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Myrcia

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Also listed as: Pedra hume caŠ
Related terms
Background
Evidencetable
Tradition
Dosing
Safety
Interactions
Attribution
Bibliography

Related Terms
  • Beta-amyrin, catechin, desmanthin-1, gallic acid, ginkgoic acid, guaijaverin, mearnsitrin, Myrcia multiflora, Myrcia salicifolia, Myrcia sphaerocarpa, Myrcia uniflora, myricitrin myrciacitrin I, myrciacitrin II, myrciacitrins III, myrciacitrin VI, myrciacitrin V, myrciaphenone A, myrciaphenone B, Myrtaceae, pedra hume caŠ, pedra-ume-caŠ, quercitrin, rodwood.
  • Note: Do not confuse Myrcia (Myrtaceae family) with the bayberry genus Myrica (or Morella in the Myricaceae family).

Background
  • Pedra hume caŠ is a medium-sized shrub that grows in drier regions of the Amazon and other parts of Brazil. In Brazil, the common name pedra hume caŠ refers to three species of myrcia plants that are used interchangeably-Myrcia salicifolia, Myrcia uniflorus, and Myrcia sphaerocarpa. It is unknown if reports on pedra hume caŠ can be applied to other species in the myrcia genus.
  • Pedra hume caŠ has been used by indigenous tribes in the rainforest for diabetes, diarrhea, and dysentery. The Taiwanos tribe (in northwest Amazonia) considers the leaves to be an astringent and uses them for persistent diarrhea. Pedra hume caŠ has had a place in Brazilian traditional medicine for many years.
  • It remains a very popular natural remedy for diabetes throughout South America; the traditional use is a simple leaf tea with a pleasant, slightly sweet taste. It is also used for high blood pressure, enteritis (inflammation of the bowels), hemorrhage, and mouth ulcers.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Myrcia has been used traditionally by indigenous tribes in the rainforest to treat diabetes. Human study has not confirmed a blood sugar lowering benefit in type 2 diabetic patients. More research is warranted to make a strong recommendation.

C
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)


Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

  • Antioxidant, astringent, cardiotonic, diarrhea, diabetic peripheral neuropathy (prevention), diabetic retinopathy, dysentery (severe diarrhea), enteritis (inflammation of the bowels), goiter (enlarged thyroid), hemorrhage, high blood pressure, hyperthyroidism (overactive thyroid), tonic (gastrointestinal), ulcers (mouth).

Dosing

Adults (18 years and older)

  • Based on the available scientific evidence, there is no proven safe or effective dose for myrcia. Traditionally, one cup of leaf infusion has been taken 2-3 times daily with meals or 1-2 grams of leaf powder in tablets or capsules has been taken with meals. Infusion of 3 grams of leaves per day for 56 days has been used in one human trial with no clinical benefit.

Children (younger than 18 years)

  • Based on the available scientific evidence, there is no proven safe or effective dose for myrcia in children and use is not recommended.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

  • Avoid in individuals with a known allergy or hypersensitivity to myrcia.

Side Effects and Warnings

  • There are no reports currently available describing the adverse effects of myrcia. Dizziness, drowsiness, flatulence (gas), abdominal discomfort, bloating, diarrhea, and nausea are possible adverse effects.
  • Myrcia has been used historically for high blood pressure. Theoretically, it may cause hypotension (low blood pressure) in some patients. Use myrcia cautiously in patients taking blood pressure medications and in patients with low blood pressure.
  • Myrcia may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a qualified healthcare professional including a pharmacist, and medication adjustments may be necessary.
  • Patients may experience hypothyroidism with myrcia. Use myrcia cautiously in patients taking medications for hyperthyroidism. Based on its similar activity to some anti-thyroid medications, myrcia may cause agranulocytosis (an acute blood disorder), chills, fever, and loss of taste.

Pregnancy and Breastfeeding

  • Myrcia is not recommended in pregnant and breastfeeding women. Myrcia may affect blood sugar levels and thyroid function. Uncontrolled diabetes or thyroid dysfunction during pregnancy can lead to abnormal fetal development.

Interactions

Interactions with Drugs

  • Myrcia may interact with amiodarone causing either an increase or decrease in hypothyroid effects. Caution is advised.
  • Myrcia may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
  • Myrcia may alter the activity of other blood pressure lowering agents. Caution is advised.
  • Myrcia may increase the effects of medications used for hyperthyroidism leading to hypothyroidism. Because of potential effects on thyroid hormones, patients who begin taking myrcia may require dosage adjustments on their existing medications due to changes in metabolism.

Interactions with Herbs and Dietary Supplements

  • Myrcia may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
  • Myrcia may alter the activity of other blood pressure lowering agents. Caution is advised.
  • Myrcia may increase the effects of herbs and supplements used for hyperthyroidism leading to hypothyroidism. Consult with a qualified healthcare professional, including a pharmacist, before combining therapies.

Attribution
  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography
  1. Ferreira AC, Neto JC, da Silva AC, et al. Inhibition of Thyroid Peroxidase by Myrcia uniflora Flavonoids. Chem Res Toxicol. 2006;19(3):351-355.
  2. Matsuda H, Nishida N, Yoshikawa M. Antidiabetic principles of natural medicines. V. Aldose reductase inhibitors from Myrcia multiflora DC. (2): Structures of myrciacitrins III, IV, and V. Chem Pharm Bull.(Tokyo) 2002;50(3):429-431.
  3. Pepato MT, Oliveira JR, Kettelhut IC, et al. Assessment of the antidiabetic activity of Myrcia uniflora extracts in streptozotocin diabetic rats. Diabetes Res 1993;22(2):49-57.
  4. Russo EM, Reichelt AA, De Sa JR, et al. Clinical trial of Myrcia uniflora and Bauhinia forficata leaf extracts in normal and diabetic patients. Braz.J Med Biol Res 1990;23(1):11-20.
  5. Yoshikawa M, Shimada H, Nishida N, et al. Antidiabetic principles of natural medicines. II. Aldose reductase and alpha-glucosidase inhibitors from Brazilian natural medicine, the leaves of Myrcia multiflora DC. (Myrtaceae): structures of myrciacitrins I and II and myrciaphenones A and B. Chem Pharm Bull.(Tokyo) 1998;46(1):113-119.

Copyright © 2011 Natural Standard (www.naturalstandard.com)


The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.

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