Investigation of total zinc contents and zinc-protein profile in medicinal plants traditionally used for diabetes treatment Ammar M. Ebrahim . Ahmed O. Alnajjar . Maged E. Mohammed . Abubakr M. Idris . Mohammed E. A. Mohammed . Bernhard Michalke Received: 3 November 2019 / Accepted: 29 November 2019 Ó Springer Nature B.V. 2019 Abstract This study aims at the assessment of total zinc contents, water zinc extract contents and zinc- protein profile in medicinal plants traditionally used for diabetes treatment. While zinc-protein profile was screened in plant samples using the online coupling of size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC–ICP–MS), total zinc contents and zinc water extract contents were deter- mined using inductively coupled plasma-optical emis- sion spectrometry (ICP-OES). The analysis of two certified reference materials with similar matrix for total zinc content revealed recovery values of 97.1% and 100.5% while the average of recovery of the summed Zn concentrations from protein fractions compared to total Zn was 103.0 ± 4.8%. Based on the FAO/WHO classification, Sesamum indicum, Nigella sativa, Trigonella Foenum-graecum and Pennisetum glaucum are classified as highest Zn-content. For protein profile, zinc was quantified in 330–430 and 50–60 kDa fractions of all examined plants while no contents were quantified in the inorganic fraction 0.05–0.4 kDa of all plant species. Also, only three plant species recorded Zn contents in the phytate fraction (0.9–1.5 kDa fraction). The fruits of the Momordica Charantia and the Citrullus colocynthis were with the highest extractable zinc concentration; A. M. Ebrahim Research and Consulting Institute, King Faisal University, Hofuf, Saudi Arabia A. M. Ebrahim Sudan Atomic Energy Commission, Khartoum, Sudan A. O. Alnajjar Department of Chemistry, College of Science, King Faisal University, Hofuf 31982, Saudi Arabia M. E. Mohammed Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Hofuf 31982, Saudi Arabia M. E. Mohammed Department of Pharmacognosy, College of Pharmacy, Zagazig University, Zagazig 44519, Egypt A. M. Idris (&) Á M. E. A. Mohammed Department of Chemistry, College of Science, King Khalid University, Abha 61321, Saudi Arabia e-mail: abubakridris@hotmail.com A. M. Idris Research Center for Advanced Materials Science (RCAMS), King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia B. Michalke Research Unit Analytical BioGeoChemistry, Helmholtz Center, Munich, Germany B. Michalke Research Center for Environmental Health, Neuherberg, Germany 123 Biometals https://doi.org/10.1007/s10534-019-00230-3