What Is the Primary Source of Phlorizin?

December 11, 2025 •

2 min read

First isolated from apple tree bark in 1835, phlorizin is a natural plant compound extensively studied for its potential health benefits, particularly its role as an SGLT inhibitor. This dihydrochalcone's most abundant source is the apple tree, though it is found in varying concentrations in other plants as well.

Quick Summary

Phlorizin is primarily found in apple trees, concentrated in the bark, leaves, and seeds, with other sources including sweet tea, certain berries, and plums.

Key Points

Apple Tree Parts are Primary Sources: The most significant sources of phlorizin are the vegetative parts of apple trees, including the bark, leaves, and seeds, rather than the ripe fruit's pulp.
High Concentration in Leaves: Apple leaves, often a byproduct of farming, contain exceptionally high levels of phlorizin, making them an economically viable and sustainable source for extraction.
Sweet Tea is an Alternative: The leaves of sweet tea (Lithocarpus polystachyus) have been identified as another very rich natural source of phlorizin, with concentrations potentially exceeding those in apples.
Found in Lesser Amounts in Other Foods: Trace amounts of phlorizin can be found in a range of other plants, such as cranberries, strawberries, and pomegranate pulp.
Distribution Varies by Species: Phlorizin is notably present in Malus species but is absent in closely related plants like pear trees, highlighting its species-specific biosynthesis.
SGLT Inhibitor Discovery: Phlorizin's function as a sodium-glucose cotransporter (SGLT) inhibitor in the 19th century was a foundational discovery for developing modern diabetes medications.

The Primary Source of Phlorizin: The Apple Tree

The apple tree (Malus species) is the most significant natural source of phlorizin, a flavonoid-based dihydrochalcone. While the fruit contains notable amounts, the highest concentrations are typically in the non-edible parts, suggesting a protective role for the plant. Historically, researchers focused on extracting phlorizin from apple bark and root bark due to their high levels.

Where Phlorizin is Found in Apple Trees

High concentrations are found in: apple leaves, bark and root bark, unripe fruit and seeds, and the fruit peel.

Other Natural Sources of Phlorizin

Besides apple trees, phlorizin is found in other plants. These sources contribute to dietary intake, often alongside other polyphenols.

Alternative Sources

Sources include Sweet Tea (Lithocarpus polystachyus), berries like cranberries and strawberries, pomegranate pulp, and fruits from the Prunus genus like plums and peaches. Phlorizin is also noted in some teas and red wines.

Comparison of Phlorizin Sources

The table below shows the relative concentrations of phlorizin in different sources.


Source	Primary Plant	Typical Location	Relative Concentration	Notes
Apple Tree (Waste Material)	Malus domestica	Leaves, bark, root bark	Very High	Concentration is highest in vegetative tissue and unripe parts.
Sweet Tea	Lithocarpus polystachyus	Leaves	Very High	Notably high concentration, making it a strong potential source.
Apples (Cultivated)	Malus domestica	Peel > Pulp	Moderate to Low	Phlorizin is more abundant in the peel; overall lower than in vegetative parts.
Apples (Wild)	Malus sieversii, etc.	Fruit Peel	High	Wild varieties can contain significantly more phlorizin than cultivated ones.
Cranberries	Vaccinium macrocarpon	Fruit Pulp	Low	Trace amounts are present along with other beneficial compounds.
Strawberries	Fragaria × ananassa	Fruit Flesh	Low	Phlorizin has been found in trace amounts in strawberries.

Phlorizin's Role in Plants and Potential in Human Health

In plants, phlorizin may act as a defense against pests and diseases. Its bitterness might also deter herbivores. Phlorizin is also used in plant classification.

For humans, phlorizin is known as an inhibitor of sodium-glucose cotransporters (SGLTs). This property was key in developing SGLT-inhibitor drugs for type 2 diabetes. Research also indicates other potential health benefits.

Conclusion

The apple tree remains the primary source of phlorizin, with higher concentrations found in vegetative parts like leaves and bark compared to the fruit. Other significant sources like sweet tea demonstrate nature's diversity. Utilizing agricultural byproducts such as apple leaves for extraction presents a sustainable approach. This knowledge is valuable for research and the development of nutraceuticals and potential new therapies.

Understanding the Synthesis of Phlorizin

Phlorizin is synthesized in plants via a metabolic pathway involving enzymes. Understanding these pathways is important for extraction and production, particularly in the nutraceutical industry.

The Importance of Agricultural Byproducts

Using apple leaves and bark, which are often agricultural waste, as sources for phlorizin is important for sustainability. Repurposing these byproducts turns waste into a valuable resource, reducing environmental impact and improving economic efficiency.

Frequently Asked Questions

For the highest concentration, the vegetative parts of the apple tree, particularly the leaves and bark, are the best source. The leaves of sweet tea also contain very high levels.

Yes, you can get phlorizin from eating apples, but the concentration is much higher in the peel than in the pulp. The highest levels are in unripe apples and the non-edible parts of the tree.

Yes, phlorizin is found in smaller amounts in other fruits and plants, including the pulp of pomegranate, peaches, certain berries like cranberries and strawberries, and the leaves of sweet tea.

The high concentration in apple leaves and bark likely serves as a natural defense mechanism for the plant against pests and diseases. It is a metabolic byproduct of the tree's natural processes.

Phlorizin is a glycoside, a molecule containing a sugar group, specifically glucose. Phloretin is the aglycone of phlorizin, meaning it is the molecule without the sugar group. The body converts phlorizin to phloretin during metabolism.

Supplements can be derived from various natural sources rich in phlorizin, with apple leaves and sweet tea being potential candidates due to their high concentrations. Extraction methods are used to concentrate the compound from these plant materials.

No, harvesting phlorizin from apple leaves typically uses agricultural waste from pruning, which does not negatively impact fruit production. This approach creates a sustainable and economically beneficial use for otherwise discarded plant material.