The four fractions obtained were analysed with standard screening tests to detect the principal secondary metabolites. From residues of the ethanol extractions lipids were extracted with chloroform–methanol (2:1).12 Flavonoids were analysed using planar chromatography with two different mobile phases

(BAW: n-butanol–acetic acid–water, 4:1:5; Forestal: acetic acid–conc. HCl–water, 30:3:10). For lipids, a one-dimensional system was used on Silica gel G60 impregnated with ammonium sulphate, with benzene–acetone–water (30:91:8) as mobile phase.13 Pigments were determined from the soluble fractions in dichloromethane in Silica gel G60-calcium carbonate (2:1) with petroleum ether–acetone–i-propanol (35.5:14:0.5) used as mobile phase. 14 Furthermore, the second exhaustive extraction http://www.selleckchem.com/products/rgfp966.html of pigments was performed using acetone and MgCO3 to avoid the accidental formation of chlorophyll metabolites. The extracts were centrifuged at 670 × g, dried under vacuum and resuspended in 500 μl of acetone. The extracts where analysed by HPLC-RP-DAD. 15 The pigments were identified by co-chromatography with appropriate standards during elution, and by comparing their absorption spectra with reference standards. Standards and extracts were run through a C18 column, using a solution of acetonitrile: water (90:10) as mobile phase, at 1 ml/min flow rate and readings

were taken at 436 nm. Bosutinib in vivo The scavenging activity on diphenyl-2-picryl hydrazyl (DPPH) radicals of ethanolic and dichloromethane fractions (A and B respectively, Fig. 1) was assayed. The radical scavenging activities expressed either as percentage inhibition of DPPH were calculated.16 The SC50 values

were calculated by linear regression.17 Only high polar extracts (Fraction A) were analysed by the wheat rootlet growth inhibition bioassay (Triticum sativum) 18 since assay requires the sample to be soluble in water. Vinblastine sulphate was used as a positive control. The toxicity of the extracts was monitored by the brine shrimp lethality test.19 The efficiency of biomass production and the four fractions obtained is shown in Tables 1 and 2. The phytochemical screening showed in all samples the presence of carbohydrates of low molecular weight, lipids, and steroids. Cardenolids were only present in the exponential phase samples, and triterpenes only in the exponential phase samples of the bleached strains. With the exception of the MAT (ph), tannins were present in the exponential phase of all the other samples. In contrast, flavonoids were only detected in the stationary phase samples of photosynthetic strains (Table 3). The presence in all photosynthetic samples of chlorophylls a, b; β, β-carotenes; diadinoxanthin and neoxanthin was verified by TLC. The second analysis performed by RP-HPLC-DAD allowed yields between 33% (UTEX-h-ST) and 68.8% (MAT-ph-ST). Table 4 shows for each pigment detected the retention times (RT), the real absorption maxima in the elution solvent, and the extraction yields.