Influence of postharvest processing and storage conditions on key antioxidants in puha (Sonchus oleraceus L.).

OBJECTIVES: To investigate effects of different postharvest drying processes and storage conditions on key antioxidants in Sonchus oleraceus L. leaves. METHODS: Fresh leaves were oven-dried (60°C), freeze-dried or air-dried (∼25°C) for 6 h, 24 h and 3 days, respectively. Design of experiments (DOE) was applied to study the stability of antioxidants (caftaric, chlorogenic and chicoric acids) in S. oleraceus leaves and leaf extracts stored at different temperatures (4, 25 and 50°C) and relative humidities (15%, 43% and 75%) for 180 days. The concentration of antioxidants was quantified by a HPLC-2,2'-diphenylpicrylhydrazyl post-column derivatisation method. Antioxidant activity was assessed by a cellular antioxidant activity assay. KEY FINDINGS: The three antioxidants degraded to unquantifiable levels after oven-drying. More than 90% of the antioxidants were retained by freeze-drying and air-drying. Both leaf and extract samples retained >90% of antioxidants, except those stored at 75% relative humidity. Leaf material had higher antioxidant concentrations and greater cellular antioxidant activity than corresponding extract samples. CONCLUSION: Freeze-drying and air-drying preserved more antioxidants in S. oleraceus than oven-drying. From DOE analysis, humidity plays an important role in degradation of antioxidants during storage. To preserve antioxidant activity, it is preferable to store S. oleraceus as dried leaf material.

Application of an online post-column derivatization HPLC-DPPH assay to detect compounds responsible for antioxidant activity in Sonchus oleraceus L. leaf extracts.

OBJECTIVES: To use an online assay to identify key antioxidants in Sonchus oleraceus leaf extracts and to investigate the effect of leaf position and extraction conditions on antioxidant concentration and activity. METHODS: Separation of phytochemicals and simultaneous assessment of antioxidant activity were performed online using HPLC and post-column reaction with a free-radical reagent (2, 2-diphenylpicrylhydrazyl, DPPH). Active compounds were identified using nuclear magnetic resonance spectroscopy and mass spectrometry. We applied the online HPLC-DPPH radical assay to evaluate antioxidants in leaves from different positions on the plant and to assess the effect of pre-treatment of leaves with liquid N(2) before grinding, extraction time, extraction temperature and method of concentrating extracts. KEY FINDINGS: Key antioxidants identified in S. oleraceus leaf extracts were caftaric acid, chlorogenic acid and chicoric acid. Middle leaves contained the highest total amount of the three key antioxidant compounds, consisting mainly of chicoric acid. Pre-treatment with liquid N(2), increasing the extraction temperature and time and freeze-drying the extract did not enhance the yield of the key antioxidants. CONCLUSION: 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.

The effects of an orally administered probiotic on sulfasalazine metabolism in individuals with rheumatoid arthritis: a preliminary study.

AIM: To carry out a pilot study to investigate the effect of short-term oral probiotic administration on the metabolism of sulfasalazine (SSZ) in patients with rheumatoid arthritis (RA) stabilized on SSZ. METHODS: Twelve subjects with RA taking stable doses of SSZ for a minimum of 3 months prior to the study, received a probiotic preparation contained three strains of bacteria (1.8 x 10(9) CFU/day) twice daily for 1 week. Single point blood and 12-h urine samples were taken before and after probiotic treatment and 3 weeks following discontinuation of probiotics, for determination of SSZ and its metabolites. The presence of the probiotic bacteria in the feces of patients was investigated by denaturing gradient gel electrophoresis (DGGE). RESULTS: Adverse events recorded were three instances of gastrointestinal disturbance and one flare of RA. Plasma and urinary levels of SSZ and its metabolites showed no statistically significant changes after probiotic administration and the incidence of gastrointestinal disturbance did not appear to be ascribed to higher sulfapyridine plasma levels. Probiotic-specific DGGE bands were detected in the feces of some patients after the treatment period. CONCLUSIONS: Short-term treatment of RA patients with a multi-strain probiotic did not significantly influence SSZ metabolism as has been demonstrated in animal models.

Veratrum poisoning.

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.