Loquat (eriobotrya japonica) is a subtropical fruit that contains extracts that may be beneficial in treating inflammation, diabetes, cancer, bacterial infection, aging, pain and allergy (1)
This article focuses on the benefits of the active compounds found in different loquat extracts and their different medicinal properties.
Different parts of the loquat fruit, flower, leaves and seeds have been shown to provide a wide range of medicinal benefits in tests performed on mice and rats.
The 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 (4); the leaves of loquat have long been used in Japanese and Chinese cultures to treat chronic bronchitis, coughs, phlegm, high fever and gastroenteric disorders (5); and terpenoids (naturally occurring organic chemical compounds) extracted from loquat leaves have shown to provide anti-tumor, antiviral and anti-inflammatory properties (6).
Ursolic acid, found in loquat leaf extracts, may treat lung inflammation. Pulmonary inflammation plays a role in many lung diseases, including chronic bronchitis, asthma and cough. Ursolic acid has shown to have an anti-inflammatory effect on alveolar macrophages (the first line of defense against microbial invasion of infectious, toxic or allergic particles in the lower airways) in rats with induced chronic bronchitis. In addition, loquat tea extract made from roasted fresh loquat leaves has the ability to significantly decrease the edema (swelling caused by the buildup of fluid in the body’s tissues) in the paws of mice (7).
Loquat leaf and seed extracts are beneficial in the prevention and control of both type-1 and type-2 diabetes (8). Studies reveal that the terpenes and flavonoids found in the loquat leaf significantly lower the plasma glucose levels in diabetic mice. In another study, ethanol extracts of loquat seeds suppressed the increase in blood glucose for four months and improved the glucose tolerance in mice (9).
Loquat extracts may aid in anti-cancer activity. Researchers have found that loquat extracts have the potential to suppress cell carcinogenesis at different stages, such as cancer initiation, proliferation and metastasis (10). One finding revealed that both water and ethanol extracts of loquat leaf inhibited the development of breast cancer in rats by significantly suppressing the start and spread of tumor cells (11).
Loquat seeds extracts may inhibit the development of liver fibrosis (scarring of the liver) in rats. Unsaturated linolenic and linoleic acids and the sterol beta-sitosterol contained in these extracts may also aid in the improvement of the function of the liver (12).
A study published in the Journal of Pharmacy and Pharmacology reports that triterpene acids of loquats have a positive preventative effect on lung fibrosis and can improve the structure of the lung and alleviate fibrogenesis. (13).
Loquat leaf may treat and prevent osteoporosis. Bone density decreases with age, especially in post-menopausal women. In one study, mice that had their ovaries removed were fed a diet supplemented with 5 percent loquat leaves for 15 days. The results revealed that the loss of bone mineral density (BMD) was significantly prevented in three areas of the body: the trabecular bone of the head, abdomen and lumbar. Researchers are furthering their study into the potential of loquat leaves possessing the potential of anti-osteoporosis effects (14).
Loquat leaf extracts may lower high triglyceride levels. In a study published by the International Journal of Molecular Medicine, scientists discovered that leaf extracts provided anti-atherosclerotic activity to hypercholesterolemic zebrafish; a significant inhibition of the increase in total cholesterol and triglyceride levels were found (15). Research is ongoing into the potential for cholesterol-lowering effects in humans.
Loquat may have anti-aging skin benefits. Researchers studied 18 triterpenoids from loquat leaves and their effectiveness on the prevention and treatment of such skin conditions as acne, allergy and aging activities. Some of the results showed that twelve compounds exhibited an anti-acne effect; four compounds displayed anti-allergy and anti-inflammatory activity; and ursolic acid, pomolic acid, colosolic acid and its methylated derivative exhibited the highest anti-aging activity by stimulating collagen and hyaluronic acid production (16). This early evidence shows the potential of these compounds and acids to have impressive cosmetic or skin care health benefits, finding itself in many wrinkle and bb creams.
Loquat leaves are frequently used in the preparation of oriental herbal teas (17). Drinking excessive amounts have been found to be potentially troublesome.
According to a study published by the Annals of the Rheumatic Diseases, a 39-year-old male drank two liters of loquat tea daily for two weeks to help lower his elevated triglyceride level. While he had a remarkable decrease in triglycerides and an increase in high density lipoprotein (HDL), he also developed toxic myopathy (muscle inflammation, muscle weakness and muscle pain (18)). The study noted that other factors may have had a role in the myopathy of the patient, but that the ingestion of loquat leaves should be a consideration in the differential diagnosis of myopathy (19).
There is currently not enough information to recommend the proper supplemental dose of this plant for medicinal purposes.
While research is ongoing, one study referenced that the recommended human dose for consuming seeds is approximately 40mg/kg (about to 3-5 grams of the seeds for adults) (20).
Before consuming loquat seeds or drinking tea made from loquat leaves, it is best to first consult with your physician.
Loquat has been used as a medicinal plant in China and Japan for thousands of years. Research shows the potential for treating and preventing numerous health issues, including inflammation, diabetes, cancer, skin disorders and allergies. Active research in the efficacy, dosage and safety of loquat leaves and seeds is ongoing. Scientists stress that while the results of recent studies are encouraging and the efficacy of loquat as used in traditional Chinese medicine is supported by scientific evidence, more research is needed to determine the potential effect of the loquat plant as an effective treatment for various medical conditions. In addition, the potential toxicity of loquat extracts in animal or cell models is receiving more attention (21).