Several species of the Veratrum genus are associated with toxicity in humans and animals. The principal toxins are steroid alkaloids; some have a modified steroid template, whereas others differ in their esterified acid moieties. These alkaloids act by increasing the permeability of the sodium channels of nerve cells, causing them to fire continuously. Increased stimulation, associated with the vagal nerve results in a reflex that causes the triad of responses known as the Bezold-Jarisch reflex: hypotension, bradycardia and apnoea. Clinically, various Veratrum extracts were marketed for clinical use as antihypertensive drugs, but because of their narrow therapeutic index were withdrawn from the market. Following the ingestion of Veratrum alkaloids, expected signs and symptoms include vomiting and abdominal pain, followed by cardiovascular effects such as bradycardia, hypotension and cardiac conduction abnormalities and death. Similar symptoms arise in other mammalian species ingesting these alkaloids; teratogenic effects may occur to the fetuses of animals that have grazed on Veratrum californicum. Treatment consists of supportive care, with an emphasis on haemodynamic stability with fluid replacement, atropine and vasopressors. The onset of symptoms occurs between 30 minutes and 4 hours, and the duration of the illness can range from 1 to 10 days; however, with prompt supportive care, patients typically make a full recovery within 24 hours.

The online HPLC-DPPH radical assay was validated as a useful screening tool for investigating individual antioxidants in leaf extracts. Optimized extraction conditions were middle leaves pre-treated with liquid N(2), extraction at 25°C for 0.5 h and solvent removal by rotary evaporation.

Short-term treatment of RA patients with a multi-strain probiotic did not significantly influence SSZ metabolism as has been demonstrated in animal models.

No abstract

1996. Cytokinins and fruit development in the kiwifruit {Actinidia deticiosa). I. Changes during fruit development. -Physiol. Plant. 98: 179-186. The cytokinin content in fruit tissue of the kiwifruit [Actinidia dehciosa [A. Chev.| C. E. Liang et A. R. Ferguson var. deliciosa cv.Hayward) was monitored daring fruit development to identify which cytokinins were present and if they were linked with specific stage.s of fruit growth. Cytokinins were isolated and purified by column chromatography and high-performance liquid chromatography and quantified by radioimmunoassay. A novel HPLC step utilising an amine column was successfully introduced as a preparative step in the separation of the O-and 9-glucosides from the free base.s and ribosides. The radioimmunoassay results were validated, and the different cjtokinins identified, by gas chromatography-mass spech-ometry. Cytokinins detected in fruit included the cytokinin free bases, zealin and isopentenyladenine, their ribosides, nucleotides and both O-and 9-glueosides. Both qualitative and quantitative changes of the cytokinins occurred during fruit development. . A decrease in cytokinin concentration occurred after anthesis (from 342 pmol g ' fresh weight at anthe.sis to 41 pmol g"' fresh weight 27 days after anthesis). A large increase in cytokinin concentration and content per fruit occurred as the fruit reached commercial maturity (to 1 900 pmo! £"' fresh weiaht). Individual cytokinins showed quite different patterns. Zeatin, in par-Ticular, showed a peak in concentration (13 pmoi g"' fresh weight) 11 days after anthesis that correlated with the beginning of the cell division phase of fruit growth. The accumulation of cytokinin (mostly zeatin riboside or zeatin nudeotide) in mature fruit may he of significance tor the postharvest storage of kiwifrtiit fiuit.