IngredientsHoney loquat syrup — known in Cantonese Chinese as pei pa koa (枇杷膏) and in Mandarin as pípá gāo or chuānbèi pípá gāo (川貝枇杷膏) — is a traditional East Asian herbal preparation whose central botanical ingredient is the loquat plant, Eriobotrya japonica (Thunb.) Lindl. Eriobotrya japonica (Thunb.) Lindl. (EJ), commonly known as loquat, is a fruit tree from the Rosaceae family, traditionally used in various cultures for its medicinal properties. It is a subtropical evergreen tree native to China and widely cultivated in various regions, including the Mediterranean. The dried leaf, known formally as Folium Eriobotryae or pi pa ye (枇杷葉) in Traditional Chinese Medicine (TCM), is the plant organ most commonly used in syrup preparations, though the fruit itself also contributes to the product's flavour and phytochemical profile.
The syrup is not a single-ingredient product. Honey loquat syrup, also known as "pei pa koa," has its roots in Traditional Chinese Medicine (TCM), where it has been used for centuries to soothe the throat, reduce coughing, and address mild respiratory discomfort. The main ingredients typically include loquat leaf (Eriobotrya japonica), honey, and various other herbs, each attributed with moistening and soothing properties according to TCM principles.
In its most widely recognized commercial form — Nin Jiom Pei Pa Koa — the full ingredient list is considerably more complex. Pei pa koa is made up of a blend of herbal ingredients including the fritillary bulb (Bulbus fritillariae cirrhosae, 川貝母), loquat leaf (Eriobotrya japonica, 枇鈀葉), fourleaf ladybell root (Adenophora tetraphylla, 南沙參), Indian bread (Wolfiporia extensa, 茯苓), pomelo peel (Citrus maxima, 化橘紅), Chinese bellflower root (Platycodon grandiflorum, 桔梗), prepared pinellia rhizome (Pinellia ternata, 半夏), Schisandra seed (Schisandra chinensis, 五味子), Trichosanthes seed (Trichosanthes kirilowii, 栝蔞), coltsfoot flower (Tussilago farfara, 款冬花), Thinleaf Milkwort root (Polygala tenuifolia, 遠志), bitter apricot kernel (Prunus armeniaca, 苦杏仁), fresh ginger (Zingiber officinale, 生薑), licorice root (Glycyrrhiza uralensis, 甘草), and menthol in a syrup and honey base.
Different organs of loquat have been used historically as folk medicines, and this has been recorded in Chinese history for thousands of years. The historical use of loquat leaves in TCM spans centuries, where they are known as "pi pa ye" and are valued for their purported ability to clear lung heat and reduce phlegm. In Chinese folk medicine, loquat leaf has been used since ancient times to treat inflammatory diseases such as cough, chronic bronchitis (CB), and asthma.
Within the framework of TCM, the loquat leaf is classified as having a bitter and slightly cold nature, acting primarily on the Lung and Stomach meridians. In China, loquat flowers and leaves are frequently utilized as medicinal herbs, purportedly offering benefits such as wind dispersal, cough relief, and nasal decongestion. They are traditionally employed for symptoms such as headaches, nasal obstruction, rhinorrhea, persistent cough due to fatigue, and blood-streaked sputum.
King-to Nin Jiom Pei Pa Koa is a Chinese patent medicine used for the relief of sore throat, coughs, hoarseness, and aphonia. It is believed the cough syrup was invented by a Qing Dynasty official named Yeung Kan, who developed the loquat syrup — based on a recipe from a famous physician called Ip Tin-See — for his mother who was suffering from a persistent cough. He then worked to make the syrup available for everyone and named it nin jiom, which means "memory of mother." It originated from the transmission of the famous Qing Dynasty physician Ye Tianshi, using more than ten precious Chinese herbs and pure honey for refinement.
Originating from Southeast China, loquat has been utilized in traditional medicine across countries like Indonesia, Japan, India, and Turkey. Loquat leaves have been used in Moroccan traditional medicine to treat diabetes and its complications. In Japan, loquat leaf tea (Biwa cha) has been a longstanding folk remedy. Used in Oriental medicine for over a thousand years to soothe sore throats and as a syrup to ease coughs, the fruit of the loquat is also nutritious.
The phytonutritional composition of extracts of different organs varies considerably: loquat leaf and flower are rich in phenolics and triterpenes; fruit is rich in sugars, organic acids, carotenoids, flavonoids, phenolic acids, and vitamins; the kernel is a good source of proteins, starch, tannins, and minerals.
A systematic review covering publications from 1931 to 2022 found that loquat leaves contain over 164 identified compounds, mainly triterpenes, flavonoids, sesquiterpene glycosides, and organic acids, with demonstrated anti-diabetic, anti-inflammatory, anti-tumour, antioxidant, hepatoprotective, bronchodilatory, and antitussive activities.
As the principal functional components of loquat leaf, triterpene acids (TAs) have shown notable anti-inflammatory activity. The most studied individual triterpenes include:
Phytochemical analysis of E. japonica leaves identified 30 compounds, including flavonoids, phenolics, and megastigmanes. The flavonoids isolated from the leaves include flavones, flavans, flavolignans, flavonoid glycosides, and coumaroyl flavonoid glycosides. Flavonoid and phenolic compounds demonstrated significant antioxidant and α-glucosidase inhibitory effects. Notably, coumaroyl flavonoid rhamnosides, which consist of flavonoids combined with the phenolic acid coumaric acid, exhibited excellent anti-diabetic effects. Key individual flavonoids include quercetin, kaempferol, epicatechin, and rutin.
The leaf contains trace amounts of amygdalin (a cyanogenic glycoside), which can release tiny amounts of hydrogen cyanide during metabolism. In recent years, amygdalin has been regarded as a promising natural substance with diverse anticancer effects. In addition, amygdalin can be used to treat respiratory diseases such as cough and asthma.
The honey base of the syrup is itself a phytochemically active contributor. There is some evidence supporting honey's general effectiveness in soothing sore throats due to its demulcent and mild antimicrobial properties. The WHO and multiple treatment guidelines have acknowledged these properties of honey in respiratory conditions (see Section 4 below).
Both aqueous and ethanol extracts of growing and fallen loquat leaves contain antitussive and expectorant activities. An aqueous extract of growing loquat leaves with a higher flavonoid content displayed a stronger expectorant activity, while the ethanol extract of fallen loquat leaves containing a higher content of triterpenoid acids induced a stronger antitussive activity. The anti-inflammatory effects of the identified triterpenoids in loquat may be related to the inhibition of MAPK signal transduction. Ethanol fractions of fallen loquat leaves with higher contents of triterpenoids showed better antitussive activity. These results validated the conclusion that triterpenoids may be the main constituents responsible for relieving coughing.
Increased levels of inducible nitric synthase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8) have been correlated with inflammation. Decreasing these pro-inflammatory mediators and/or increasing anti-inflammatory cytokine (such as IL-10) secretions are important mechanisms for the anti-inflammatory effects of loquat extracts.
The anti-inflammatory effects of loquat tea extract may also rely on the inhibition of the production of iNOS, nitric oxide (NO), IL-6, TNF-α, and on the downregulation of the TGF-β-activated kinase-mediated MAPK and NF-κB pathways in mouse macrophage-like RAW 264.7 cells.
A 2020 animal study examined the COPD pathway specifically: The loquat leaf has long been used as an important material for both functional and medicinal applications in the treatment of lung disease in China and Japan. As the principal functional components of loquat leaf, triterpene acids (TAs) have shown notable anti-inflammatory activity. It was shown that TAs significantly decreased the production of inflammatory cytokines in a chronic bronchitis model induced by the endotracheal instillation of lipopolysaccharide via inhibition of NF-κB activation.
Terpenoids are strikingly potent blood-glucose-lowering compounds by enhancing insulin sensitivity, promoting insulin secretion, inhibiting protein tyrosine phosphatase 1B, α-glucosidase, aldose reductase (AR), and dipeptidyl peptidase-4 (DPP-4) activities, further reducing liver glycogen decomposition and gluconeogenesis. Corosolic acid from Eriobotrya japonica has attracted particular attention for its antidiabetic activity in animal experiments and clinical trials, including reduction of post-challenge plasma glucose levels in humans.
Corosolic acid isolated from loquat leaf promoted ³H-glucose uptake, inhibited the differentiation of preadipocytes into adipocytes, and downregulated the expression of peroxisome proliferator-activated receptor (PPAR)-γ and the CCAAT/enhancer binding protein-α in 3T3-L1 adipocytes. Therefore, corosolic acid might regulate carbohydrate metabolism without increasing adiposity.
Loquat extracts contain many antioxidants, and different extracts exhibit bioactivity capable of counteracting inflammation, diabetes, cancer, bacterial infection, aging, pain, allergy, and other health issues. Total flavonoids (TF) from loquat leaf significantly reduced body weight, liver-to-body-weight ratio, and blood lipids in PM₂.₅-induced NAFLD mice. TF treatment alleviated oxidative stress by preventing the accumulation of oxidative product malondialdehyde (MDA) and by strengthening the anti-oxidative capacity of superoxide dismutase (SOD).
The honey component contributes a coating, demulcent action on the pharyngeal mucosa. This physical barrier mechanism — distinct from the biochemical activities of the herbal components — provides direct soothing of irritated membranes and is the basis for honey's traditional use in cough and sore throat.
The primary application of honey loquat syrup across its entire history has been upper respiratory tract symptoms — cough, sore throat, and phlegm — and the greatest concentration of evidence relates to its components' effects in this domain.
Evidence for loquat leaf (antitussive/expectorant):
The most direct antitussive evidence remains preclinical. Both aqueous and ethanol extracts of growing and fallen leaves of loquat contained antitussive and expectorant activities in murine models. These findings were published in Revista Brasileira de Farmacognosia (2018). No large, blinded human clinical trials specifically investigating loquat leaf extract as an isolated antitussive agent in humans were identified. Loquat leaf itself has demonstrated certain anti-inflammatory and antioxidant effects in preliminary laboratory studies, but these have not been conclusively linked to sore throat relief in humans.
Evidence for honey (cough):
The honey component of the syrup has been much more extensively studied in clinical trials than loquat leaf extract. The Cochrane systematic review (Oduwole et al., 2018) included six randomised controlled trials involving 899 children. Using a 7-point Likert scale, honey probably reduces cough frequency better than no treatment or placebo (no treatment: mean difference (MD) −1.05, 95% CI −1.48 to −0.62; I² = 0%; 2 studies; 154 children; moderate-certainty evidence). Overall, evidence quality was low to moderate, and some studies did not blind participants.
The World Health Organization and many treatment guidelines have proposed or endorsed the use of honey to treat acute cough. Honey has been examined in several randomized controlled trials, but the results varied. The latest systematic reviews published in 2018 and 2021 stated that honey is an effective treatment for cough and causes no severe harm; therefore, it could be used to treat acute cough.
Evidence for the combined syrup product:
Scientific validation for honey loquat syrup specifically is limited. While there is some evidence supporting honey's general effectiveness in soothing sore throats due to its demulcent and mild antimicrobial properties, robust clinical trials on the syrup as a combined product are lacking. The available scientific studies are often small, lack rigorous controls, or focus on individual components rather than the syrup as a whole. Thus, the primary justification for its use is rooted in tradition rather than strong scientific validation.
Summary of evidence strength: Moderate-certainty evidence supports honey alone for pediatric acute cough; preclinical (animal/in vitro) evidence supports loquat leaf antitussive and anti-inflammatory activity; no high-quality RCTs exist for the polyherbal syrup product as a whole.
Loquat was considered an ancient remedial plant in many traditional systems of medicine to potentially treat diabetes mellitus, heart diseases, and various inflammatory diseases. Modern pharmacological research has identified multiple mechanisms by which loquat compounds could influence glycemia.
Flavonoid and phenolic compounds from E. japonica leaves demonstrated significant antioxidant and α-glucosidase inhibitory effects. Coumaroyl flavonoid rhamnosides exhibited excellent anti-diabetic effects, and molecular docking analysis confirmed that these compounds effectively bind to the α-glucosidase enzyme.
Several studies have investigated the bioactive constituents of loquat and their potential therapeutic applications. One notable study focused on sesquiterpene glycosides isolated from loquat leaves, which demonstrated significant effects on hyperglycemia and inflammation in a type 2 diabetes mellitus (T2DM) mouse model. The study found that SG1, a specific sesquiterpene glycoside, could prevent insulin resistance and inflammation by modulating gut microbiota composition.
Summary of evidence strength: Evidence is predominantly from in vitro enzyme-inhibition assays and animal models. The clinical evidence for corosolic acid specifically (from loquat and other sources) includes some human pharmacokinetic and glucose-challenge data, but high-quality RCTs of honey loquat syrup for glycemic outcomes in humans are absent. This is a promising but preliminary area of research.
Loquat leaf extracts enriched with triterpene acids, especially ursolic acid, showed anti-inflammatory effects on alveolar macrophages in rats with LPS-induced chronic bronchitis. The COPD-related research used a murine model: Male C57BL/6 mice were challenged with cigarette smoke (CS) for 12 weeks, and from the seventh week of CS exposure, mice were fed with TAs (50 and 100 mg/kg) for 6 weeks to figure out the therapeutic effect and molecular mechanism of TAs in CS-induced COPD inflammation.
Summary of evidence strength: All current anti-inflammatory evidence for loquat comes from animal and cell-culture models. No human clinical trials in COPD, bronchitis, or similar inflammatory lung conditions using honey loquat syrup have been identified in the peer-reviewed literature.
After 15 days of feeding normal diet or diet supplemented with 5% loquat leaves, the loss of bone mineral density (BMD) in loquat-fed ovariectomized (OVX) mice was significantly prevented in three parts of the body, especially in the trabecular bone of the head (P < 0.05), abdomen (P < 0.01), and lumbar (P < 0.05) compared to the control group. Through bioactivity-guided fractionation, ursolic acid was isolated and inhibited osteoclast differentiation under 4 and 10 μg/mL.
Summary of evidence strength: Preliminary animal data only. No human studies have been conducted with honey loquat syrup for bone outcomes.
Mice were exposed to PM₂.₅ to induce non-alcoholic fatty liver disease (NAFLD), and body weight, liver-to-body-weight ratio, and blood lipids increased significantly. Total flavonoids (TF) from loquat leaf significantly reduced the above parameters. TF treatment alleviated oxidative stress by preventing the accumulation of MDA and strengthening the anti-oxidative capacity of SOD.
Summary of evidence strength: Animal models only. No human clinical hepatoprotective evidence for the syrup formulation exists.
To explore biological activities of E. japonica leaves against skin disorders, 18 triterpenoids were evaluated for anti-melanogenesis, anti-acne, anti-allergy, and anti-aging activities. Results revealed that eight compounds showed anti-melanogenesis activity, of which ursolic acid and maslinic acid were the most potent. However, there are no evidence-based studies on the skin-care effects of E. japonica leaves.
The dosages documented for the most widely studied commercial product, Nin Jiom Pei Pa Koa, are as follows:
Nin Jiom Pei Pa Koa is made up of a blend of herbal ingredients including Tendrilleaf Fritillary Bulb, Loquat, Platycodon Root, Menthol, Ginger, and Honey. Suggested use: Adults aged over 12: take 1 tablespoonful (15 ml) each time, 3 times a day. Children: aged 7–12: take 2/3 tablespoonful (10 ml) each time, 3 times a day; aged 4–6: take 1/3 tablespoonful (5 ml) each time, 3 times a day.
The official Nin Jiom labelling as registered on the Drugs.com monograph (NIN JIOM MEDICINE MANUFACTORY (HK) LTD, NDC code 57708-888) states: Adults and children 2 years of age and older: 2 teaspoonfuls every 2 hours as needed or as directed by a doctor or dentist. Children under 2 years of age: consult a doctor or dentist.
A Canadian health-product label (NPN80038615) specifies constituent amounts per 5 ml dose: Tendrilleaf Fritillary Bulb (Bulbus Fritillarae Cirrhosae) 60 mg; Unprepared Licorice Root (Radix Glycyrrhizae) 55 mg; Loquat (Eriobotrya japonica, Leaf) 14 mg; Pummelo Peel (Citrus maxima) 8 mg; Coltsfoot (Tussilago farfara, Flower) 8 mg; Thinleaf Milkwort (Polygala tenuifolia, Root) 8 mg; Platycodon Root (Platycodon grandiflorus) 5 mg; Menthol (l-Menthol) 2 mg; Fourleaf Ladybell Root (Radix Adenophorae) 2 mg; Indian Bread (Wolfiporia extensa) 2 mg.
For traditional dried loquat leaf as used in TCM decoctions, one source documents: typically dosing is 4–12 grams of dried leaf, or 15–30 grams if the leaves are fresh. These doses refer to the dried leaf as a single-ingredient decoction within classical TCM practice, not to the commercial syrup.
The main safety concern relating to mechanical, not chemical, preparation: the dense trichomes (fine hairs) on the underside of the leaf must be thoroughly removed before use. If ingested, these hairs irritate the mucous membranes of the throat and respiratory tract, causing coughing, throat swelling, and potentially vomiting. Commercial preparations process leaves to remove this hazard.
The leaf contains trace amounts of amygdalin (a cyanogenic glycoside), which can release tiny amounts of hydrogen cyanide during metabolism. The principal risk from amygdalin in the Eriobotrya japonica plant is concentrated in the seeds, not the leaves. Mean concentrations of amygdalin in loquat seeds were 5,900 mg/kg, equating to approximately 420 mg/kg HCN equivalents. In a laboratory analysis of twelve powdered loquat seed samples, seven out of twelve were at risk for exceeding the acute reference dose (ARfD) of cyanide. By contrast, loquat leaf and fruit pulp used in the syrup do not contain the seed-level cyanogenic load. High-dose exposures to amygdalin can produce cyanide toxicity. Consumers of the prepared syrup (which uses leaf, not seed) are exposed to negligible amygdalin quantities.
A 13-week subchronic toxicity study in rats found no treatment-related adverse effects at doses up to 1,000 mg/kg/day. Genotoxicity testing also showed no mutagenic potential.
Honey could be contaminated with Clostridium botulinum; infants less than 1 year of age should be restricted from consuming honey. This applies directly to honey loquat syrup, which contains honey as a primary excipient and active component.
Adverse events in clinical trials included mild reactions (nervousness, insomnia, and hyperactivity) experienced by seven children (9.3%) from the honey group and two (2.7%) from the dextromethorphan group; the difference was not statistically significant.
Loquat may interact with certain medications, such as blood thinners and diabetes drugs. The presence of corosolic acid and other compounds with documented α-glucosidase inhibitory and insulin-sensitizing activities suggests a theoretical pharmacodynamic interaction with hypoglycemic agents, though this has not been confirmed in clinical pharmacology studies.
Overconsumption of loquat leaves, especially in tea, may lead to toxic myopathy, a muscle disease. Not enough is known about the safety of loquat during pregnancy and breastfeeding.
The product labelling for Nin Jiom Pei Pa Koa states: do not use if you are pregnant or breastfeeding; consult a doctor before taking if you have a fever over 38°C, or if symptoms persist for more than a week; consult a healthcare practitioner if taking other medications; consult a healthcare practitioner for prolonged use.
The plant shows promise for future drug development, but further mechanistic and clinical studies are needed. The mechanisms of action of many compounds remain partially understood, and comprehensive toxicity studies are lacking. Formal regulatory oversight differs by jurisdiction; in the United States, honey loquat syrup products are sold as dietary supplements or over-the-counter throat demulcents, while in some Asian markets they hold status as registered traditional medicines.
Health conditions that Honey loquat syrup may help support.
Honey loquat syrup is a traditional Chinese medicine preparation combining honey and loquat leaf (Eriobotrya japonica) specifically used for bronchitis, cough, and respiratory inflammation. Loquat leaf is classified in TCM as an expectorant and anti-tussive herb. In vivo studies confirm antitussive and expectorant activities of loquat leaf decoction.
Honey loquat syrup (Pi Pa Gao) is a classical Chinese herbal OTC preparation used since the Tang Dynasty for cough, sore throat, and upper respiratory irritation. It combines honey's demulcent properties with loquat leaf's antitussive and expectorant effects. It is among the most widely used OTC herbal cough preparations in China.
Body systems that Honey loquat syrup may help support.
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