951125-99-8Relevant articles and documents
Stability studies and determination of carnosic acid and its oxidative degradation products by gas chromatography–mass spectrometry
Razbor?ek, Ma?a Islam?evi?,Ivanovi?, Milena
, p. 29 - 39 (2016)
The stability of carnosic acid (CA, an important abietane ferruginol-type diterpene, with anti-oxidant, anti-inflammatory, anti-bacterial, and anti-mutagenic properties) exposed to different stress conditions (daylight, high temperatures, different solvents, and humidity) was investigated. Gas chromatography–mass spectrometry (GC–MS) was used to analyse the degraded samples. Structural identification of degradation products was assigned based upon MS fragmentation patterns. The stability experiments were performed on pure CA (96% purity) as well as on commercially-available rosemary extract (containing 50.27% of CA and 5.65% of a diterpene lactone carnosol-C). For the extraction of target compounds three different techniques were compared: ultrasonic extraction (UE), Soxhlet (SE) and microwave extraction (MWE). It was shown that CA always occurs in combination with C, which is produced by oxidation and ring closure from CA, but with UE transformation of CA into C was minimal and constant when compared to SE or MWE. CA dissolved in tetrahydrofuran (THF) remained stable for at least 5?h at room temperature. After a certain time, under all tested conditions, the concentration of CA lowered as a result of the formation of degradation products such as C, rosmanol, 12-O-methyl-CA, 6,7-de-hydro-CA, 7-keto-CA and other unidentified degradants. In comparison to the solid state, the degradation of CA dissolved in organic solvents (THF and ethanol) was significantly faster. In general, protic solvents lead to faster degradation of CA. Only extremely high temperatures (200–300?°C) and long-term exposure to light and humidity (6 months) caused the degradation of CA in powdered samples. The GC–MS method described was also used for determination of CA and C in five different species of the Lamiaceae family (Rosmarinus officinalis L., Salvia officinalis L., Satureja Montana L., Salvia sclarea L., and Salvia glutinosa L.).
