Global Yields, Chemical Compositions, and Antioxidant activities of extracts from Achyrocline alata and Achyrocline satureioides

Extracts from leaves and thin branches of Achyrocline alata and Achyrocline satureioides were obtained by supercritical fluid extraction, hydrodistillation, and low-pressure ethanol extraction. The supercritical extractions were done at pressures of 100, 200, and 300 bar and temperatures of 30 and 40 oC. The chemical constituents of the extracts and volatile oil were identified by GC-MS and quantified by GC-FID. The antioxidant activity was determined using the coupled oxidation of linolenic acid and β-carotene. Larger yields were detected at 200 bar and 300 C. Low-pressure ethanol extraction yield was 2.96% (m/m, dry basis) for A. satureioides and 3.98% (m/m, dry basis.) for A. alata. The major compounds of the extracts were trans-caryophyllene and α-humulene; the content of trans-caryophyllene in the A. alata extract obtained at 200 bar and 300 C was 5 times larger than that of the A. satureioides extracts. All extracts exhibited antioxidant activity stronger than β -carotene.