Chinotto (Citrus myrtifolia Raf.) is a widely diffused plant native from China and its fruits have a wide-spread use in confectionary and drinks. Remarkably, only little has been reported thus far on its bioactive properties, in contrast to those of the taxonomically related bergamot (Citrus bergamia Risso). The present study aimed to investigate potential in vitro anti-inflammatory and radical scavenging properties of chinotto essential oils (CEOs) and to establish to what extent their composition and bioactivities are dependent on maturation. Essential oil from half ripe chinotto (CEO2) reduced the production of nitric oxide (NO) and the expression of inflammatory genes, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), cytokines, including interleukin-1β (IL-1β) and interleukin-6 (IL-6), and chemokine monocyte chemotactic protein-1 (MCP-1) by lipopolysaccharide (LPS)-stimulated RAW264,7 macrophages. Limonene, linalool, linalyl acetate, and γ-terpinene were found to be the main components in CEO2. Moreover, CEO2 showed high radical scavenging activity measured as Trolox equivalents (TE) against both 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). These findings show that chinotto essential oil represents a valuable part of this fruit and warrants further in vivo studies to validate its anti-inflammatory potential.
Keywords: Citrus; antioxidant; inflammation; macrophages; nitric oxide.