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The kinetics of the supercritical fluid extraction of bioactive compounds from sunflower using CO2 as solvent were studied in order to establish an efficient method for this extraction. The influence of time of extraction at different solvent flow rates was investigated. The extraction pressure and temperature were optimized in previous studies and these values used were 400 bar and 50°C. The extraction yields and the bioactivity levels of the extracts were also analysed. The results indicate that the most appropriate extraction time is between 120 and 180 min depending on the solvent flow and the pretreatment of the sample. The dried sample extracted at 40 g/min, the congealed sample extracted at the same flow and 180 min, and the dried sample extracted at 25 g/min for 120 min showed the best activity profiles. The extractions were carried out in a pilot plant with an extraction vessel with a capacity of 2 L.

From the medium, polar bioactive fractions of leaf aqueous extract of Helianthus annuusL., heliespirones B (2) and C (3) have been isolated. The structural elucidation was based on extensive spectral studies. A probable biogenesis of heliespirone skeleton is proposed and discussed. The structure of heliespirone B has been confirmed by X-ray diffraction analysis.

Six new sesquiterpene lactones, annuolide H (3), helivypolides F, H−J (4, 11−13), and helieudesmanolide A (6), together with known compounds, were isolated from polar bioactive fractions of Helianthus annuus cv. SH-222 and Stella fresh leaf water extracts. Spectroscopic analysis of the new data for 1,2-anhydroniveusin A and 1-methoxy-4,5-dihydroniveusin A corrects some previous assignments. The compounds were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species (STS) (Lepidium sativum, Allium cepa, Lactuca sativa, Lycopersicon esculentum, and Triticum aestivum) from 5 × 10-4 to 10-5 M. The most phytotoxic compounds were helivypolide F and 15-hydroxy-3-dehydrodeoxyfruticin, both of which have a carbonyl group at C-3 conjugated with two double bonds.