| Botany
A decidious tropical flowering tree, 5
to 10 m high, sometimes growing to a height of 20 meters. Leaves, large,
spatulate, oblong to elliptic-ovate, 2-4 inches in width, 5-8 inches
in length; shedding its leaves the
first months of the year. Before shedding, the leaves are bright orange
or red during which time it is thought to contain higher levels of corosolic
acid). Flowers are racemes, pink to lavender; flowering from March
to June. After flowering, the tree bears large clumps of oval nutlike
fruits.
Distribution
Grows wild; widely distributed in the
Philippines, in the secondary forests at low and medium altitudes.
Cultivated for its beautiful flowers. Propagation by seeds.
Chemical constituents
• Rich in tannin: fruit, 14 to 17 %; leaves
13 %; bark, 10%.
• Studies have isolated: (1) corosolic acid (2) ellagitannin Lagerstroemin (3) gallotannins
• Penta-O-galloyl-glucopyranose (PPG) – identified as the most potent of the gallotannins, with a higher glucose transport stimulatory activity than Lagerstroemin. In addition to stimulating glucose uptake in fat cells, it also has anti-adipogenic properties.
Parts utilized
Leaves, fruits, flowers and bark.
Uses
Folkloric
- Roots have been
used for a variety of stomach ailments. Leaf decoction for diabetes;
also use as a diuretic and purgative.
- Decoction of old leaves and dried fruit (dried from one to two weeks),
50 gms to a pint of boiling water, 4 to 6 cups daily has been used for
diabetes. Old leaves and ripe fruit are preferred, believed to have
greater glucose lowering effect. Young leaves and flowers have a similar
effect, though only 70% that of matures leaves and fruits. The wood
has no known glucose lowering effect; the bark, a very small amount.
A decoction of 20 gms of old leaves or dried fruit in 100 cc of water
was found to have the equivalent effect to that of 6 to 7.7 units of
insulin.
- The bark decoction has been used for the treatment of diarrhea.
- The bark, flowers and leaves used to facilitiate bowel movements.
- Decoction of fruits or roots gargled for aphthous stomatitis.
- Decoction of leaves and flowers used for fevers and as diuretic.
- Leaf decoction or infusion used for bladder and kidney inflammation,
dysuria, and other urinary dysfunctions.
Studies
• Corosolic Acid / Lagerstroemin / Gallotannins: Studies have identified several compounds as responsible for its anti-diabetic activity. (1) corosolic acid (2) Lagerstroemin, an ellagitannin (3) gallotannins, of which PPG – penta-O-galloyl-glucopyranose–was identified as the most potent, with a higher glucose transport stimulatory activity than Lagerstroemin. In addition to stimulating glucose uptake in fat cells, it also has anti-adipogenic properties.
• Inhibition of TNF-induced Activation: Diabetes leads to cardiomyocyte hypertrophy in association with upregulation of vasoactive factors and activation of nuclear factor (NF)-kappaB and activating protein-1. Study results indicate L speciosa can inhibit DNA-binding of NF-kappaB which may explain its possible inhibition of diabetes-induced cardiomyocyte hypertrophy.
• Ellagitannins / Insulin-like Glucose Uptake Stimulatory/Inhibitory Activities / Adipocyte Differentiation-Inhibitory Activity: Study yielded seven ellagitannins, including lagerstroemin from the leaves of L speciosa. The ellagitannins exhibited strong activities in both stimulating insulin-like glucose uptake and inhibiting adipocyte differentiation . Also, ellagic acid derivatives showed inhibitory effect on glucose trasport.
• Diabetes: (1) Banaba has been extensively studied for its application
in the treatment of diabetes. Early on, Its ability to lower blood sugar was attributed
to corosolic acid, a triterpenoid glycoside, belived to facilitate
glucose-transport into cells. (2) Studied with abutra,
akapulko, makabuhay
for antidiabetic activity through activation of gucose transporter activity.
One of the active principles from Banaba was the tripertene, corosolic
aicd.
• Weight loss: Studies in mice suggest an antiobesity effect.
It is becoming a common ingredient in weight-loss supplements / products
as a metabolic enhancer.
• Hypertension: It is also being studied for its use in the
treatment of blood pressure, renal and immune system benefits.
•
Lipid-lowering: Studies in mice suggest
a lipid lowering effect - decreasing triglyceride and total cholesterol
levels. To date, no toxicity has been identified.
• Hypoglycemic Activity of Irradiated Banaba
Leaves: Study showed the effects of nBLE and iBLE were comparable
to the hypoglycemic effects of insulin.
• Xanthine oxidase inhibitors from the leaves
of Lagerstroemia speciosa (L.) Pers: Xanthine oxidase is a key
enzyme involved with hyperuricemia, catalyzing the oxidation of hypoxanthine
to xanthine to uric aicd. The study supports the dietary use of the
aqueous extracts from Banaba leaves for the prevention and treatment
of hyperuricemia.
• Antidiabetic Activity: Study showed a significant reduction
of blood glucose levels with the soft gel formulation showing better
bioavailability than a dry-powder formulation.
• Other studies report potential uses:
(1) antibacterial effects from seed extracts (2) significant protection
of HIV-infected cells by ellagic acid constituents (3) antioxidative
activity of a water extract (4) inhibition of xanthine oxidase by aqueous
extract, 31 and anti-inflammatory activity in mice.
• Anti-Inflammatory / Free Radical Scavenging: Study showed antioxidant and anti-inflammatory activities from the ethyl acetate and ethanol extracts of Lagerstroemia speciosa.
Availability
Wildcrafted.
Cultivated for flowers.
Commercial: Tablets, extracts, capsules, powder and tea.
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