ChEBI: Limonene is a monoterpene that is cyclohex-1-ene substituted by a methyl group at position 1 and a prop-1-en-2-yl group at position 4 respectively. It has a role as a human metabolite. It is a monoterpene and a cycloalkene. It derives from a hydride of a p-menthane.NCI Thesaurus (NCIt): Lemon Oil is the oil extracted from the fruit peel of Citrus limon. Lemon oil is used as a flavoring and for its aromatic qualities. It is also said to have many medicinal purposes.NCI Thesaurus (NCIt): Limonene, (+/-)- is a racemic mixture of limonene, a natural cyclic monoterpene and major component of the oil extracted from citrus rind with chemo-preventive and antitumor activities. The metabolites of DL-limonene, perillic acid, dihydroperillic acid, uroterpenol and limonene 1,2-diol are suggested to inhibit tumor growth through inhibition of p21-dependent signaling, induce apoptosis via the induction of the transforming growth factor beta-signaling pathway, inhibit post-translational modification of signal transduction proteins, result in G1 cell cycle arrest as well as cause differential expression of cell cycle- and apoptosis-related genes.