The aim of this work was to determine the antioxidant activities of a range of phytoestrogenic isoflavones. The antioxidant activity in the aqueous phase was determined by means of the ABTS.+ total antioxidant activity assay. The results show that the order of reactivity in scavenging the radical in the aqueous phase is genistein > daidzein = genistin approximately equal to biochanin A = daidzin > formononetin approximately equal to ononin, the latter displaying no antioxidant activity. The importance of the single 4'-hydroxyl group in the reactivity of the isoflavones, as scavengers of aqueous phase radicals, as well as the 5'7-dihydroxy structure is demonstrated. Examination of their abilities to enhance the resistance of low density lipoproteins to oxidation supports the observation that genistein is the most potent antioxidant among this family of compound studied, both in the aqueous and in the lipophilic phases.

Increasing consumption of tobacco and alcohol has led to a steady increase in the incidence of head and neck cancers in Asia. The drawbacks associated with the existing chemotherapeutic and surgical interventions have necessitated the development of a safer alternative for therapy of head and neck cancers. In this study we have explored the synergistic therapeutic potential of a phytochemical and chemotherapeutic agent using PEGylated liposomes as a delivery vehicle. Resveratrol and 5-fluorouracil were successfully coencapsulated in a single PEGylated nanoliposome. The thermal analysis and the nuclear magnetic resonance results revealed that resveratrol localized near the glycerol backbone of the liposomal membrane while 5-fluorouracil localized closer to the phosphate moiety, which influenced the release kinetics of both drugs. The nanoformulation was tested in vitro on a head and neck cancer cell line NT8e and was found to exhibit a GI50 similar to that of free 5-fluorouracil. Further, gene expression studies showed that the combination of resveratrol and 5-fluorouracil exhibited different effects on different genes that may influence the net antagonistic effect. The coencapsulation of resveratrol and 5-fluorouracil in a liposomal nanocarrier improved the cytotoxicity in comparison with the free drug combination when tested in vitro.

The investigation of chemotherapeutic agents for the treatment of cancer since the early 1940s has resulted in the discovery of over 50 drugs till date. However, most of these drugs result in severe side effects causing physical and mental trauma to patients. In order to eliminate the side effects, search for better and safer drugs has been ongoing for several decades, which has resulted in the discovery of anti-cancer properties of many phytochemicals. Polyphenols represent a unique class of phytochemicals that possess excellent anti- oxidant, anti-inflammatory properties and also modulate cell signalling pathways leading to anti-cancer effects. However, the use of these compounds as anti-cancer agents is not as effective and hence combinations of chemotherapeutic drugs with these molecules have been attempted. Promising results in in vitro and in vivo experiments while using combinations of polyphenols and chemotherapeutic agents open up new avenues for the discovery of the ideal drug combinations for cancer therapy. This review highlights the efficacy of the combination of phytochemicals with synthetic anti � neoplastic drugs over the conventional combinations of anti-neoplastic drugs and the possible interventions in the clinical settings. The review also discusses the inclusion of polyphenols in emerging therapeutic modalities like nanotechnology and photodynamic therapy.

The present study investigates dose-dependent effects of trans-resveratrol on the membrane fluidity using planar lipid bilayer and liposome models. The complex admittance plots obtained for the lipid bilayer show that resveratrol below 60 μM preferentially interacts with the polar headgroups at the membrane-electrolyte interface, leading to enhanced membrane admittance and vice versa at higher concentrations (>60 μM). This was confirmed using solid-state (13)C and (31)P NMR studies and membrane fluidization studies. The localization of resveratrol in the membrane bilayer was found to alter the membrane rigidity, which resulted in a dose-dependent blebbing and lysis of erythrocytes. The protective effect of trans-resveratrol against DPPH also confirms that its localization in the hydrophobic region prevents lipid peroxidation. The cytotoxic effect of resveratrol on a breast cancer cell line also displays a progressive pattern, indicating possible correlation with its membrane rigidifying properties and localization in the lipid bilayer.

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