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Solidago canadensis L., Canadian goldenrod (Asteraceae) has been used in European phytotheraphy for centuries as a component of urological and antiphlogistical remedies. High-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD) and online mass spectrometry (MS) has been used for the separation and quantification of phenolics (chlorogenic acid, caffeic acid, kaempferol-3-O-~-L-rutinoside (nicotiflorin), quercetin-3-O-13-Drutinoside (rutin), quercetin-3-O-13-D-galactoside (hyperoside), quercetin-3-O-13-D-glucoside (isoquercitrin), quercetin-3-O-13-D-rhamnoside (quercitrin), kaempferol-3-O-~-L-rhamnoside (afzelin) and quercetin from Solidaginis herba. Extracts have been obtained using different technologies. Three aqueous and three alcoholic extracts were studied separately. Reversedphase high-performance liquid chromatography separation of polyphenols on octadecyl sorbent Hypersil was performed, using acetonitrile: acetic acid 2.5 v/v % as eluent in gradient elution. Our results confirm previous reports concerning the presence of several flavonoids. Quantification of the main quercetin glycosides in pharmaceuticals is also reported.

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Sulphur limitation may restrain cell growth and viability. In the green alga Chlamydomonas reinhardtii, sulphur limitation may induce H production lasting for several days, which can be exploited as a renewable energy source. Sulphur limitation causes a large number of physiological changes, including the inactivation of photosystem II (PSII), leading to the establishment of hypoxia, essential for the increase in hydrogenase expression and activity. The inactivation of PSII has long been assumed to be caused by the sulphur-limited turnover of its reaction center protein PsbA. Here we reinvestigated this issue in detail and show that: (i) upon transferring Chlamydomonas cells to sulphur-free media, the cellular sulphur content decreases only by about 25%; (ii) as demonstrated by lincomycin treatments, PsbA has a significant turnover, and other photosynthetic subunits, namely RbcL and CP43, are degraded more rapidly than PsbA. On the other hand, sulphur limitation imposes oxidative stress early on, most probably involving the formation of singlet oxygen in PSII, which leads to an increase in the expression of GDP-L-galactose phosphorylase, playing an essential role in ascorbate biosynthesis. When accumulated to the millimolar concentration range, ascorbate may inactivate the oxygen-evolving complex and provide electrons to PSII, albeit at a low rate. In the absence of a functional donor side and sufficient electron transport, PSII reaction centers are inactivated and degraded. We therefore demonstrate that the inactivation of PSII is a complex and multistep process, which may serve to mitigate the damaging effects of sulphur limitation.

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Some current oils and their main components were studied to determine their antioxidant values. This was done by using the modified method of ferric reducing ability of plasma. It has been established that volatile oils of medicinal plants have on average a reducing capacity of 3.5Ð220 mmol/kg oil. The reducing capacities of the main constituents of volatile oils are 0.165Ð65.5 mmol/kg in concentrated oils. The highest reducing capacity was showd for phellandrene (65.438 ð 0.166 mmol/kg) and anethole (50.087 ð 0.160 mmol/kg) while the lowest values were obtained for menthol (0.165 ð 0.023 mmol/kg) and menthone (0.168 ð 0.010 mmol/kg). It has been stated that the antioxidant values of the main constituents are lower than those of volatile oils. The reducing capacity of the main constituents of medicinal plant drugs at different concentrations was also determined.