Ceibinin, a new positional isomer of mangiferin from the inflorescence of Ceiba pentandra (Bombacaceae), elicits similar antioxidant effect but no anti-inflammatory potential compared to mangiferin
Bamigboye J. Taiwo,
Alex H. Miller,
Alistair J. Fielding,
Satyajit D. Sarker,
Fannie R. van Heerden,
Amos A. Fatokun
Affiliations
Bamigboye J. Taiwo
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria; Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK; School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa; Corresponding author. Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
Alex H. Miller
Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK; Current Address: Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
Alistair J. Fielding
Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
Satyajit D. Sarker
Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
Fannie R. van Heerden
School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa
Amos A. Fatokun
Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK; Corresponding author. Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK.
Ceiba pentandra (L.) Gaertn. (Bombacaceae) is popular for the quality of its wood. However, its leaf, stem bark and root bark have been popular in ethnomedicine and, apart from the inflorescence, have been subject of extensive phytochemical investigations. In this study, two compounds were isolated from the crude methanol extract of the inflorescence. Through data from UV, NMR, MS, electrochemical studies, differential scanning calorimetry, and thermogravimetric analysis, the structures were elucidated as 3-C-β-d-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone (1) and 2-C-β-d-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone (mangiferin, 2). They were assessed for antioxidant efficacy (DCFDA assay) and for anti-inflammatory efficacy using the lipopolysaccharide (LPS)-induced inflammation model in the RAW 264.7 macrophages (nitrite levels quantified, using Griess Assay, as surrogate for nitric oxide (NO)). Compound 1 (named ceibinin) was established as a novel positional isomer of mangiferin (2). While both 1 and 2 were antioxidant against basal and hydrogen peroxide (100 μM)-induced oxidative stress (6.25 μg/ml abrogated peroxide-induced oxidative stress), ceibinin (1) demonstrated no anti-inflammatory potential, unlike mangiferin (2) which, as previously reported, showed anti-inflammatory effect. Our work reports a positional isomer of mangiferin for the first time in C. pentandra and demonstrates how such isomerism could underlie differences in biological activities and thus the potential for development into therapeutics.
