Chemical constituents and pharmacological activities of Lagerstroemia speciosa Pers.:research advances / 国际药学研究杂志

Lagerstroemia speciosa Pers,also known as banaba,belongs to Lythraceae and contains ursolic acid,corosolic ac?id,asiatic acid and 30 other kinds of effective components.It has multiple pharmacological activities,including hypoglycemic,hypo?lipidemic,anti-oxidant and anti-viral activities,and is mainly used for the treatment of obesity and diabetes in folk medcine.This re?view summarizes the recent advances in chemical composition and pharmacological effects of L.speciosa Pers,so as to provide the theo?retical basis and reference for its further research and application.

In vitro antioxidant activity of the individual herbs of DIA-2, a herbal mixture containing standardized extracts of Allium sativum and Lagerstroemia speciosa.

Hyperglycemia induced oxidative stress is one of the main mechanism involved in the pathogenesis of diabetic complications. Use of antioxidants as an adjuvant therapeutic approach in diabetes could prevent or delay the progression of oxidative stress induced diabetic complications. Many herbal drugs possess multiple pharmacological actions like anti-hyperglycemic, anti-obesity and anti-oxidant properties etc., which could act through multiple pathways and may offer beneficial effect in the management of multi-factorial diseases such as diabetes. Development of herbal formulation with ingredients having multiple actions could be a potential approach for improving therapeutic efficacy. We here report the free radical scavenging activity of a herbal mixture, DIA-2 and its individual herbs. DIA-2, a herbal formulation containing fixed combination of standardized aqueous extracts of Allium sativum (ASE) bulbs and Lagerstroemia speciosa (LSE) leaves. The present study was undertaken to investigate whether a combination of ASE and LSE shows a synergistic antioxidant effect than its individual herbs. In vitro antioxidant activity for individual herbs and DIA-2 was determined by DPPH radical scavenging, nitric oxide scavenging assay, total antioxidant capacity, reducing power assay and ABTS radical scavenging methods respectively. Our results suggest that DIA-2 could synergistically enhance the antioxidant activity and could be attributed due to the synergistic actions of the individual ingredients. The data obtained suggests the combined use of ASE and LSE as active ingredients in the development of antidiabetic herbal formulation, synergizing its therapeutic value in treating hyperglycemia and associated oxidative stress.

In vitro activity of methanolic extract from Lagerstroemia speciosa (Linn. ex. Murray) bark against pathogenic bacteria.

Crude methanolic extract of Lagerstroemia speciosa barks (Linn. ex. Murray) was subjected to antimicrobial screening including six Gram-positive and eight Gram-negative bacteria. The extract demonstrated significance antibacterial activities on 5 tested bacteria with the inhibition zone ranging from 10-15 mm. The minimum inhibitory concentration (MIC) of the extract was assessed by microdilution method. MIC value of Bacillus spizizenii ATCC6633, Bacillus cereus and Streptococcus coagulase-negative (SCN) was 0.25 mg/ml whilst Bacillus licheniformis and Acinetobacter anitratus showed MIC value of 0.50 mg/ml. However, only B. spizizenii ATCC6633 and B. licheniformis showed the minimum bactericidal concentration (MBC) value of 2.00 mg/ml and 1.00 mg/ml, respectively. The morphological changes of B.spizizenii ATCC6633 and A. anitratus with the treatment of the extract were observed under Scanning Electron Microscope (SEM). The results suggested that the L. speciosa methanolic extract had caused membrane structural degenerations of the cells and finally leading to cell-lysis.

Antioxidant and antimicrobial activity of flowers of Wendlandia thyrsoidea, Olea dioica, Lagerstroemia speciosa and Bombax malabaricum.

Flowers of higher plants have been used for centuries for several purposes such as medicine, food and garnishing food in many parts of the world. In the present study, we have determined the antioxidant and antimicrobial activity of methanol extract of flowers of Wendlandia thyrsoidea (Roemer & Schultes) Steudel (Rubiaceae), Olea dioica Roxb. (Oleaceae), Lagerstroemia speciosa L. (Lythraceae) and Bombax malabaricum DC. (Bombacaceae). Antioxidant efficacy of various concentrations of flower extracts was evaluated by DPPH free radical scavenging assay and Ferric reducing assay. Antimicrobial activity was determined against four bacteria and two fungi by agar well diffusion method. Total phenolic and flavonoid contents were determined by Folin-Ciocalteau reagent and Aluminium chloride colorimetric estimation methods respectively. The DPPH free radical scavenging effect of flower extracts was concentration dependent and was higher in case of extract of L. speciosa followed by W. thyrsoidea, B. malabaricum and O. dioica. In ferric reducing assay, it was shown that the absorbance of reaction mixture at 700nm increased on increasing the concentrations of flower extracts indicating reducing power of extracts. The reducing ability was also highest in L. speciosa extract. Extract of L. speciosa displayed marked inhibitory activity against bacteria and fungi than other flower extracts. Gram positive bacteria have shown more susceptibility than Gram negative bacteria. Among fungi, C. neoformans was more inhibited than C. albicans. Extracts of B. malabaricum and O. dioica were not effective against C. albicans. The phenolic and flavonoid contents were higher in L. speciosa and O. dioica respectively. A positive correlation has been observed between total phenolic content of flower extracts and antioxidant and antimicrobial activity. The flowers can be employed as a remedy for treatment of infectious diseases and oxidative damage. Further, isolation of active components from flower extracts and their biological activity determinations are under progress.

Ellagic acid & gallic acid from Lagerstroemia speciosa L. inhibit HIV-1 infection through inhibition of HIV-1 protease & reverse transcriptase activity.

Background & objectives: Banaba (Lagerstroemia speciosa L.) extracts have been used as traditional medicines and are effective in controlling diabetes and obesity. The aim of this study was to evaluate the anti-HIV property of the extracts prepared from the leaves and stems of banaba, and further purification and characterization of the active components. Methods: Aqueous and 50 per cent ethanolic extracts were prepared from leaves and stems of banaba and were evaluated for cytotoxicity and anti-HIV activity using in vitro reporter gene based assays. Further, three compounds were isolated from the 50 per cent ethanolic extract of banaba leaves using silica gel column chromatography and characterization done by HPLC, NMR and MS analysis. To delineate the mode of action of the active compounds, reverse transcriptase assay and protease assay were performed using commercially available kits. Results: All the extracts showed a dose dependent inhibition of HIV-1-infection in TZM-bl and CEM-GFP cell lines with a maximum from the 50 per cent ethanolic extract from leaves (IC50 = 1 to 25 μg/ml). This observation was confirmed by the virus load (p24) estimation in infected CEM-GFP cells when treated with the extracts. Gallic acid showed an inhibition in reverse transcriptase whereas ellagic acid inhibited the HIV-1 protease activity. Interpretation & conclusions: The present study shows a novel anti-HIV activity of banaba. The active components responsible for anti-HIV activity were gallic acid and ellagic acid, through inhibition of reverse transcriptase and HIV protease, respectively and hence could be regarded as promising candidates for the development of topical anti-HIV-1 agents.