Pharmacognostic approach to evaluate the micromorphological, phytochemical and biological features of Citrus lumia seeds

This study evaluated the micro-morphology as well as the chemical and biological features of Citrus lumia seeds. The cream-colored pyriform seed showed a woody coat covered by a thick layer of mucilage and an embryo with two large cotyledons rich in oil bodies. Hydroxycinnamic acid glycosides and flavonoids are the most abundant compounds in methanol and ethyl acetate extracts (ME and EAE), respectively. Conversely, fatty acids and α-tocopherol represent the main bioactive compounds in the hexane extract (HE). ME showed the most promising antioxidant and anti-inflammatory activities already in cell-free assays. These results were confirmed by experiments carried out on human primary cells. Indeed, ME showed the best inhibitory activity against heat-induced haemolysis and ROS formation in erythrocytes. Moreover, the same order of potency (ME > EAE > HE) was observed also on peripheral blood mononuclear cells, in which the seed extracts were able to decrease TNF-α and IL-6 release after LPS-induced inflammation.

Essential oil of Citrus lumia Risso: Phytochemical profile, antioxidant properties and activity on the central nervous system

The use of essential oils (EOs) is known since long time in traditional medicine and aromatherapy for the management of various oxidative stress-related disorders and has been further increased recently for their neuroprotective and anti-aging potentials as well as for reducing anxiety and stress. The purpose of this work was to evaluate, for the first time, the chemical composition of Citrus lumia Risso EO and its antioxidant, anti-cholinesterase, and neuroactive properties by cell-free and cell-based assays. The EO has shown strong antioxidant and free radical scavenging properties, particularly in hydrogen atom transfer based assays (β-carotene bleaching and ORAC, IC₅₀ 22 μg/mL and 46 μg/mL, respectively), that can be attributed to the high content of monoterpenes, especially d-Limonene (48.905%), and Linalool (18.245%). Furthermore, the EO has shown an interesting anti-acetylcholinesterase activity (IC₅₀ 258.25 μg/mL). Data from MTT analysis indicate that the cytotoxicity of EO, evaluated on L929 mouse fibroblasts, is very low, with an IC₅₀ higher than 500 μg/mL at 48 h. Rat neuronal networks subjected to EO showed a concentration-dependent inhibition of spontaneous electrical activity. Results indicate that C. lumia EO could be an important source of natural antioxidants suggesting an important preventive role in the onset of oxidative stress-related pathologies.