Regional variation in the chemical composition and antioxidant activity of Rosmarinus officinalis L. from China and the Mediterranean region

ABSTRACT

Rosemary is an aromatic evergreen shrubby herb that is native to the Mediterranean region. This herb is now widely cultivated in many regions of the world. Rosemary is widely used in traditional Chinese medicines, foods, nutraceuticals and cosmetics. Hydro distilled essential oils, obtained from rosemary in China and the Mediterranean region, were analysed by gas chromatography-mass spectrometry [GC-MS]. Thirty-seven compounds accounting for 94.97%-99.72% of the oils were identified. The majority of the compounds in the essential oils exhibited no significant differences [table 1 and fig. 1]. The extracts were prepared with three solvents of different polarity [dichloromethane, ethyl acetate and aqueous]. The ethyl acetate fractions exhibited the highest phenol content and were found to be significantly more active than the dichloromethane and aqueous fractions [fig. 2]. Antioxidant activity [by DPPH radical scavenging, ferric ion reduction [FRAP] and thiobarbituric acid reactive substance [TBARS]] was also assessed. The ethyl acetate extracts of Yunnan had the highest amount of antioxidant capacity from China by DPPH and TBARS, with the lowest IC50 values being 0.0011 mg/ml, and 1.6611 mg/ml, respectively. In conclusion, the antioxidant activities of the essential oils and ethyl acetate extracts from rosemary obtained by three different testing methods revealed higher antioxidant activity from rosemary grown in China than in the Mediterranean region. These results suggested that Chinese rosemary should be widely used in food, traditional medicine, cosmetics and perfume products, as well as other chemical industries