Khalid M. Naji | Sana'a University (original) (raw)

Papers by Khalid M. Naji

University of Aden Journal of Natural and Applied Sciences, Apr 22, 2023

Universal journal of pharmaceutical research, Jan 15, 2018

Objectives: Paracetamol has emerged as an important environmental contaminant due to its extensiv... more Objectives: Paracetamol has emerged as an important environmental contaminant due to its extensive use. The purpose of this work was toisolate, identify, and characterize fungal species able to degrade paracetamol from pharmaceutical wastewater effluent at Sana'a City, Yemen. Methods: The fungi were isolated and purified from wastewater samples using enrichment and selective media. The isolated fungi were identified according to phenotypic characterization. Two species of isolated fungi were able to utilize the paracetamol as the sole of carbon and energy sources. These fungi were designated as F1 and F2 and identified as Aspergillus niger and Fusarium oxysporium, respectively. Optimum temperature and pH for growth of both species were 25˚C and 6.0, respectively. Also, the biodegradation of paracetamol was influenced by glucose concentration. Results: F1 and F2 were able to degrade 35.7% and 26.1% of 1000 and 2000 mg/l, respectively, paracetamol in 60 days. This is the first report on the ability of Aspergillus niger and Fusarium oxysporium to degrade paracetamol. Conclusion: The reported findings highlight the potential use of the isolated microorganisms for treatment of paracetamolcontaminated wastewater.

Microchemical Journal, 2018

Sesame seeds collected in eight provinces of Yemen were used to prepare cold-pressed sesame oil o... more Sesame seeds collected in eight provinces of Yemen were used to prepare cold-pressed sesame oil over three consecutive years. After ascertaining the nutritional quality and compliance with official norm of each batch of oil, mineral composition was determined by ICP-OES. No major and significant variations were detected over three years indicating the high reproducibility of Yemeni sesame oil composition as a function of its geographic origin. Three physico-chemically distinct subgroups were identified. A subgroup includes sesame oil from Al Bayda, Marib, Ibb, and Taiz; a second is constituted by sesame oil from Abyan, Shabwa, and Hadhramount while sesame oil from Hodeida presents its own specificity. Calcium content was between 3.02 and 9.66 mg/kg, this cation making up 50% of the total mineral content. The two other most abundant minerals were potassium (0.824-4.251 mg/kg) and magnesium (0.811-4.742 mg/kg). Potentially toxic metal (Cd, Pb, Cu, Sn and Zn) content was very low in all samples. Principal component analysis showed that Abyan oil presents a unique metal-content profile. The precise geographic origin of Yemeni sesame oil can be determined by element content analysis. Recent studies have focused on the composition of locally produced

Planta Medica, 2012

In Nigeria, Aframomum melegueta seed tincture extract is used in the management of cardiovascular... more In Nigeria, Aframomum melegueta seed tincture extract is used in the management of cardiovascular disease and obesity. This study thus evaluates the antioxidant and anti-hyperlipidemic activity in Triton X-100 induced hyperlipidemic rats. The phytochemical constituents of the extract were identified using gas chromatography linked with mass spectrometer. In vitro antioxidant activity of the extract (0.2-1.0 mg/mL) was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, and hydroxyl radical. In vivo antioxidant and antihyperlipidemic properties of the extract were evaluated in Triton X-100 induced hyperlipidemia in rats. Gas-chromatogram indicates the presence of 11 components with Trans β-ocimene being the major constituent. The extract scavenged DPPH, H 2 0 2 and OH − radical concentration dependently. Triton X-100 significantly (p b 0.05) increased the serum total cholesterol, triacylglycerol and low-density lipoprotein with a concomitant reduction in high-density lipoprotein cholesterol. These alterations were significantly ameliorated by the extract. Triton X-100-mediated decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase were significantly (p b 0.05) attenuated. Altered levels of glutathione reduced and glutathione disulfide were significantly (p b 0.05) restored to normal. Triton X-100-mediated increase in the concentrations of malondialdehyde and protein carbonyl were significantly (p b 0.05) lowered by the extract. It is evident from this study that hydroethanolic extract of A. melegueta seed possess antioxidants and antihyperlipidemic properties.

International journal of chemical science, Nov 1, 2017

University of Aden Journal of Natural and Applied Sciences, Oct 31, 2019

The aim of this study is to prepare immobilized protease with high hydrolytic activity forbiotech... more The aim of this study is to prepare immobilized protease with high hydrolytic activity forbiotechnological applications. Local Bean Seeds (Dolichos Lablab L.) were used for the extraction of acidprotease using tris-buffer, pH 4.5 as enzyme solvent. Free acidic protease was immobilized on entrapment in calcium alginate gel (in situ activated) by covalent binding method. Their activity and immobilization efficiency for hemoglobin hydrolysis was investigated. Temperature and pH maxima of the immobilized protease showed no changes before and after immobilization. The immobilized protease exhibited good thermal stability and re-usability.

Microorganisms

Rosenbergiella bacteria have been previously isolated predominantly from floral nectar and identi... more Rosenbergiella bacteria have been previously isolated predominantly from floral nectar and identified in metagenomic screenings as associated with bees. Here, we isolated three Rosenbergiella strains from the robust Australian stingless bee Tetragonula carbonaria sharing over 99.4% sequence similarity with Rosenbergiella strains isolated from floral nectar. The three Rosenbergiella strains (D21B, D08K, D15G) from T. carbonaria exhibited near-identical 16S rDNA. The genome of strain D21B was sequenced; its draft genome contains 3,294,717 bp, with a GC content of 47.38%. Genome annotation revealed 3236 protein-coding genes. The genome of D21B differs sufficiently from the closest related strain, Rosenbergiella epipactidis 2.1A, to constitute a new species. In contrast to R. epipactidis 2.1A, strain D21B produces the volatile 2-phenylethanol. The D21B genome contains a polyketide/non-ribosomal peptide gene cluster not present in any other Rosenbergiella draft genomes. Moreover, the Ros...

BMC Microbiology

Background Environmental contamination from synthetic plastics and their additives is a widesprea... more Background Environmental contamination from synthetic plastics and their additives is a widespread problem. Phthalate esters are a class of refractory synthetic organic compounds which are widely used in plastics, coatings, and for several industrial applications such as packaging, pharmaceuticals, and/or paints. They are released into the environment during production, use and disposal, and some of them are potential mutagens and carcinogens. Isophthalate (1,3-benzenedicarboxylic acid) is a synthetic chemical that is globally produced at a million-ton scale for industrial applications and is considered a priority pollutant. Here we describe the biochemical characterization of an enzyme involved in anaerobic degradation of isophthalate by the syntrophically fermenting bacterium Syntrophorhabdus aromaticivorans strain UI that activate isophthalate to isophthalyl-CoA followed by its decarboxylation to benzoyl-CoA. Results Isophthalate:Coenzyme A ligase (IPCL, AMP-forming) that activat...

Physical weathering of parent rocks, mining, and other anthropogenic activities lead to impermiss... more Physical weathering of parent rocks, mining, and other anthropogenic activities lead to impermissible levels of heavy metals in plant tissues. Effect of Cd 2+ , Hg 2+ , and Zn 2+ on metabolic enzymes, Amylase (EC; 3.2.1.1), and AP (EC; 3.1.3.2), were studied to assess horse gram response to these heavy metal stress. Enzyme activity and TC were evaluated. Amylase decreased in response to increasing Cd 2+ concentration, with great impact at 48-72h. It rose under 5 ppm Hg 2+ , while dropped under 10 ppm beyond 24h reaching ~25% of control, and recovered with time to reach 80-90% under 20 ppm. Under Zn 2+ stress, amylase rose in concentration-and time-dependent manner. AP declined under metal stress in concentration, time-dependent manner, except at 100 ppm Zn 2+. TC fluctuated in metal-specific manner with positive influence by Zn 2+ (300-600 ppm) and Cd 2+ (100-200 ppm) at 24 h. TC diminished under Cd 2+ stress beyond 24 h, and over entire duration under Hg 2+ stress. It can deduce that Hg 2+ and Cd 2+ exhibited toxic effects on horse gram while Zn 2+ had positive effects. Amylase responded negatively to Hg 2+ , positively to Zn 2+ , and showed mixed response to Cd 2+. AP levels decreased under metal stresses, except Zn 2+ .

The ability of plants to tolerate drought conditions is crucial for plant survival and crop produ... more The ability of plants to tolerate drought conditions is crucial for plant survival and crop production worldwide. The present data confirm previous findings reported existence of a strong relation between abscisic acid (ABA) content and amino acid accumulation as response water stress which is one of the most important defense mechanism activated during water stress in many plant species. Therefore, free amino acids were measured to determine any changes in the metabolite pool in relation to ABA content. The ABA defective mutants of Arabidopsis plants were subjected to leaf dehydration for Arabidopsis on Whatman 3 mm filter paper at room temperature while, tomato mutant plants were subjected to drought stresses for tomato plants by withholding water. To understand the signal transduction mechanisms underlying osmotic stress-regulating gene induction and activation of osmoprotectant free amino acid synthesizing genes, we carried out a genetic screen to isolate Arabidopsis mutants defective in ABA biosynthesis under drought stress conditions. The present results revealed an accumulation of specific free amino acid in water stressed tissues in which majority of free amino acids are increased especially those playing an osmoprotectant role such as proline and glycine. Drought stress related Amino acids contents are significantly reduced in the mutants under water stress condition while they are increased significantly in the wild types plants. The exhibited higher accumulation of other amino acids under stressed condition in the mutant plants suggest that, their expressions are regulated in an ABA independent pathways. In addition, free amino acids content changes during water stress condition suggest their contribution in drought toleration as common compatible osmolytes.

International Journal for Agro Veterinary and Medical Sciences, 2011

Licorice has been used in Chinese folk medicine for the treatment of various disorders. Licorice ... more Licorice has been used in Chinese folk medicine for the treatment of various disorders. Licorice has the biological capabilities of detoxication, antioxidation, and antiinfection. In this study, we evaluated the antihepatotoxic effect of licorice aqueous extract (LE) on the carbon tetrachloride (CCl 4)-induced liver injury in a rat model. Hepatic damage, as reveled by histology and the increased activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) activities, and decreased levels of serum total protein (TP), albumin (Alb) and globulin (G) were induced in rats by an administration of CCl 4 at 3 mL/kg b.w. (1:1 in groundnut oil). Licorice extract significantly inhibited the elevated AST, ALP and ALT activities and the decreased TP, Alb and G levels caused by CCl 4 intoxication. It also enhanced liver super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), Glutathione S-transferase (GST) activities and glutathione (GSH) level, reduced malondialdehyde (MDA) level. Licorice extract still markedly reverses the increased liver hydroxyproline and serum TNF-α levels induced by CCl 4 intoxication. The data of this study support a chemopreventive potential of licorice extract against liver oxidative injury.

European Journal of Medicinal Plants, 2011

... Ethnopharm. Bull., 93(1), 43 49. Kuku, A., Odekanyin, O., Adeniran, K., Adewusi, M., Olonad... more ... Ethnopharm. Bull., 93(1), 43 49. Kuku, A., Odekanyin, O., Adeniran, K., Adewusi, M., Olonade, T. (2009). Purification of a mannose/glucose-specific lectin with antifungal activity from pepper seeds (Capsicum annum). Afr. J. Biochem. Res., 3(6), 272-278. ...

The khat plant (Catha edulis) leaves is grown and consumed daily in Yemen as a natural stimulant ... more The khat plant (Catha edulis) leaves is grown and consumed daily in Yemen as a natural stimulant by chewing the young buds and tender leaves that contain the stimulant "Cathinone" for the mild stimulant effect. Cathinone is believed to be the main active ingredient in fresh khat leaves. In Yemen this habit has a deep-rooted socio-cultural tradition in which consumers spend part of their time chewing khat (ranging between 6-8 hours per day). The effect of this habit on blood constituent has not been adequately studied in human. There is an extensive literature on khat which estimated the effectiveness and specificity for these substances on kidney and liver function test in animals than humans. The present study was undertaken to investigate the biochemical changes associated with chewing Khat.

Brazilian Journal of Plant Physiology, 2011

High temperature and salinity are the major ecological factors challenging crop productivity in t... more High temperature and salinity are the major ecological factors challenging crop productivity in the arid and semiarid regions of the world. Effects of high temperature (43-45°C) and salt stress (0.6 M) on Macrotyloma uniflorum (Lam.) Verdc. (Horse gram), were evaluated in terms of antioxidants and antioxidant enzymes. Both treatments caused typical stress responses in this tropical leguminosae. Oxidative stress indicators such as H 2 O 2 , TBARS, and proline were significantly elevated. Similarly, the antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), guaiacol peroxidase (POX; EC 1.11.1.7) and acid phosphates (AP; EC 3.1.3.2) were significantly elevated while catalase (CAT; EC 1.11.1.6) was reduced. These treatments had contrasting effects on glutathione reductase (GR; EC1.6.4.2) and b-amylase (EC 3.2.1.1). While temperature stress caused increase in GR and decrease in b-amylase, salt stress caused a counter effect. Contrast was also observed in ascorbate and glutathione which increased in temperature stress and reduced in salt stress. SDS-PAGE analysis indicated entirely different protein profiles in temperature and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their controls. Taken together these data describes the similarities and peculiarities of key biochemical responses of Horse gram to high temperatures and salinity.

The mechanismof plant toleranceagainst dehydration is differs according to the growth status of t... more The mechanismof plant toleranceagainst dehydration is differs according to the growth status of the plant. To understand the similarities and differences in the drought responses of two different growth situations of horse gram, seedlings of normal plants along with regenerated tissue culture were subjected to dehydration stresshave been investigated. Enzymatic and non-enzymatic antioxidants of both seedlings behaved similar albeit minor variations. Activity of antioxidant enzymes of both seedlings compared to their controls showed a similar trend. Peroxidase (POX; EC 1.11.1.7), Superoxide dismutase (SOD; EC 1.15.1.1) and Glutathione reductase (GR; EC 1.6.4.2) were elevated. However, Catalase (CAT; EC 1.11.1.6) was reduced in both stressed seedlings. Also the antioxidants levels in both stressed plantlets exhibited 2 folds elevation of ascorbic acid and ~3 folds of GSH, but the elevation of proline was different where it was 6 folds in callus, while normal seedlings increased by 10 times compared to control. Stress markers hydrogen peroxide and thiobarbeturic acid reactive substances (TBARS) 2 folds increased, these coincides with higher levels of Peroxidase, reflecting a great damage of membrane in both stressed status. These suggest that horse gram seedlings behave in similar manner even if grown in different conditions and circumstances which confirm their similar biochemical resistance mechanism when exposed to water deficiency stress.

Sophisticated mummification using chemical preservation was prevalent in ancient Yemeni civilizat... more Sophisticated mummification using chemical preservation was prevalent in ancient Yemeni civilization as noted in the 4th century B.C. mummies of the National Museum of Yemen, Sana'a, used in this study. Five of these mummies were used to evaluate hydrolytic enzymes produced as a result of fungal contamination. Forty-seven fungal species were isolated, thereby reflecting a high degree of contamination which may have resulted from the poor ventilation and preservation system. Aspergillus was the most common genus isolated (48.9%). Fifteen isolates exhibited ability to produce cellulase (EC; 3.2.1.4), Aspergillus candidus being the highest celluloseproducer. Pectin lyase (PL, EC; 4.2.2.2) and pectin methyl esterase (PME, EC; 3.1.1.11) were produced by Trichoderma hamatum, whereas chitinase (EC; 3.2.1.14) was produced by Aspergillus niger. Protease activity was noted by only Cladosporium herbarum. The higher activities of these fungal hydrolytic enzymes represent the major threats of biodeterioration including deteriorating linen bandages as well as the mummy bodies. Therefore, it is recommended to improve the preservation system of the mummies at the National Museum to minimize the contamination up to the lowest level and protect the mummies from biodeterioration.

Arabian Journal for Science and Engineering, 2014

Catha edulis (Khat) is one of the major economic, social and health problems in Yemen. This paper... more Catha edulis (Khat) is one of the major economic, social and health problems in Yemen. This paper aimed to study the effect of Khat on the oxidative status of Khat chewers by measuring the levels of enzymatic and non-enzymatic antioxidant as well as lipid peroxidation. The results exhibited significant reduction in erythrocytes superoxide dismutase (SOD, EC: 1.15.1.1), and catalase (CAT, EC: 1.11.1.6) in Khat chewers, in addition to elevation of serum glutathione-S-transferase (GST, EC: 2.5.1.18). Furthermore, non-enzymatic antioxidants glutathione (GSH) and vitamin C were significantly reduced (p < 0.001; p < 0.015), whereas malondialdehyde (MDA) was significantly elevated (p < 0.001). The depletion of GSH and vitamin C along with MDA elevation in Khat chewers compared with control reflects the obvious oxidative status, a result of enormous

Leaves and buds of Catha edulis plant (Khat) that contain Cathinone were consumed daily in Yemen ... more Leaves and buds of Catha edulis plant (Khat) that contain Cathinone were consumed daily in Yemen as a social habit for the mild stimulant effect of cathinine. Chewing Khat has socio-cultural tradition in which consumers spend part of their time ranging between 4-8 hours per day, in chewing khat. This study aimed to investigate the changes in biochemical markers and antioxidants associated with chewing khat. The results showed a major alteration in the estimated biochemical and the antioxidant markers. It reveal that chewing khat has a toxic effect, on blood constituents, and induce the oxidative stress. The alteration in the clinical biomarkers could be an indicator for liver and kidney toxicity. These proposed that; the daily chewing khat for long time leads to alter in the biochemical composition of blood and enhancing oxidative state, these may contribute in the failure of the body organs, further detailed studies are recommended.

This investigation is aimed at studying the influence of different drying temperatures on the ant... more This investigation is aimed at studying the influence of different drying temperatures on the antioxidant activity for thyme leaves. In the present study different spectrophotometric methods (DPPH, FRAP) are using to investigate the antioxidant activities of thyme plants. The results showed that the drying temperature influences the antioxidant activity. The antioxidant activity of all studied extracts decreased with increasing temperature attending decreasing in total phenol. Fresh thyme shows the highest antioxidant activity (0.014 BHTE.mL-1, 0.0064 AAE and 0.0062 GAE).mL-1 extract and total phenol content (8.78 10-4 mol GAE and 7.50 10-3 mol AAE).mL-1 of extract. Whereas thyme dried at 40°C show the lowest antioxidant activity, (0.0042 BHTE, 0.0019 AAE and 0.0018 GAE).mL-1 of plant extract and total phenol contents (4.30 10-3 AAE and 4.68 10-4 GAE).mL-1 of plant extract.