Curry Leaf and its Antioxidant Potential: A Systematic Study to Enhance its Activity in Aqueous Medium

Background: We have done a systematic study on the antioxidant activity of the methanol and petroleum ether (60-80°C) extracts (MEC and PEC respectively) of Curry leaves (Murraya koenigii Spreng. Family: Rutaceae) using various in-vitro chemical methods. Methods: Both of these two extracts were found to be highly efficient in the formation of Ag and Au nanoparticles. So, we have explored their ability to form the nanoparticles to study their antioxidant activity. In all the assay systems, MEC showed higher activity over PEC in aqueous medium. This may be due to the higher solubility of MEC and its active components, like polyphenols and flavonoids in the aqueous medium. PEC contains lesser amount of these water soluble active components but PEC was rich in carbazole types of alkaloids which are hydrophobic in nature. So, to enhance the antioxidant activity of PEC and its carbazole constituents, like 2-hydroxy carbazole and mahanimbine, we have encapsulated these in the biopolymeric matrix of the mucilage isolated from an edible vegetable, Abelmoschus esculentus L. (commonly known as Lady's finger, family: Malvaceae). Result: It was interesting to note that, PEC and its carbazole compounds showed better antioxidant activity (ferrous ion chelation and ferric reducing antioxidant activity) in aqueous medium after this encapsulation process. Conclusion: The protocols used in the present study were very simple and can be implemented in any lab set-up. In future, this work can be extended to evaluate antioxidant potentials of other plant based materials.