@article{5a7d83a0edc046409dca5007ab9af150,
title = "A simple, economical and environmental-friendly method for staining protein gels using an extract from walnut-husk",
abstract = "We wish to present a simple, rapid, cost-effective and environmentally safe method for staining proteins in polyacrylamide gels, using aqueous-based natural extracts from fresh green walnut (Juglans regia) hulls/husks. The technique takes not more than 10 min for staining and is comparable in sensitivity to the most commonly used Coomassie R-250 staining method when applied to different concentrations of Bovine Serum Albumin (BSA) and various amounts of E. coli extracts. The protein (BSA) band (~0.5 μg) and E. coli extract comprising ~25 μg total protein can be visualized on polyacrylamide gels. Compared to both Coomassie and Ponceau S staining, the current method displayed more intense bands when proteins are transferred to polyvinylidene fluoride (PVDF) membrane. Although the walnut-dye (WD) method does not require a time-consuming destaining step, excess background stain can simply be removed by washing in water. Extract from old dried black husks and extract from fresh green husks kept for a year was also effective. Using LC-MS, Myricetin and/or Kaempferol were found to be active compounds responsible for staining proteins. Compared to traditional Coomassie method, the inclusion of expensive and toxic solvents (methanol and acetic acid) is completely avoided resulting in positive health, environmental and economic benefits. In view of all these advantages, the WD method has immense potential to replace currently used protein staining techniques.",
keywords = "Coomassie, GC-MS, Juglans regia, Myricetin, Natural product, Protein, SDS-PAGE, Staining, Walnut husk",
author = "Umar Mushtaq and Bhat, {Sehar Saleem} and Parray, {Arif Ali} and Sumaiya Nabi and Wani, {Aflaq Hamid} and Qurashi, {Ahsanul Haq} and Siddiqui, {Khawar Sohail} and Khanday, {Firdous Ahmad}",
note = "Funding Information: This work was supported by the project grant, (No.BT/PR19153/MED/122/20/2016) from the Department of Biotechnology ( DBT ), New Delhi to Dr. Firdous A. Khanday and by CSIR-University Grants Commission No F. 09/251(0060)/2015-EMR-I . Funding Information: Release of hazardous chemicals in environment and exposure of toxic substances to humans and wildlife is currently a major concern. Based on Green Chemistry Concept supported by Environmental Protection Agency (EPA) in collaboration with The Green Chemistry Institute, American Chemical Society (ACS); the safest way to tackle the issue is by invention, improvement, replacement and application of methods that limit or exclude the use of hazardous chemicals harmful to human health, wildlife and the environment [31,32]. Currently, protein staining is routinely done employing Coomassie based dyes whose synthesis and applications are associated with harmful effects. In contrast, our alternative WD method is aqueous based from extraction to application thus eliminating chemicals harmful to human health and aquatic life. Collectively, UV spectrum and GC-MS analysis showed that the active ingredients in walnut husk responsible for staining proteins are non-toxic flavanols (myricetin/kaempferol) found in numerous edible plants. Further studies are needed to optimize the production of the extract on a commercial scale especially from the old dried husks that are available throughout the year. Alternatively, extract from fresh green husks can be stored in liquid form for at least a year or can be dried and reconstituted later when needed. There is also scope for the further enhancement in the sensitivity of protein detection (<0.5 μg/band) especially on polyacrylamide gels. On possible way could be treatment of destained gel with solution containing Fe+3 leading to the red-shift in Myricetin-iron complex [33].This work was supported by the project grant, (No.BT/PR19153/MED/122/20/2016) from the Department of Biotechnology (DBT), New Delhi to Dr. Firdous A. Khanday and by CSIR-University Grants Commission No F. 09/251(0060)/2015-EMR-I. Publisher Copyright: {\textcopyright} 2020 Elsevier B.V.",
year = "2021",
month = jan,
day = "5",
doi = "10.1016/j.cbi.2020.109310",
language = "British English",
volume = "333",
journal = "Chemico-Biological Interactions",
issn = "0009-2797",
publisher = "Elsevier Ireland Ltd",
}