MAIN ACTIONS | OTHER ACTIONS | STANDARD DOSAGE |
Leaves | ||
Infusion: 1 cup 2-3 times | ||
daily with meals | ||
Capsules: 1-2 g 2-3 times | ||
daily with meals |
Pedra hume caá is a medium-sized shrub that grows in drier regions of the Amazon and other parts of Brazil. It has small, green leaves and large, orange-red flowers. A member of the myrtle family, it is one of more than 150 species of Myrcia indigenous to tropical South America and the West Indies. In Brazil, the common name pedra hume caá refers to three species of Myrcia plants which are used interchangeably—Myrcia salicifolia, M. uniflorus, and M. sphaerocarpa.
Pedra hume caá 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 astringent and use it for persistent diarrhea. It has had a place in Brazilian traditional medicine for many years. Dr. G. L. Cruz, a leading Brazilian practitioner and herbalist, nicknamed it "vegetable insulin" in 1965. Dr. Cruz noted in his book Livro Verde das Plantas Medicinais e Industriais do Brasil that "one uses all parts of the plant in infusions, decoctions or extracts to combat diabetes. Specialists that have made careful study of medicinal plants affirm that the regular use of this plant produces surprising results in the treatment of this ailment, as in a short space of time the sugar disappears from the urine. Hence the name ‘vegetable insulin.’" Even 30 years later, Dr. Cruz and other Brazilian researchers and practitioners are recording the actions and uses of pedra hume caá for diabetes in much the same manner. 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 diarrhea, hypertension, enteritis, hemorrhages, and mouth ulcers.
Phytochemical analysis of pedra hume caá reveals a high content of flavonoids, flavonols, and flavanones. In 1998, Japanese researchers reported the discovery of several novel and biologically active phytochemicals. These new flavanone glucosides were named myrciacitrins I and II; the new acetophenone glucosides were named myrciaphenones A and B. Their published study reported that a methanol extract of pedra hume caá (as well as these novel chemicals) demonstrated potent inhibitory activities on aldose reductase and alphaglucosidase.
Aldose reductase inhibitors (ARIs) are substances that act on nerve endings exposed to high blood sugar concentration to prevent some of the chemical imbalances that occur, and thus protect the nerves. Alpha-glucosidase inhibitors delay the digestion and subsequent absorption of sugar in the gastrointestinal tract. For this reason, the novel compounds in pedra hume caá that act upon aldose and glucosidase were seen to be (at least partially) responsible for pedra hume caá’s blood sugar-balancing properties. Various ARIs (both synthetic and natural) are being studied by researchers; it is believed that these compounds may be helpful in reducing or preventing some side effects of diabetes — including diabetic neuropathy and macular degeneration.
Other flavonoids found in pedra hume caá (notably quercitrin, myricitrin, guaijaverin, and desmanthin) also have shown in numerous studies to inhibit aldose reductase and xanthine oxidase (xanthine oxidase inhibitors block the production of uric acid). The main plant chemicals documented in pedra hume caá include: beta-amyrin, catechin, desmanthin, gallic acid, ginkgoic acid, guaijaverin, mearnsitrin, myrciacitrin I–V, myrciaphenone A, myrciaphenone B, myricitrin, and quercitrin.
Brazilian scientists have documented leaf extracts of pedra hume caá with hypoglycemic activity since 1929. Two clinical studies published in the 1990s again demonstrated its hypoglycemic activity and confirmed its traditional use for diabetes. In a 1990 double-blind placebo clinical study with normal and Type II diabetic patients, pedra hume caá (3 g powdered leaf daily) demonstrated the ability to lower plasma insulin levels in the diabetic group. In a 1993 study, 250 mg/kg of a leaf extract demonstrated the ability to reduce appetite and thirst, and to reduce urine volume, urinary excretion of glucose and urea in diabetic rats. The extract also inhibited the intestinal absorption of glucose. This study concluded that "aqueous extracts of Myrcia have a beneficial effect on the diabetic state, mainly by improving metabolic parameters of glucose homeostasis."
Pedra hume caá continues to be one of the more popular natural remedies for diabetes throughout South America, where it is widely known. The studies with animals and humans have confirmed its safety and no toxic effects or side effects were noted. It is hoped that, with the growing diabetes epidemic in North America, health practitioners here will look for natural alternatives and incorporate this wonderful rainforest remedy into their natural health practices. These tropical shrubs grow very quickly and growth is encouraged by pruning. A single shrub can be harvested of its leaves by hard pruning 4 times a year or more - producing approximately 50-60 kg of leaves annually. It is truly a wonderful and sustainable resource the rainforest offers!
Main Preparation Method: decoction Main Preparation Method:infusion or capsules
Main Actions (in order): Main Uses:
antidiabetic, alpha-glucosidase inhibitor, aldose reductase inhibitor, appetite suppressant, hypoglycemic Other Properties/Actions Documented by Traditional Use: Cautions: It lowers blood sugar levels. It is contraindicated in hypoglycemia. Diabetics should monitor their glucose levels closely. |
Traditional Preparation: One cup of leaf infusion 2-3 times daily with meals. One to 2 g of leaf powder in tablets or capsules with meals can be substituted if desired. See Herbal Preparation Methods instructions if necessary.
Contraindications: | |
Country | Uses |
Amazonia | for diabetes, diarrhea, and as an astringent |
Brazil | for diabetes, diarrhea, dysentery, enteritis, heart problems, hemorrhages, hypertension, mouth ulcers, and as an astringent and diuretic |
2. "Pedra huma-caa, nicknamed 'vegetable insulin," has been researched in Brazil for the treatment of diabetes. It was used by early South American Indians as a powerful healing poultice."
3. "Pedra Huma-Caa, nicknamed "vegetable insulin" has been the subject of studies in Brazil for the treatment of diabetes."
8. "Pedra Huma-Caa contains a lot of tannin and its astringent action makes it a very useful plant. Brazilian uses and folklore: Pedra Huma-Caa tea is taken in Brazil to help relieve the symptoms of diabetes."
21. "Myrcia salicifolia DeCandolle, Prodr. 3 (1828) 246.
The leaves are considered by the Taiwanos to be efficacious against persistent diarrhea. The dried leaves are mixed with farina they are said to be astringent and, if taken in excess, to be emetic."