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ABSTRACT: A novel terpenoid coumarin, clausmarin-C, has been isolated from Clausena pentaphylla. Its structure has been established by extensive 1D- and 2D-NMR analysis and chemical transformation.
Natural product research 12/2009; 23(18):1671-6. · 1.01 Impact Factor
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ABSTRACT: A number of O-alkylated xanthone, carbazoles and coumarins have been synthesised and screened for their in vitro anti-diabetic activity, such as glucose-6-phosphatase, glycogen phosphorylase and alpha glucosidase inhibitors. Compounds which were showing significant percentage inhibition were also tested for in vivo anti-hyperglycemic activity in sucrose loaded normal and streptozotocin (STZ)-induced diabetic rats. These compounds show 22.1, 24.4 and 26.7% and 20.8, 25.0, 20.5% lowering in sucrose loaded normal rats and STZ-induced diabetic rats at a dose of 100 mg kg(-1).
Natural product research 02/2009; 23(1):60-9. · 1.01 Impact Factor
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ABSTRACT: Thirty-four novel hybrid lupeol derivatives (4-18) were prepared and evaluated for antimalarial activity in vitro against Plasmodium falciparum. Three compounds (13d, 16a and 17a) have shown antimalarial activity at lower dose (10 microg mL(-1)) than lupeol.
Natural Product Research 04/2008; 22(4):305-19. · 1.01 Impact Factor
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ABSTRACT: Beta,beta-dimethyl acryl shikonin is an extract from the root of plant Arnebia nobilis which has been shown to possess anti-cancer activity. However, its toxicity limited further development of shikonin as a therapeutic agent. Subsequently, several analogues of beta,beta-dimethyl acryl shikonin were synthesized. One of these analogues, shikonin 93/637 was found to be significantly less toxic compared to shikonin. This study is aimed to determine the cell cycle associated differences in the susceptibility of U937 cells to apoptosis induced by shikonin analogue 93/637 (SA). Lower concentrations of SA (approximately 100 nM) showed no significant changes in cell growth. However, higher concentrations (approximately 500 nM) resulted in growth inhibition of U937 cells after 48 h of treatment with SA as measured by MTT assay. Flow cytometric analysis showed that SA treatment resulted in blocking of cell cycle progression in G1 phase. Decreased expression of Cyclin D, CDK 4 and PCNA was observed with SA treatment corroborating the G1 block. DNA gel electrophoresis showed an oligonucleotide ladder pattern, a distinct characteristic of DNA fragmentation associated with programmed cell death. Ribonuclease protection assay revealed inhibition of bcl2 expression at transcriptional level. SA treatment also resulted in induction of caspase-3 activity. The results suggest the involvement of bcl2 and Caspase-3 in SA induced apoptosis of human U937 cells.
Frontiers in Bioscience 02/2008; 13:561-8. · 3.52 Impact Factor
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ABSTRACT: Lymphatic filariasis continues to be a major health problem in tropical and subtropical countries. A macrofilaricidal agent capable of eliminating adult filarial parasites is urgently needed. In the present study, we report the antifilarial activity in the extract of stem portion of the plant Lantana camara. The crude extract at 1 g/kg for 5 days by oral route killed 43.05% of the adult Brugia malayi parasites and sterilized 76% of surviving female worms in the rodent model Mastomys coucha. A 34.5% adulticidal activity along with sterilization of 66% of female worms could be demonstrated in the chloroform fraction. Remarkable antifilarial activity was observed in the adult B. malayi transplanted gerbil model where up to 80% of the adult worms could be killed at the same dose and all the surviving female parasites were found sterilized. The extract was also found effective against a subcutaneous rodent filariid Acanthocheilonema viteae maintained in Mastomys coucha, where it exerted strong microfilaricidal (95.04%) and sterilization (60.66%) efficacy with mild macrofilaricidal action. Two compounds, oleanonic acid and oleanolic acid, isolated from hexane and chloroform fractions showed LC100 at 31.25 and 62.5 mug/ml, respectively, on B. malayi in vitro. This is the first ever report on the antifilarial efficacy of Lantana camara.
Parasitology Research 03/2007; 100(3):439-48. · 2.15 Impact Factor
