Isotopic characteristics (δ13C, δ15N, and δ18O) of honey from Bangladesh retail markets: Investigating sugar manipulation, botanical and geographical authentication

•First analysis on carbon, nitrogen and oxygen isotopes of Bangladesh origin honey.•Mustard honey, multifloral including Sundarban honey are adulterated with C-4 sugar.•Isotopic features explored botanical diversity among floral origins.•Geographical discrimination of honey identified by carbon and nitrogen isotopes.•Black seed honey was a unique type among all studied indigenous and exogenous honey.