Limonene in Citrus: A String of Unchecked Literature Citings?

Abstract

In organic chemistry textbooks (S)-(−)-limonene, (−)-limonene or Llimonene, is often given credit for the smell of lemons, while the R-analogue, (+)-limonene or D-limonene, is credited with that of oranges. Results from two odor tests revealed that few persons in the test associated (R)-(+)-limonene with oranges and (S)-(−)-limonene with lemons, when these compounds were of analytical grade. Quality and composition of standard compounds and mixtures used in these olfactory tests were corroborated by gas chromatographic analyses. The statement of (R)-(+)-limonene being responsible for orange odor and (S)-(−)-limonene for the lemon odor apparently stems from an often quoted article from 1971. This investigation was a lesson for both our students and us. Textbooks in organic chemistry that still promote (R)-(+)-and (S)-(−)-limonene as, respectively, the "orange" and "lemon" smell ingredient should be corrected.

Limonene as natural product extraction solvent

“…47 Its use on large scale to extract natural products, however, needs to take into account its flammability, toxicity at high dosage for the eyes and airways, as well as the adverse effects of the main products formed upon contact with air's oxygen in the presence of sunlight: cisand trans-limonene-1,2-oxide, cisand transcarveol, carvone and a number of hydroperoxy derivatives. 48 The latter hydroperoxides act as potent contact allergens, 4 and readily irritate the skin and airways. 7,49 Indeed, simultaneous occurrence of contact dermatitis and bronchial asthma of workers at Citrus fruit processing plant has been reported, 9 along with contact dermatitis of a worker using limonene (in place of xylene) to dissolve paraffin in histological analyses.…”

“…3 As recently reported by Kvittingen and co-workers, numerous organic chemistry textbooks (and scientific articles) of primary relevance in use today (in the 2020s) claim that "(+) limonene is primarily responsible for the smell of oranges and (−) limonene of lemons". 4 The only limonene isomer present in all Citrus fruits (orange, lemon, grapefruit, mandarin, citron, etc. ), however, is the dextrorotary isomer.…”

Synthesis of Cyclic Fragrances via Transformations of Alkenes, Alkynes and Enynes: Strategies and Recent Progress

“…The scope of this reaction is rather broad, encompassing chiral cyclohexenes with various substituents, including those treated as homologs of (−)-limonene. Although odor studies were not performed for these products, they may be useful to solve the fragrance mystery of limonene and the related terpenoids [ 118 ].…”

Impact of the Interactions between Fragrances and Cosmetic Bases on the Fragrance Olfactory Performance: A Tentative to Correlate SPME-GC/MS Analysis with That of an Experienced Perfumer

“…α-pinene Herbal, balsamic, woody and pine-like note (turpentine-like) [18] camphene Woody note benzaldehyde Bitter almond note β-pinene Herbal, green, woody and pine-like note [18] β-myrcene Spicy, peppery, balsamic, herbaceous and musky note (cloves like) [19] α-phellandrene Black pepper, mint and citrus note p-cymene Spicy [25], earthy and musky note limonene Fresh, orange and citrus note [20] γ-terpinene Herbal, lemon and citrus note [25] linalool Fresh floral [25] and citrus note phenylethyl alcohol Fresh and rose (phenolic) note ethyl maltol Sweet and sugar note, strawberry-like, gourmand note 3-phenylpropanol Balsamic-floral sweet, mild oriental note linalyl acetate Floral [24] and citrus fresh note. Sweet, lavender-like cinnamaldehyde Spicy, sweet and warm, cinnamon-like [24] verdox Fresh fruity [24], woody and herbal note, with a scent of green apple cinnamic alcohol Floral [24], sweet and powdery note with cinnamon scent vertenex Sweet, rich, fruity, floral and woody note α-terpinyl acetate Fresh and balsamic note.…”