Banaba

Scientific Name(s): Lagerstroemia speciosa (L.) Pers. Family: Lythraceae

Common Name(s): Banaba , queens crape myrtle , queen's flower , pride of India

Uses

Banaba leaf preparations have been used as a folk medicine among people with diabetes in the Philippines. Certain constituents, such as corosolic acid, have been found to possess hypoglycemic activity. Several animal studies support this effect, but more human studies are needed for confirmation.

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Dosing

None well documented. In one small, randomized clinical trial involving type 2 diabetic patients, researchers found that dosages of 32 and 48 mg of a banaba extract standardized to 1% corosolic acid (glucosol preparation) administered for 2 weeks significantly reduced blood glucose levels.

Contraindications

None well documented.

Pregnancy/Lactation

Because of the lack of pharmacological and toxicity data, avoid the use of banaba during pregnancy and lactation.

Interactions

None well documented. However, because of the glucose-lowering actions of the plant, caution is warranted with use of other diabetic medications, as the effects could be additive.

Adverse Reactions

None well documented.

Toxicology

No toxicity has been reported, even in high doses. Large oral doses produce no toxic effects or convulsions.

Botany

Banaba is a deciduous, tropical, flowering tree that can grow to 18 m in height, with a 9 to 12 m spread. The large, oblong, dark-green, leathery leaves measure 5 to 10 cm wide by 12 to 30 cm long. The leaves turn an orange-red color in the fall. The flowers are pink to purple in color, giving way to oval, nut-like fruits. The bark of the tree is thin, mottled, and peeling. 1 , 2

History

Banaba has been used as a folk medicine among people with diabetes in the Philippines. Folkloric use also includes diuretic and purgative action from leaf decoctions and the use of root parts for stomach ailments. The plant is being studied for its application in the treatment of diabetes. 2

Chemistry

Banaba leaves contain ellagic acid derivatives. 3 A later report confirms ellagitannins, lagerstroemin, flosin B, and reginin A, which are all possible glucose transport enhancers. 4 Lagertannins, beta-sitosterol, stigmasterol, campesterol, and some olefins also have been found in banaba leaves and extracts. 4 , 5 , 6 , 7 Lageracetal (1,1-Dibutoxybutane), 1-pentanol, ellagic acid, and corosolic acid (a triterpene) have been isolated from leaves. 8 , 9 Another study reports 16 amino acids, pyrogallol tannins, and lipids also present in banaba leaf. 10 From the neutral fraction of hot ethanol extracts of banaba leaves, nonacosane, hentriacontane, tritriacontane, olefins, and esters of palmitic, daturic, stearic, arachinic, and behenic acids were identified. 11

Banaba bark was found to contain similar constituents to its leaves. One report finds ellagic acids, beta-sitosterols, and colosolic acids from bark extracts. 12

L. speciosa seeds contain caprylic, lauric, myristic, palmitic, steric, arachidic, behenic, lignoceric, oleic, and linoleic acids in the oil. 13 9-keotoctadec-cis-11-enoic acid has been isolated from seed oil as well. 14 Chemical investigation of amino acid components in banaba seed oil has been performed. 15 Components nonanedioic acid, 12-acetyloxy-9-octadecenoic acid, and 16-methyl-heptadecandic acids present in seed extracts have been identified as having antibacterial activity. 16

L. speciosa and related species contained ellagic acid, campesterol, stigmasterol, and beta-sitosterol in their stem parts. 17

Uses and Pharmacology

Certain constituent, such as corosolic acid, possess hypoglycemic activity. Several animal studies support this effect, but more human studies are needed for confirmation.

Diabetes

Constituent corosolic acid from the plant was shown to be a glucose transport activator, suggesting antidiabetic activity. 18 Another report observed inhibitory effects of banaba on postprandial hyperglycemia by inhibiting alpha-amlyase and alpha-glucosidases. 19 Further investigation revealed valoneaic acid dilactone as the amylase inhibitor. 20

In vitro data

Amino acids in both crude and tannin-free, spray-dried extracts isolated from banaba leaves constitute an insulin-like action responsible for hypoglycemic activity. 10 Glucose uptake-inducing activity was also demonstrated in cells, by banaba extract, along with absence of adipocyte differentiation actions and effective inhibition of adipocyte differentiation (induced by insulin plus 3-isobutyl-1-methylxanthine and dexamethasone). These effects suggest banaba may be useful for treatment of hyperglycemia and obesity in type 2 diabetic patients. 21 Ellagitannins lagerstroemin, flosin B, and reginin A increased glucose uptake of rat adipocytes in another report. 4 Another report evaluates deterioration of this insulin-like principle from banaba, demonstrating, for example, that 20 g of old leaves or fruits dried 1 to 2 weeks had hypoglycemic activity equivalent to 6 to 7.7 units of insulin. Banaba differs from insulin in that it is thermostable and lowers blood sugar upon oral administration instead of by injection. 22

Animal data

Bioactive compounds in the leaves including lageracetal, 1-pentanol, ellagic acid, lagertannin, and corosolic acid, affect glucose transport activity in vivo. 9 Genetically, diabetic mice fed certain banaba preparations for a period of 5 weeks experienced hypoglycemic effects, suggesting banaba to be beneficial in controlling plasma glucose levels in non-insulin-dependent diabetes mellitus. 23 A 1% corosolic acid preparation ( Glucosol ) from banaba demonstrated significant blood glucose reduction 90 minutes after administration when given to diabetic rats vs control animals. 24 Banaba extract was also found to have beneficial effects on obese female mice, reducing triglycerides. 25 Hypoglycemic activity of an alcoholic extract of banaba was found, 2 weeks after discontinuation of oral dosing, when studied in diabetic rats. 26

A review of blood glucose-lowering effects of banaba-mulberry extract in rats is available. 27

Clinical data

Human trials performed on the effect of banaba lowering blood glucose are lacking in mainstream, credible medical literature. Web sites mention studies performed: eg, in 1998 (Tokyo Jikeikai Medical School, Japan), 24 type 2 diabetic patients given corosolic acid had reduced blood glucose levels after 4 weeks. Although results of this study sound promising, no credible evidence was found to support these claims.

One credible human trial was found in a small, randomized, clinical trial involving type 2 diabetic patients receiving a daily oral dose of banaba standardized extract, Glucosol (1% corosolic acid). Researchers found that dosages of 32 and 48 mg administered for 2 weeks significantly reduced blood glucose levels. Glucosol in a softgel capsule showed a 30% decrease vs a 20% drop seen with a dry powder-filled, hard gelatin capsule, suggesting better bioavailability from the former product. 28

Other potential uses

Other reported actions of banaba preparations include: antibacterial effects from seed extracts, 16 , 29 significant protection of HIV-infected cells by ellagic acid constituents, 12 antioxidative activity of a water extract, 30 inhibition of xanthine oxidase by aqueous extract, 31 and anti-inflammatory activity in mice. 6

Dosage

None well documented. In one small, randomized, clinical trial involving type 2 diabetic patients, researchers found that dosages of 32 and 48 mg of a banaba extract standardized to 1% corosolic acid (glucosol preparation) administered for 2 weeks significantly reduced blood glucose levels. 28

Pregnancy/Lactation

Because of the lack of pharmacological and toxicity data, avoid the use of banaba during pregnancy and lactation.

Interactions

None well documented. However, because of the glucose-lowering actions of the plant, caution is warranted with use of other diabetic medications, as the effects could be additive.

Adverse Reactions

None well documented.

Toxicology

No toxicity has been reported, even in high doses. 32 Large oral doses produce no toxic effects or convulsions. 22

Bibliography

1. Gilman EF, Watson DG. Lagerstroemia speciosa Queens Crape-Myrtle . US Forest Service. Department of Agriculture. November 1998. Available at: http://hort.ifas.ufl.edu/trees/LAGSPEA.pdf . Accessed August 10, 2004.
2. Philippine Medicinal Plants. Banaba- Lagerstroemia speciosa . Available at: http://www.stuartxchange.com/Banaba.html . Accessed August 10, 2004.
3. Takahashi M, et al. The components of the plants of Lagerstroemia genus. IV. On the presence of the ellagic acid derivatives from the leaves of Lagerstroemia subcostata Koehne, and L. speciosa (L.) Pers. and the synthesis of 3,4-di-O-methylellagic acid [in Japanese]. Yakugaku Zasshi . 1977;97:880-882.
4. Hayashi T, Maruyama H, Kasai R, et al. Ellagitannins from Lagerstroemia speciosa as activators of glucose transport in fat cells. Planta Med . 2002;68:173-175.
5. Takahashi M, Osawa K, Ueda J, Yamamoto F, Tsai CT. The components of the plants of Lagerstroemia genus. ΙΙΙ. On the structure of the new tannin “lagertannin” from the leaves of Lagerstroemia speciosa (L.) Pers. [in Japanese]. Yakugaku Zasshi . 1976;96:984-987.
6. Garcia LL, Fojas FR, Castro IR, Venzon EL, Sison FM, Capal TV. Pharmaceutico-chemical and pharmacological studies on a crude drug from Lagerstroemia speciosa (L.) Pers. Philipp J Sci . 1987;116:361-375.
7. Tanaka T, Tong HH, Xu Y, Ishimaru K, Nonaka G, Nishioka I. Tannins and related compounds. CXVII. Isolation and characterization of three new ellagitannins, lagerstannins A, B, and C, having a gluconic acid core, from Lagerstroemia speciosa (L.) Pers. Chem Pharm Bull . 1992;40:2975-2980.
8. Takahashi M, Osawa K, Sato T, Ueda J, Fujita Y. The chemical structure of the new component “lageracetal” from the leaves of Lagerstroemia speciosa (L.) Pers. [in Japanese]. Yakugaku Zasshi . 1973;93:861-863.
9. Egawa K. Lagerstroemia speciosa (Banaba) . Ota M, Shokuhin KS II, eds. Tokyo, Japan: Shi Emu Shi; 2001:237-241.
10. Manalo J, DeVera FV, Bonifacio TS, Unalivia FD, Arida VP. Phytochemical investigation of Lagerstroemia speciosa leaves (banaba) I. Pers. Philipp J Sci . 1993;122:15-31.
11. Takahashi M, Osawa K, Ueda J, Yamazaki J. The components of the plants of Lagerstroemia speciosa (L.) Pers [in Japanese]. Annual Report of the Tohoku College of Pharmacy. 1979;26:65-68.
12. Faruk MJ, Nahar N, Aziz MA, Mosihuzzaman M, Rashid MA. Two new ellagic acids from Lagerstroemia speciosa Linn. Plant. J Bangladesh Chem Soc . 2002;15:73-78.
13. Badami R, Kudari SM. Component acids of Lagerstroemia speciosa seed oil. Indian J Appl Chem . 1970;33:213-215.
14. Jehan C, Daulatabad D, Mirajkar AM. A keto fatty acid from Lagerstroemia speciosa seed oil. Phytochemistry . 1990;29:2323-2324.
15. Laskarz S, Sinhababu A, Thakur S, Basak B. Extraction and chemical investigation of Lagerstroemia speciosa seed proteins. Am Lab . 1998;30:22,24.
16. Sinhababu A, Das S, Laskar S, Thakur S, Sen SK. Characterization and identification of antibacterial components in extracts of seeds from Lagerstroemia speciosa . Adv Food Sci . 1999;21:19-22.
17. Takahashi M, Sato T, Ueda J. The components of the plants of Lagerstroemia genus. VII. The components in the stems. Annual Report of the Tohoku College of Pharmacy. 1981;28:85-87.
18. Murakami C, Myoga K, Kasai R, et al. Screening of plant constituents for effect on glucose transport activity in Ehrlich ascites tumour cells. Chem Pharm Bull . 1993;41:2129-2131.
19. Suzuki Y, Hayashi K, Sakane I, Kakuda T. Effect and mode of action of banaba ( Lagerstroemia speciosa L.) leaf extracts on postprandial blood glucose in rats [in Japanese]. Nihon Eiyo Shokuryo Gakkai Shi . 2001;54:131-137.
20. Hosoyama H, Sugimoto A, Suzuki Y, Sakane I, Kakuda T. Isolation and quantitative analysis of the α-amylase inhibitor in Lagerstroemia speciosa (L.) Pers. (Banaba) [in Japanese]. Yakugaku Zasshi . 2003;123:599-605.
21. Liu F, Kim J, Li Y, Liu X, Li J, Chen X. An extract of Lagerstroemia speciosa L. has insulin-like glucose uptake-stimulatory and adipocyte differentiation-inhibitory activities in 3T3-L1 cells. J Nutr . 2001;131:2242-2247.
22. Garcia F. Distribution and deterioration of the insulin-like principle in Lagerstroemia speciosa (banaba). Acta Med Philipp . 1941;3:99-104.
23. Kakuda T, Sakane I, Takihara T, Ozaki Y, Takeuchi H, Kuroyanagi M. Hypoglycemic effect of extracts from Lagerstroemia speciosa L. leaves in genetically diabetic KK-AY mice. Biosci Biotechnol Biochem . 1996;60:204-208.
24. Hamamoto S, Kogami H, Kohata K, Moriwaki M, Kanada H, Matsuyama F. Glucosol effect on blood glucose in rats [in Japanese]. Yakuri To Chiryo . 1999;27:1075-1077.
25. Suzuki Y, Unno T, Ushitani M, Hayashi K, Kakuda T. Antiobesity activity of extracts from Lagerstroemia speciosa L. leaves on female KK-Ay mice. J Nutr Sci Vitaminol . 1999;45:791-795.
26. Mishra Y, Khan MS, Zafar R, Agarwal SS. Hypoglycaemic activity of leaves of Lagerstroemia speciosa (L.) Pers. Indian J Pharmacol . 1990;22:174-176.
27. Kazama M. Influence of Banaba-kuwa extracted powder on plasma glucose level in rat. Food Style . 2002;6:98-102.
28. Judy WV, Hari SP, Stogsdill WW, Judy JS, Naguib YM, Passwater R. Antidiabetic activity of a standardized extract ( Glucosol ) from Lagerstroemia speciosa leaves in type II diabetics. J Ethnopharmacol . 2003;87:115-117.
29. Sinhababu A, Basak B, Laskar S, Chakrabarty D, Sen SK. Effect of different fractions of petroleum ether (60-80 degrees) extract of the seeds of Lagerstroemia speciosa (Linn. ex Murray) Pers. on some microorganisms. Hindustan Antibiot Bull . 1994;36:39-45.
30. Unno T, Sakane I, Masumizu T, Kohno M, Kakuda T. Antioxidative activity of water extracts of Lagerstroemia speciosa leaves . Biosci Biotechnol Biochem . 1997;61:1772-1774.
31. Unno T, Sakane I, Kakuda T. Inhibition of xanthine oxidase by an aqueous extract of banaba leaves ( Lagerstroemia speciosa ) [in Japanese]. Nippon Shokuhin Kagaku Kogaku Kaishi . 2000;47:740-743.
32. Vohora SB, Khan MS. Pharmacological studies on Lagerstroemia speciosa . J Res Ayur Sidba . 1982;3:23-27.

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