Antidiabetic activity of a standardized extract (Glucosol) from Lagerstroemia speciosa leaves in Type II diabetics. A dose-dependence study

The antidiabetic activity of an extract from the leaves of Lagerstroemia speciosa standardized to 1% corosolic acid (Glucosol) has been demonstrated in a randomized clinical trial involving Type II diabetics (non-insulin-dependent diabetes mellitus, NIDDM). Subjects received a daily oral dose of Glucosol and blood glucose levels were measured. Glucosol at daily dosages of 32 and 48mg for 2 weeks showed a significant reduction in the blood glucose levels. Glucosol in a soft gel capsule formulation showed a 30% decrease in blood glucose levels compared to a 20% drop seen with dry-powder filled hard gelatin capsule formulation (P<0.001), suggesting that the soft gel formulation has a better bioavailability than a dry-powder formulation.

Active compounds from Lagerstroemia speciosa, insulin-like glucose uptake-stimulatory/inhibitory and adipocyte differentiation-inhibitory activities in 3T3-L1 cells

Seven ellagitannins, lagerstroemin (1), flosin B (2), stachyurin (3), casuarinin (4), casuariin (5), epipunicacortein A (6), and 2, 3-(S)-hexahydroxydiphenoyl-alpha/beta-D-glucose (7), together with one ellagic acid sulfate, 3-O-methyl-ellagic acid 4'-sulfate (8), ellagic acid (9), and four methyl ellagic acid derivatives, 3-O-methylellagic acid (10), 3,3'-di-O-methylellagic acid (11), 3,4,3'-tri-O-methylellagic acid (12), and 3,4,8,9,10-pentahydroxydibenzo[b,d]pyran-6-one (13), were identified by the bioassay-directed isolation from the leaves of Lagerstroemia speciosa (L.) Pers. The chemical structures of these components were established on the basis of one- and two-dimensional NMR and high-resolution mass spectroscopic analyses. Other known compounds, including corosolic acid, gallic acid, 4-hydroxybenzoic acid, 3-O-methylprotocatechuic acid, caffeic acid, p-coumaric acid, kaempferol, quercetin, and isoquercitrin, were also isolated from the same plant. The obtained ellagitannins exhibited strong activities in both stimulating insulin-like glucose uptake (1-5 and 7) and inhibiting adipocyte differentiation (1 and 4) in 3T3-L1 cells. Meanwhile, ellagic acid derivatives (10-13) showed an inhibitory effect on glucose transport assay. This study is the first to report an inhibitory effect for methyl ellagic acid derivatives.

Antiviral activity and possible mode of action of ellagic acid identified in Lagerstroemia speciosa leaves toward human rhinoviruses

BACKGROUND

Human rhinoviruses (HRVs) are responsible for more than half of all cases of the common cold and cause billions of USD annually in medical visits and school and work absenteeism. An assessment was made of the cytotoxic and antiviral activities and possible mode of action of the tannin ellagic acid from the leaves of Lagerstroemia speciosa toward HeLa cells and three rhinoviruses, HRV-2, -3, and -4.

METHODS

The antiviral property and mechanism of action of ellagic acid were evaluated using a sulforhodamine B assay and real-time reverse transcription-PCR (RT-PCR) with SYBR Green dye. Results were compared with those of the currently used broad-spectrum antiviral agent, ribavirin.

RESULTS

As judged by 50% inhibitory concentration values, natural ellagic acid was 1.8, 2.3, and 2.2 times more toxic toward HRV-2 (38 μg/mL), HRV-3 (31 μg/mL), and HRV-4 (29 μg/mL) than ribavirin, respectively. The inhibition rate of preincubation with 50 μg/mL ellagic acid was 17%, whereas continuous presence of ellagic acid during infection led to a significant increase in the inhibition (70%). Treatment with 50 μg/mL ellagic acid considerably suppressed HRV-4 infection only when added just after the virus inoculation (0 h) (87% inhibition), but not before -1 h or after 1 h or later (<20% inhibition). These findings suggest that ellagic acid does not interact with the HRV-4 particles and may directly interact with the human cells in the early stage of HRV infections to protect the cells from the virus destruction. Furthermore, RT-PCR analysis revealed that 50 μg/mL ellagic acid strongly inhibited the RNA replication of HRV-4 in HeLa cells, suggesting that ellagic acid inhibits virus replication by targeting on cellular molecules, rather than virus molecules.

CONCLUSIONS

Global efforts to reduce the level of antibiotics justify further studies on L. speciosa leaf-derived materials containing ellagic acid as potential anti-HRV products or a lead molecule for the prevention or treatment of HRV infection.

Ring Expansive Routes to Quinolizidine Alkaloids: Formal Synthesis of (−)-Lasubine II

The application of two nitrogen ring expansion reactions to lasubine alkaloid synthesis is reported. The approach involves a conjugate reduction/alkylation sequence carried out on triisopropylsilyl-protected (S)-4-(-)-hydroxycyclopentenone, the formation of the quinolizidone ring system through nitrogen ring expansion, and the addition of an arylmetallic species to the resulting lactam. This work resulted in the preparation of 2-epi-lasubine II and a formal synthesis of lasubine II. [reaction: see text]

In vitro and in vivo inhibitory activities of four Indian medicinal plant extracts and their major components on rat aldose reductase and generation of advanced glycation endproducts

The polyol enzyme aldose reductase (AR) and advanced glycation endproducts (AGEs) play an important role in diabetic complications such as cataracts. The purpose of this study was to investigate four standardized plant extracts used for the treatment of diabetes and related diseases, and their principal components for AR inhibitory activity and to find out their influence in diabetic complications. Thus, Boswellia serrata Triana & Planch. (Burseraceae), Lagerstroemia speciosa (L.) Pers. (Lythraceae), Ocimum gratissimum (L.) (Lamiaceae) and Syzygium cumin (L.) Skeels. (Myrthaceae) and their respective major constituents, boswellic acid, corosolic acid, ursolic acid and ellagic acid, were studied for their inhibitory activity against rat lens AR, rat kidney AR, human recombinant AR and generation of AGEs. In addition, in vivo inhibition of lens galactitol accumulation by the major constituents of the plants in galactose-fed rat has been studied. The results revealed that all the tested extracts and their active ingredients possess significant AR inhibitory actions in both in vitro and in vivo assays with urosolic acid showing the most potent effect. Furthermore, the study indicates the potential of the studied plants and their major constituents as possible protective agents against long-term diabetic complications.

Effects of malted barley extract and banaba extract on blood glucose levels in genetically diabetic mice

This study investigated the therapeutic effects of a malted barley extract (MBE) and of banaba extract on blood glucose, insulin, and other biochemical parameters in genetically diabetic mice (C57BL/KsJ(-) m (+/+) Lepr (db)). The mice were divided into three groups-control, MBE, and banaba-according to supplementation. Both MBE and banaba extracts were orally administered to the animals for 12 weeks at doses of 62.5 mg/kg of body weight and 0.8 mg/kg of body weight, respectively. The body and organ (liver and kidney) weights were not different among groups. Fasting blood glucose was significantly lower in the MBE group compared with the control (P < .05). Hemoglobin A1c content was significantly lower in the MBE group compared with either the control or banaba group (P < .05). There was no significant difference in the serum insulin level among groups. The glucose-6-phosphatase activity in kidney was significantly lower in both the MBE and banaba groups compared with the control group (P < .05), but there was no significant difference between the MBE and banaba groups. Therefore, the results of this study demonstrate that MBE alleviates many of the symptoms of diabetes in genetically obese mice and may offer promise as a therapeutic supplement for the normalization of blood glucose levels in humans with hyperglycemia and have beneficial effects in patients with non-insulin-dependent diabetes mellitus.

Fluoride Exposure Aggravates the Testicular Damage and Sperm Quality in Diabetic Mice: Protective Role of Ginseng and Banaba

Fluoride toxicity is known to pose infertility in fluoride-intoxicated animals as well as in people residing in fluoride endemic zones. The present study addresses the degree of impairments caused due to co-exposure of high fluoride toxicity in diabetic mice. Swiss mice, Mus musculus, were subjected to fluoride toxicity by providing fluoride-supplemented drinking water (600 ppm NaF) for a period of 30 days after the confirmation of streptozotocin-induced diabetes(STZ, 50 mg/kgbw). Consequently, aggravated hyperglycemia and tissue fluoride accumulation were witnessed in fluoride-intoxicated diabetic mice; later, these toxicated mice were treated with ginseng extract (GE) and banaba leaf extract, (BLE) at dose of 150 mg/kgbw/day alone and in combination for 15 and 30-day duration to check the efficacy of phytoextracts in reversing the toxicity. The spermatological indices studied, such as sperm density, motility, viability and morphology as well as the testicular biochemical parameters showed enhanced impairment in reproductive status of fluoride-intoxicated diabetic mice. Further, 15-days administration of GE and BLE in combination at a dose of 150 mg/kgbw/day was found to be beneficial in normalizing the alterations observed upon fluoride intoxication to diabetic mice. However, the correlates showed moderate association between blood glucose levels and the spermatological as well as biochemical indices wherein the tissue fluoride levels correlate least.

Suppression of mitochondrial oxidative phosphorylation and TCA enzymes in discrete brain regions of mice exposed to high fluoride: amelioration by Panax ginseng (Ginseng) and Lagerstroemia speciosa (Banaba) extracts

Chronic fluoride intoxication results in pathophysiological complications pertaining to soft tissues, called non-skeletal fluorosis. This study examined whether fluoride-induced alterations in selected parameters that are indicative of mitochondrial dysfunction accompany the toxic effects of fluoride in discrete brain regions in vivo and also explored the possibility of treatment with Ginseng (GE) and Banaba (BLE) either alone or with their co-exposure which is capable of reversing parameters indicative of fluoride-induced impairments in mitochondrial function. Swiss mice, Mus musculus, were given 270 ppm fluoride (600 ppm NaF) in their drinking water for 30 days, while continuing the fluoride exposure, toxicated animals were given differential doses (50-250 mg/kg body wt) of phytoextracts through oral gavage for 2 weeks. Discrete brain regions separated from dissected animals to perform biochemical assessments. Disturbances in mitochondrial enzyme complexes (I-IV) and decrements in TCA enzymes (ICDH, SDH, and aconitase) were noted in discrete brain regions upon F exposure, suggesting mitochondrial dysfunction. In addition, a significant reduction in oxidative stress indices with increased MDA content as well as decrease in reduced glutathione content and increases in catalase and SOD enzyme activity suggests the involvement of severe oxidative stress affecting the mitochondrial function(s). Treatment with either GE or BLE reversed F-induced alterations in augmenting the suppressed complex enzymes followed by TCA enzymes and oxidative stress indices in a dose independent manner. However, the co-exposure of GE and BLE at a dose of 150 mg/kgbw appeared to restore mitochondrial functioning. These results provide in vivo evidence supporting the hypothesis that fluoride induces impairments in mitochondrial function, which can be reversed by treatment with GE and BLE as well their co-exposure at 150 mg/kgbw.

[Isolation and quantitative analysis of the alpha-amylase inhibitor in Lagerstroemia speciosa (L.) Pers. (Banaba)]

Banaba [Lagerstroemia speciosa (L.) Pers.] has been used as a folk medicine for diabetes in the Philippines. Using bioassay-guided separation, valoneaic acid dilactone (1) was isolated from the leaves as a potent alpha-amylase inhibitor. A simple and efficient method for the quantitative determination of valoneaic acid and its derivatives in Banaba extract was established. Valoneaic acid exists as the structural part of the polyphenols, which like flosin A, reginin A, and lagerstroemin, are characteristic constituents of Banaba. These derivatives were hydrolyzed to valoneaic acid by HCl and extracted with 2-butanone. This extract was subjected to HPLC analysis, and the contents of valoneaic acid determined as the whole valoneaic acid contents. Using this method, the whole valoneaic acid contents were measured in eight Banaba leaf decoctions. The alpha-amylase-inhibiting activities of the decoctions were dependent on the whole valoneaic acid contents. In addition, a strong linear correlation was observed between the whole valoneaic acid contents and total polyphenol contents. This analytical procedure is applicable to the chemical evaluation of Banaba.

Sorption and recovery of platinum from simulated spent catalyst solution and refinery wastewater using chemically modified biomass as a novel sorbent

In this study, Lagerstroemia speciosa biomass modified by polyethylenimine (PEI-LS) was developed as a potential biosorbent for sorption and recovery of platinum(II) from platinum bearing waste solutions. Batch experiments were conducted to study the effect of various parameters on the sorption and recovery of platinum(II) using PEI-LS. The equilibrium time for platinum(II) sorption process was found to be 6 h. Both the sorption kinetics and sorption isotherm data fits pseudo second-order kinetic model and Langmuir isotherm, respectively. The maximum sorption capacity of platinum(II) onto PEI-LS at pH 2 for the studied temperature range (25-45 °C) is in the range of 122-154 mg/g. Evaluation of thermodynamic parameters suggests that the platinum(II) sorption is spontaneous and endothermic in nature. The regeneration of PEI-LS can be achieved using acidic thiourea as an eluent for recovery of platinum from the biosorbent. Fourier transform infrared (FT-IR) analysis suggests many functional groups were involved in platinum(II) sorption onto PEI-LS. Both the scanning electron microscope/energy dispersive spectroscopy (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) analysis suggest a successful modification of raw biomass with PEI. The XPS analysis further concludes that platinum(II) sorption is governed by ion-exchange and co-ordination reaction. Finally, the PEI-LS was shown to recover ≥ 90% of platinum from two simulated solutions: the acid-leached spent catalyst solution and refinery wastewater. The biosorbent developed in this study is a low-cost and eco-friendly media that can be effectively used for platinum recovery from industrial wastewater.

Terpenoids and sterols from Lagerstroemia speciosa

The leaves of Lagerstroemia speciosa afforded a new natural product, 31-norlargerenol acetate (4), along with known compounds 24-methylenecycloartanol acetate (1), its 31-nor analog (2), largerenol acetate (3), tinotufolins C (5) and D (6), lutein, phytol, sitosterol and sitosterol acetate. The structure of 4 was elucidated by 1D and 2D NMR and mass spectroscopy.

Biphenylquinolizidine alkaloids from Lagerstroemia indica

Two new biphenylquinolizidine alkaloids, 5-epi-dihydrolyfoline (1) and its stereoisomer, dihydrolyfoline (2), along with lagerine (3) were isolated from the aerial parts of Lagerstroemia indica. The structures of compounds 1-3 were elucidated by extensive spectroscopic techniques.

Corosolic acid content and SSR markers in Lagerstroemia speciosa (L.) Pers.: a comparative analysis among populations across the Southern Western Ghats of India

Lagerstroemia speciosa commonly known as 'Banaba' is native of south-east Asia which exhibits both horticultural and therapeutic value. The anti-diabetic and anti-obese property of the tree is attributed to corosolic acid (CRA)-a pentacyclic triterpene seen predominantly in the mature leaves. Although there are studies on either chemical or genetic variation in L. speciosa from different regions, none have dealt with their association to discuss the formation of chemical diversity. For the first time, we have analyzed CRA content in 12 natural populations corresponding to 42 samples seen in the Southern Western Ghats (SWG) using chromatography techniques and genetic variation estimated using SSR markers. Significant variation in percentage distribution of CRA ranging from 0.005% to 0.868% dr.wt. was recorded wherein populations from the north SWG contain relatively more active principle (mean=0.321%) than their counterparts in the south (mean=0.064%). Similarly, SSR data showing relatively high rate of gene flow (Nm=2.72) and low genetic differentiation (FST=0.14) is indicative that populations from north are genetically more diverse than those in the south (Nm=0.48; FST=0.38). The scatter plot derived by Principle Component Analysis (PCA) of chemical and genetic data shows similar pattern of clustering that reveals strong association between the two sets of data. It is concluded that the observed variation in CRA content in natural populations of the species depends more on the genetic background and less on edaphic factors.

Synthesis, characterization and application of Lagerstroemia speciosa embedded magnetic nanoparticle for Cr(VI) adsorption from aqueous solution

Lagerstroemia speciosa bark (LB) embedded magnetic nanoparticles were prepared by co-precipitation of Fe²⁺ and Fe³⁺ salt solution with ammonia and LB for Cr(VI) removal from aqueous solution. The native LB, magnetic nanoparticle (MNP), L. speciosa embedded magnetic nanoparticle (MNPLB) and Cr(VI) adsorbed MNPLB particles were characterized by SEM-EDX, TEM, BET-surface area, FT-IR, XRD and TGA methods. TEM analysis confirmed nearly spherical shape of MNP with an average diameter of 8.76nm and the surface modification did not result in the phase change of MNP as established by XRD analysis, while led to the formation of secondary particles of MNPLB with diameter of 18.54nm. Characterization results revealed covalent binding between the hydroxyl group of MNP and carboxyl group of LB particles and further confirmed its physico-chemical nature favorable for Cr(VI) adsorption. The Cr(VI) adsorption on to MNPLB particle as an adsorbent was tested under different contact time, initial Cr(VI) concentration, adsorbent dose, initial pH, temperature and agitation speed. The results of the equilibrium and kinetics of adsorption were well described by Langmuir isotherm and pseudo-second-order model, respectively. The thermodynamic parameters suggest spontaneous and endothermic nature of Cr(VI) adsorption onto MNPLB. The maximum adsorption capacity for MNPLB was calculated to be 434.78mg/g and these particles even after Cr(VI) adsorption were collected effortlessly from the aqueous solution by a magnet. The desorption of Cr(VI)-adsorbed MNPLB was found to be more than 93.72% with spent MNPLB depicting eleven successive adsorption-desorption cycles.

Investigation of biological activities of the flowers of Lagerstroemia speciosa, the Jarul flower of Bangladesh

BACKGROUND

Lagerstroemia speciosa (L.) Pers. (Family: Lythraceae) is used in traditional medicine in the treatment of diarrhea, diabetes and other diseases. The study was performed to conduct antioxidant, cytotoxic, thrombolytic, membrane stabilizing, antimicrobial, peripheral and central analgesic and hypoglycemic activity assays and phenobarbitone sodium-induced sleeping time test using crude methanol extract of flowers of L. speciosa and its different partitionates.

METHOD

The antioxidant potential was evaluated by determining the ability of the samples to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The cytotoxic potential was examined following the procedures of brine shrimp lethality bioassay. Thrombolytic potential was assayed using streptokinase as standard. The samples were subjected to membrane stabilizing activity assay under heat induced condition. Antimicrobial potential was observed by disc diffusion method. The ability of the extract to inhibit writhing induced by acetic acid was determined in peripheral analgesic activity assay. The extract was also tested for central analgesic and hypoglycemic activities by tail flicking and tail tipping methods in Swiss albino mice model, respectively. CNS depressant activity was evaluated by an assay in which sleep was induced in mice using phenobarbitone sodium.

RESULTS

The chloroform soluble fraction of L. speciosa extract demonstrated the highest antioxidant activity (IC50 = 4.20 ± 0.41 μg/ml) while the most prominent cytotoxic potency was showed by hexane soluble fraction (LC50 = 2.00 ± 0.31 μg/ml). Among the test samples, the carbon tetrachloride soluble fraction induced clot lysis (64.80 ± 0.27%) and prevented heat induced haemolysis (41.90 ± 0.10%) to the maximum extent. The largest zone of inhibition (19.0 mm) against Staphylococcus aureus, was also observed for the same fraction. In peripheral analgesic activity assay, 16.68% inhibition of writhing was documented for the L. speciosa extract (400 mg/kg body weight dose). The extract (400 mg/kg dose) also reduced blood sugar level by 56.12% after three hours of administration of glucose solution. In CNS depressant activity assay, mice of the sample group slept for shorter period of time compared to control group.

CONCLUSIONS

From our investigation, it can be suggested that, the extract should be further studied for possible phytochemicals responsible for the observed biological activities.

Two new phenolic glucosides from Lagerstroemia speciosa

Two new phenolic glucosides, 1-O-benzyl-6-O-E-caffeoyl-β-d-glucopyranoside and 1-O-(7S,8R)-guaiacylglycerol-(6-O-E-caffeoyl)-β-d-glucopyranoside, were isolated from the aerial parts of Lagerstroemia speciosa, along with ten known compounds. The structures of the isolated compounds were determined based on 1D- and 2D-NMR, Q-TOF MS and optical rotation spectroscopic data. All of the compounds showed moderate inhibitory activities against nitric oxide production in lipopolysaccharide-treated RAW264.7 cells, with IC₅₀ values of 69.5–83.3 μM.

Lagerstroemia speciosa (L.) Pers Leaf Extract Attenuates Lung Tumorigenesis via Alleviating Oxidative Stress, Inflammation and Apoptosis

One of the major etiological factors that account for lung cancer is tobacco use. Benzo(a)pyrene [B(a)P], one of the main constituents of tobacco smoke, has a key role in lung carcinogenesis. The present study was conducted to investigate the cytotoxicity of an aqueous ethanolic extract of Lagerstroemia speciosa (L.) Pers leaves (LLE) on human lung adenocarcinoma cells (A549), as well as its in vivo antitumor effect on a lung tumorigenesis mice model. Our results revealed that LLE possesses cytotoxic activity against the A549 cell line. Mice orally administered B(a)P (50 mg/kg body weight) showed an increase in relative lung weight with subsequent decrease in final body weight. Serum levels of tumor marker enzymes AHH, ADA and LDH and the inflammatory mediator NF-κB increased, while total antioxidant capacity (TAC) decreased. In addition, we observed the increased activity of metalloproteinases (MMP-2 and MMP-12) and levels of the tumor angiogenesis marker VEFG and the lipid peroxidation marker MDA, as well as decreased levels of the non-enzymatic antioxidant GSH and enzymatic antioxidants CAT and GSH-Px in lung tissues. Moreover, B(a)P administration up-regulated the expression of the COX-2 gene, pro-inflammatory cytokines TNF-α and IL-6, and an anti-apoptotic gene Bcl-2, and at the same time down-regulated expression of pro-apoptotic genes BAX and caspase-3 and the p53 gene. Pre- and post-treatment with LLE (250 mg/kg body weight) attenuated all these abnormalities. Histopathological observations verified the protective effect of LLE. Overall, the present data positively confirm the potent antitumor effect of L. speciosa leaves against lung tumorigenesis.

Determination of anthocyanins and exploration of relationship between their composition and petal coloration in crape myrtle (Lagerstroemia hybrid)

Petal coloration and pigment components in 12 American crape myrtle cultivars (Lagerstroemia indicaxLagerstroemia fauriei) and five Chinese crape myrtle cultivars (L. indica hybrids) were studied. Color was measured by CIEL*a*b* scale and anthocyanin composition of crape myrtle was determined using high-performance liquid chromatography coupled to photodiode array detection and electrospray ionization mass spectrometry. The presence of the previously reported delphinidin 3-O-glucoside, petunidin 3-O-glucoside and malvidin 3-O-glucoside were confirmed. Cyanidin 3-O-glucoside was identified in crape myrtle for the first time. We explored the relationship between petal color and anthocyanin contents by multiple linear regression analyses. The results indicated that total flavones and flavonols were important variables and contributed to blue-enhancing in crape myrtle. Based on anthocyanins and co-pigments analysis, flower color breeding in crape myrtle towards true-red and blue were discussed.

Lagerstroemia speciosa extract inhibit TNF-induced activation of nuclear factor-kappaB in rat cardiomyocyte H9c2 cells

AIM OF THE STUDY

Lagerstroemia speciosa has been used as a folk medicine among people with diabetes in the Philippines. It is known to exhibit antidiabetic, antiobesity, and glucose transport activities through mechanisms not well defined. Diabetes leads to cardiomyocyte hypertrophy in association with an upregulation of vasoactive factors and activation of nuclear factor (NF)-kappaB and activating protein-1. We therefore investigated the effect of Lagerstroemia speciosa on the activation of NF-kappaB as a key mediator of cardiomyocyte hypertrophy, in rat cardiomyocyte H9c2 cells.

MATERIALS AND METHODS

Water extract of Lagerstroemia speciosa (Lythraceae family) was prepared. H9c2 cells were used for treatment of Lagerstroemia speciosa extract with/without tumor necrosis factor (TNF). To examine NF-kappaB's activation, we performed an electrophoretic mobility shift assay (EMSA).

RESULTS

The activation of NF-kappaB by TNF was completely blocked by a Lagerstroemia speciosa extract in a dose- and time-dependent manner in H9c2 cells.

CONCLUSION

Overall, our results indicate that Lagerstroemia speciosa can inhibit DNA-binding of NF-kappaB. This may explain its possible inhibition of diabetes-induced cardiomyocyte hypertrophy.

Biphenyl and biphenyl ether quinolizidine N-oxide alkaloids from Lagerstroemia indica L

Four new biphenyl and biphenyl ether quinolizidine N-oxide alkaloids, 5- EPI-dihydrolyfoline N-oxide (1), decamine N-oxide (2), lagerstroemine N-oxide (3), and lagerine N-oxide (4), were isolated from the aerial parts of Lagerstroemia indica, and their structures were established by extensive spectroscopic studies. In addition, the inhibitory effects of isolated compounds on rat lens aldose reductase (RLAR) were examined.

Sesquiterpenoid and phenolic glucoside gallates from Lagerstroemia balansae

Three new compounds, including a sesquiterpenoid glucoside gallate, 2 Z,4 E,1' R,2' S,4' R,6' S-dihydrophaseic acid 4'-O-(6''-O-galloyl)-β-D-glucopyranoside (1), two new phenolic glucoside gallates, 4-hydroxy-3,5-dimethoxybenzoic acid 4-O-(6'-O-galloyl)-β-D-glucopyranoside (2) and 3,4-dimethoxyphenol 1-O-(6'-O-galloyl)-β-D-glucopyranoside (3), together with eight known compounds (4-11), have been isolated from the stems of Lagerstroemia balansae. Their structures were elucidated on the basis of chemical and spectroscopic evidences.

Amelioration of cisplatin induced nephrotoxicity in mice by an ethyl acetate extract of Lagerstroemia speciosa (L)

We studied an ethyl acetate (EtoAC) extract of leaves obtained from the medicinal and ornamental tree, Lagerstroemia speciosa L, for nephroprotective activity in cisplatin-induced acute renal injury in Balb/C mice. The EtoAC extract at dose levels of 50 and 250 mg/kg showed a dose-dependent reduction in cisplatin-induced elevations in urea and creatinine concentrations. Additionally, treatment with the EtoAC extract prevented the cisplatin-induced decline of the renal antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione. The findings suggest that the EtoAC extract from L. speciosa possesses marked nephroprotective activity and could offer a promising role in the treatment of acute renal injury caused by a nephrotoxin like cisplatin.

In vitro cytotoxic, antioxidative and alpha-glucosidase inhibitory potential of a herbal mixture comprised of Allium sativum and Lagerstroemia speciosa

BACKGROUND

Hyperglycemia induced over production of free radicals in the mitochondrial electron transport chain is now considered as one of the central mechanisms in the pathogenesis of diabetic complications. Allium sativum and Lagerstroemia speciosa contains active principles possessing anti-diabetic and antioxidant properties. This study is aimed at evaluating the evidence that supports this traditional claim and investigates the possible synergistic effect on these herbs when given as a herbal mixture in vitro.

AIM

The present study investigates the cytotoxic, antioxidant and a-glucosidase inhibitory potential of Allium sativum (ASE), Lagerstroemia speciosa (LSE) and their combinations using in vitro methods.

MATERIALS AND METHODS

The total phenol, total flavonoid and total tannin content were determined in ASE and LSE. The cytotoxic effects of ASE, LSE and their combination in the ratio of 1:2, 1:1 w/w were evaluated using 3T3 L1 preadipocyte cells. Effect of ASE, LSE and its mixture on intracellular reactive oxygen species (ROS) production were determined by 2', 7'dichlorfluorescein diacetate (DCF DA) staining technique in 3T3-L1 adipocytes. The ability of the herbal extracts and their combination to scavenge super oxide radicals and to inhibit alpha-glucosidase enzyme (a carbohydrate metabolising enzyme) were measured using in vitro methods.

RESULTS

The total phenols and tannins were expressed as microgram (microg) of gallic acid equivalents/mg of extract (GAE/mg), flavonoids as microg of quercetin equivalents/mg of extract (QE/mg). LSE had significant higher total phenol (300.11 +/- 1.99), flavonoid (53.12 +/- 0.48) and tannin content (118.90 +/- 0.15) compared to ASE which possessed total phenol (159.93 +/- 0.87); flavonoid (9.37 +/- 0.73) and tannin content (80.5 +/- 0.19). The IC50 value, the concentration of the extracts that cause 50% inhibition or cell death was measured as an index of cytotoxicity. The IC50 value was found to be in the following decreasing order: 1:2 mixture (98 microg/ml) > ASE (323.6 microg/ml) > 1:1 mixture (428.1 microg/ml) > LSE (2154 microg/ml). The 1:1 mixture was comparatively less cytotoxic under the tested concentration range (1 x 10(0) pg - 1 x 10(8) pg) than 1:2 combinations. The results observed with lactate dehydrogenase (LDH) release were similar to that of cell viability assay. The 1:1 mixture (DIA-2 hereafter) was considered for further investigations. DIA-2 inhibited the ROS levels, which is evidenced by the decreased DCF fluorescence. DIA-2 could also efficiently scavenge the super oxide radical generated from PMS/NADH-NBT system showing an IC50 value 69.99 microg/ml, the IC50 value of ASE (157.7 microg/ml), LSE (20.43 microg/ml), and ascorbic acid (49.64 microg/ml) used as positive control. The results of in vitro a-glucosidase inhibitory assay showed highest IC50 value with LSE (0.3 microg/ml) and DIA-2 (0.7 microg/ml) than ASE (136.3 microg/ml) and positive control miglitol (651.8 microg/ml).

CONCLUSIONS

DIA-2 exerts synergistic effect in scavenging the ROS and inhibiting the enzyme alpha-glucosidase in vitro compared to its individual extracts. The possible synergistic therapeutic effects may be due the presence of the antioxidant rich flavonoids, phenols and tannins present in LSE and ASE.

antitussive potentiality offlower extract using a cough model induced by sulfur dioxide in mice

The methanol extract of the flowers of Lagerstroemia parviflora Roxb (Family: Lythraceae) was investigated for its effect on a cough model induced by sulphur dioxide gas in mice. It exhibited significant antitussive activity when compared with the control in a dose-dependent manner. The extract (100, 200, 300 mg kg(-1)) showed maximum inhibition of cough reflex at 90 min after drug administration and the antitussive activity was comparable to that of codeine phosphate, a standard antitussive agent.

DIA-2, a polyherbal formulation ameliorates hyperglycemia and protein-oxidation without increasing the body weight in type II diabetic rats

BACKGROUND

The dried bulbs of Allium sativum (Garlic) and leaves of Lagerstroemia speciosa (Banaba) are used as medicinal food for the treatment of diabetes and other ailments.

AIM

The present study was undertaken to ascertain whether the combination of both garlic and banaba extract produces synergistic therapeutic effect in diabetic state.

METHODS

In the in vitro studies, the effect of standardized aqueous extract of Allium sativum (ASE), methanolic extract of Lagerstroemia speciosa (LSE) and their mixture (1:1 ratio), DIA-2 on insulin stimulated glucose uptake in 3T3-L1 cells, erythrocyte sorbitol accumulation and protein glycation were evaluated. Impetus from the in vitro findings triggered to screen the anti-diabetic potential of DIA-2 in rat model of type II diabetes and associated oxidative stress. In the in vivo studies, acute oral toxicity of DIA-2 was determined following OECD-423 guidelines in female rats. Anti-diabetic activity of DIA-2 was investigated in high fat diet/low dose streptozotocin induced type II diabetes at four dose levels (62.5, 125, 250 and 500 mg/kg b.w) in rats.

RESULTS

Combination of ASE and LSE produced synergistic and a dose dependent increase in glucose uptake in 3T3 adipocyte cell lines when compared to the individual extracts. A similar effect was observed in the inhibition of sorbitol accumulation and protein glycation tests. DIA-2 restored the glucose and lipid level near to normal level without gain in body weight which is the most commonly encountered side effect with the use of conventional antidiabetic agents, particularly insulin, insulin secretagogues, sulfonylureas and thiazolidinediones. DIA-2 also decreased hepatic protein carbonyl content levels significantly in the diabetic rats.

CONCLUSIONS

The study concluded that DIA-2 posses potent anti-diabetic activity and anti-oxidant effects.