ORCID Profile
0000-0002-9333-6536
Current Organisation
University of Western Australia
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Publisher: Elsevier BV
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 27-11-2019
DOI: 10.1038/S41598-019-54217-8
Abstract: The antibacterial activity of honeys derived from the endemic flora of the southwest corner of Western Australia, including the trees Jarrah ( Eucalyptus marginata ) and Marri ( Corymbia calophylla ), remains largely unexplored. Investigation of these honeys showed minimum inhibitory concentrations (MICs) of 6.7–28.0% (w/v) against Gram positive and negative bacteria. Honey solutions showed enhanced antibacterial activity after hydrogen peroxide was allowed to accumulate prior to testing, with a mean MIC after accumulation of 14.3% compared to 17.4% before accumulation. Antibacterial activity was reduced after treatment with catalase enzyme, with a mean MIC of 29.4% with catalase compared to 15.2% without catalase. Tests investigating the role of the Gram negative outer membrane in honey susceptibility revealed increases in activity after destabilisation of the outer membrane. Honeys reduced both the formation of biofilm and the production of bacterial pigments, which are both regulated by quorum sensing. However, these reductions were closely correlated with global growth inhibition. Honey applied to existing biofilms resulted in decreased metabolic activity and minor decreases in viability. These results enhance our understanding of the mechanisms of antibacterial action of Jarrah and Marri honeys, and provide further support for the use of honey in the treatment of infected wounds.
Publisher: MDPI AG
Date: 02-12-2022
DOI: 10.3390/MOLECULES27238491
Abstract: Honeys are commonly subjected to a series of post-harvest processing steps, such as filtration and/or radiation treatment and heating to various temperatures, which might affect their physicochemical properties and bioactivity levels. Therefore, there is a need for robust quality control assessments after honey processing and storage to ensure that the exposure to higher temperatures, for ex le, does not compromise the honey’s chemical composition and/or antioxidant activity. This paper describes a comprehensive short-term (48 h) and long-term (5 months) study of the effects of temperature (40 °C, 60 °C and 80 °C) on three commercial honeys (Manuka, Marri and Coastal Peppermint) and an artificial honey, using high-performance thin-layer chromatography (HPTLC) analysis. S les were collected at baseline, at 6 h, 12 h, 24 h and 48 h, and then monthly for five months. Then, they were analysed for potential changes in their organic extract HPTLC fingerprints, in their HPTLC-DPPH total band activities, in their major sugar composition and in their hydroxymethylfurfural (HMF) content. It was found that, while all the assessed parameters changed over the monitoring period, changes were moderate at 40 °C but increased significantly with increasing temperature, especially the honeys’ HPTLC-DPPH total band activity and HMF content.
Publisher: PeerJ
Date: 22-09-2021
DOI: 10.7717/PEERJ.12186
Abstract: High-Performance Thin-Layer Chromatography (HPTLC) was used in a chemometric investigation of the derived sugar and organic extract profiles of two different honeys (Manuka and Jarrah) with adulterants. Each honey was adulterated with one of six different sugar syrups (rice, corn, golden, treacle, glucose and maple syrups) in five different concentrations (10%, 20%, 30%, 40%, and 50% w/w). The chemometric analysis was based on the combined sugar and organic extract profiles’ datasets. To obtain the respective sugar profiles, the amount of fructose, glucose, maltose, and sucrose present in the honey was quantified and for the organic extract profile, the honey’s dichloromethane extract was investigated at 254 and 366 nm, as well as at T (Transmittance) white light and at 366 nm after derivatisation. The presence of sugar syrups, even at a concentration of only 10%, significantly influenced the honeys’ sugar and organic extract profiles and multivariate data analysis of these profiles, in particular cluster analysis (CA), principal component analysis (PCA), principal component regression (PCR), partial least-squares regression (PLSR) and Machine Learning using an artificial neural network (ANN), were able to detect post-harvest syrup adulterations and to discriminate between neat and adulterated honey s les. Cluster analysis and principal component analysis, for instance, could easily differentiate between neat and adulterated honeys through the use of CA or PCA plots. In particular the presence of excess amounts of maltose and sucrose allowed for the detection of sugar adulterants and adulterated honeys by HPTLC-multivariate data analysis. Partial least-squares regression and artificial neural networking were employed, with augmented datasets, to develop optimal calibration for the adulterated honeys and to predict those accurately, which suggests a good predictive capacity of the developed model.
Publisher: MDPI AG
Date: 13-11-2020
DOI: 10.3390/MOLECULES25225289
Abstract: Honey adulteration, where a range of sugar syrups is used to increase bulk volume, is a common problem that has significant negative impacts on the honey industry, both economically and from a consumer confidence perspective. This paper investigates High-Performance Thin Layer Chromatography (HPTLC) for the authentication and detection of sugar adulterants in honey. The sugar composition of various Australian honeys (Manuka, Jarrah, Marri, Karri, Peppermint and White Gum) was first determined to illustrate the variance depending on the floral origin. Two of the honeys (Manuka and Jarrah) were then artificially adulterated with six different sugar syrups (rice, corn, golden, treacle, glucose and maple syrup). The findings demonstrate that HPTLC sugar profiles, in combination with organic extract profiles, can easily detect the sugar adulterants. As major sugars found in honey, the quantification of fructose and glucose, and their concentration ratio can be used to authenticate the honeys. Quantifications of sucrose and maltose can be used to identify the type of syrup adulterant, in particular when used in combination with HPTLC fingerprinting of the organic honey extracts.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2023
DOI: 10.1007/S00764-023-00243-2
Abstract: A novel, simple and reliable high-performance thin-layer chromatography (HPTLC) method was developed and validated for the quantification of trehalulose in stingless bee honey. The chromatographic separation was performed using silica gel 60 F 254 HPTLC plates and 1-butanol‒2-propanol‒aqueous boric acid solution (5 mg/mL) (30:50:10, V/V ) as the mobile phase. The retardation factor ( R F ) for trehalulose was found to be 0.045. The method showed linearity over the concentration range of 100–800 ng per band with a coefficient of correlation ( R ) of 0.9996. The limit of detection and limit of quantification for trehalulose were found to be 20.04 ng per band and 60.72 ng per band, respectively and the mean per cent recovery of trehalulose was 101.8%. The method has been validated for its specificity, linearity, sensitivity, precision, accuracy, repeatability and robustness following the International Council for Harmonisation Q2 (R1), and it has been successfully applied in the determination of trehalulose in stingless bee honey.
Publisher: MDPI AG
Date: 27-03-2022
DOI: 10.3390/MOLECULES27072154
Abstract: Despite its cultural and nutritional importance for local Aboriginal people, the unusual insect honey produced by Western Australian honeypot ant (C onotus inflatus) has to date been rarely investigated. This study reports on the honey’s physicochemical properties, its total phenolic, major sugars and 5-hydroxymethylfurfural contents, and its antioxidant activities. The honey’s color value is 467.63 mAU/63.39 mm Pfund, it has a pH of 3.85, and its electric conductivity is 449.71 µSiemens/cm. Its Brix value is 67.00, corresponding to a 33% moisture content. The total phenolics content is 19.62 mg gallic acid equivalent/100 g honey. Its antioxidant activity measured using the DPPH* (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing–antioxidant power) assays is 1367.67 µmol Trolox/kg and 3.52 mmol Fe+2/kg honey, respectively. Major sugars in the honey are glucose and fructose, with a fructose-to-glucose ratio of 0.85. Additionally, unidentified sugar was found in minor quantities.
Publisher: MDPI AG
Date: 12-01-2023
Abstract: This study reports on the total phenolic content and antioxidant activity as well as the phenolic compounds that are present in Calothamnus spp. (Red Bell), Agonis flexuosa (Coastal Peppermint), Corymbia calophylla (Marri) and Eucalyptus marginata (Jarrah) honeys from Western Australia. The honey’s total phenolic content (TPC) was determined using a modified Folin–Ciocalteu assay, while their total antioxidant activity was determined using FRAP and DPPH assays. Phenolic constituents were identified using a High Performance Thin-Layer Chromatography (HTPLC)-derived phenolic database, and the identified phenolic compounds were quantified using HPTLC. Finally, constituents that contribute to the honeys’ antioxidant activity were identified using a DPPH-HPTLC bioautography assay. Based on the results, Calothamnus spp. honey (n = 8) was found to contain the highest (59.4 ± 7.91 mg GAE/100 g) TPC, followed by Eucalyptus marginata honey (50.58 ± 3.76 mg GAE/100 g), Agonis flexuosa honey (36.08 ± 4.2 mg GAE/100 g) and Corymbia calophylla honey (29.15 ± 5.46 mg GAE/100 g). In the FRAP assay, Calothamnus spp. honey also had the highest activity (9.24 ± 1.68 mmol Fe2+/kg), followed by Eucalyptus marginata honey (mmol Fe2+/kg), whereas Agonis flexuosa (5.45 ± 1.64 mmol Fe2+/kg) and Corymbia calophylla honeys (4.48 ± 0.82 mmol Fe2+/kg) had comparable FRAP activity. In the DPPH assay, when the mean values were compared, it was found that Calothamnus spp. honey again had the highest activity (3.88 ± 0.96 mmol TE/kg) while the mean DPPH antioxidant activity of Eucalyptus marginata, Agonis flexuosa, and Corymbia calophylla honeys were comparable. Kojic acid and epigallocatechin gallate were found in all honeys, whilst other constituents (e.g., m-coumaric acid, lumichrome, gallic acid, taxifolin, luteolin, epicatechin, hesperitin, eudesmic acid, syringic acid, protocatechuic acid, t-cinnamic acid, o-anisic acid) were only identified in some of the honeys. DPPH-HPTLC bioautography demonstrated that most of the identified compounds possess antioxidant activity, except for t-cinnamic acid, eudesmic acid, o-anisic acid, and lumichrome.
Publisher: Springer Science and Business Media LLC
Date: 10-2020
Publisher: Public Library of Science (PLoS)
Date: 20-07-2021
DOI: 10.1371/JOURNAL.PONE.0254857
Abstract: In this paper, we describe a novel approach to the development of a reference standard for the quality control of complex natural products, which will assist in the assessment of their authenticity and purity. The proposed method provides a template for the selection of s les, which can be pooled to obtain a reference standard. A shortfall of such an approach is, however, that the pooled s le is static in nature and therefore unable to capture difference in processing conditions or natural variations triggered by geographical or climatic impacts over time. To address this, the paper also outlines the development of a dynamic reference standard, which allows for ongoing adjustments to future variations. The method employs High-Performance Thin Layer Chromatography (HPTLC) derived extract profiles processed by multivariate analysis. The development of the dynamic reference standard is illustrated using honey, a complex natural matrix, as an ex le.
Publisher: MDPI AG
Date: 07-02-2021
Abstract: The use of High-Performance Thin-Layer Chromatography (HPTLC) coupled with the use of DPPH* (2,2-diphenyl-1-picrylhydrazyl) as a derivatisation reagent is a novel approach to the analysis of antioxidant activity of honeys. The method facilitates the visualisation of in idual constituents that contribute to the overall antioxidant activity of the honey, even if they are not yet chemically identified, and allows for the quantification of their antioxidant activity as gallic acid equivalents. The method supports a more in-depth study of the antioxidant activity of honey as it allows for a comparative analysis of the antioxidant fingerprints of honeys of different floral origin and is able to capture differences in their in idual bioactive constituents. Further, it supports the tracking of changes in antioxidant activity of in idual honey constituents over time upon exposure to different temperature conditions, which demonstrates the potential value of the method for in-process quality control.
Publisher: Informa UK Limited
Date: 31-05-2022
No related grants have been discovered for Md Khairul Islam.