102 Paper Birch

Names

Common name – Paper Birch

Scientific name – Betula papyrifera

Other names – White Birch or Canoe Birch

Fig 52.1: A mature Paper Birch (Betula papyrifera) tree displaying its characteristic bright white bark in a natural woodland setting.

Fig 52.2: Detailed texture of the iconic white, peeling bark of the Paper Birch tree, highlighting its horizontal lenticels.

Fig 52.3: Traditional harvesting marks on a Paper Birch trunk, demonstrating sustainable peeling practices.

Fig 52.4: Close-up view of Paper Birch (Betula papyrifera) foliage showing its distinctive ovate, doubly serrated leaves.

Fig 52.5: Chemical structure of Betulin, a lupane-type pentacyclic triterpene primarily responsible for the therapeutic properties of Paper Birch bark.

Fig 52.6: Chemical structure of Betulinic Acid, an oxidized derivative of betulin with enhanced solubility and bioactivity.

General Information

Paper Birch (Betula papyrifera), also known as White Birch or Canoe Birch, is a deciduous tree of the Betulaceae (Birch) family, native to northern North America ^{[7, 9]}. This iconic tree has been extensively used by Indigenous peoples throughout its range for medicinal purposes, particularly for treating skin conditions and various inflammatory disorders ^{[3, 4]}. The bark contains unique triterpene compounds, primarily betulin and betulinic acid, which provide its therapeutic properties ^{[1, 8]}.

Traditional Medicinal Uses by Indigenous Peoples

The Elders speak of Paper Birch as a medicine of great versatility and strength, a tree that offered healing for both the body and the spirit ^[3]. Its bark was used for many ailments e.g. boiled into teas or made into poultices to ease pain, soothe wounds, and heal the skin ^[3]. When the bark was prepared as a tea, it cleansed the digestive tract, fighting infections and calming disorders of the stomach and intestines ^{[3, 6]}. People relied on it when their bodies ached; its pain-relieving and blood-thinning powers helped those troubled by rheumatism, arthritis, or general soreness ^{[3, 7]}. For fevers, a decoction from the bark brought down heat and restored balance, while its cleansing properties helped dissolve kidney stones and flush toxins from the body ^{[3, 4]}.

The inner bark was prized for treating frostbite and burns, applied gently to draw out the pain and promote healing ^[3]. The leaves and twigs, when boiled, created a medicine that reduced swelling and inflammation, bringing comfort to weary joints and sore muscles ^{[3, 7]}. Some also used the bark to clean and strengthen the blood, believing it carried a cool, purifying energy from the tree’s white skin ^[3].

Biochemical Basis for Medicinal Properties

Primary Bioactive Compounds

Paper Birch bark contains several classes of bioactive compounds, with pentacyclic triterpenes being the most therapeutically significant ^{[1, 11]}:

1. Primary Active Compounds

• Betulin (Birch Camphor) – Primary triterpene compound (10-25% in outer bark) ^{[8, 11]}
• Betulinic Acid – Oxidized derivative of betulin with enhanced bioactivity ^{[1, 14]}
• Lupeol – Supporting triterpene compound ^[8]
• Oleanolic Acid – Secondary triterpene with therapeutic properties ^[8]
• β-Sitosterol – Plant sterol with multiple bioactivities ^[8]

2. Supporting Compounds

• Flavonoids – Antioxidant and anti-inflammatory compounds ^[13]
• Tannins – Astringent and antimicrobial properties ^[7]
• Phenolic acids – Supporting antioxidant compounds ^[13]
• Essential oils – Volatile compounds with antimicrobial effects ^[9]
• Suberin – Protective waxy compound in bark ^[11]

Chemical Structure and Properties of Key Compounds

Betulin – Primary Active Compound

Key Structural Components: ^[8]

• Ring System: Lupane-type pentacyclic framework
• Hydroxyl Groups: C3 secondary OH and C28 primary alcohol
• Double Bond: C20=C29 exocyclic methylene group
• Methyl Groups: Six methyl substituents providing rigidity
• Stereochemistry: Defined 3β configuration

Betulinic Acid – Active Metabolite

• Structure: Betulin with C28 oxidized to carboxylic acid (-COOH) ^[1]
• Enhanced Activity: More potent biological effects than betulin ^{[1, 12]}
• Improved Solubility: Carboxylic acid group increases water solubility ^[1]

Molecular Mechanisms of Action

1. Anti-inflammatory Mechanisms

NF-κB Pathway Inhibition:

Betulin/Betulinic Acid → NF-κB suppression → Reduced inflammatory gene expression ^{[8, 13]}

– Prevents IκBα degradation ^[8]

– Blocks NF-κB nuclear translocation ^{[8, 14]}

– Decreases TNF-α, IL-1β, IL-6 production ^{[8, 14]}

– Reduces cyclooxygenase-2 (COX-2) expression ^[13]

– Anti-inflammatory cytokine regulation ^[14]

MAPK Pathway Modulation:

Betulinic Acid → MAPK inhibition → Reduced inflammatory signaling ^[12]

– p38 MAPK suppression ^[12]

– ERK1/2 pathway modulation ^[12]

– JNK signaling inhibition ^[12]

– Downstream anti-inflammatory effects ^[12]

2. Antimicrobial Mechanisms

Cell Membrane Disruption:

Betulin → Bacterial membrane interaction → Membrane permeabilization ^[5]

– Lipophilic triterpene inserts into membrane ^[5]

– Disrupts membrane integrity ^[5]

– Increases permeability ^[5]

– Cellular content leakage ^[5]

– Bacterial cell death ^[5]

Antifungal Activity:

Betulin → Fungal cell wall/membrane targeting → Growth inhibition ^[5]

– Ergosterol biosynthesis interference ^[5]

– Cell membrane disruption ^[5]

– Inhibition of fungal growth ^[5]

– Broad-spectrum antifungal effects ^[5]

3. Wound Healing and Tissue Repair

Collagen Synthesis Stimulation:

Betulinic Acid → Fibroblast activation → Enhanced collagen production ^{[2, 10]}

– Increased Type I collagen synthesis ^[10]

– Enhanced wound tensile strength ^[10]

– Accelerated healing process ^{[2, 10]}

– Reduced scar formation ^[10]

Angiogenesis Promotion:

Betulin → VEGF upregulation → New blood vessel formation ^[2]

– Vascular endothelial growth factor increase ^[2]

– Enhanced tissue perfusion ^[2]

– Improved nutrient delivery ^[2]

– Faster healing rates ^[2]

4. Hepatoprotective Mechanisms

Antioxidant Defense Enhancement:

Betulinic Acid → Nrf2 activation → Antioxidant enzyme upregulation ^[12]

– Glutathione S-transferase increase ^[12]

– Catalase and SOD enhancement ^[12]

– Reduced oxidative stress ^[12]

– Liver protection ^[12]

Extraction and Concentration in Bark

Seasonal Variation: ^{[6, 11]}

• Highest betulin content in late spring/early summer ^[11]
• Outer bark contains 15-25% betulin by dry weight ^[11]
• Inner bark has lower but significant concentrations ^[11]
• Age of tree affects compound concentration ^[6]

Traditional Extraction Methods: ^{[3, 4]}

• Hot water extraction (tea preparation) ^[3]
• Alcohol-based tinctures ^[4]
• Direct bark chewing ^[3]
• Poultice preparations ^[3]
• Steam distillation for essential oils ^[7]

Safety and Traditional Wisdom

Traditional Safety Profile: ^{[3, 7]}

• Extensive historical use without significant toxicity ^[3]
• Topical applications generally well-tolerated ^[3]
• Internal use in traditional dosages appears safe ^[3]
• Pregnancy/lactation: Traditional caution advised ^[7]

References

1. American Chemical Society. (n.d.). Betulinic acid. https://www.acs.org/molecule-of-the-week/archive/b/betulinic-acid.html
2. Ebeling, S., Naumann, K., Pollok, S., Wardecki, T., Vidal-y-Sy, S., Nascimento, J. M., Boerries, M., Schmidt, G., Brandner, J. M., & Merfort, I. (2014). From a traditional medicinal plant to a rational drug: Understanding the clinically proven wound healing efficacy of birch bark extract. PLOS ONE, 9 (1), Article e86147. https://doi.org/10.1371/journal.pone.0086147
3. Elders and Community members of the Cayoose Creek Band of Sekw’el’was. (n.d.).
4. Garden Guides. (n.d.). Medicinal uses for paper birch trees. https://www.gardenguides.com/115425-medicinal-uses-paper-birch-trees.html
5. Hamion, G., et al. (2024). Action of betulinic acid on the membrane of Staphylococcus aureus and Candida albicans biofilms. International Journal of Antimicrobial Agents. https://doi.org/10.1021/acschembio.5c00681.s001
6. Minnesota Public Radio. (2005, March 10). Birch bark promises better health. http://news.minnesota.publicradio.org/features/2005/03/10_hemphills_birchbark/
7. Natural Medicinal Herbs. (n.d.). Paper birch – Betula papyrifera. http://www.naturalmedicinalherbs.net/herbs/b/betula-papyrifera=paper-birch.php
8. Shanmugam, M. K., Nguyen, A. H., Kumar, A. P., & Sethi, G. (2022). Anti-inflammatory and anticancer properties of birch bark-derived betulin: Recent developments. Frontiers in Pharmacology, 13, 8705846. https://doi.org/10.3390/plants10122663
9. Song of the Woods. (2025, February 7). White birch syn. paper birch – Betula papyrifera. https://www.songofthewoods.com/white-birch-betula-papyrifera/
10. Wang, Y., et al. (2022). Betulinic acid accelerates diabetic wound healing by modulating hyperglycemia-induced oxidative stress, inflammation and glucose intolerance. Burns & Trauma, 10, tkac007. https://doi.org/10.1093/burnst/tkac007
11. Wikipedia contributors. (2025, October 9). Birch bark. Wikipedia. https://en.wikipedia.org/wiki/Birch_bark
12. Yi, J., Xia, W., Wu, J., Yuan, L., Wu, J., Tu, D., & Qiu, Y. (2020). Betulinic acid protects against cyclophosphamide-induced liver injury through Nrf2/HO-1 and MAPKs/NF-κB pathways. Food and Chemical Toxicology, 142, 111458. https://doi.org/10.1016/j.biopha.2016.11.028
13. Yoon, J., Kim, J., Lee, H., & Choi, S. (2013). Study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation. Phytotherapy Research, 27 (12), 1814–1821. https://doi.org/10.1186/1752-153x-6-137
14. Zhao, W., Zhang, H., Chen, H., & Xu, L. (2012). Betulinic acid regulates generation of neuroinflammatory mediators responsible for tissue destruction in multiple sclerosis in vitro. Acta Pharmacologica Sinica, 33 (10), 1241–1249. https://doi.org/10.1038/aps.2012.181