Phytochemical profiling of Azima tetracantha Lam. leaf methanol extract and elucidation of its potential as a chain-breaking antioxidant,anti-inflammatory and anti-proliferative agent

Azima tetracantha, a traditional medicinal plant included in the order Brassicales and family Salvadoraceae, is widely used as a dietary supplement in folklore medicines. The plant is also used for the treatment of rheumatism, diarrhea and other inflammatory disorders. The present investigation focused on the phytochemical composition, radical scavenging, reducing potential and anti-proliferative activities of the A. tetracantha leaves. Quantitative estimation of the polyphenols and flavonoids revealed significantly elevated levels in the methanol extract. Corroborating with this, methanol extract exhibited higher in vitro anti-radical scavenging effect against 2,2-diphenyl-1- picrylhydrazyl (34.14 ± 2.19 μg/mL), and hydrogen peroxide (44.96 ± 1.77 μg/mL), as well as ferric reducing properties (58.24 ± 6.98 μg/mL). The methanolic extract also showed strong lipoxygenase (71.42 ± 6.36 μg/mL) and nitric oxide inhibitory activities (94.23 ± 8.11 μg/mL). Cytotoxic activity against MCF7 cells was found to be higher (IC50= 37.62 ± 2.94 μg/mL), than that of MDAMB231 cells (IC50= 69.11 ± 5.02 μg/mL). The qPCR-based analysis indicated dose-dependent increase in the expression of the pro-apoptotic genes such as executioner caspases and apoptotic protease activating factor-1. Overall, the results indicated the possible use of methanol extract of A. tetracantha leaves as a chain-breaking antioxidant molecule and are capable of inhibiting inflammatory enzymes and the proliferative potential of breast cancer cells.     

Indirect organogenesis and plant regeneration in Helicteres isora L., an important medicinal plant

Abstract    Helicteres isora is a medicinal plant effective against asthma, diabetes, hypolipidemia, HIV, polio besides a good source of diosgenin. Seed dormancy and low natural fruit production rate make this plant a perfect candidate for developing an in vitro regeneration method. However, to date, no such work has been procured in this plant. An efficient method for plant regeneration via shoot organogenesis from callus cultures has been developed using nodal explants in H. isora. Murashige and Skoog (MS) media counting 2,4-Dichlorophenoxyacetic acid (2,4-D, 2.26 to 13.57 μM), Indole-3-acetic acid (IAA, 2.85 to 17.13 μM), Indole-3-butyric acid (IBA, 2.46 to 14.70 μM), 6-Benzylaminopurine (BA, 2.22 to 13.32 μM) and Kinetin (Kin, 2.32 to 13.92 μM) either singly or in the following combinations (IAA + BA; IAA + Kin, and BA + Kin) produced granular callus except BA + Kin which resulted in compact, hard, greenish-white (CHGW) callus. The optimum CHGW callus (2.62 g fresh weight/ explant) was produced on MS media with 13.32 μM BA + 2.32 μM Kin with over 93% callus induction frequency. Optimum shoot organogenesis (67% frequency) was achieved in CHGW callus with lower level of BA (2.22 μM) and Kin (2.32 μM) and produced 3.2 shoots/0.5 g callus within 35 d of culture. Microshoots were rooted successfully (62% frequency) after 35 d of culture on 1/2MS containing 4.90 μM IBA and hardened off. Antioxidant enzymes such as catalase, peroxidase, polyphenol oxidase, and biochemical parameters viz. hydrogen peroxide, reducing and nonreducing sugars, starch, proteins, phenols, and proline contents were studied in regenerating and nonregenerating CHGW calluses to establish a correlation between these parameters and shoot morphogenesis. All the enzyme activities and biochemical parameters were found more in regenerating callus than in nonregenerating except phenols.     

First evidence of putrescine involvement in mitigating the floral malformation in mangoes: A scanning electron microscope study

Floral malformation is the most destructive disease in mangoes. To date, the etiology of this disease has not been resolved. There are indications that stress-stimulated ethylene production might be responsible for the disease. Putrescine mediates various physiological processes for normal functioning and cellular metabolism. Here, the effect of putrescine in concentration ranging from 10^?1 to 10^?3 M was evaluated on disease incidence during mango flowering seasons of 2012 and 2013. In a scanning electron microscopy (SEM) study, putrescine (10^?2 M)-treated malformed floral buds bloomed into opened flowers with separated sepals and/or petals like healthy, whereas the untreated (control) malformed buds remained deformed. Further, malformed flowers recovered upon putrescine treatment, displaying clearly bilobed anthers, enclosing a large number of normal pollen grains and functional ovary with broad stigmatic surface as compared to control. The present findings provide the first report to demonstrate the role of putrescine in reducing various adverse effects of stress ethylene via decelerating the higher pace of its biosynthesis. It stabilizes the normal morphology, development, and functions of malformed reproductive organs to facilitate successful pollination, fertilization, and, thereby, fruit set in mango flowers. However, putrescine–ethylene-mediated cell signaling network, involving various genes to trigger the response, which regulates a wide range of developmental and physiological processes leading to normal cell physiology, needs to be investigated further.     

Brain-specific knockdown of miR-29 results in neuronal cell death and ataxia in mice

Several microRNAs have been implicated in neurogenesis, neuronal differentiation, neurodevelopment, and memory. Development of miRNA-based therapeutics, however, needs tools for effective miRNA modulation, tissue-specific delivery, and in vivo evidence of functional effects following the knockdown of miRNA. Expression of miR-29a is reduced in patients and animal models of several neurodegenerative disorders, including Alzheimer''s disease, Huntington''s disease, and spinocerebellar ataxias. The temporal expression pattern of miR-29b during development also correlates with its protective role in neuronal survival. Here, we report the cellular and behavioral effect of in vivo, brain-specific knockdown of miR-29. We delivered specific anti-miRNAs to the mouse brain using a neurotropic peptide, thus overcoming the blood-brain-barrier and restricting the effect of knockdown to the neuronal cells. Large regions of the hippocampus and cerebellum showed massive cell death, reiterating the role of miR-29 in neuronal survival. The mice showed characteristic features of ataxia, including reduced step length. However, the apoptotic targets of miR-29, such as Puma, Bim, Bak, or Bace1, failed to show expected levels of up-regulation in mice, following knockdown of miR-29. In contrast, another miR-29 target, voltage-dependent anion channel1 (VDAC1), was found to be induced several fold in the hippocampus, cerebellum, and cortex of mice following miRNA knockdown. Partial restoration of apoptosis was achieved by down-regulation of VDAC1 in miR-29 knockdown cells. Our study suggests that regulation of VDAC1 expression by miR-29 is an important determinant of neuronal cell survival in the brain. Loss of miR-29 results in dysregulation of VDAC1, neuronal cell death, and an ataxic phenotype.     

A Highlights from MBoC Selection: Peptide TFP5/TP5 derived from Cdk5 activator P35 provides neuroprotection in the MPTP model of Parkinson’s disease

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by the loss of dopamine neurons in the substantia nigra, decreased striatal dopamine levels, and consequent extrapyramidal motor dysfunction. Recent evidence indicates that cyclin-dependent kinase 5 (Cdk5) is inappropriately activated in several neurodegenerative conditions, including PD. To date, strategies to specifically inhibit Cdk5 hyperactivity have not been successful without affecting normal Cdk5 activity. Previously we reported that TFP5 peptide has neuroprotective effects in animal models of Alzheimer’s disease. Here we show that TFP5/TP5 selective inhibition of Cdk5/p25 hyperactivation in vivo and in vitro rescues nigrostriatal dopaminergic neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP/MPP+) in a mouse model of PD. TP5 peptide treatment also blocked dopamine depletion in the striatum and improved gait dysfunction after MPTP administration. The neuroprotective effect of TFP5/TP5 peptide is also associated with marked reduction in neuroinflammation and apoptosis. Here we show selective inhibition of Cdk5/p25 ­hyperactivation by TFP5/TP5 peptide, which identifies the kinase as a potential therapeutic target to reduce neurodegeneration in Parkinson’s disease.     

Efficient parallel synthesis of macrocyclic peptidomimetics

A new method for solid phase parallel synthesis of chemically and conformationally diverse macrocyclic peptidomimetics is reported. A key feature of the method is access to broad chemical and conformational diversity. Synthesis and mechanistic studies on the macrocyclization step are reported.     

Design of azidoproline containing gluten peptides to suppress CD4+ T-cell responses associated with celiac disease

Celiac disease is an intestinal disease caused by intolerance for gluten, a common protein in food. A life-long gluten-free diet is the only available treatment. As it is well established that the interaction between proline-rich gluten derived peptides and the human HLA-DQ2 molecules induces immune responses that lead to disease development, we have now designed a series of gluten peptides in which proline residues were replaced by azidoprolines. These peptides were found to bind to HLA-DQ2 with an affinity similar to that of the natural gluten peptide. Moreover, some of these peptides were found to be non-immunogenic and block gluten induced immune responses. These can thus serve as lead compounds for the development of HLA-DQ2 blocker peptides.