Banaba Leaf

Last Updated: September 28, 2022

Lagerstroemia, also known as Banaba, is a plant whose leaves have been used for anti-diabetic purposes. It contains a variety of molecules such as corosolic acid which may confer benefit to glucose control.

Banaba Leaf is most often used for.

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Source and Composition



Banaba leaf (of the family Lythraceae) is a term used to refer to the genus of Lagerstroemia, commonly referred to as Crape myrtle.[1]) The supplement sold as 'Banaba' tends to refer to the species of Lagerstroemia Speciosia (Giant Crape Myrtle, Pride of India, or Banaba) with the species of indica or fauriei also being sold at times.[2]

Unless otherwise stated, this article on Banaba Leaf refers to the plant Lagerstroemia Speciosa although the term of 'Banaba' sometimes is applied to the entire genus of Lagerstroemia falsely



The herb Banaba (Lagerstroemia Speciosa) usually contains the following compounds which are seen as relatively unique to Banaba:

  • Valoneaic acid dilactone (VAD) at 0.057% dry weight (leaves)[3][4] which can be increased up to 2% after being subject to hydrolysis, and non-hydrolyzed Banaba can have the VAD content increased up to 0.184% via roasting the leaves;[4] VAD is also present in Pomegranate rinds[5]
  • Some unique ellagitannin structures such as Lagerstroemin,[6] Ellagic Acid (common),[7] Flosin A and Reginin A,[4] Casuarinin, Casurariin, Epipunicacortein A, stachyurin, and 2, 3-(S)-hexahydroxydiphenoyl-α/β-D-glucose[6]
  • Ethyl Gallate (3,4,5-Trihydroxybenzoic acid ethyl ester)[8]
  • The triterpenoid 3β,23-dihydroxy-1-oxo-olean-12-en-28-oic[9]

With the following compounds in Banaba meaning more general:

  • Anthocyanins in the flowers due to the coloration.[1] Cyanidin-3-Glucoside may comprise up to 15% of total anthocyanin content,[1] and Delphinidin-3-Glucoside is also present[1]
  • Flavonoids indlucing Orobol-7-O-D-glucoside[10]
  • Triterpenoids such as Corosolic Acid (up to 14% dry weight of concentrated extracts,[11] 3% dry weight of leaves is a better estimate[12]), Maslinic Acid (4958mg/kg[11]), 23-Hydroxyursolic, Oleanolic Acid, Arjunolic Acid, and Asiatic Acid;[3] Ursolic Acid itself is also present at 2108mg/kg (2.1%)[11]
  • Betulinic acid at 257mg/kg[11]
  • P-coumaric acid, Caffeic Acid, 4-Hydroxybenzoic Acid, and 3-O-Methylprotocatechuic Acid (derivative of anthocyanins)[6]
  • Bioflavonoids such as Kaempferol, Quercetin, and Isoquercetin[6]

The main bioactives that exert the benefits associated with Banaba Leaf appear to be Valoneaic Acid and Corosolic Acid; the latter being very common among plants but Lagerstroemia Speciosa being a very good source of Corosolic Acid

The content of Valoneaic Acid (VA) in Banaba leaves can be increased by roasting (15 minutes at 170°C) from 0.057% to 0.184% the weight of the dry leaves (222% increase), and VA can be produced by the breakdown of the compounds Lagerstroemin, flosin A, and reginin A.[4]

Extracts of Banaba appear to have anti-oxidant effects, which have been confirmed in the serum of rats fed 50-500mg/kg Banaba leaf (1% Corosolic Acid) over 60 days.[13] In vitro tests suggest this extract has an anti-oxidant potency (measured by ABTS+) of 0.012umol of Trolox equivalents per gram.[13] The fruits also have anti-oxidant potential, which is comparable to some other fruits although not inherently remarkable in potency.[14]

Some (unremarkable) antioxidant properties, and roasting the leaves may increase the content of Valoneaic Acid by breaking down some tannins structures into Valoneaic Acid






Following oral administration of 20mg/kg Ethyl Gallate (a polyphenolic in Banaba leaves) to rats, a Cmax of 544.02+/-274.22ng/mL is reached at a Tmax of 6.17+/-2.23 minutes with a half-life of 11.90+/-4.37 minutes (AUC to infinity of 9418.38+/-4378.01).[8]

A metabolite, gallic acid, appears in plasma after 12 minutes (Tmax) with a maximum concentration (Cmax) of 175.13+/-45.22ng/mL and a half-life of 34.01+/-11.51 minutes.[8]


Cardiovascular Health



The anti-inflammatory effects of Banaba appear to extend to the heart, where in isolated Hc92 cardiomyocytes concentrations of Lagerstroemia Speciosa between 0.25-1mg/mL are able to reduce the nuclear activity of NF-kB induced by TNF-α, with 1mg/mL effectively abolishing NF-kB activation.[15]


Interactions with Glucose Metabolism



When looking at fractions of Banaba leaf the acetone, ethanolic, butanolic, and water extracts all appear to have similar inhibitory potential on the alpha-myalse enzyme (35-50% inhibition at 200ug/mL in vitro) with a fraction containing 24% Valoneaic Acid Dilactone (VAD) reaching near 100% inhibition at 200ug/mL.[4] VAD and Valoneaic Acid (VA) appear to be highly correlated with alpha-amylase inhibition from Banaba Leaf.[4] Triterpenoids have failed to exert any significant inhibition of alpha-amylase.[3]

Alpha glucosidase may also be inhibited by triterpenoid compounds, with Corosolic Acid being most potent (IC50 of 3.53ug/mL; uncompetitive inhibition) with notable inhibition coming from Maslinic Acid (5.52+/-0.19μg/mL) and Oleanolic Acid (6.29+/-0.37μg/mL) with the ethyl acetate fraction itself tested being 88.72+/-1.02μg/mL.[3] One other study has noted that the extract itself has an IC50 of 0.3μg/mL, suggesting other compounds may be contributing beyond Corosolic Acid.[16]

There appear to be compounds within Banaba that can inhibit the absorption of carbohydrates from the intestines

One acute study using 10mg Corosolic Acid (99% pure) given 5 minutes prior to a 75g Glucose Tolerance Test in humans noted that at 60-120 minutes post-ingestion that there was reductions in blood glucose and that the 90 minute time point was statistically significant.[17]

Corosolic acid appears to have some degree of efficacy in humans



An ellagitannin from Banaba, Lagerstroemin, appears to act as an agonist of the insulin receptor.[18] A such, it works via PI3K and is inhibited by Wortmannin.[18]

A Lagerstroemin unique tannin structure may directly activate the insulin receptor



A study in streptozotocin-induced diabetic mice given an extract of Banaba standardize to 1% Corosolic acid (50-500mg/kg bodyweight) for 2 months noted that measurements at 10 days or sooner failed to show any benefit but that all doses reduced blood glucose concentrations at day 15 and maintained similar potency up to day 60.[13]

Isolated Corosolic acid from Banaba at 0.023% of the diet in KK-Ay diabetic mice noted reduced serum (32%) and hepatic (46%) cholesterol concentrations after 10 weeks.[19] Corosolic acid is the bioactive which is thought to mediate most effects of Banaba leaf due to its high concentration and known bioactivities.[20]

Glucosol, a patented blend of Banaba, appears to be able to reduce blood glucose in the serum of diabetic rats within 90 minutes of administration.[21]

Various benefits in animal models associated with the Corosolic Acid content

One human study (not located online, but noted in this review as citation 19[20]) notes that oral administration of Banaba Leaf over a year in pre-diabetic persons (glucose greater than 110mg/dL) was associated with a 16.6% reduction in blood glucose with no reported hypoglycemia nor adverse effects.

One study using the Brand name product 'Glucosol' (no funding from company producing Glucosol) noted that 32-48mg of this product standardized to 1% Corosolic Acid was able to reduce the blood glucose of Type II Diabetics after 15 days in a dose-dependent manner.[12] The degree of reduction was 3.18-4.9% at 16mg (failed to reach statistical significance), 6.5-10.7% at 32mg, and 20.2-30% at 48mg; oddly, soft gels appeared to be more effective than hard capsules.[12] There is also apparently an unpublished study (again mentioned in a review of human trials[20]) where a soft gel of Banaba leaf (10mg Corosolic Acid) was used over 30 days in prediabetics or type II diabetics and resulted in 10% reductions of blood glucose (fasting and postprandial) relative to placebo.

Other studies include a trial using a product blend (Banaba Leaf, Green tea and coffee (for green tea catechins and chlorogenic acid respectively) and Garcinia Cambogia) noted reductions in blood glucose of 13.5% with no significant influence on HbA1c, Fructosamine, Insulin, Total cholesterol, HDL-C, Triglycerides, Leptin or Body Weight in persons with high serum glucose (n=20).[22] One other highly confounded study exists where over 12 weeks participants consumed Banaba (16mg), Bitter Melon (100mg), Garcinia Cambogia (1500mg, 60% HCA), Gymnema extract (133mg) Black Pepper extract at 1.6mg, and the dietary minerals Magnesium (50mg), Vanadium (50mcg), and Chromium (167mcg) which preceded a weight loss of 6.29kg.[23]

Although a variety of human studies exist, a few are too confounded with other nutrients to draw conclusions from and many of these studies are inaccessible online. There appears to be some benefit associated with oral Banaba Leaf which is possibly related to the Corosolic Acid content, but there is a lack of published and large double-blind trials


Interactions with Body Fat



The tannin structures appear to be able to increase glucose uptake in isolated rat adipocytes via GLUT4 translocation, with Lagerstroemin, flosin B, and reginin A being unique bioactives in Banaba shown to do so,[24] with tannic acid itself being a contributing factor.[25] At a concentration of 0.04mg/mL, a few tannins showed potency in inducing glucose uptake similar to 100nM insulin (Flosin B, Stachyurin, Casuarinin, Lagerstroemin, and 2,3-(S)-hexahydroxydiphenoyl-α/β-D-glucose), with all tannins reaching maximal glucose uptake in the range of 24-49% at concentrations below 1mg/mL.[24] A hot water extract of Banaba still exerts glucose uptake effects to a lesser potency than insulin (due to less concentration of bioactives)[26] and there do not appear to be additive nor synergistic effects with insulin itself.[26]

Corosolic acid has also been shown to induce GLUT4 mobilization in adipocytes[27] and other cells.[28]

At least one ellagic acid derivative (3-O-methylellagic acid, of which ellagic acid passively degrades into) has been noted to suppress glucose uptake.[24]

Mixed effects on glucose uptake, but many of the tannin structures appear to be able to stimulate GLUT4 translocation and promote glucose uptake into cells

In regards to adipocyte proliferation, the proliferation of adipocytes (with 100% set as control) is reduced at a concentration of 0.1mg/mL to 62-64% with either 3-O-methyl-ellagic acid 4'-sulfate or 3,4,3'-tri-O-methylellagic acid and is reduced to 38% with 3-O-methylellagic acid; these inhibitory effects are lost at 0.5mg/mL.[24] In 3T3-L1 adipocytes, a basic Banaba Leaf hot water extract has shown these suppressive effects on fat cell proliferation in the presence of corticosteroids and insulin in vitro at 0.1-0.25mg/mL.[26]

Some compounds may suppress fat cell proliferation

2.^Klein G, Kim J, Himmeldirk K, Cao Y, Chen XAntidiabetes and Anti-obesity Activity of Lagerstroemia speciosaEvid Based Complement Alternat Med.(2007 Dec)
3.^Hou W, Li Y, Zhang Q, Wei X, Peng A, Chen L, Wei YTriterpene acids isolated from Lagerstroemia speciosa leaves as alpha-glucosidase inhibitorsPhytother Res.(2009 May)
4.^Hosoyama H, Sugimoto A, Suzuki Y, Sakane I, Kakuda TIsolation and quantitative analysis of the alpha-amylase inhibitor in Lagerstroemia speciosa (L.) Pers. (Banaba)Yakugaku Zasshi.(2003 Jul)
5.^Jain V, Viswanatha GL, Manohar D, Shivaprasad HNIsolation of Antidiabetic Principle from Fruit Rinds of Punica granatumEvid Based Complement Alternat Med.(2012)
7.^Unno T, Sugimoto A, Kakuda TXanthine oxidase inhibitors from the leaves of Lagerstroemia speciosa (L.) PersJ Ethnopharmacol.(2004 Aug)
8.^Gao S, Zhan Q, Li J, Yang Q, Li X, Chen W, Sun LLC-MS/MS method for the simultaneous determination of ethyl gallate and its major metabolite in rat plasmaBiomed Chromatogr.(2010 May)
9.^Okada Y, Omae A, Okuyama TA new triterpenoid isolated from Lagerstronemia speciosa (L.) PersChem Pharm Bull (Tokyo).(2003 Apr)
14.^Fu L, Xu BT, Xu XR, Qin XS, Gan RY, Li HBAntioxidant capacities and total phenolic contents of 56 wild fruits from South ChinaMolecules.(2010 Nov 29)
15.^Ichikawa H, Yagi H, Tanaka T, Cyong JC, Masaki TLagerstroemia speciosa extract inhibit TNF-induced activation of nuclear factor-kappaB in rat cardiomyocyte H9c2 cellsJ Ethnopharmacol.(2010 Mar 2)
16.^Kesavanarayanan KS, Sathiya S, Ranju V, Sunil AG, Ilavarasan R, Saravana Babu C, Kavimani S, Prathiba DIn vitro cytotoxic, antioxidative and alpha-glucosidase inhibitory potential of a herbal mixture comprised of Allium sativum and Lagerstroemia speciosaEur Rev Med Pharmacol Sci.(2012 Jul)
17.^Fukushima M, Matsuyama F, Ueda N, Egawa K, Takemoto J, Kajimoto Y, Yonaha N, Miura T, Kaneko T, Nishi Y, Mitsui R, Fujita Y, Yamada Y, Seino YEffect of corosolic acid on postchallenge plasma glucose levelsDiabetes Res Clin Pract.(2006 Aug)
18.^Hattori K, Sukenobu N, Sasaki T, Takasuga S, Hayashi T, Kasai R, Yamasaki K, Hazeki OActivation of insulin receptors by lagerstroeminJ Pharmacol Sci.(2003 Sep)
19.^Takagi S, Miura T, Ishihara E, Ishida T, Chinzei YEffect of corosolic acid on dietary hypercholesterolemia and hepatic steatosis in KK-Ay diabetic miceBiomed Res.(2010 Aug)
20.^Miura T, Takagi S, Ishida TManagement of Diabetes and Its Complications with Banaba (Lagerstroemia speciosa L.) and Corosolic AcidEvid Based Complement Alternat Med.(2012)
24.^Hayashi T, Maruyama H, Kasai R, Hattori K, Takasuga S, Hazeki O, Yamasaki K, Tanaka TEllagitannins from Lagerstroemia speciosa as activators of glucose transport in fat cellsPlanta Med.(2002 Feb)
27.^Miura T, Itoh Y, Kaneko T, Ueda N, Ishida T, Fukushima M, Matsuyama F, Seino YCorosolic acid induces GLUT4 translocation in genetically type 2 diabetic miceBiol Pharm Bull.(2004 Jul)
28.^Murakami C, Myoga K, Kasai R, Ohtani K, Kurokawa T, Ishibashi S, Dayrit F, Padolina WG, Yamasaki KScreening of plant constituents for effect on glucose transport activity in Ehrlich ascites tumour cellsChem Pharm Bull (Tokyo).(1993 Dec)