Extraction and isolation procedures

In the subsequent years, a number of other monohydroxy- A1-THC derivatives have been isolated from various metabolizing systems (Figure 2). These have been of two types hydroxyls allylic to the M-double bond and sidechain hydroxyls. No evidence for aromatic hydroxylation has thus far been reported, although these positions are chemically reactive and there is biochemical evidence for C-C glucuronide formation at the 4 -position of A6-THC. Possibly such catechol type metabolites of A1-THC are unstable and may be lost during the extraction and isolation procedures. 

Isolation of AUatostatins from CA. For the isolation of allatostatins from CA, 6000 pairs of glands were dissected from virgin and mated females. The extraction and isolation procedures were the same as those described in Woodhead et al. (1 ) except that the first HPLC separation employed a RP column with a shallow gradient (10-35% over 50 min., 1 ml/min flow rate) of acetonitrile with 0.1% trifluoroacetic acid. Approximately 500 CA equivalents were applied for each of 12 runs. Synthetic allatostatins 1-4 were used as markers for collection of fractions. Two fractions were collected on the basis of the elution time of synthetic allatostatins one expected to contain allatostatin 4 and the other to contain allatostatins 1, 2 and 3. These were separated by about 0.7 min. The second HPLC separation, on a C RP column, was as described in Woodhead et al. (l i), and peaks of UV-absorbing material were collected by hand. A third separation of the Cg fraction which showed biological activity corresponding to... 

In 1933, Fischer and Schmitz first claimed to have isolated a pure heparin preparation. Their lengthy extraction and isolation procedure culminated in the isolation of a microcrystalline brucine salt 32 times as active as the starting material. No evidence other than that of appearance was quoted in support of the claimed crystallinity of the product. It was concluded that heparin was a carbohydrate (Molisch test) and contained a uronic acid. 

The amounts of this alkaloid and of (— )-alloelaeocarpiline varied markedly in the crude alkaloids from different batches of plant material and it has been suggested that the amounts may depend upon small differences in the extraction and isolation procedures (5). (+ )-Epi-alloelaeocarpiline (22) (mp 136-137° [ccj +139° in CHClg) resembles... 

The methanol extract of E. herbacea flowers was subjected to the conventional extraction and isolation procedures for alkaloids. A new Erythrina alkaloid, 10-hydroxy-ll-oxoerysotrine (29), was isolated together with five known compounds. The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass spectra (MS). The new compound is a rare C-10 ox ygenated Erythrina alkaloid [49]. 

From the aerial parts of Evodia lepta, we isolated and identified thirteen 2,2-dimethyl-chromenes, four dichromenes, eight 2,2-dimethyl-chromans, one sesquiterpene and two fiavones. Figure 2 shows the extraction and isolation procedure. 

---