Paul Agastian

Antidiabetic effect of plumbagin isolated from Plumbago zeylanica L. root and its effect on GLUT4 translocation in streptozotocin-induced diabetic rats.

Plumbago zeylanica L. root is widely used in Indian medicine to treat diabetes mellitus. The aim of the present investigation was to evaluate the antidiabetic effects of plumbagin isolated from P. zeylanica L. root and its effect on GLUT4 translocation in STZ-induced diabetic rats. Plumbagin (15 and 30 mg/kg b wt) was orally administered to STZ-induced diabetic rats for 28 days. An oral glucose tolerance test was performed on 21st day. The effect of plumbagin on body weight, blood glucose, plasma insulin, total protein, urea, creatinine, liver glycogen, plasma enzymes (SGOT, SGPT and ALP) and carbohydrate metabolism enzymes (glucose-6-phosphatase, fructose-1,6-bisphosphatase and hexokinase) were investigated. GLUT4 mRNA and protein expression in skeletal muscles were also studied. Plumbagin significantly reduced the blood glucose and significantly altered all other biochemical parameters to near normal. Further, plumbagin increased the activity of hexokinase and decreased the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase significantly in treated diabetic rats. Enhanced GLUT4 mRNA and protein expression were observed in diabetic rats after treatment with plumbagin. The results indicated that plumbagin enhanced GLUT4 translocation and contributed to glucose homeostasis. It could be further probed for use as a drug to treat diabetes.

Potential hepatoprotective activity of ononitol monohydrate isolated from Cassia tora L. on carbon tetrachloride induced hepatotoxicity in wistar rats

Ononitol monohydrate, structurally similar to glycoside was isolated from Cassia tora L. leaves. Fifty Male rats were divided into five groups. Group I served as normal control. Group II, III and IV rats were induced hepatotoxicity by CCl(4) administering single dose of CCl(4) on 8th day only. Group III was treated with ononitol monohydrate (20mg/kg body weight) and group IV was treated with reference drug silymarin (20mg/kg body weight) both dissolved in corn oil and administering for 8 days. Ononitol monohydrate with corn oil alone was given for 8 days (group V). At the end of the experimental period all the animals were sacrificed and analyzed for biochemical parameters to assess the effect of ononitol monohydrate treatment in CCl(4) induced hepatotoxicity. In in vivo study, ononitol monohydrate decreased the levels of serum transaminase, lipid peroxidation and TNF-alpha but increased the levels of antioxidant and hepatic glutathione enzyme activities. Compared with reference drug silymarin ononitol monohydrate possessed high hepatoprotective activity. Histopathological results also suggested the hepatoprotective activity of ononitol monohydrate with no adverse effect. Hence we conclude that ononitol monohydrate is a potent hepatoprotective agent.

In vitro antioxidant, antidiabetic and antilipidemic activities of Symplocos cochinchinensis (Lour.) S. Moore bark.

Symplocos cochinchinesis is used in Indian system of traditional medicine to treat diabetes mellitus. The present study investigates the in vitro antioxidant, antidiabetic and antilipidemic activities of S. cochinchinensis bark methanolic extract (SCBe) in streptozotocin (STZ) induced diabetic rats. In in vitro studies SCBe showed very good scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC(50) 820.34 ± 1.74 μg/ml), hydroxyl (IC(50) 884.19 ± 0.45 μg/ml) and nitric oxide (IC(50) 860.21 ± 1.18 μg/ml) radicals, as well as high reducing power. SCBe (250 and 500 mg/kg) was administered to STZ (40 mg/kg) induced diabetic rats for 28 days. SCBe showed a significant decrease in blood glucose and significant increase in plasma insulin and liver glycogen levels in treated diabetic rats. Further, SCBe showed antilipidemic activity as evidenced by significant decrease in serum TC, TG, LDL-C levels and significant increase in HDL-C level in treated diabetic rats. SCBe also restored the altered plasma enzymes (SGOT, SGPT and ALP), total protein, urea and creatinine levels to near normal. The action of SCBe was comparable to the antidiabetic drug glibenclamide. Results of this experimental study indicated that SCBe possessed antioxidant, antidiabetic and antilipidemic activities.

Antimicrobial activity of Ulopterol isolated from Toddalia asiatica (L.) Lam.: A traditional medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE The leaves of Toddalia asiatica (L.) Lam. (Rutaceae) are widely used in folk medicine in India to treat various ailments like cough, malaria, indigestion, influenza lung diseases and rheumatism, fever, stomach ailments, cholera and diarrhea. In our earlier communication we have reported the antimicrobial study on the various extracts of the leaves and the isolation and identification of Flindersine, a quinolone alkaloid as the major active principle. In the present study, we report the antibacterial and antifungal activities of Ulopterol, a coumarin isolated as another major active antimicrobial principle. MATERIALS AND METHODS The leaves were successively extracted with hexane, chloroform, ethyl acetate, methanol and water. The extracts were studied for their antimicrobial activity against selected bacteria and fungi by using disc-diffusion method. The ethyl acetate extract which was found to possess highest antimicrobial activity was subjected to activity guided fractionation by column chromatography over silica gel. This resulted in the isolation of the coumarin, Ulopetrol, an active principle besides Flindersine which was reported by us earlier. The structure of the compound was elucidated using physical and spectroscopic data. Flindersine and Ulopterol were quantified by HPLC. RESULTS Ulopterol showed activity against the bacteria viz. Staphylococcus epidermidis, Enterobacter aerogenes, Shigella flexneri, Klebsiella pneumoniae (ESBL-3967), Escherichia coli (ESBL-3984) and fungi viz. Aspergillus flavus, Candida krusei and Botrytis cinerea. Quantification by HPLC showed the content of Flindersine and Ulopterol to be 0.361% and 0.266% respectively on dry weight basis of the leaves. CONCLUSIONS Ethyl acetate extract (successive extraction) contained Ulopterol, a coumarin, besides Flindersine, a quinolone alkaloid, as a major active principle in the antimicrobial studies. This is the first report of the antimicrobial activity of Ulopterol and also its first report from the plant.

In vitro studies on α-glucosidase inhibition, antioxidant and free radical scavenging activities of Hedyotis biflora L.

Aim of this study was to evaluate the in vitro α-glucosidase inhibition and antioxidant activity of hexane, ethyl acetate and methanol extracts of Hedyotis biflora L. (Rubiaceae). In in vitro α-glucosidase inhibition and antioxidant activity, the methanol extract showed potent effect compared to hexane and ethyl acetate extracts. The methanol extract of H. biflora (HBMe) showed 50% α-glucosidase inhibition at the concentration of 480.20 ± 2.37 μg/ml. The total phenolic content of HBMe was 206.81 ± 1.11 mg of catechol equivalents/g extract. HBMe showed great scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC(50) 520.21 ± 1.02 μg/ml), hydroxyl (IC(50) 510.21 ± 1.51 μg/ml), nitric oxide (IC(50) 690.20 ± 2.13 μg/ml) and superoxide (IC(50) 510.31 ± 1.45 μg/ml) radicals, as well as high reducing power. HBMe also showed a strong suppressive effect on lipid peroxidation. Using the β-carotene method, the scavenging values of HBMe was significantly lower than BHT, and metal chelating ability of HBMe also showed a strong inhibition effect when compared to the reference standard. The active compound ursolic acid from HBMe was identified using various spectroscopical studies. The results obtained in this study clearly indicate that HBMe has a significant potential to use as a natural α-glucosidase inhibition, antioxidant agent.

Gastroprotective effect of epoxy clerodane diterpene isolated from Tinospora cordifolia Miers (Guduchi) on indomethacin-induced gastric ulcer in rats.

The present study evaluated the gastroprotective effect of epoxy clerodane diterpene (ECD), isolated from Tinospora cordifolia on indomethacin-induced gastric ulcer in rats. Administration of indomethacin exhibits extreme levels of ulcer index (UI) and myeloperoxidase (MPO) activity. Indomethacin down regulated PGE2, anti-inflammatory cytokines (IL-4, IL-10) and pro-angiogenic factors (VEGF and EGF). The ECD pretreatment considerably increased the levels of PGE2, anti-inflammatory cytokines and pro-angiogenic factors. The ulcer-healing activity of ECD was inhibited by pre-administration of the specific COX-1 inhibitor (SC560) and nonspecific NOS inhibitor (L-NAME), which indicates the involvement of PGE2 and NOS in ECD induced ulcer healing activity. These findings suggest that ECD exerts its antiulcer activity by reinforcement of defensive elements and diminishing the offensive elements.

In-vitro antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinone isolated from Aegle marmelos (Linn.) Correa

BackgroundPlant metabolites have wide applications and have the potential to cure different diseases caused by microorganisms. The aim of the study was to evaluate the antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinine isolated from Aegle marmelos (Linn.) Correa.MethodsA compound was obtained by eluting the crude extract, using varying concentrations of the solvents by the chromatographic purification. Broth micro dilution method was used to assess the antimicrobial activity and anticancer study was evaluated using MTT assay. Larvicidal activity was studied using leaf disc no-choice method.ResultsBased on the IR, 13C NMR and 1H NMR spectral data, the compounds were identified as quinone related antibiotic. It exhibited significant activity against Gram positive and Gram negative bacteria. The lowest Minimum Inhibitory Concentration (MIC) of the compound against Bacillus subtilis and Staphylococcus aureus was 100 and 75 μg mL-1 respectively. Against Escherichia coli and Pseudomonas aeruginosa it exhibited MIC value of 25 μg mL-1. The MIC of the compound against Aspergillus niger, A. clavatus, Penicillium roqueforti was 20 μg mL-1 and that against Fusarium oxysporum (20 μg mL-1), A. oryzae (40 μg mL-1), and Candida albicans (60 μg mL-1), respectively. It showed effective antibiofilm activity against E. coli, S. typhii and P. aeroginosa at 8 μg mL-1 and did not exhibit considerable cytotoxic activity against Vero and HEP2 cell lines. Additionally, the compound documented significant antifeedant and larvicidal activities against Helicoverpa armigera and Spodoptera litura at 125, 250, 500 and 1000 ppm concentrations.ConclusionThe results concluded that the compound can be evaluated further in industrial applications and also an agent to prepare botanical new pesticide formulations.

Characterization and phylogenetic analysis of novel polyene type antimicrobial metabolite producing actinomycetes from marine sediments: Bay of Bengal, India.

OBJECTIVE To isolate and indentify the promising antimicrobial metabolite producing Streptomyces strains from marine sediment samples from Andrapradesh coast of India. METHODS Antagonistic actinomycetes were isolated by starch casein agar medium and modified nutrient agar medium with 1% glucose used as a base for primary screening. Significant antimicrobial metabolite producing strains were selected and identified by using biochemical and 16S rDNA level. Minimum inhibitory concentrations of the organic extracts were done by using broth micro dilution method. RESULTS Among the 210 actinomycetes, 64.3% exhibited activity against Gram positive bacteria, 48.5 % showed activity towards Gram negative bacteria, 38.8% exhibited both Gram positive and negative bacteria and 80.85 % isolates revealed significant antifungal activity. However, five isolates AP-5, AP-18, AP-41 and AP-70 showed significant antimicrobial activity. The analysis of cell wall hydrolysates showed the presence of LL-diaminopimelic acid and glycine in all the isolates. Sequencing analysis indicated that the isolates shared 98.5%-99.8% sequence identity to the 16S rDNA gene sequences of the Streptomyces taxons. The antimicrobial substances were extracted using hexane and ethyl acetate from spent medium in which strains were cultivated at 30°Cfor five days. The antimicrobial activity was assessed using broth micro dilution technique. Each of the culture extracts from these five strains showed a typical polyene-like property. The lowest minimum inhibitory concentrations of ethyl acetate extracts against Escherichia coli and Curvularia lunata were 67.5 and 125.0 µg/mL, respectively. CONCLUSIONS It can be concluded that hexane and ethyl acetate soluble extracellular products of novel isolates are effective against pathogenic bacteria and fungi.

Phytochemical and antibacterial studies of leaves of Tridax procumbens L.

Abstract Objective To investigate the phytochemical screening and antibacterial activity of pet. ether, chloroform and ethanolic extracts of Tridax procumbens (T. procumbens ). Methods The antibacterial activity of leaves of T. procumbens was evaluated by agar well diffusion method against three selected gram positive and gram negative bacterial species. Results The presence of carbohydrates, proteins, tannins, steroids, alkaloids and purines in the different leaf extracts were established by phytochemical analysis. The chloroform extract was more effective against bacteria and the activity was comparable with that of standard drug ampicillin. Conclusions The results in the present study suggest that T. procumbens leaves can be used for treating diseases caused by the tested organisms.

Actinomycetes from Western Ghats of Tamil Nadu with its antimicrobial properties

Abstract Objective To isolate the actinomycetes from Western Ghats of Tamil Nadu with its antimicrobial properties. Methods Starch casein agar medium supplemented with actidione and nalidixic acid was used to isolate actinomycetes from Western Ghates region of Kanyakumari, Thirunelveli, Dindigul and Nilgiri districts. Modified nutrient medium was used as the base for screening actinomycetes against pathogenic Gram positive, Gram negative and filamentous fungi. Results Among 367 actinomycetes; 17.71% showed activity against both bacteria and fungi. The highest antibacterial activity was observed against B. subtilis , 140 isolates (38.1%), S. aureus 128 (34.9%); S. epidermidis 123 (33.5%); P. aeruginosa 105 (28.6%); K. pneumoniae 88 (24%); Xanthomonas sp 62 (16.9%). Less number of actinomycetes showed activity against Erwinia, S. typhi, V. fischeri and P. vulgaris . Hundred and three isolates showed activity against B. cinerea and A. niger . Twenty five isolates revealed activity against T. simii . Conclusions Present investigation concludes that Western Ghats region of Tamil Nadu is the potential place for actinomycetes diversity. Further studying about these medically important strains from this region can be useful in identification of valuable bio-molecules.