Tahir Mehmood

Bio: Tahir Mehmood is an academic researcher from University of Veterinary and Animal Sciences. The author has contributed to research in topics: Solid-state fermentation & Gallic acid. The author has an hindex of 11, co-authored 60 publications receiving 412 citations. Previous affiliations of Tahir Mehmood include University of Sargodha & University of Strasbourg.

Anti-Helicobacter pylori and Urease Inhibition Activities of Some Traditional Medicinal Plants

Abstract: Different parts of Acacia nilotica (L.) Delile, Calotropis procera (Aiton) W.T. Aiton, Adhatoda vasica Nees, Fagoniaar abica L. and Casuarina equisetifolia L. are traditionally used in folk medicine for the treatment of a variety of common ailments like nausea, cold, cough, asthma, fevers, diarrhea, sore throat, swelling, etc. The present study was aimed to evaluate the anti-Helicobacter pylori and urease inhibition activities of extracts produced from the above selected medicinal plants native to Soon Valley (home to an old civilization) in the Punjab province of Pakistan. Methanol, acetone and water extracts of the plants were evaluated for anti-bacterial activity against thirty four clinical isolates and two reference strains of H. pylori. Minimum inhibitory concentrations (MICs) of the extracts were determined using the agar dilution method and compared with some standard antibiotics like amoxicillin (AMX), clarithromycin (CLA), tetracycline (TET) and metronidazole (MNZ), used in the triple therapy for H. pylori eradication. H. pylori urease inhibition activity of the extracts was assessed by the phenol red method, wherein, Lineweaver-Burk plots were used to determine Michaelis-Menten constants for elucidating the mechanism of inhibition. Methanol and acetone extracts from Acacia nilotica and Calotropis procera exhibited stronger anti-H. pylori activity than MNZ, almost comparable activity with TET, but were found to be less potent than AMX and CLT. The rest of the extracts exhibited lower activity than the standard antibiotics used in this study. In the H. pylori urease inhibitory assay, methanol and acetone extracts of Acacia nilotica and Calotropis procera showed significant inhibition. Lineweaver-Burk plots indicated a competitive mechanism for extract of Acacia nilotica, whereas extract of Calotropis procera exhibited a mixed type of inhibition.

Mentha: A genus rich in vital nutra-pharmaceuticals-A review.

Abstract: The genus Mentha comprises several aromatic species, which are cultivated world-over due to their distinct aroma and commercial value. In addition to traditional food flavoring uses, Mentha are well recognized for their folk medicinal uses, especially to treat cold, fever, and digestive and cardiovascular disorders. A number of biological activities such as antioxidant, antimicrobial, biopesticidal, antitumor, anticancer, antiviral, antiallergic, antiinflammatory, antihypertensive, and urease inhibitory activity have been ascribed to Mentha. The traditional pharmacological attributes of Mentha herbs can be linked to the occurrence of bioactive phytochemicals such as terpenoids, alcohols, rosmarinic acid, and antioxidant phenolics among others. A rich source of bioactives, different species of Mentha, can be explored as a promising candidate for the development of nutra-pharmaceuticals. This review covers the nutritional, phytochemical, and traditional medicinal aspects and multiple biological activities of some commonly available species of Mentha so as to explore their potential applications for nutra-pharmaceutical and cosmo-nutraceutical industry. Detailed chemical profile and pharmaceutical attributes of various Mentha essential oils are also covered. Moreover, based on computational analysis, quantitative chemical component-antioxidant activity relationship model is reviewed to predict and correlate structure-activity relationship of potential bioactives in selected Mentha essential oils leading to discovery and developmenmt of novel natural drugs.

Protease—A Versatile and Ecofriendly Biocatalyst with Multi-Industrial Applications: An Updated Review

Abstract: Proteases are important industrial biocatalysts that constitute the largest group of enzymes acting as proteinases, peptidases, and amidases with a broad range of industrial applications. In this review, particular attention has been given to comprehensively scrutinize the proteases. After the succinct introduction, classification of proteases as exopeptidases (amino and carboxy proteases) and endopeptidases (serine, aspartic, cysteine, and metalloproteases), sources of alkaline, acidic and neutral protease like animal, plant and microbial sources along with the multi-industrial applications have been dissertated. Now a day’s, mostly proteases, which are present in the market, are produced from microbial sources because of the fast production rate and the limited requirement of cultivation. In addition to this, a critique on the applications of proteases in food, detergent, leather, pharmaceutical, cosmetics, silk degumming, silver recovery, chemical industry, and wastewater treatment industries is also concisely addressed. Finally, protein engineering and immobilization strategies to improve the catalytic properties of protease are thoroughly vetted. The quest for novel sources of protease enzyme has been encouraged to fulfill their ever-increasing demands for industrial exploitation.

Deoxyelephantopin induces apoptosis in HepG2 cells via oxidative stress, NF‐κB inhibition and mitochondrial dysfunction

Abstract: Deoxyelephantopin (DET), a naturally occurring sesquiterpene lactone present in Chinese medicinal herb, Elephantopus scaber has been shown to exert anti-inflammatory as well as anticancer effects in various cancer cells of human origin in vitro. However, the exact molecular mechanism underlying DET-induced apoptosis remains largely unexplored, particularly in human hepatocellular carcinoma G2 (HepG2) cells. In the present study, we found that DET inhibits proliferation and induces apoptosis in HepG2 cells in a dose-dependent manner. This DET-mediated apoptosis was found to be associated with reactive oxygen species generation, glutathione depletion and decreased activity of thioredoxin reductase, mitochondrial membrane potential disruption, Bcl-2 family proteins modulation, cytochrome c release, caspases-3 activation, PARP cleavage and inhibition of NF-κB activation. DET inhibited the constitutive as well as induced-translocation of NF-κB into nucleus and augmented the apoptotic effect of Gemcitabine. IKK-16 (NF-κB inhibitor) further enhanced the cytotoxicity of DET and gemcitabine indicating that DET induces apoptosis in HepG2 cells at least partially through inhibition of NF-κB activation. Further mechanistic study demonstrated that DET inhibits the translocation of constitutive as well as induced-NF-κB into nucleus by decreasing phosphorylation of IкBα. Moreover, pretreatment of cells with 3 mM NAC reversed DET-mediated cell death and NF-κB inhibition, indicating that DET exerts its anticancer effects mainly through oxidative stress. Therefore, DET may be developed into a lead chemotherapeutic drug as a single agent or in combination with clinical drugs for the effective treatment of liver cancer. © 2016 BioFactors, 43(1):63-72, 2017.

Pectinase Production from Schizophyllum commune Through Central Composite Design Using Citrus Waste and Its Immobilization for Industrial Exploitation

Abstract: Pectinase is an important group of industrial enzymes. Pectinase manufacturing occupies about 10% of the overall enzyme production world over. The aim of this study is to produce pectin lyase from Schizophyllum commune using the mosambi (sweet lime) fruit peels as substrate in solid state fermentation. The cultural parameters optimized through response surface methodology showed maximum pectin lyase production of 480.45 U/mL at initial medium pH of 6, incubation temperature of 35 °C, time period of 1 day, substrate concentration of 15 g and 3 mL of inoculum size. A purification fold of 3.08 with 355 U/mg specific activity and 4.16% yield was obtained after purification. Enzyme immobilization was done by entrapment with sodium alginate and adsorption with chitosan. Chitosan immobilized enzyme exhibited best thermal stability in the range of 45–55 °C and pH 8.0–9.0. Enzyme activity was stimulated in the presence of Ca2+ and Mg2+ while EDTA inhibited the enzyme activity. Chitosan immobilized pectin lyase was stable up to six cycles of reuse. The pH and thermal stability of S. commune pectin lyase makes it an important enzyme for industrial use. The results showed that pectin lyase produced from S. commune has significant potential for applications in the detergent and fruit juice industry. The enzyme produced from citrus agro waste via the proposed optimized biotechnological process can be explored for multiple industrial applications.

Health Belief Model

Abstract: This article presents an introduction to the Health Belief Model (HBM). The HBM states that the perception of a personal health behavior threat is influenced by at least three factors: general health values, interest and concern about health; specific beliefs about vulnerability to a particular health threat; and beliefs about the consequences of the health problem. Once an individual perceives a threat to his health and is simultaneously cued to action, if his perceived benefits outweighs his perceived costs, then the individual is most likely to undertake the recommended preventive health action. Key words: health promotion, health belief model, perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, self-efficacy. Content available only in Romanian.

Integrated analysis of somatic mutations and focal copy-number changes identifies key genes and pathways in hepatocellular carcinoma

Abstract: Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Here, we performed high-resolution copy-number analysis on 125 HCC tumors and whole-exome sequencing on 24 of these tumors. We identified 135 homozygous deletions and 994 somatic mutations of genes with predicted functional consequences. We found new recurrent alterations in four genes (ARID1A, RPS6KA3, NFE2L2 and IRF2) not previously described in HCC. Functional analyses showed tumor suppressor properties for IRF2, whose inactivation, exclusively found in hepatitis B virus (HBV)-related tumors, led to impaired TP53 function. In contrast, inactivation of chromatin remodelers was frequent and predominant in alcohol-related tumors. Moreover, association of mutations in specific genes (RPS6KA3-AXIN1 and NFE2L2-CTNNB1) suggested that Wnt/β-catenin signaling might cooperate in liver carcinogenesis with both oxidative stress metabolism and Ras/mitogen-activated protein kinase (MAPK) pathways. This study provides insight into the somatic mutational landscape in HCC and identifies interactions between mutations in oncogene and tumor suppressor gene mutations related to specific risk factors.

Dewatering of microalgal cultures : a major bottleneck to algae-based fuels

Abstract: Microalgae dewatering is a major obstruction to industrial-scale processing of microalgae for biofuel prodn. The dil. nature of harvested microalgal cultures creates a huge operational cost during dewatering, thereby, rendering algae-based fuels less economically attractive. Currently there is no superior method of dewatering microalgae. A technique that may result in a greater algal biomass may have drawbacks such as a high capital cost or high energy consumption. The choice of which harvesting technique to apply will depend on the species of microalgae and the final product desired. Algal properties such as a large cell size and the capability of the microalgae to autoflocculate can simplify the dewatering process. This article reviews and addresses the various technologies currently used for dewatering microalgal cultures along with a comparative study of the performances of the different technologies.

The roles of protein kinases in learning and memory

Abstract: In the adult mammalian brain, more than 250 protein kinases are expressed, but only a few of these kinases are currently known to enable learning and memory. Based on this information it appears that learning and memory-related kinases either impact on synaptic transmission by altering ion channel properties or ion channel density, or regulate gene expression and protein synthesis causing structural changes at existing synapses as well as synaptogenesis. Here, we review the roles of these kinases in short-term memory formation, memory consolidation, memory storage, retrieval, reconsolidation, and extinction. Specifically, we discuss the roles of calcium/calmodulin-dependent kinase II (CaMKII), the calcium/calmodulin kinase cascade, extracellular signal regulated kinase 1 and 2 (ERK1/2), cAMP-dependent protein kinase A (PKA), cGMP-dependent protein kinase G (PKG), the phosphatidylinositol 3-kinase (PI3K) pathway, and protein kinase M ζ (PKMζ). Although these kinases are important for learning and memory processes, much remains to be learned as to how they act. Therefore, it will be important to identify and characterize the critical phosphorylation substrates so that a sophisticated understanding of learning and memory processes will be achieved. This will also allow for a systematic analysis of dysfunctional kinase activity in mental disorders.

An epigenetic framework for neurodevelopmental disorders: from pathogenesis to potential therapy.

Abstract: Neurodevelopmental disorders (NDDs) are characterized by aberrant and delayed early-life development of the brain, leading to deficits in language, cognition, motor behaviour and other functional domains, often accompanied by somatic symptoms. Environmental factors like perinatal infection, malnutrition and trauma can increase the risk of the heterogeneous, multifactorial and polygenic disorders, autism and schizophrenia. Conversely, discrete genetic anomalies are involved in Down, Rett and Fragile X syndromes, tuberous sclerosis and neurofibromatosis, the less familiar Phelan-McDermid, Sotos, Kleefstra, Coffin-Lowry and "ATRX" syndromes, and the disorders of imprinting, Angelman and Prader-Willi syndromes. NDDs have been termed "synaptopathies" in reference to structural and functional disturbance of synaptic plasticity, several involve abnormal Ras-Kinase signalling ("rasopathies"), and many are characterized by disrupted cerebral connectivity and an imbalance between excitatory and inhibitory transmission. However, at a different level of integration, NDDs are accompanied by aberrant "epigenetic" regulation of processes critical for normal and orderly development of the brain. Epigenetics refers to potentially-heritable (by mitosis and/or meiosis) mechanisms controlling gene expression without changes in DNA sequence. In certain NDDs, prototypical epigenetic processes of DNA methylation and covalent histone marking are impacted. Conversely, others involve anomalies in chromatin-modelling, mRNA splicing/editing, mRNA translation, ribosome biogenesis and/or the regulatory actions of small nucleolar RNAs and micro-RNAs. Since epigenetic mechanisms are modifiable, this raises the hope of novel therapy, though questions remain concerning efficacy and safety. The above issues are critically surveyed in this review, which advocates a broad-based epigenetic framework for understanding and ultimately treating a diverse assemblage of NDDs ("epigenopathies") lying at the interface of genetic, developmental and environmental processes. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.