1,8-Cineole

For eucalyptus-oil-derived 1,8-cineole, production normally begins with vacuum rectification to remove lighter components such as pinenes, limonene, and p-cymene, followed by collection of a cineole-rich fraction and further rectification, low-temperature crystallisation, or separation steps to raise purity. China's GB 1886.119-2015 specifies that food-additive 1,8-cineole (isolated) is prepared from eucalyptus oil by rectification, freezing, and separation, with a minimum content of 98.0% (National Health and Family Planning Commission of China, 2015, GB 1886.119-2015 National Food Safety Standard—Food Additive 1,8-Cineole). A published Chinese recovery process first used packed-column rectification at approximately 2.4 kPa to remove low-boiling impurities from low-grade eucalyptus-oil by-product, then applied steam rectification to obtain a 1,8-cineole fraction; one patent example reported 99.2% purity at 70.5% recovery, illustrating that final performance depends on feed composition, column efficiency, reflux ratio, and separation sequence (CN201210241199.8). China also discloses a synthetic route that dehydrates α-terpineol over a solid-acid catalyst to form 1,8-cineole, so customers should select material by natural versus synthetic origin, target purity, food-standard applicability, and complete GC impurity profile; our 99% minimum GC specification is a standard commercial release criterion, while 99.6–99.8% must be confirmed by the COA for the individual batch.

In Germany, Soledum® Capsules (100 mg) and Soledum® forte (200 mg) are enteric capsule products containing cineole, while Sinolpan® 100 mg and Sinolpan® forte 200 mg also use pure cineole as the active ingredient for symptomatic or adjunctive treatment of bronchitis, cold-related respiratory symptoms, and sinusitis; the approved indication must be confirmed from the product information in the country of sale. In a double-blind placebo-controlled trial of 32 patients with steroid-dependent asthma, 1,8-cineole at 600 mg/day for 12 weeks was associated with a larger prednisolone reduction, but this small study supports further assessment as medically supervised adjunctive treatment rather than replacement of standard asthma care (Juergens et al., 2003, Respiratory Medicine). A randomised double-blind study in 242 patients with acute bronchitis found that 600 mg/day cineole improved the bronchitis-sum score and cough-fit frequency versus placebo after four days (Fischer & Dethlefsen, 2013, Cough), while a six-month adjunctive study in 242 patients with stable COPD reported reductions in exacerbation frequency, severity, and duration (Worth et al., 2009, Respiratory Research). The EMA position on eucalyptus oil is a traditional-use conclusion for cough associated with colds and localised muscle pain, and the EMA specifically notes that bronchitis and asthma studies used 1,8-cineole rather than eucalyptus oil itself; bulk 1,8-cineole therefore cannot claim a medicinal indication from these studies alone and still requires separate formulation, dose, safety, and market-authorisation development.

Eucalyptus globulus, Eucalyptus polybractea, and Eucalyptus smithii are the principal botanical sources of medicinal and commercial 1,8-cineole-type eucalyptus oils; both the European Pharmacopoeia and the EMA identify these species as eucalyptus-oil sources rich in 1,8-cineole (EMA HMPC, 2024, European Union Herbal Monograph on Eucalyptus Oil). Species, origin, chemotype, leaf maturity, and distillation conditions can materially change crude-oil composition; EMA-reviewed data report 1,8-cineole typically at 70–85% in E. globulus oil and 70–77% in E. smithii oil, so botanical name alone does not establish the actual assay. For medicinal eucalyptus oil, the European Pharmacopoeia requires not less than 70% 1,8-cineole, whereas China's GB 1886.119-2015 requires not less than 98.0% for isolated food-additive 1,8-cineole; these are specifications for different material levels and intended uses (National Health and Family Planning Commission of China, 2015, GB 1886.119-2015 National Food Safety Standard—Food Additive 1,8-Cineole). We recommend specifying Latin botanical name, plant part, origin, distillation method, and full GC/GC-MS profile when purchasing crude eucalyptus oil, while isolated-product procurement should focus on target assay, impurity limits, and the regulatory standard for the intended application.