Enhanced bioavailability of zeaxanthin in a milk-based formulation of wolfberry (Gou Qi Zi; Fructus barbarum L.).

The carotenoid zeaxanthin is concentrated within the macula. Increased macular zeaxanthin is suggested to lower the risk of age-related macular degeneration. The small red berry, wolfberry (Fructus barbarum L.; Gou Qi Zi and Kei Tze), is one of the richest natural sources of zeaxanthin. However, carotenoid bioavailability is low, and food-based products with enhanced bioavailability are of interest. The present study investigated zeaxanthin bioavailability from three wolfberry formulations. Berries were homogenised in hot (80 degrees C) water, warm (40 degrees C) skimmed milk and hot (80 degrees C) skimmed milk, with freeze drying of each preparation into a powdered form. A zeaxanthin-standardised dose (15 mg) of each was consumed, in randomised order, together with a standardised breakfast by twelve healthy, consenting subjects in a cross-over trial, with a 3-5-week washout period between treatments. Blood samples were taken via a venous cannula immediately before (fasting) and 2, 4, 6, 7, 8 and 10 h post-ingestion. Zeaxanthin concentration in the triacylglycerol-rich lipoprotein fraction of plasma was measured by HPLC. Results showed that triacylglycerol-rich lipoprotein zeaxanthin peaked at 6 h post-ingestion for all formulations. Zeaxanthin bioavailability from the hot milk formulation was significantly higher (P < 0.001) than from the others. Mean area under the curve (n 12) results were 9.73 (sem 2.45), 3.24 (sem 0.72) and 3.14 (sem 1.09) nmol x h/l for the hot milk, warm milk and hot water formulations, respectively. Results showed clearly that homogenisation of wolfberry in hot skimmed milk results in a formulation that has a 3-fold enhanced bioavailability of zeaxanthin compared with both the 'classical' hot water and warm skimmed milk treatment of the berries.

Assessment of membrane protection by traditional Chinese medicines using a flow cytometric technique: preliminary findings.

In this preliminary study, we used a 'living cell' flow-cytometric approach to membrane protection by four traditional Chinese medicines (TCMs). Cells were incubated, separately, for 30 min with aqueous extracts (1.5% w/v) of lingzhi (Ganoderma lucidum), ginger (Zingiber officianale), ginseng (Panax ginseng), and green tea (Camellia sinensis). Membranes were labelled with a fluorescent probe, cells were then incubated with cumene hydroperoxide, and site-specific oxidation induced by iron/ascorbate. Oxidation of membrane lipids quenches fluorescence. Forward-scatter fluorescence was measured at timed intervals after initiation of oxidation. Results indicate that lingzhi and ginger contain antioxidant component(s) that act within the cell membrane and slow lipid peroxidation in situ. Results demonstrate also that this living cell model is a useful biomonitoring tool to help determine molecular aspects of putative health effects of TCMs.