Supercritical fluid extraction and analysis of compounds from Clivia miniata for uterotonic activity.

In this descriptive study, the superciritical fluid extract of the roots of Clivia miniata L. was tested for uterotonic activity using guinea pig uterine smooth muscle in vitro. Extraction was performed with water modified supercritical carbon dioxide at 400 atm and 80 degrees C. The uterine contractions induced by this extract were compared to those induced by the aqueous extract and found to be active at lower doses. The active compounds were isolated and the structures elucidated by spectroscopic and chromatographic techniques. Both linoleic acid and 5-hydroxymethyl-2-furancarboxaldehyde isolated from the extract were found to induce muscle contractions individually. The pharmacological mode of action of 5-hydroxymethyl-2-furancarboxaldehyde was assessed using two receptor agonists and antagonists. This compound was found to mediate its effect through cholinergic receptors.

The uterotonic activity of compounds isolated from the supercritical fluid extract of Ekebergia capensis.

The wood of Ekebergia capensis Sparrm. is used by the local Zulu community in KwaZulu-Natal Province, South Africa to facilitate childbirth. In this investigation, the uterotonic properties of extracts from this tree were evaluated using both pregnant and non-pregnant guinea pig uterine smooth muscle in vitro. The extracts were prepared using water modified supercritical carbon dioxide at 400 atm and 80 degrees C. As samples of these extracts displayed positive results when screened for uterotonic activity, gravity column chromatography followed by NMR spectroscopy was performed in an attempt to isolate and elucidate the structures of the compounds that were present in the extract. The extract yielded five known compounds of which only two, viz. oleanonic acid and 3-epioleanolic acid, displayed uterotonic activity. Receptor binding assays were subsequently performed with 3-epioleanolic acid to ascertain its mode of action. Bradykinin (30 ng/100 microl) and acetylcholine (1 microg/100 microl) were used as the B2 and cholinergic receptor agonists respectively with icatibant (HOE 140) (30 ng/100 microl) and atropine (60 micro/100 microl) as their corresponding antagonists. 3-epioleanolic acid was observed to mediate its effect through the cholinergic receptor. The results of this study show that two compounds from the extract of this tree possess varying degrees of agonist activity on uterine smooth muscle with minor changes in the molecular structure affecting its intrinsic activity on uterine muscle.

Coupling SFE to uterotonic bioassay: an on-line approach to analysing medicinal plants.

Supercritical fluid extraction has been directly coupled on-line to a uterotonic bioassay, using guinea pig uterine smooth muscle in vitro. This technique was developed for the detection of uterotonic compounds present in medicinal plants used during pregnancy to induce or augment labour. The direct passage of CO2 into the muscle chamber led to adiabatic cooling of the physiological fluid and inhibition of muscle contraction. This was alleviated by the construction of a CO2 reduction interface together with the passage of carbogen which aided in the rapid displacement of excess CO2. The on-line system was evaluated with four plants (Clivia miniata (Lindl.) Regel, Ekebergia capensis Sparrm., Grewia occidentalis L. and Asclepias fruticosa L.) that are currently used during pregnancy by some black South African women. Extractions were performed with water modified supercritical CO2. Fractions of supercritical fluid extracts, obtained by sequentially increasing the pressure from 200 to 300 and 400 atm at constant temperature were transferred directly to the muscle chamber to identify the active fractions. The 400 atm extracts of C. miniata, A. fruticosa and E. capensis displayed maximum uterotonic activity while only the 300 atm extract of G. occidentalis induced uterine muscle contraction. This technique proved to be a safe and sensitive method for analyzing medicinal plants that contain uterotonic substances hence assisting in rapidly validating the uterotonic properties and detecting any toxic effects of these extracts.

Rapid analysis of polyolefin antioxidants and light stabilisers by supercritical fluid chromatography.

Nineteen commercial antioxidants and light stabilisers, with a wide range of relative molecular masses and boiling-points, present in polyolefins were analysed by packed column supercritical fluid chromatography on four different phases with CO2 or 10% MeOH-CO2 as the mobile phase and with UV detection. The technique is shown to yield short analysis times and sufficient resolution for a number of additives present in a given polyolefin.