Total Phenolic Content, Volatile Constituents and Antioxidative Effect of Coriandrum sativum, Murraya koenigii and Mentha arvensis

Background: Coriander, curry leaf and wild mint are among the most popular spices, and well known for their nutraceutical and Essential Oils (EOs) bearing properties. Objective: The present study aims to estimate total phenolic content, proline content, free radical scavenging activity, and volatile composition of the fresh leaves of coriander, curry leaf and wild mint. Method: A modified Folin-Ciocalteu method was used to estimate the total phenolic content and proline content, whereas 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric ion reducing antioxidant power assay (FRAP) methods were used to determine the free radical scavenging activity. EOs were extracted through hydro-distillation method and subjected to GC-MS to identify their components. Results: Curry leaf was found to have highest total phenolic content (70.12 mg GAE/g), followed by wild mint (29.04 mg GAE/g) and coriander (24.02 mg GAE/g), whereas the uppermost proline content was obtained in curry leaf (453 mg/g), followed by mint (402 mg/g) and coriander (397 mg/g). All the extracts showed remarkable free-radical scavenging activity with EC 50 values of 56.38 mg/100 g for curry leaf, 50.55 mg/100 g for wild mint and 49.89 mg/100 g for coriander. trans 2- Dodecenal (17%), 2-methylenecyclopentanol (9%), dodecanal (8%), cyclooctane (8%), 9-tetradecenal (8%) and decanal (8%) were found to be the major components in coriander oil. The wild mint EO contained menthol (52%), limonene (11%) and trans-dihydrocarvone (5%) as main components, whereas caryophyllene (19%), β -panasinsene (16%) and caryophyllene oxide (9%) were the principal constituents of curry leaf EO. Conclusion: The study concluded that coriander, curry leaf and wild mint are the rich source of antioxidants, and phenolics contents, and thus, could be used as potent nutraceutical agents in daily foods. Moreover, the EOs obtained from these spices contained various oxygenated compounds which might be useful for food and pharmaceutical industries.