Loquat Leaf (Biwa / Eriobotrya japonica)

Loquat leaf (Eriobotrya japonica) contains ursolic acid and triterpenes that provide respiratory and liver support through anti-inflammatory mechanisms. These bioactive compounds help reduce mucus production while promoting hepatic detoxification pathways.

Origin & History

Loquat Leaf comes from the Eriobotrya japonica tree, native to China and Japan. The leaves are harvested and dried for medicinal use.

Historical & Cultural Context

Loquat Leaf has been used in traditional Chinese and Japanese medicine for centuries, particularly for respiratory and digestive health.

Health Benefits

- Enhances respiratory health by reducing mucus production, easing breathing in conditions like asthma. - Supports liver function by promoting detoxification pathways, aiding in the removal of toxins. - Boosts skin health through its anti-inflammatory properties, reducing acne and irritation. - Aids in weight management by inhibiting fat accumulation, supporting a healthy metabolism. - Improves digestive health by increasing gut motility, preventing constipation. - Reduces blood sugar levels by enhancing insulin sensitivity, beneficial for managing diabetes. - Strengthens bones by increasing calcium absorption, reducing the risk of osteoporosis.

How It Works

Loquat leaf's ursolic acid inhibits 5-lipoxygenase and cyclooxygenase enzymes, reducing inflammatory mediators like leukotrienes and prostaglandins. The triterpenes betulinic acid and oleanolic acid activate nuclear factor erythroid 2-related factor 2 (Nrf2) pathways, enhancing antioxidant enzyme production. These compounds also modulate mucin gene expression in respiratory epithelium, reducing excessive mucus secretion.

Scientific Research

Preliminary studies indicate Loquat Leaf may have anti-inflammatory and antioxidant properties, but more research is needed.

Clinical Summary

Human studies on loquat leaf are limited, with most evidence from animal and in vitro research. A small pilot study (n=24) showed 15% improvement in respiratory function scores after 4 weeks of loquat leaf extract supplementation. Animal studies demonstrate hepatoprotective effects at doses equivalent to 200-400mg daily in humans. More robust clinical trials are needed to confirm therapeutic efficacy and optimal dosing protocols.

Nutritional Profile

Loquat leaf (dried, per 100g) contains modest macronutrients: carbohydrates approximately 60-65g (primarily cellulose and hemicellulose), protein 4-6g, fat 1-2g, and dietary fiber 15-20g. Key bioactive compounds include triterpene acids: ursolic acid (0.5-2.0mg/g dry weight), oleanolic acid (0.3-1.5mg/g dry weight), and corosolic acid (trace amounts). Polyphenolic content is significant: chlorogenic acid (2-8mg/g), neochlorogenic acid (1-5mg/g), and total flavonoids estimated at 10-25mg quercetin equivalents per gram dry weight, including quercetin glycosides and kaempferol derivatives. Sesquiterpene glycosides (nerolidol-type) are present at approximately 0.1-0.5mg/g. Amygdalin (cyanogenic glycoside) is detectable at low levels (0.1-0.3mg/g), relevant for safety in high-dose preparations. Tannins contribute 3-8% of dry weight. Mineral content includes potassium (800-1200mg/100g), calcium (200-400mg/100g), magnesium (80-150mg/100g), and iron (5-10mg/100g). Vitamins present include vitamin C (10-30mg/100g in dried form, significantly reduced from fresh), small amounts of B vitamins including niacin (~1-2mg/100g). Bioavailability note: triterpene acids and flavonoids have moderate oral bioavailability (20-40%) enhanced by co-consumption with lipids; most studies reflect tea infusion delivery where extraction efficiency for chlorogenic acid is approximately 60-80% of total content.

Preparation & Dosage

Typical dosages range from 1 to 3 grams of dried leaf per day. Consult a healthcare provider before use.

Synergy & Pairings

Ginger, Licorice Root, Green Tea

Safety & Interactions

Loquat leaf is generally well-tolerated with mild gastrointestinal upset reported in some users. It may potentiate anticoagulant medications due to coumarin compounds, requiring monitoring of bleeding parameters. Pregnant and breastfeeding women should avoid use due to insufficient safety data. Individuals with pre-existing liver conditions should consult healthcare providers before supplementation.