Subcritical Water Extraction of Antioxidant Compounds from Rosemary Plants

Abstract

Subcritical water extraction at several temperatures ranging from 25 to 200 degrees C has been studied to selectively extract antioxidant compounds from rosemary leaves. An exhaustive characterization of the fractions obtained using subcritical water at different temperatures has been carried out by LC-MS, and the antioxidant activities of the extracts have been measured by a free radical method (DPPH). Results indicate high selectivity of the subcritical water toward the most active compounds of rosemary such as carnosol, rosmanol, carnosic acid, methyl carnosate, and some flavonoids such as cirsimaritin and genkwanin. The antioxidant activity of the fractions obtained by extraction at different water temperatures was very high, with values around 11.3 microg/mL, comparable to those achieved by SFE of rosemary leaves. A study of the effect of the temperature on the extraction efficiency of the most typical rosemary antioxidant compounds has been performed.

Ultrasound versus microwave as green processes for extraction of rosmarinic, carnosic and ursolic acids from rosemary

“…The tendency observed tend to show a degradation of carnosic acid with temperature. However, different conclusions are obtained throughout literature: either enhanced extraction with temperature (from 100 to 200°C using pressurized water extraction [18,29]) while others report a degradation with mild temperatures in stability studies (40°C or less; [30,31]). Overall, it seems that temperature is not the sole factor impacting on the extraction of carnosic acid.…”

Recent developments in the rapid analysis of plants and tracking their bioactive constituents

“…Of course this methodology is only suitable and useful for thermostable phytochemicals which are not soluble in water at 100°C or lower. The technique requires high pressure vessels (Ibañez et al 2003). The higher temperatures can also lead to improved extraction and thus higher yields (Lang and Wai 2003).…”

Dry fermented buffalo sausage with sage oil extract: Safety and quality

“…The effectiveness of sage essential oil as antioxidant has been demonstrated in a large variety of food stuffs including refrigerated beef (Djenane et al, 2003), frozen pork patties (McCarthy et al, 2001). The antioxidant activity of sage essential oil is mainly related to two phenolic di-terpenes: carnosic acid and carnosol which are considered two effective free radical scavengers (Dorman et al, 2003;Ibanez et al, 2003).…”