Solvent extraction tubers

Lipids can be identified and quantified using thin-layer chromatography (TEC) and gas chromatography (GC) (Galliard, 1968). Extraction of lipids is achieved by homogenizing potato tubers with isopropanol in a blender, followed by a series of filtrations and extractions with chloroform-methanol (2 1). Chloroform is removed by rotary evaporation and the residue is redissolved in benzene-ethanol (4 1). This extract is passed through a DEAE-cellulose column, and the fractions collected are subjected to TEC on 250 p,m layers of silica gel G, using three solvent systems. Fatty acid methyl esters for GC analysis are prepared by transmethylation of the parent lipids, or by diazomethane treatment of the free fatty acids released by acid... 

The dried powder (10 mg dry weight) of tuberous root was extracted five times with diethyl ether (5 mL). After evaporation of the solvent, the residue was redissolved in MeOH and diluted with PBS (1 16), and then filtered by Millex-HV filter (0.45-/im filter unit Milli-pore Products, Bedford, MA, U.S.A.) to remove insoluble portions. The filtrate was loaded onto the immunoaffinity column and allowed to stand for 90 min at 4°C. The column was washed with the washing buffer solution (10 mL). After forskolin disappeared, the column was eluted with PBSM (45%) at a flow rate of 0.1 mL/min. The fraction containing forskolin was lyophilized and extracted with diethyl ether. ForskoUn... 

Stout tuberous roots of kuth are characterized by a penetrating aroma. Pale yellow or brownish viscous oil or costus oil is obtained from the roots either by steam distillation or through extracting with solvents. The oil contains resinoids (6%), essential oil (1.5%), Saussurine and other alkaloids (0.05%). Biological actions of costus oil are hyposensitive, bronchiodialatoiy, and antiseptic against streptococcus and streptophylococcus (Anonymous, 1976). 

The alkaloid or poisonous principle was isolated from the powdered and dried tubers by extraction with 96% ethanol that contained some acetic acid (40). The sirupy residue, after removal of the solvent, was agitated with aqueous sodium carbonate solution and the base extracted with chloroform. Crystallization of the base proved difficult but its purification as hydrobromide by fractional crystallization proved satisfactory. The alkaloid recovered represents 0.21% of the weight of the dried tubers (0.04% of the fresh tubers). It is a low melting solid and is sufficiently basic to liberate ammonia from its salts. 

The procedure for purifying the russet scab toxin is outlined in F pre 2. Chtoroform extract was fractionated by silica gel column diromatography. Only the 10% MeOH - CHCI3 fiaction induced necrosis by the tuber slice assi. This fraction was rechromatognqihed using a different solvent syston. The active fraction was flien purified by prepariaive TLC and sqiarated into five fractions... 

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