Identification of antidiabetic compounds from the aqueous extract of Sclerocarya birrea leaves

SUPPLEMENTARY MATERIALS : TABLE S1: 1H NMR and 13C NMR data of Myricetin (1) in methanol-d4 compared to those reported [35] in DMSO-d6; TABLE S2: 1H NMR and 13C NMR data of Myricetin-3-O-β-D-glucuronide (2) in methanol-d4 compared to those reported [36] in methanol-d4; TABLE S3: 1H NMR and 13C NMR data of Quercetin-3-O-β-D-glucuronide (3) in methanol-d4 compared to those reported by [37] in methanol-d4; FIGURE S4: Relative Glucose uptake activity of Marula fractions in C2C12 myocytes over a range of 0.01-100µg/ml. Activity is expressed relative % to the baseline glucose uptake (control) set at 0% and the positive control insulin (Ins) set at 100%. Active fraction (fraction 3) exhibited comparable potency to Insulin. p value < * p < 0.05, ** p < 0.01. *** p < 0.001; FIGURE S5: ESI negative-mode BPI chromatogram of compound 1 (Myricetin) isolated from Fraction 4; FIGURE S6: ESI negative-mode BPI chromatogram of compound 2 (Myricetin3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S7: ESI negative-mode BPI chromatogram of compound 3 (Quercetin-3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S8: MS fragmentation pattern of peak 1 overlaid with MSMS fragmentation pattern of peak 1; FIGURE S9: MS fragmentation pattern of peak 2 overlaid with MSMS fragmentation pattern of peak 2; FIGURE S10: MS fragmentation pattern of peak 3 overlaid with MSMS fragmentation pattern of peak 3; FIGURE S11: MS fragmentation pattern of peak 4 overlaid with MSMS fragmentation pattern of peak 4; FIGURE S12: MS fragmentation pattern of peak 5 overlaid with MSMS fragmentation pattern of peak 5; FIGURE S13: MS fragmentation pattern of peak 6 overlaid with MSMS fragmentation pattern of peak 6.DATA AVAILABILITY STATEMENT : All the data supporting the findings of this study are available within the article and/or its Supplementary Materials.Diabetes, a prevalent metabolic condition with a wide range of complications, is fast becoming a global health crisis. Herbal medicine and enhanced extracts are some of the therapeutic options used in the management of diabetes mellitus. The plant-derived molecules and their suitable structure modification have given many leads or drugs to the world such as metformin used as an antidiabetic drug. The stem extract of Sclerocarya birrea has been reported as a potent antidiabetic (glucose uptake) agent. However, the bioactive compounds have not been reported from S. birrea for treatment of diabetes. In this study, the spray-dried aqueous leaf extracts of S. birrea were investigated as an antidiabetic agent using a 2-deoxy-glucose (2DG) technique showing good stimulatory effect on glucose uptake in differentiated C2C12 myocytes with % 2DG uptake ranging from 110–180% that was comparable to the positive control insulin. Three compounds were isolated and identified using bioassay-guided fractionation of the spray-dried aqueous extract of S. birrea leaves: myricetin (1), myricetin-3-O- -D-glucuronide (2) and quercetin-3-O- -D-glucuronide (3). Their chemical structures were determined using NMR and mass spectrometric analyses, as well as a comparison of experimentally obtained data to those reported in the literature. The isolated compounds (1–3) were studied for their stimulatory actions on glucose uptake in differentiated C2C12 myocytes. The three compounds (1, 2 and 3) showed stimulatory effects on the uptake of 2DG in C2C12 myocytes with % 2DG uptake ranging from 43.9–109.1% that was better compared to the positive control insulin. Additionally, this is the first report of the flavonoid glycosides (myricetin-3-O- -D-glucuronide) for antidiabetic activity and they are the main bioactive compound in the extract responsible for the antidiabetic activity. This result suggests that the S. birrea leaves have the potential to be developed for treatment of diabetes.The Department of Science and Innovation, South Africa, University of KwaZulu-Natal, South Africa and Biomedical Research and Innovation Platform, South African Medical Research Council.https://www.mdpi.com/journal/moleculesam2023Chemistr

Insights on the use of metal complexes of thiourea derivatives as highly efficient adsorbents for ciprofloxacin from contaminated water

Despite the wide use of synthesised metal complexes of thiourea and their derivatives in medicine and corrosion inhibition, a paucity of research exists on their application as adsorbents for pollutants. This study was aimed at investigating the adsorption potential of the copper (II) and zinc (II) complexes of 4-nitro-substituted thiourea derivatives of aminophenol for ciprofloxacin (CPF). The metal complexes were synthesised and characterised. Fourier transform infrared spectroscopy, scanning electron microscopy and a BET surface area analyzer were utilised to determine the surface structure and properties of the synthesised adsorbents. Isotherms were conducted by the application of Langmuir, Freundlich and Scatchard models and revealed a heterogeneous multilayer adsorption process. Kinetic evaluation showed best fit with the pseudo second order model (R2 > 0.991) compared to the pseudo first order and Bangham equations. Thermodynamics showed an endothermic spontaneous abstraction process. The metal complexes showed over 80% desorption of CPF using 0.2 M NaOH and were stable over three cycles of regeneration and reuse. This research revealed the potential of the metal complexes of thiourea as adsorbents for CPF supported by the high adsorption capacity compared to other reported adsorbents.http://www.tandfonline.com/loi/ttrs202020-07-12hj2020Chemistr