Studies on Triterpenes. IV

Studies on Self-Sterility. IV. Selective Fertilization.

INTRODUCTION .................................................................. 346 Discussion of the problem ..................................................... 348 Pollen-tube frequency distributions ............................................. 349 Influence of growth of compatible pollen tubes upon incompatible pollen tubes.. .. 352 SUMMARY AND DISCUSSION ....................................

Structural studies on human type IV collagen.

Type IV collagen was isolated from limited pepsin digests of human placenta by selective salt precipitation at acidic and neutral pH. The native protein was resistant to human skin collagenase but was cleaved by a rat mast cell protease. Molecular sieve chromatography of the reduced and alkylated material separated relatively homogeneous components of molecular weight 140,000 (140K) and 100,000...

Studies on Plasma Protein. IV. Leprosy

Triterpenes from Mimusops elengi.

Pentacyclic triterpenes (1) and (2) have been isolated from Mimusops elengi and assigned structures 3beta,6beta,19alpha,23-tetrahydroxy-urs-12-ene and 1beta-hydroxy-3beta-hexanoyllup-20 (29)-ene-23, 28-dioic acid, respectively, on the basis of spectroscopic studies including 2D-NMR. The compound 1 showed moderate inhibiting activity against beta-glucuronidase enzyme

Studies on inhibitors of skin-tumor promotion. Inhibitory effects of triterpenes from Cochlospermum tinctorium on Epstein-Barr virus activation.

Arjunolic acid, an oleanene-type triterpene isolated from the rhizome of Cochlospermum tinctorium, its triacetate derivative, and their methyl esters were tested using the short-term in vitro assay on EBV-EA activation in Raji cells induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Their inhibitory effects on skin tumor promotors were found to be greater than those of previously studied n...