Taofeek Yekeen | Shantou University (original) (raw)

Papers by Taofeek Yekeen

Research paper thumbnail of Biological Activities and Cytogenotoxicity Evaluation of Green Synthesized Corn Silk-Mediated Silver Nanoparticle

Nano Plus: Science and Technology of Nanomaterials, 2021

Nanoparticles have been proven to have a wide range of applications due to their peculiar propert... more Nanoparticles have been proven to have a wide range of applications due to their peculiar properties. Of the metallic nanoparticles, green synthesized silver nanoparticles (AgNPs) have been widely used in various applications. This study evaluates the potentials of corn silk extract in the synthesis of silver nanoparticles (CS-AgNPs). The biological activities are tested through various applications as well as their safety. Powdered corn silk (1g) was heated in 100 ml of distilled water at 60°C for 1h, cooled, and centrifuged at 4000 rpm for 30 minutes. Then, 1ml of the extract was added to 40ml of 1mM AgNO3 to reduce Ag+ to nano size. Characterization of CS-AgNPs was through UV-visible spectroscopy, Fourier-transform-infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and Energy Dispersive X-ray (EDX) analysis. The efficacy of CS-AgNPs as a larvicidal, anticoagulant, thrombolytic, and antioxidant agent was evaluated. Safety evaluation was carried out using Allium ...

Research paper thumbnail of Neonatal physical measurement in relation to electronic waste recycling exposure in the community

Research paper thumbnail of Placental IGF-1 and IGFBP-3 expression correlate with PAH and PBDE levels from prenatal exposure to electronic waste

ISEE Conference Abstracts, 2013

Research paper thumbnail of Antidiabetic properties of phytosynthesized gold nanoparticles (AuNPs) fromDatura stramoniumseed

IOP Conference Series: Materials Science and Engineering, 2020

The gold nanoparticles synthesized from Datura stramonium seed was investigated for its antidiabe... more The gold nanoparticles synthesized from Datura stramonium seed was investigated for its antidiabetic properties in the present study. A total number of 42 healthy male albino rats with body weight ranges of 150±20 g were purchased and 7 days acclimatization was carried out after which they were randomly divided into 7 groups (A-G) of 6 animals each. Group A, the control was not induced while the other six groups (B-G) were induced with 150 mg/kg of alloxan by intraperitoneal administration. After 72 h, measurement of the tail vein blood glucose was done to confirm hyperglycemia. Experimental rats with fasting glucose levels (5.6-6.9 mmol/l) were considered diabetic. Group B received no treatment, Group C received 1000 μg/kg of Datura stramonium seed extract, Group D received 500 μg/ml of synthesized AuNPs, Group E received 750 μg/ml of synthesized AuNPs, Group F received 1000 μg/ml of synthesized AuNPs and Group G received 1000 μg/ml of standard drug (glibenclamide). This treatment was administered every day for 21 days. The result showed that the weight of the rats reduced after diabetes induction but after 21 days of treatment, the weight of the treated groups increased when compared to the untreated group. Furthermore, it was observed that after the treatment with 500 and 750 μg/ml AuNPs, the blood sugar was down regulated unlike the untreated groups. Due to the alloxan induction, there were increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea and creatinine levels in the serum of experimental rats, which were significantly reduced after the treatment with Datura stramonium seed extract and the synthesized nanoparticles at 500, 750 and 1000 μg/ml. The histopathology of the pancreas of alloxan induced rats showed severe fibrotic interlobular connective tissues with severely diffused, degenerated, and necrotized Islets of langerhans which were also normalized by treatments with AuNPs. It was confirmed in this research that AuNPs could be embedded in drugs or folk medicine aimed at reducing blood sugar levels.

Research paper thumbnail of Silver‐gold alloy nanoparticles biofabricated by fungal xylanases exhibited potent biomedical and catalytic activities

Biotechnology Progress, 2019

This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as

Research paper thumbnail of Biofabrication of Gold Nanoparticles Using Xylanases Through Valorization of Corncob by Aspergillus niger and Trichoderma longibrachiatum: Antimicrobial, Antioxidant, Anticoagulant and Thrombolytic Activities

Waste and Biomass Valorization, 2018

Research paper thumbnail of Enterococcus species for the one-pot biofabrication of gold nanoparticles: Characterization and nanobiotechnological applications

Journal of photochemistry and photobiology. B, Biology, 2017

In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of... more In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of food origin, were studied for the green synthesis of gold nanoparticles (AuNPs), and characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The AuNPs were evaluated for their Anopheles gambiae larvicidal, dye degradation, antioxidant and thrombolytic activities. The blue-black colloidal AuNPs which absorbed maximally at 549-552nm were nearly spherical in shape, and crystalline in nature with size of 8-50nm. The EDX spectra showed formation of AuNPs to the tune of 89-94%. The prominent FTIR peaks obtained at 3251-3410, 2088 and 1641-1643cm(-1) alluded to the fact that proteins were involved in the biofabrication and capping of AuNPs. AuNPs degraded methylene blue and malachite green by 24.3-57.6%, and 88.85-97.36% respectively in 24h, whereas at 12h, larvicidal activities with LC50 of 21.28-42.33μg/ml w...

Research paper thumbnail of Assessment of health risk of trace metal pollution in surface soil and road dust from e-waste recycling area in China

Environmental science and pollution research international, Jan 27, 2016

Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden... more Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden on the ecosystem in Guiyu, China. In this investigation, we evaluated the trace metal concentration of community soil and road dust samples from 11 locations in Guiyu and 5 locations (consisting of residential areas, kindergarten/school, and farm field) in a reference area using graphite furnace atomic absorption spectrophotometer. The study spanned four seasons, 2012-2013, with a view to assess the risk associated with e-waste recycling in the study area. The concentrations of Pb, Cd, Cr, and Mn were 448.73, 0.71, 63.90, and 806.54 mg/kg in Guiyu soil and 589.74, 1.94, 69.71, and 693.74 mg/kg, in the dust, respectively. Pb and Cd values were significantly higher (P ≤ 0.05) than the reference area, and the mixed model analysis with repeated seasonal measurements revealed soil Pb and Cd levels that were 2.32 and 4.34 times, while the ratios for dust sample were 4.10 and 3.18 times higher...

Research paper thumbnail of Ambient Air Heavy Metals in PM2.5 and Potential Human Health Risk Assessment in an Informal Electronic-Waste Recycling Site of China

Aerosol and Air Quality Research, 2016

In this study, we characterized the concentration of heavy metals in PM 2.5 in the community with... more In this study, we characterized the concentration of heavy metals in PM 2.5 in the community with e-waste dismantling, Guiyu, China and assessed potential public health risk associated with heavy metal composition of PM 2.5 for local residents. Daily samples of PM 2.5 were collected with Harvard Impactors on the roof of 3-story buildings from March 2012-April 2013 in Guiyu (n = 133) and seasonal samples were collected in a reference site, Haojiang (n = 33). The concentrations of PM 2.5 mass and heavy metals were analyzed gravimetrically and by graphite furnace atomic absorption spectrometry, respectively. The geometric mean concentrations of PM 2.5 , Pb and Cd in Guiyu were higher than in the reference area (PM 2.5 : 49.9 µg m-3 vs. 37.6 , p < 0.01; Pb: 160 ng m-3 vs. 69 ng m-3 , p < 0.001; Cd: 5.7 ng m-3 vs. 3.4 ng m-3 , p < 0.01), but Cr and Mn concentrations were not statistically different (Cr: 4.5 ng m-3 vs. 3.8 ng m-3 , p > 0.05; Mn: 17 ng m-3 vs. 16 ng m-3 , p > 0.05). The metal concentrations in PM 2.5 from Guiyu were also higher when compared to other Asian cities. We observed higher heavy metal concentrations during winter and spring than summer and fall. Human health risk assessment showed that the total potential cancer risk for both adults and children are higher than the safe acceptable range recommended by the US EPA. Furthermore, the carcinogenic and non-carcinogenic elements in PM 2.5 pose higher public health risk to children than adults. The results indicate that air pollution emitted from informal e-waste recycling activities might be affecting the health of local residents, especially children.

Research paper thumbnail of Evaluation of the Acute and Sublethal Effects of Ethanolic Extracts of Piper Guineense in Mice

The West African Black Pepper, Piper guineese is a commonly used spice to flavor food and as trad... more The West African Black Pepper, Piper guineese is a commonly used spice to flavor food and as traditional medicine for the cure of some ailments in Nigeria. Its acute and sublethal effects through LD50 determination, induction of abnormal sperm morphology and effects of haematolgical indices, weights and histopathology of liver, kidney and lungs using mice were evaluated. For LD50 determination, the test animals were exposed intraperitoneally (IP) to 0.5ml of the ethanolic extract at concentrations of 5.0% (parts per thousand), 6.0%, 7.0%, 8.0% and 9.0% for five consecutive days. An LD50 of 6.45% was obtained. The sublethal effects were analysed at doses of 1.0%, 2.0%, 3.0%, 4.0% and 5.0% of the test chemical. Blood samples taken per week for 3 weeks showed that the extracts of P. guineese did not induce any significant effect on the haematolgical parameters except the white blood cell whose values were significantly different (p<0.05, ANOVA) from the controls. Absolute and relati...

Research paper thumbnail of Erratum to: Increase male genital diseases morbidity linked to informal electronic waste recycling in Guiyu, China

Environmental Science and Pollution Research, 2014

Research paper thumbnail of Evaluation of toxic effects of lambdacyhalothrin on the haematology and selected biochemical parameters of African catfishClarias gariepinus

Zoology and Ecology, 2013

ABSTRACT The potential acute and chronic toxic effects of lambdacyhalothrin (LCT) on African catf... more ABSTRACT The potential acute and chronic toxic effects of lambdacyhalothrin (LCT) on African catfish Clarias gariepinus were evaluated. Lethal concentrations (LC) were determined using 0.2, 0.3, 0.4, 0.5 and 0.6 ppm of LCT. Haematological and biochemical parameters were evaluated on fish treated with 0.001, 0.005, 0.010 and 0.025 ppm of LCT. Blood samples were collected on the 15th, 30th, 45th and 60th day of exposure and 60th day of recovery. Fish treated with LCT showed behavioural abnormalities compared to the control, which included reduced swimming activity, loss of equilibrium, vertical hanging and air gulping. The LC50 values of LCT were 0.571, 0.380, 0.337 and 0.325 ppm at the exposure time of 24, 48, 72 and 96 h, respectively. Significant reductions (p 0.05) were observed in the packed cell volume, red blood cell count and haemoglobin concentration values in exposed fish. Initial increase in the value of the white blood cell count was observed, which later declined. Serum glucose increased significantly (p 0.05), while globulin decreased significantly. Albumin did not show any significant difference among tested concentrations. The results revealed that the emulsifiable concentrate form of LCT caused reduction in haematological and biochemical parameters of C. gariepinus. The data obtained in this study provide more information on the potential impacts of LCT on non-target organisms and thus will assist in future ecotoxicological evaluations.Straipsnyje įvertinamas ūmus ir lėtinis lambdacihalotrino poveikis afrikiniam šamui Clarias gariepinus. Letalios koncentracijos (LC) nustatytos naudojant 0,2, 0,3, 0,4, 0,5 ir 0,6 dalelių milijone (ppm) lambdacihalotriną. Žuvų biocheminiai ir hematologiniai rodikliai ištirti paveikus jas 0,001, 0,005, 0,010 ir 0,025 dalelių milijone (ppm) koncentracijos lambdacihalotrinu. Kraujo mėginiai buvo imami 15, 30, 45 ir 60 poveikio dieną bei praėjus 60 dienų po poveikio. Lambdacihalotrinu paveiktoms žuvims nustatyti elgsenos sutrikimai – sumažėjęs plaukiojimo aktyvumas, pusiausvyros praradimas, vertikali kūno padėtis ir išnirimas įkvėpti oro. Žuvis veikiant lambdacihalotrinu 24, 48, 72 ir 96 valandas, LC50 buvo 0,571, 0,380, 0,337 ir 0,325 dalelių milijone atitinkamai. Nustatytas žymus hematokrito rodiklio, raudonųjų kraujo kūnelių skaičiaus ir hemoglobino koncentracijos sumažėjimas (p 0,05). Baltųjų kraujo kūnelių skaičiaus padidėjimas buvo stebimas tik poveikio pradžioje. Gliukozės kiekis serume ženkliai padidėjo (p 0,05), o globulino kiekis ženkliai sumažėjo. Albuminų skaičiaus pakitimai buvo nereikšmingi. Gauti duomenys praplečia informaciją apie lambdacihalotrino poveikį organizmams ir gali būti panaudoti kitiems ekotoksikologiniams tyrimams.

Research paper thumbnail of Biogenic Synthesis of Silver Nanoparticles, Using Bougainvillea spectabilis Willd. Bract Extract

National Academy Science Letters, 2012

ABSTRACT

Research paper thumbnail of Chromium exposure among children from an electronic waste recycling town of China

Environmental Science and Pollution Research, 2013

Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal el... more Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal electronic waste (e-waste) recycling activities. A 3-year (2004, 2006, and 2008) independent cross-sectional study on blood chromium (BCr) levels of 711 children from Guiyu and a control area was investigated. Questionnaire completed by parents/guardians was used to assess the risk factors of chromium (Cr) exposure, while physical examination, for the year 2008 only, was used to evaluate the effects of long-term exposure to Cr on child physical development. Children living in Guiyu had significantly higher BCr levels compared with those living in Chendian at the same period from 2004 to 2008 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). The predominant risk factors related to elevated child BCr levels included the use of house as a family workshop, parent involved in e-waste recycling, and child residence in Guiyu. Children&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s weight and chest circumferences in group with high exposure to Cr (upper quartile) were higher than in the low-exposure group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), although the difference was less significant for boys between the two groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The results suggest that elevated child BCr in Guiyu due to informal e-waste recycling activities might be threatening the health of children, with implications on physical growth and development.

Research paper thumbnail of Assessment of association between the dopamine D2 receptor (DRD2) polymorphism and neurodevelopment of children exposed to lead

Environmental Science and Pollution Research, 2014

Research paper thumbnail of Increase male genital diseases morbidity linked to informal electronic waste recycling in Guiyu, China

Environmental Science and Pollution Research, 2013

Research paper thumbnail of ALAD genotypes and blood lead levels of neonates and children from e-waste exposure in Guiyu, China

Environmental Science and Pollution Research, 2014

Extensive e-waste recycling activity in Guiyu, China, has been conducted using primitive techniqu... more Extensive e-waste recycling activity in Guiyu, China, has been conducted using primitive techniques for the last 20 years, resulting in serious heavy metal environmental contamination. A polymorphic variant of the δ-aminolevulinic acid dehydratase (ALAD) gene has been found to influence lead uptake and, thus, may influence an individual&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s susceptibility to lead toxicity. We therefore explored whether the ALAD gene polymorphism affects blood lead levels of newborns and children in Guiyu. A total of 273 newborns and 504 children, and a combination of 2004/2005 and 2006 independent recruitments were used for this study. Umbilical cord blood from newborns (Guiyu/exposed group 189 vs. Chaonan/reference group 84) and venous blood from children (exposed group, 319 vs. Chendian/reference group 185) were collected. Blood lead levels (BLLs) were measured via graphite furnace atomic absorption spectrometry (GFAAS) for all samples, while ALAD genotyping was performed using PCR-RFLP for 273 neonate cord blood and 246 children&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s blood. The median BBLs of neonates in exposed group vs. the reference group were 10.50 (2.36-40.78) vs. 7.79 (0.8-19.51) for 2004/2005 and 9.41 (9.28-47.60) vs. 5.49 (0.35-18.68) for 2006, while child mean BLLs were 15.31 ± 5.79 vs. 9.94 ± 4.05 for 2004/2005 and 13.17 ± 5.98 vs. 10.04 ± 4.85 for 2006. The genotype frequencies in newborns were 98.90 % for the ALAD-1/ALAD-1 homozygote and 1.10% for the ALAD-1/ALAD-2 heterozygotes, while the values were 95.93 and 4.07%, respectively, in children. The allele frequencies of the ALAD-1 and ALAD-2 were 99.45 and 0.55% for newborns, but 97.97 and 2.03% for children, respectively. No significant differences in blood lead levels were found between ALAD-1/ALAD-1 and ALAD-1/ALAD-2 either in newborns or in children. The frequency distribution of the ALAD-2 allele in newborns from the exposed group was lower than that of the reference group. There were no significant differences, between the two different ALAD genotypes in the lead load of newborns and children. The frequency distribution of ALAD gene does not influence the blood lead levels of newborns and children in this case, which means that the higher lead burden in the exposed children was possibly influenced by e-waste recycling, but not ALAD genotypes.

Research paper thumbnail of Evaluation of some Heavy Metals in Soils along a Major Road in Ogbomoso, South West Nigeria

Research paper thumbnail of Nutritional qualities and cytotoxic evaluation of Vernonia amygdalina, Amaranthus caudatum and Telfairia occidentalis vegetables widely consumed in South West Nigeria

Nutritional qualities of vegetables, Vernonia amygdalina; Amaranthus caudatum and Telfairia occid... more Nutritional qualities of vegetables, Vernonia amygdalina; Amaranthus caudatum and Telfairia occidentalis, were evaluated along with the cytotoxic effects of their aqueous extracts to ascertain the potential risk that may be associated with the consumption of vegetables from unknown sources. Leaves of the plants were used for proximate analysis, while microscopic and macroscopic tests of the aqueous extracts of each of the vegetables were conducted using 0.25,

Research paper thumbnail of Cobweb as novel biomaterial for the green and eco-friendly synthesis of silver nanoparticles

Applied Nanoscience, 2015

In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver na... more In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. The efficacy of biosynthesized particles as antibacterial agents was evaluated using multidrug resistant clinical bacterial isolates through sensitivity testing with AgNPs and combination of AgNPs with some selected antibiotics. In addition, the potential application of the particles as additives in paints was demonstrated using some bacterial and fungal isolates. The synthesized AgNPs which were dark brown in color displayed maximum absorbance at the wavelength of 436 nm. It was observed that the reaction mixture of 1:40 (extract:AgNO 3 solution) at pH of 8.5 produced particles with maximum absorbance at 436 nm. The FTIR spectrum showed peaks at 3298, 2359, 2089, and 1635 cm-1 , indicating that proteins were the capping and stabilization molecules in the synthesis of AgNPs. The particles were spherical in shape with size ranging about 3-50 nm. The energy-dispersive X-ray analysis showed the presence of silver as the most prominent metal, while the selected area electron diffraction pattern conformed to the face-centered cubic phase and crystalline nature of AgNPs. The AgNPs inhibited the growth of several bacterial isolates including S. aureus, E. coli, Klebsiella granulomatis and P. aeruginosa in the range of 10-17 mm at concentration of 100 lg/ml. It was also demonstrated that AgNPs potentiated the activities of augmentin, ofloxacin and cefixime in the AgNP-antibiotic synergy studies. Similarly, the inclusion of AgNPs as additive in white emulsion paint led to the total inhibition of growth of E. coli, P. aeruginosa, Aspergillus niger and A. fumigatus. To the best of our knowledge, this is the first report of the use of cobweb for the green synthesis of AgNPs. The immense antimicrobial activities of the particles can be explored in the creation of novel products, where it can be used as additive to protect materials against microbial attack.

Research paper thumbnail of Biological Activities and Cytogenotoxicity Evaluation of Green Synthesized Corn Silk-Mediated Silver Nanoparticle

Nano Plus: Science and Technology of Nanomaterials, 2021

Nanoparticles have been proven to have a wide range of applications due to their peculiar propert... more Nanoparticles have been proven to have a wide range of applications due to their peculiar properties. Of the metallic nanoparticles, green synthesized silver nanoparticles (AgNPs) have been widely used in various applications. This study evaluates the potentials of corn silk extract in the synthesis of silver nanoparticles (CS-AgNPs). The biological activities are tested through various applications as well as their safety. Powdered corn silk (1g) was heated in 100 ml of distilled water at 60°C for 1h, cooled, and centrifuged at 4000 rpm for 30 minutes. Then, 1ml of the extract was added to 40ml of 1mM AgNO3 to reduce Ag+ to nano size. Characterization of CS-AgNPs was through UV-visible spectroscopy, Fourier-transform-infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and Energy Dispersive X-ray (EDX) analysis. The efficacy of CS-AgNPs as a larvicidal, anticoagulant, thrombolytic, and antioxidant agent was evaluated. Safety evaluation was carried out using Allium ...

Research paper thumbnail of Neonatal physical measurement in relation to electronic waste recycling exposure in the community

Research paper thumbnail of Placental IGF-1 and IGFBP-3 expression correlate with PAH and PBDE levels from prenatal exposure to electronic waste

ISEE Conference Abstracts, 2013

Research paper thumbnail of Antidiabetic properties of phytosynthesized gold nanoparticles (AuNPs) fromDatura stramoniumseed

IOP Conference Series: Materials Science and Engineering, 2020

The gold nanoparticles synthesized from Datura stramonium seed was investigated for its antidiabe... more The gold nanoparticles synthesized from Datura stramonium seed was investigated for its antidiabetic properties in the present study. A total number of 42 healthy male albino rats with body weight ranges of 150±20 g were purchased and 7 days acclimatization was carried out after which they were randomly divided into 7 groups (A-G) of 6 animals each. Group A, the control was not induced while the other six groups (B-G) were induced with 150 mg/kg of alloxan by intraperitoneal administration. After 72 h, measurement of the tail vein blood glucose was done to confirm hyperglycemia. Experimental rats with fasting glucose levels (5.6-6.9 mmol/l) were considered diabetic. Group B received no treatment, Group C received 1000 μg/kg of Datura stramonium seed extract, Group D received 500 μg/ml of synthesized AuNPs, Group E received 750 μg/ml of synthesized AuNPs, Group F received 1000 μg/ml of synthesized AuNPs and Group G received 1000 μg/ml of standard drug (glibenclamide). This treatment was administered every day for 21 days. The result showed that the weight of the rats reduced after diabetes induction but after 21 days of treatment, the weight of the treated groups increased when compared to the untreated group. Furthermore, it was observed that after the treatment with 500 and 750 μg/ml AuNPs, the blood sugar was down regulated unlike the untreated groups. Due to the alloxan induction, there were increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea and creatinine levels in the serum of experimental rats, which were significantly reduced after the treatment with Datura stramonium seed extract and the synthesized nanoparticles at 500, 750 and 1000 μg/ml. The histopathology of the pancreas of alloxan induced rats showed severe fibrotic interlobular connective tissues with severely diffused, degenerated, and necrotized Islets of langerhans which were also normalized by treatments with AuNPs. It was confirmed in this research that AuNPs could be embedded in drugs or folk medicine aimed at reducing blood sugar levels.

Research paper thumbnail of Silver‐gold alloy nanoparticles biofabricated by fungal xylanases exhibited potent biomedical and catalytic activities

Biotechnology Progress, 2019

This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as

Research paper thumbnail of Biofabrication of Gold Nanoparticles Using Xylanases Through Valorization of Corncob by Aspergillus niger and Trichoderma longibrachiatum: Antimicrobial, Antioxidant, Anticoagulant and Thrombolytic Activities

Waste and Biomass Valorization, 2018

Research paper thumbnail of Enterococcus species for the one-pot biofabrication of gold nanoparticles: Characterization and nanobiotechnological applications

Journal of photochemistry and photobiology. B, Biology, 2017

In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of... more In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of food origin, were studied for the green synthesis of gold nanoparticles (AuNPs), and characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The AuNPs were evaluated for their Anopheles gambiae larvicidal, dye degradation, antioxidant and thrombolytic activities. The blue-black colloidal AuNPs which absorbed maximally at 549-552nm were nearly spherical in shape, and crystalline in nature with size of 8-50nm. The EDX spectra showed formation of AuNPs to the tune of 89-94%. The prominent FTIR peaks obtained at 3251-3410, 2088 and 1641-1643cm(-1) alluded to the fact that proteins were involved in the biofabrication and capping of AuNPs. AuNPs degraded methylene blue and malachite green by 24.3-57.6%, and 88.85-97.36% respectively in 24h, whereas at 12h, larvicidal activities with LC50 of 21.28-42.33μg/ml w...

Research paper thumbnail of Assessment of health risk of trace metal pollution in surface soil and road dust from e-waste recycling area in China

Environmental science and pollution research international, Jan 27, 2016

Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden... more Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden on the ecosystem in Guiyu, China. In this investigation, we evaluated the trace metal concentration of community soil and road dust samples from 11 locations in Guiyu and 5 locations (consisting of residential areas, kindergarten/school, and farm field) in a reference area using graphite furnace atomic absorption spectrophotometer. The study spanned four seasons, 2012-2013, with a view to assess the risk associated with e-waste recycling in the study area. The concentrations of Pb, Cd, Cr, and Mn were 448.73, 0.71, 63.90, and 806.54 mg/kg in Guiyu soil and 589.74, 1.94, 69.71, and 693.74 mg/kg, in the dust, respectively. Pb and Cd values were significantly higher (P ≤ 0.05) than the reference area, and the mixed model analysis with repeated seasonal measurements revealed soil Pb and Cd levels that were 2.32 and 4.34 times, while the ratios for dust sample were 4.10 and 3.18 times higher...

Research paper thumbnail of Ambient Air Heavy Metals in PM2.5 and Potential Human Health Risk Assessment in an Informal Electronic-Waste Recycling Site of China

Aerosol and Air Quality Research, 2016

In this study, we characterized the concentration of heavy metals in PM 2.5 in the community with... more In this study, we characterized the concentration of heavy metals in PM 2.5 in the community with e-waste dismantling, Guiyu, China and assessed potential public health risk associated with heavy metal composition of PM 2.5 for local residents. Daily samples of PM 2.5 were collected with Harvard Impactors on the roof of 3-story buildings from March 2012-April 2013 in Guiyu (n = 133) and seasonal samples were collected in a reference site, Haojiang (n = 33). The concentrations of PM 2.5 mass and heavy metals were analyzed gravimetrically and by graphite furnace atomic absorption spectrometry, respectively. The geometric mean concentrations of PM 2.5 , Pb and Cd in Guiyu were higher than in the reference area (PM 2.5 : 49.9 µg m-3 vs. 37.6 , p < 0.01; Pb: 160 ng m-3 vs. 69 ng m-3 , p < 0.001; Cd: 5.7 ng m-3 vs. 3.4 ng m-3 , p < 0.01), but Cr and Mn concentrations were not statistically different (Cr: 4.5 ng m-3 vs. 3.8 ng m-3 , p > 0.05; Mn: 17 ng m-3 vs. 16 ng m-3 , p > 0.05). The metal concentrations in PM 2.5 from Guiyu were also higher when compared to other Asian cities. We observed higher heavy metal concentrations during winter and spring than summer and fall. Human health risk assessment showed that the total potential cancer risk for both adults and children are higher than the safe acceptable range recommended by the US EPA. Furthermore, the carcinogenic and non-carcinogenic elements in PM 2.5 pose higher public health risk to children than adults. The results indicate that air pollution emitted from informal e-waste recycling activities might be affecting the health of local residents, especially children.

Research paper thumbnail of Evaluation of the Acute and Sublethal Effects of Ethanolic Extracts of Piper Guineense in Mice

The West African Black Pepper, Piper guineese is a commonly used spice to flavor food and as trad... more The West African Black Pepper, Piper guineese is a commonly used spice to flavor food and as traditional medicine for the cure of some ailments in Nigeria. Its acute and sublethal effects through LD50 determination, induction of abnormal sperm morphology and effects of haematolgical indices, weights and histopathology of liver, kidney and lungs using mice were evaluated. For LD50 determination, the test animals were exposed intraperitoneally (IP) to 0.5ml of the ethanolic extract at concentrations of 5.0% (parts per thousand), 6.0%, 7.0%, 8.0% and 9.0% for five consecutive days. An LD50 of 6.45% was obtained. The sublethal effects were analysed at doses of 1.0%, 2.0%, 3.0%, 4.0% and 5.0% of the test chemical. Blood samples taken per week for 3 weeks showed that the extracts of P. guineese did not induce any significant effect on the haematolgical parameters except the white blood cell whose values were significantly different (p<0.05, ANOVA) from the controls. Absolute and relati...

Research paper thumbnail of Erratum to: Increase male genital diseases morbidity linked to informal electronic waste recycling in Guiyu, China

Environmental Science and Pollution Research, 2014

Research paper thumbnail of Evaluation of toxic effects of lambdacyhalothrin on the haematology and selected biochemical parameters of African catfishClarias gariepinus

Zoology and Ecology, 2013

ABSTRACT The potential acute and chronic toxic effects of lambdacyhalothrin (LCT) on African catf... more ABSTRACT The potential acute and chronic toxic effects of lambdacyhalothrin (LCT) on African catfish Clarias gariepinus were evaluated. Lethal concentrations (LC) were determined using 0.2, 0.3, 0.4, 0.5 and 0.6 ppm of LCT. Haematological and biochemical parameters were evaluated on fish treated with 0.001, 0.005, 0.010 and 0.025 ppm of LCT. Blood samples were collected on the 15th, 30th, 45th and 60th day of exposure and 60th day of recovery. Fish treated with LCT showed behavioural abnormalities compared to the control, which included reduced swimming activity, loss of equilibrium, vertical hanging and air gulping. The LC50 values of LCT were 0.571, 0.380, 0.337 and 0.325 ppm at the exposure time of 24, 48, 72 and 96 h, respectively. Significant reductions (p 0.05) were observed in the packed cell volume, red blood cell count and haemoglobin concentration values in exposed fish. Initial increase in the value of the white blood cell count was observed, which later declined. Serum glucose increased significantly (p 0.05), while globulin decreased significantly. Albumin did not show any significant difference among tested concentrations. The results revealed that the emulsifiable concentrate form of LCT caused reduction in haematological and biochemical parameters of C. gariepinus. The data obtained in this study provide more information on the potential impacts of LCT on non-target organisms and thus will assist in future ecotoxicological evaluations.Straipsnyje įvertinamas ūmus ir lėtinis lambdacihalotrino poveikis afrikiniam šamui Clarias gariepinus. Letalios koncentracijos (LC) nustatytos naudojant 0,2, 0,3, 0,4, 0,5 ir 0,6 dalelių milijone (ppm) lambdacihalotriną. Žuvų biocheminiai ir hematologiniai rodikliai ištirti paveikus jas 0,001, 0,005, 0,010 ir 0,025 dalelių milijone (ppm) koncentracijos lambdacihalotrinu. Kraujo mėginiai buvo imami 15, 30, 45 ir 60 poveikio dieną bei praėjus 60 dienų po poveikio. Lambdacihalotrinu paveiktoms žuvims nustatyti elgsenos sutrikimai – sumažėjęs plaukiojimo aktyvumas, pusiausvyros praradimas, vertikali kūno padėtis ir išnirimas įkvėpti oro. Žuvis veikiant lambdacihalotrinu 24, 48, 72 ir 96 valandas, LC50 buvo 0,571, 0,380, 0,337 ir 0,325 dalelių milijone atitinkamai. Nustatytas žymus hematokrito rodiklio, raudonųjų kraujo kūnelių skaičiaus ir hemoglobino koncentracijos sumažėjimas (p 0,05). Baltųjų kraujo kūnelių skaičiaus padidėjimas buvo stebimas tik poveikio pradžioje. Gliukozės kiekis serume ženkliai padidėjo (p 0,05), o globulino kiekis ženkliai sumažėjo. Albuminų skaičiaus pakitimai buvo nereikšmingi. Gauti duomenys praplečia informaciją apie lambdacihalotrino poveikį organizmams ir gali būti panaudoti kitiems ekotoksikologiniams tyrimams.

Research paper thumbnail of Biogenic Synthesis of Silver Nanoparticles, Using Bougainvillea spectabilis Willd. Bract Extract

National Academy Science Letters, 2012

ABSTRACT

Research paper thumbnail of Chromium exposure among children from an electronic waste recycling town of China

Environmental Science and Pollution Research, 2013

Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal el... more Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal electronic waste (e-waste) recycling activities. A 3-year (2004, 2006, and 2008) independent cross-sectional study on blood chromium (BCr) levels of 711 children from Guiyu and a control area was investigated. Questionnaire completed by parents/guardians was used to assess the risk factors of chromium (Cr) exposure, while physical examination, for the year 2008 only, was used to evaluate the effects of long-term exposure to Cr on child physical development. Children living in Guiyu had significantly higher BCr levels compared with those living in Chendian at the same period from 2004 to 2008 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). The predominant risk factors related to elevated child BCr levels included the use of house as a family workshop, parent involved in e-waste recycling, and child residence in Guiyu. Children&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s weight and chest circumferences in group with high exposure to Cr (upper quartile) were higher than in the low-exposure group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), although the difference was less significant for boys between the two groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The results suggest that elevated child BCr in Guiyu due to informal e-waste recycling activities might be threatening the health of children, with implications on physical growth and development.

Research paper thumbnail of Assessment of association between the dopamine D2 receptor (DRD2) polymorphism and neurodevelopment of children exposed to lead

Environmental Science and Pollution Research, 2014

Research paper thumbnail of Increase male genital diseases morbidity linked to informal electronic waste recycling in Guiyu, China

Environmental Science and Pollution Research, 2013

Research paper thumbnail of ALAD genotypes and blood lead levels of neonates and children from e-waste exposure in Guiyu, China

Environmental Science and Pollution Research, 2014

Extensive e-waste recycling activity in Guiyu, China, has been conducted using primitive techniqu... more Extensive e-waste recycling activity in Guiyu, China, has been conducted using primitive techniques for the last 20 years, resulting in serious heavy metal environmental contamination. A polymorphic variant of the δ-aminolevulinic acid dehydratase (ALAD) gene has been found to influence lead uptake and, thus, may influence an individual&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s susceptibility to lead toxicity. We therefore explored whether the ALAD gene polymorphism affects blood lead levels of newborns and children in Guiyu. A total of 273 newborns and 504 children, and a combination of 2004/2005 and 2006 independent recruitments were used for this study. Umbilical cord blood from newborns (Guiyu/exposed group 189 vs. Chaonan/reference group 84) and venous blood from children (exposed group, 319 vs. Chendian/reference group 185) were collected. Blood lead levels (BLLs) were measured via graphite furnace atomic absorption spectrometry (GFAAS) for all samples, while ALAD genotyping was performed using PCR-RFLP for 273 neonate cord blood and 246 children&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s blood. The median BBLs of neonates in exposed group vs. the reference group were 10.50 (2.36-40.78) vs. 7.79 (0.8-19.51) for 2004/2005 and 9.41 (9.28-47.60) vs. 5.49 (0.35-18.68) for 2006, while child mean BLLs were 15.31 ± 5.79 vs. 9.94 ± 4.05 for 2004/2005 and 13.17 ± 5.98 vs. 10.04 ± 4.85 for 2006. The genotype frequencies in newborns were 98.90 % for the ALAD-1/ALAD-1 homozygote and 1.10% for the ALAD-1/ALAD-2 heterozygotes, while the values were 95.93 and 4.07%, respectively, in children. The allele frequencies of the ALAD-1 and ALAD-2 were 99.45 and 0.55% for newborns, but 97.97 and 2.03% for children, respectively. No significant differences in blood lead levels were found between ALAD-1/ALAD-1 and ALAD-1/ALAD-2 either in newborns or in children. The frequency distribution of the ALAD-2 allele in newborns from the exposed group was lower than that of the reference group. There were no significant differences, between the two different ALAD genotypes in the lead load of newborns and children. The frequency distribution of ALAD gene does not influence the blood lead levels of newborns and children in this case, which means that the higher lead burden in the exposed children was possibly influenced by e-waste recycling, but not ALAD genotypes.

Research paper thumbnail of Evaluation of some Heavy Metals in Soils along a Major Road in Ogbomoso, South West Nigeria

Research paper thumbnail of Nutritional qualities and cytotoxic evaluation of Vernonia amygdalina, Amaranthus caudatum and Telfairia occidentalis vegetables widely consumed in South West Nigeria

Nutritional qualities of vegetables, Vernonia amygdalina; Amaranthus caudatum and Telfairia occid... more Nutritional qualities of vegetables, Vernonia amygdalina; Amaranthus caudatum and Telfairia occidentalis, were evaluated along with the cytotoxic effects of their aqueous extracts to ascertain the potential risk that may be associated with the consumption of vegetables from unknown sources. Leaves of the plants were used for proximate analysis, while microscopic and macroscopic tests of the aqueous extracts of each of the vegetables were conducted using 0.25,

Research paper thumbnail of Cobweb as novel biomaterial for the green and eco-friendly synthesis of silver nanoparticles

Applied Nanoscience, 2015

In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver na... more In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. The efficacy of biosynthesized particles as antibacterial agents was evaluated using multidrug resistant clinical bacterial isolates through sensitivity testing with AgNPs and combination of AgNPs with some selected antibiotics. In addition, the potential application of the particles as additives in paints was demonstrated using some bacterial and fungal isolates. The synthesized AgNPs which were dark brown in color displayed maximum absorbance at the wavelength of 436 nm. It was observed that the reaction mixture of 1:40 (extract:AgNO 3 solution) at pH of 8.5 produced particles with maximum absorbance at 436 nm. The FTIR spectrum showed peaks at 3298, 2359, 2089, and 1635 cm-1 , indicating that proteins were the capping and stabilization molecules in the synthesis of AgNPs. The particles were spherical in shape with size ranging about 3-50 nm. The energy-dispersive X-ray analysis showed the presence of silver as the most prominent metal, while the selected area electron diffraction pattern conformed to the face-centered cubic phase and crystalline nature of AgNPs. The AgNPs inhibited the growth of several bacterial isolates including S. aureus, E. coli, Klebsiella granulomatis and P. aeruginosa in the range of 10-17 mm at concentration of 100 lg/ml. It was also demonstrated that AgNPs potentiated the activities of augmentin, ofloxacin and cefixime in the AgNP-antibiotic synergy studies. Similarly, the inclusion of AgNPs as additive in white emulsion paint led to the total inhibition of growth of E. coli, P. aeruginosa, Aspergillus niger and A. fumigatus. To the best of our knowledge, this is the first report of the use of cobweb for the green synthesis of AgNPs. The immense antimicrobial activities of the particles can be explored in the creation of novel products, where it can be used as additive to protect materials against microbial attack.