Multiple ligand simultaneous docking (MLSD): A novel approach to study the effect of inhibitors on substrate binding to PPO.

Multiple ligand simultaneous docking, a computational approach is used to study the concurrent interactions between substrate and the macromolecule binding together in the presence of an inhibitor. The present investigation deals with the study of the effect of different inhibitors on binding of substrate to the protein Polyphenoloxidase (PPO). The protein was isolated from Mucuna pruriens and confirmed as tyrosinases involved in L-DOPA production. The activity was measured using different inhibitors at different concentrations taking catechol as substrate. A high-throughput binding study was conducted to compare the binding orientations of individual ligands and multiple ligands employing Autodock 4.2. The results of single substrate docking showed a better binding of urea with the binding energy of -3.48 kJ mol(-1) and inter molecular energy of -3.48 kJ mol(-1) while the results of MLSD revealed that ascorbic acid combined with the substrate showed better inhibition with a decreased binding energy of -2.37 kJ mol(-1).

New role of lupeol in reticence of angiogenesis, the cellular parameter of neoplastic progression in tumorigenesis models through altered gene expression.

There is a major unmet medical need for effective and well tolerated treatment options for cancer. The search now seeks to identify active biomolecules with multiple targets. Lupeol, an important dietary triterpenoid known as anticarcinogen by inducing apoptosis. But it is still more to reveal the potency of lupeol in the inhibition of neovascularization in cancer context. The study aimed to explore the efficacy of the lupeol in targeting angiogenesis. In this study, the inhibition of neovessel formation was assessed by preliminary antiangiogenesis assays like chorio allontoic membrane (CAM) and rat corneal micro pocket models. Further, validated for the micro vessel density (MVD) in histological sections of peritoneum, solid tumor and xenograft tumor by immunostaining with anti CD31 antibody. Antitumor potency was verified in ascites carcinoma, solid lymphoma and human nueroblastoma xenograft in CAM. Altered angiogenic gene expression by RT-PCR, ELISA and gelatin zymography. Lupeol significantly inhibits the neovessel formation in CAM and in the rat cornea. The similar effect was ascertained in mice and human xenograft tumor models with the regressed growth. Eventually reflecting on the differential transcription of angiogenic genes like MMP-2 & 9, HIF-1α, VEGFa and Flt-1 was noteworthy. It is now evident from our studies that, a new avenue of dietary triterpenoid lupeol by targeting angiogenesis, potentially inferring the multimode action in cancer prevention.

Enhanced production of L-DOPA in cell cultures of Mucuna pruriens L. and Mucuna prurita H.

A comparative study on the production of 3,4-dihydroxyphenylalanine (L-DOPA) was carried out in cell cultures of two Mucuna species by elicitor treatment and precursor feeding. The influence of elicitors and the precursor molecule on L-DOPA production, polyphenol oxidase (PPO) and tyrosinase activities was also studied. Callus cultures were initiated in Mucuna pruriens L. and Mucuna prurita H. on MS medium supplemented with BAP and IAA at different concentrations. Suspension cultures were established in MS liquid medium supplemented with BAP, IAA, the elicitors methyl jasmonate, chitin and pectin or the precursor L-tyrosine at different concentrations for L-DOPA production. Compared to the controls, several-fold increases in L-DOPA concentration were observed in elicitor-treated and precursor-fed suspension cultures of both plant species. L-DOPA concentrations were comparatively higher in precursor-fed cultures than those receiving elicitor treatments. A parallel increase in tyrosinase and PPO levels was also observed. Loss of cell viability was observed at high concentrations of elicitor-treated cultures, whereas L-tyrosine did not cause any cell death. Compared to elicitor treatments, precursor feeding resulted in higher concentrations of L-DOPA production and tyrosinase activity. The efficacy of L-DOPA production was found to be higher for suspension cultures of M. pruriens compared to M. prurita in all treatments.

Hepatoprotective and Antioxidant Activities of Desmodium Triquetrum DC.

The hepatoprotective and antioxidant activities of ethanol extract of Desmodium triquetrum DC leaf were investigated against carbon tetrachloride (1 ml/kg i.p) induced hepatic damage in rats at a dose of 200 mg/kg body weight p.o. The test extract significantly (P<0.05) reduced the elevated levels of serum transaminases, alkaline phosphatase, bilirubin and reversed the antioxidant enzyme and non-enzyme levels. It dose dependently inhibited thiobarbuturic acid induced lipid peroxidation in vitro (IC(50)=59.9 µg/ml). Histopathological studies provided supportive evidence for biochemical analysis. Silymarin (25 mg/kg) is a known hepatoprotective drug used as a reference drug. The results indicated that D. triquetrum has potent hepatoprotective and antioxidant activity that may be due to the presence of flavonoids in the plant.

COX-2 gene promoter haplotypes and prostate cancer risk.

Cyclooxygenase-2 (COX-2) is a key rate-limiting enzyme that converts arachidonic acid into pro-inflammatory prostaglandins. COX-2 expression is strongly correlated with increased tumor microvasculature density and plays an important role in inhibiting apoptosis, stimulating angiogenesis and promoting tumor cell metastasis and invasion. However, little is known about the role that sequence variation of the COX-2 gene contributes to prostate cancer. Thus, we searched for polymorphisms in the promoter region of the COX-2 gene using denaturing high-performance liquid chromatography. Four single nucleotide polymorphisms (SNPs), -1285A/G, -1265G/A, -899G/C and -297C/G, were detected and confirmed by direct sequencing. Three of the SNPs in the promoter region of COX-2 gene create at least three putative transcription factor binding sites and eliminate CCAAT/enhancer binding protein alpha (C/EBP alpha) and NF-kappa B binding sites. A case-control study of the four SNPs in African American (n = 288), Bini Nigerian (n = 264) and European American (n = 184) prostate cancer cases and age-matched controls revealed that SNP -297G was associated with a decreased risk for prostate cancer [odds ratio (OR) = 0.49; CI = 0.2-0.9; P = 0.01]. The effect on risk was observed in both African Americans (OR = 0.51; CI = 0.2-0.9; P = 0.01) and European Americans (OR = 0.33; CI = 0.1-0.9; P = 0.02). In addition, SNPs -1265A and -899C were associated with increased prostate cancer risk in African Americans (OR = 2.72; CI = 1.3-5.8; P = 0.007 and OR = 3.67; CI = 1.4-9.9; P = 0.007, respectively). Haplotype analyses revealed modest effects on susceptibility to prostate cancer across populations. Haplotype GGCC conferred increased risk in the African American and Nigerian populations. Conversely, haplotype AGGG exhibited a negative association with prostate cancer risk in African Americans (OR = 0.4; CI = 0.1-0.9; P = 0.02) and European Americans (OR = 0.2; CI = 0.1-0.9; P = 0.03). These data suggest that variation of the COX-2 promoter may influence the risk and development of prostate cancer.