Summary Gossypurpurin was prepared from gossypol via diaminogossypol, and its properties compared with gossypurpurin isolated from cottonseed pigment glands. A tentative molecular formula for synthetic gossypurpurin, C30H32O7N, has been proposed on the basis of its elementary composition. The native pigment could not be obtained in the same degree of purity as the synthetic product and the analytical data could therefore not be brought into exact agreement for the two products. However solutions of both pigments in chloroform exhibit almost identical absorption spectra and identical antimony trichloride tests. Qualitative reactions seem to indicate that the functional groups of both native and synthetic gossypurpurin are identical, and the ready conversion of both products to gossypol upon contact with acid seems to indicate that their basic structures are similar.

SummaryTwenty‐one preparations from cottonseed pigment glands were tested for their acute oral toxicity in 1,208 fasted rats and for their content of extractable gossypol and gossypurpurin. LD50 studies on six samples of pure gossypol were performed on 167 fasted rats. There was no correlation between the toxicity of the various samples of cottonseed pigment glands and their extractable gossypol or gossypurpurin content. Samples containing very large amounts of extractable gossypol were less toxic than many samples with considerably lower extractable gossypol content.Various fractionation procedures carried out on the same lot of cottonseed pigment glands caused wide alterations in their toxicity, from the extreme of very marked toxicity for the water‐soluble, acetone‐soluble fraction (LD50 ca. 700 mg./kg.) to no detectable toxicity for the acetone‐insoluble residue (LD50<6,000 mg./kg.).There was a decreased toxicity of subsequently prepared pigment glands with increased time of storage of the cottonseed in a silo. Storage of the pigment glands themselves at 7°C. however had little effect on their toxicity even after 26 and 32 months.The procedures causing greatest detoxification of cottonseed pigment glands, given in the order of increasing effectiveness, were: heating in the presence of water < extraction with ethanol < extraction with acetone.In the fasted rat the acute oral toxicity of pure gossypol was less than that of 17 preparations from cottonseed pigment glands having extractable gossypol contents ranging from as little as 24 to as much as 90%.

Summary Three pure‐bred varieties of cottonseed,G. hirsutum, which were planted and grown under similar environmental conditions were stored at 38°, 77°, and 85°F. After determining the initial contents of lipids, nitrogen, moisture, gossypol, and gossypurpurin each lot of seed was stored at the different temperatures and analyzed periodically with respect to changes in pigmentation. The content of gossypurpurin was found to increase during storage in all of the samples. Its increase was proportional to the temperature and length of storage. On the other hand, gossypol decreased during storage of all samples. The antimony trichloride test for gossypol was found to be applicable only to extracts prepared from fresh cottonseed. During storage of the seed another yellow‐colored pigment(s) developed which could be separated from gossypol by alkaline extraction of the original chloroform extract of the stored seed. The alkali extractable portion of the chloroform extract gave a red‐colored antimony trichloride reaction product characteristic of gossypol. It is postulated that at least a fraction of the non‐acidic pigment(s) in the crude chloroform extracts obtained from stored cottonseed is diaminogossypol.