• Antioxidant, Anticancer and Antibacterial Activity of Withania somnifera Aqueous Root Extract

      Barnes, D. A.; Barlow, R.; Nigam, Poonam S.; Owusu-Apenten, Richard K.; University of Chester, University of Ulster (Sciencedomain international, 2015-11-10)
      Aims: To evaluate total antioxidant capacity, anticancer activity and antibacterial effects Withania somnifera aqueous-root extracts. Study Design: In vitro study. Place of Study: School of Biomedical Sciences, Ulster University, UK. Methodology: Total antioxidant capacity (TAC) of whole powder and freeze dried W. somnifera aqueous-root extracts was determined using FRAP, DPPH, Folin and ABTS assays. Anticancer activity was accessed using MDA-MB-231 breast cells and Sulforhodamine B staining for cell viability. Antibacterial activity was by disk diffusion assay with penicillin, amoxicillin and streptomycin as positive controls. Results: The TAC for W. somnifera extract was 86, 47, 195,or 443 gallic acid equivalents per 100g dry basis (mgGAE/ 100 g) using FRAP, DPPH, Folin or ABTS assays, respectively. Corresponding TAC values for freeze dried W. somnifera aqueous-root extract were, 418, 553, 1898 or, 1770 (mgGAE/100 g). W. somnifera aqueous-root extract inhibited MDA-MB-231 cell proliferation in a dose-dependent manner with IC50 = 0.19 mg/ml (21 µM GAE). Nil antibacterial effects were detected for freeze dried W. somnifera extract (0-1 mg/ml) across six species of bacteria tested. Conclusion: Withania somnifera root water extract showed significant antioxidant and anticancer activity for MDA-MB-231 breast cancer cells but no antibacterial activity under the conditions of this study.
    • Antioxidant, Anticancer and Antimicrobial, Effects of Rubia cordifolia Aqueous Root Extract

      Barlow, R.; Barnes, D. A.; Campbell, Anna M.; Nigam, Poonam S.; Owusu-Apenten, Richard K.; University of Chester, University of Ulster (Sciencedomain international, 2015-11-10)
      Aims: To evaluate the total antioxidant capacity (TAC) of Rubia cordifolia root extracts, to test anticancer activity against MDA-MB-231 breast cancer cell lines, and to evaluate antimicrobial activity of the same extract versus six Gram-positive and negative bacteria. Study Design: In vitro. Place of Study and Duration: School of Biomedical Sciences, Ulster University, July 2014-Sept 2015. Methodology: TAC was tested using ABTS, DPPH, FRAP and Folin assays and values were expressed as mg-gallic acid equivalents per 100 g (GAE/100 g) of sample. Anticancer properties were examined against MDA-MB-231 breast cancer cell lines using Sulforhodamine B assay. Antimicrobial activity was examined using a disk diffusion assay with three Gram-positive (Staphylococcus epidermidis, Staphylococcus aureus and Bacillus cereus) and three Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi) bacteria. Results: TAC of dry extracts of Rubia cordifolia ranged from 523±43 to 4513±208 (mg GAE mg/100 g) depending on the method of analysis, ABTS> FRAP> Folin > DPPH methods. R. cordifolia dry extract showed cytotoxicity against MDA-MB-231 with IC50 = 44 µg/ml or 5.1µM GAE. No antimicrobial activity was observed against the three Gram-positive, or three Gram-negative bacterial species using the water extract or R. cordifolia. Conclusion: R. cordifolia aqueous extract possess high total antioxidant capacity but values depend on the method of analysis. R. cordifolia extract inhibits MDA-MB-231 breast cancer cells proliferation but nil anti-bacterial activity was observed for three Gram-positive and three Gram-negative bacterial strains tested.
    • Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey

      Kwok, T. H.; Kirkpatrick, G.; Yusof, H. I. Mohd; Portokalakis, I; Nigam, Poonam S.; Owusu-Apenten, Richard K.; University of Chester, University of Ulster (Sciencedomain international, 2016-06-14)
      Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and other dicarbonyl compounds from Manuka honey. Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted as reagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively. Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i) regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 µM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 µM, and (v) a day-to-day precision of 16.0 and 18.3%, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99). Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey is feasible proposition. Further work is needed for method validation.
    • Total Phenols, Antioxidant Capacity and Antibacterial Activity of Manuka Honey Extract.

      Chau, Tsz Ching; Owusu-Apenten, Richard K.; Nigam, Poonam S.; Ulster University; University of Chester; (Science Domain International, 2017-10-28)
      Aims: To evaluate total phenols content (TPC), antioxidant capacity (TAC) and antibacterial activity of Manuka honey extract (MHE) and to compare such properties with those for unfractionated Manuka honey. Study Design: In vitro study. Place and Duration of Study: School of Biomedical Sciences, Ulster University, Coleraine, UK. Between September 2016 and September 2017. Methodology: MHE was prepared by solvent extraction using ethyl acetate. TPC was determined by Folin-Ciocalteu assay. The iron (III) reducing antioxidant capacity (IRAC) method was used to determine TAC. Antibacterial activity was evaluated using disc diffusion assay and 96-well microtiter plate methods with absorbance measured at 600 nm. Results: The TPC for MHE was 30-fold higher than the value for Manuka honey (33420±1685 mg vs. 1018±78 mg GAE/kg) while TAC values were~ 100-times greater (83,198±7064 vs. 793±104 TEAC, respectively). Antibacterial activity assessed by disc diffusion for Manuka honey (18.5 mm on S. aureus and 20 mm on E. coli) was two times greater than for MHE (9mm for both S. aureus and E. coli). The 96-well microtiter plate assay confirmed the greater antibacterial activity for Manuka