Supramolecular chemistry, although focused mainly on noncovalent intermolecular and intramolecular interactions, which are considerably weaker than covalent interactions, can be employed to fabricate sensors with a remarkable affinity for a target analyte. In this review the development of cyclodextrin-based electrochemical sensors is described and discussed. Following a short introduction to the general properties of cyclodextrins and their ability to form inclusion complexes, the cyclodextrin-based sensors are introduced. This includes the combination of cyclodextrins with reduced graphene oxide, carbon nanotubes, conducting polymers, enzymes and aptamers, and electropolymerized cyclodextrin films. The applications of these materials as chiral recognition agents and biosensors and in the electrochemical detection of environmental contaminants, biomolecules and amino acids, drugs and flavonoids are reviewed and compared. Based on the papers reviewed, it is clear that cyclodextrins are promising molecular recognition agents in the creation of electrochemical sensors, chiral sensors, and biosensors. Moreover, they have been combined with a host of materials to enhance the detection of the target analytes. Nevertheless, challenges remain, including the development of more robust methods for the integration of cyclodextrins into the sensing unit.

The purpose of this study was to evaluate the antioxidant properties of Vitis vinifera juice extract (grape) in rifampicin suspensions and to compare with that of ascorbic acid. Grape juice was extracted and used as antioxidant in both pure sample and commercial reconstituted samples of rifampicin. The rate of drug degradation was determined by spectroscopic method in a time dependent manner. Also, the antioxidant property of grape juice was compared with that of ascorbic acid. Phytochemical screening of the constituents in grape juice extract was carried out according to standard methods. The results revealed that rifampicin dispersions containing ascorbic acid (batches A1 to A5) showed significantly higher stability and had higher amount of drug remaining over time than the control (batch A6) containing no antioxidant (p < 0.05). However, the results revealed that grape fruit juice extract had higher antioxidant properties than the ascorbic acid (p < 0.05) in rifampicin dispersions. The results also indicated that increase in amount of both antioxidants significantly reduced the rate of drug degradation through oxidation, thereby causing a corresponding increase in the amount of rifampicin remaining over time. Grape juice extract contain alkaloids, carbohydrates, saponins, reducing sugars, steroids, tannins, proteins, flavonoids, resins, oils, terpenoids and acid compounds. Glycosides were however not found in the juice extract. Therefore, grape fruit juice extract could be used as a natural antioxidant in rifampicin suspensions.

Physiological processes exhibit distinct rhythmic patterns influenced by external cues. External cues such as photic signal play an important role in the synchronization of physiological rhythms. However, excess of or indiscriminate exposure to photic signals exerts profound effects on physiological processes, disrupting normal hormonal secretory rhythms, altering sleep/wakefulness cycle, and impairing reproductive function. Alteration in sleep/wakefulness cycle, impairment in reproductive cycle, and disruption of normal hormonal secretory rhythms characterize risk groups for photic stress such as night workers, trans-meridian travelers, and night-active people. Evidence from primary studies is increasing on the tendency of selenium to reset internal biorhythms by targeting circadian proteins and melatonin. The review highlights the chronobiological roles of selenium.