Human serum interactions with phenolic and aroma substances of Kaffir (Citrus hystrix) and Key lime (Citrus aurantifolia) juices

Abstract

To understand the therapeutic application of polyphenols extracted from Kaffir (PolKaf) and Key (PolKey) limes different analytical methods were applied. Based on quantitative analysis by two dimensional gas chromatography (GC×GC) and time of flight mass spectrometry (TOFMS) it can be observed that the biggest differences in the contents of selected terpenes of Kaffir and Key limes occur in chemical compounds such as limonene, citral and terpinen-4-ol. Limonene concentration is almost 5 times higher in the volatile fraction of Key lime than in Kaffir lime. In the case of citral, the difference in concentration of this compound in Kaffir is 20 µg/g lower than in Key lime. Higher concentration of terpinen-4-ol was noted in Kaffir lime samples and the content was almost 23 times higher. Terpinen-4-ol is the major chemical compound of volatile fraction of Kaffir lime. Among the determined terpenes, potential markers of aroma were selected: terpinen-4-ol and citral for characterization of Kaffir and Key limes. Antioxidant assays revealed the highest bioactivity of Kaffir lime. Fluorescence studies between the interaction of polyphenols with human serum albumin (HSA) showed relatively high binding abilities in comparison with some antiplatelet drugs. The docking results showed that the hydrophobic residues are responsible for the interaction with the phyto-constituents. Citral is the best scored ADMET descriptor. The antioxidant strong affinity to HSA and synergism in bioactivity are the main indices in health application of citrus fruits.