, ellagic acid, urolithins and their possible health effects is ongoing. Laboratory, cell, animal and other experimental findings do not necessarily demonstrate that the same effects will occur in humans.

The presence of a potentially beneficial plant compound does not mean that consuming larger amounts of the plant will provide greater benefits. Tannins and other plant compounds can also affect digestion, nutrient absorption and medications when consumed in sufficient quantities or concentrated preparations.

Correct plant identification is essential before consuming wild plants. Only consume plants that have been positively identified as edible, and avoid harvesting from areas that may have been contaminated by pesticides, herbicides, road runoff, animal waste or other pollutants.

Plants, herbal preparations and concentrated extracts can interact with medications and medical conditions. Speak with a qualified healthcare professional before making significant dietary changes or using concentrated plant extracts, supplements or medicinal preparations, particularly if you take medications, are pregnant or breastfeeding, or have an existing health condition.

This information should not be used to diagnose, treat, cure or prevent any medical condition.