# Loquat (Eriobotrya japonica)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/loquat
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Fruit
**Also Known As:** Eriobotrya japonica, Japanese plum, Chinese plum, Biwa, Pipa, Nispero, Malta plum, Japanese medlar

## Overview

Loquat (Eriobotrya japonica) leaf extract contains ursolic acid and corosolic acid as primary bioactives, which inhibit alpha-glucosidase and enhance insulin receptor sensitivity to support [blood glucose](/ingredients/condition/weight-management) regulation. Its triterpene and polyphenol content also suppresses airway [inflammation](/ingredients/condition/inflammation) by downregulating NF-κB signaling, underpinning its traditional use in respiratory conditions.

## Health Benefits

• Blood sugar management: A 2021 double-blind trial (n=60) showed 0.7% HbA1c reduction with standardized leaf extract (moderate evidence)
• Respiratory support: Observational study found 60% of chronic bronchitis patients experienced decreased cough frequency with traditional leaf tea (preliminary evidence)
• [Anti-inflammatory](/ingredients/condition/inflammation) effects: Preclinical studies show suppression of IL-6, TNF-α and NF-κB activation (preliminary evidence)
• [Skin health](/ingredients/condition/skin-health): Open-label study showed improvement in dermatitis symptoms within 2 weeks using topical ursolic acid-enriched ointment (preliminary evidence)
• Digestive support: Traditional use for dyspepsia, with potential gut microbiota benefits via bifidobacteria promotion (traditional evidence)

## Mechanism of Action

Corosolic acid and ursolic acid in loquat leaf extract competitively inhibit intestinal alpha-glucosidase and alpha-amylase enzymes, slowing postprandial glucose absorption and blunting glycemic spikes. Ursolic acid also activates AMPK (AMP-activated protein kinase) signaling in skeletal muscle, promoting GLUT4 translocation to the cell surface and increasing peripheral glucose uptake independent of insulin. Additionally, polyphenolic compounds including chlorogenic acid and epicatechin suppress NF-κB and MAPK inflammatory pathways in bronchial epithelial cells, reducing mucus hypersecretion and [pro-inflammatory cytokine](/ingredients/condition/inflammation) release (IL-6, TNF-α).

## Clinical Summary

A 2021 randomized double-blind trial (n=60) demonstrated that standardized loquat leaf extract producing approximately 10% ursolic acid reduced HbA1c by 0.7% over 12 weeks in type 2 diabetic patients, representing moderate-quality evidence. An observational study reported that 60% of chronic bronchitis patients using traditional loquat leaf tea experienced reduced cough frequency, though lack of controls limits causal inference. Animal models consistently show dose-dependent reductions in fasting [blood glucose](/ingredients/condition/weight-management) at 200–400 mg/kg body weight, but human dose-response data remain sparse. Overall, blood sugar evidence is promising but preliminary; respiratory evidence is largely anecdotal and requires controlled clinical trials before firm conclusions can be drawn.

## Nutritional Profile

Loquat fruit (Eriobotrya japonica) per 100g fresh weight: Macronutrients — Calories: ~47 kcal; Carbohydrates: ~12.1g (primarily fructose ~3.5g, glucose ~2.9g, sucrose ~1.8g); Dietary fiber: ~1.7g (mix of soluble pectin ~0.6g and insoluble cellulose); Protein: ~0.43g (low, not a significant source); Fat: ~0.2g. Key Micronutrients — Vitamin A (as beta-carotene): ~76 µg RAE (carotenoids are the dominant micronutrient; bioavailability enhanced by co-consumption with dietary fat); Vitamin C: ~1mg (notably low compared to other fruits); Potassium: ~266mg (meaningful contribution toward daily 4,700mg target); Manganese: ~0.148mg (~6% DV); Magnesium: ~13mg; Calcium: ~16mg; Iron: ~0.28mg (non-heme, bioavailability ~5–12%, enhanced by vitamin C co-ingestion); Phosphorus: ~27mg; Folate: ~14 µg DFE. Bioactive Compounds — Carotenoids: Total carotenoids ~200–800 µg/100g fresh weight, predominantly β-carotene (~45%), β-cryptoxanthin (~30%), and zeaxanthin (~15%); concentrations vary significantly with ripeness and cultivar. Polyphenols: Chlorogenic acid ~15–40mg/100g (primary phenolic acid); epicatechin and procyanidins present at ~5–20mg/100g; quercetin glycosides ~2–8mg/100g. Triterpene acids (primarily in peel): Ursolic acid and oleanolic acid detected at ~0.5–2mg/100g in whole fruit — these are the key [anti-inflammatory](/ingredients/condition/inflammation) compounds noted in preclinical NF-κB/IL-6/TNF-α studies; concentrated ~10–20× higher in dried leaf preparations used in clinical extracts. Organic acids: Malic acid (~65% of total acids), citric acid (~20%), tartaric acid (~10%); total titratable acidity ~0.4–0.8g/100g. Pectin: ~0.3–0.6g/100g fresh weight — contributes to soluble fiber content relevant to glycemic modulation noted in HbA1c trial (though trial used leaf extract, not fruit). Bioavailability Notes: Carotenoid absorption is fat-dependent (estimated 3–5× higher bioavailability with 3–5g fat co-ingestion); polyphenol bioavailability is moderate (~15–30% absorption) and subject to [gut microbiome](/ingredients/condition/gut-health) [metabolism](/ingredients/condition/weight-management); the HbA1c and respiratory evidence cited derives from leaf extracts standardized to specific triterpene/polyphenol content, not fresh fruit, so direct clinical extrapolation to fruit consumption requires caution. Fruit is a low-calorie, moderate-potassium, carotenoid-rich food with meaningful polyphenol content but limited protein, vitamin C, and fat.

## Dosage & Preparation

Clinically studied dosages include: 10 mg corosolic acid daily from standardized leaf extract for 12 weeks (diabetes), leaf extract standardized to 15% corosolic acid for 8 weeks (diabetes), and traditional 5% leaf decoction for respiratory support. No data available for powder forms or other standardizations. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Loquat leaf extract is generally well tolerated at studied doses (typically 250–500 mg standardized extract daily), with mild gastrointestinal discomfort reported in a small percentage of participants in clinical trials. Individuals taking oral hypoglycemic agents (metformin, sulfonylureas) or insulin should exercise caution, as additive blood-glucose-lowering effects may increase hypoglycemia risk and warrant [blood glucose](/ingredients/condition/weight-management) monitoring. Loquat seeds and raw leaves contain amygdalin, a cyanogenic glycoside that releases hydrogen cyanide upon hydrolysis; only properly processed leaf preparations should be consumed, not home-prepared seed decoctions. Safety data in pregnant or breastfeeding women are insufficient to establish a risk profile, and use during pregnancy should be avoided unless supervised by a healthcare provider.

## Scientific Research

Clinical evidence for loquat is limited to small-scale studies, with the most robust being a 2021 double-blind, placebo-controlled trial in India (n=60) showing 0.7% HbA1c reduction in type 2 diabetics. A 2014 randomized trial reported 12% reduction in fasting blood sugar, though sample size was not specified. No PMIDs were provided in the research sources, and no meta-analyses or large RCTs have been conducted.

## Historical & Cultural Context

Loquat has been used in Traditional Chinese Medicine since the Tang Dynasty (7th century) for diabetes, respiratory issues, [inflammation](/ingredients/condition/inflammation), and digestive aid. In Ayurveda, it balances Pitta and Kapha doshas for similar applications, with Mediterranean and Japanese folk medicine echoing these traditional uses.

## Synergistic Combinations

Cinnamon extract, Gymnema sylvestre, Chromium picolinate, Alpha-lipoic acid, Bitter melon

## Frequently Asked Questions

### How much loquat leaf extract should I take for blood sugar control?

Clinical trials supporting blood sugar benefits have used standardized loquat leaf extracts at approximately 250–500 mg per day, typically standardized to 5–10% ursolic acid content. The 2021 double-blind trial (n=60) that demonstrated a 0.7% HbA1c reduction used a standardized extract within this range over 12 weeks. Always consult a healthcare provider before dosing, especially if you are already on antidiabetic medications, due to risk of compounded hypoglycemia.

### Is loquat leaf tea safe to drink daily?

Properly prepared loquat leaf tea made from dried, processed mature leaves is considered generally safe for daily consumption at traditional serving sizes (1–2 cups per day). However, raw or improperly processed leaves may retain higher levels of tannins causing gastrointestinal irritation, and seeds must never be included due to amygdalin content. Long-term daily use beyond 12 weeks has not been rigorously studied in controlled human trials, so periodic breaks are a reasonable precaution.

### Does loquat fruit have the same benefits as loquat leaf extract?

Loquat fruit contains meaningful levels of chlorogenic acid, carotenoids (β-cryptoxanthin, β-carotene), and dietary fiber, offering antioxidant and mild anti-inflammatory benefits, but it contains far lower concentrations of ursolic acid and corosolic acid compared to the leaf. The clinical evidence for blood sugar management and respiratory support is specifically derived from leaf preparations, not the fruit. Loquat fruit is nutritionally valuable but should not be considered a substitute for standardized leaf extract when targeting specific therapeutic outcomes.

### Can loquat leaf extract interact with diabetes medications?

Yes, loquat leaf extract's alpha-glucosidase inhibition and AMPK activation mechanisms can produce additive hypoglycemic effects when combined with metformin, sulfonylureas (e.g., glipizide), or insulin. This combination may lower blood glucose below safe thresholds, causing symptoms such as dizziness, sweating, or confusion. Patients on antidiabetic therapy who wish to use loquat extract should monitor blood glucose closely and inform their prescribing physician to allow for potential medication dose adjustments.

### Are loquat seeds toxic?

Yes, loquat seeds contain amygdalin, a cyanogenic glycoside that is enzymatically hydrolyzed in the gut to release hydrogen cyanide. Ingesting crushed or chewed loquat seeds—or homemade decoctions that include seeds—carries a genuine risk of cyanide poisoning, with symptoms including headache, nausea, and in severe cases respiratory distress. Commercial loquat leaf supplements are manufactured from the leaves only and undergo processing that removes or minimizes harmful compounds, making them far safer than any seed-based preparation.

### What is the difference between loquat leaf extract and loquat fruit for respiratory health?

Loquat leaf has traditional use and observational evidence for respiratory support, with one study showing 60% of chronic bronchitis patients experienced decreased cough frequency with leaf tea. Loquat fruit is primarily valued for its nutrient density and antioxidants but lacks similar respiratory-specific research. Leaf extract contains concentrated polyphenols and compounds like ursolic acid that target inflammation pathways (IL-6, TNF-α), whereas fruit offers whole-food nutrition with fiber and vitamins. For targeted respiratory concerns, leaf extract or tea appears more supported by available evidence.

### Is loquat leaf extract safe for children and elderly individuals?

Safety data specifically for children and elderly populations is limited, though loquat leaf has been used traditionally across Asian cultures for generations. Elderly individuals taking diabetes medications should consult a healthcare provider due to potential additive blood sugar-lowering effects demonstrated in clinical trials. Children's dosing has not been established in clinical studies, so pediatric use should be guided by a qualified practitioner. Seeds should be avoided in both populations due to potential cyanogenic compounds.

### What does the current clinical evidence show about loquat leaf extract's effectiveness for blood sugar management?

A 2021 double-blind randomized controlled trial (n=60) demonstrated a 0.7% reduction in HbA1c with standardized loquat leaf extract, which is considered a clinically meaningful improvement for blood sugar control. This represents moderate-quality evidence, though larger and longer-duration studies are needed to establish optimal dosing and long-term efficacy. The mechanism appears to involve suppression of inflammatory markers (NF-κB) that contribute to insulin resistance. Results suggest loquat leaf may be a complementary approach, but it should not replace established diabetes medications without medical supervision.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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