Objectives: Curcumin (Cur) exhibits weak microbicidal activity owing to high lipophilicity and low cell permeability. Therefore, in the present investigation, Cur was iodinated using elemental iodine (I2) to synthesise Cur-I2 powder that was later formulated as Cur-I2 dermal cream and characterised in vitro for antimicrobial and antioxidant activities.
Methods and results: Electrophilic addition of I2 saturated the olefinic bonds of Cur, as confirmed by UV/visible spectroscopy, FT-IR, 1H NMR and DSC techniques. In addition, in vitro skin permeation and retention analysis indicated that Cur-I2 cream followed the first order and Higuchi model for drug release through the rat skin. The minimum inhibitory concentration (MIC) of Cur-I2 powder was measured to be 60 and 90 µg/ml significantly (p < 0.05) lower than 150 and 120 µg/ml of Cur against Staphylococcus aureus and Escherichia coli, respectively. Moreover, Cur-I2 also exhibited strong antioxidant potential.
Conclusions: Cur-I2 cream warrants further in vivo study to scale up the technology for clinical translation.
Keywords: Curcumin; antimicrobial activity; antioxidant activity; dermal cream; electrophilic addition; iodine.