Progress in the chemistry of organic natural products. Progrès dans la chimie des substances organiques naturelles 

About: Progress in the chemistry of organic natural products. Progrès dans la chimie des substances organiques naturelles is an academic journal. The journal publishes majorly in the area(s): Amino acid & Epothilones. Over the lifetime, 151 publications have been published receiving 4616 citations.

The pyrrolizidine alkaloids.

Abstract: Previous chapters in this series by Warren appeared in 1955 (310) and 1966 (311). Since then an authoritative book by Bull, Culvenor, and Dick, on the chemistry and pharmacology of pyrrolizidine alkaloids has been published (60). Comprehensive reviews on the alkaloids (312), their chemotaxonomic significance (77), and general pyrrolizidine chemistry (243) are available. A series of Annual Reports including pyrrolizidine alkaloids was introduced in 1971 (245). The present review follows the format of previous articles in this series and covers the literature up to early 1981.

Recent Advances in the Chemistry of Hashish

Abstract: Cannabis saliva L. (family Moraceae) is a dioecious plant of which two varieties exist, var. indica and var. non indica or typica. The flowering top of the female plant is covered with glandular hairs which secrete a resin. The resin formation ceases when the seeds mature and its function is to protect them during the ripening period. The cannabis resin is known as “hashish” in the Middle East and Europe and as “charas” in India. Frequently not only the resin but the whole flowering top is collected and used. It is then known as “ganja” in India, “kif” in North Africa, “dagga” in South Africa, “marihuana” in North America, “maconha” in Brazil, etc.

Equilibrium Sedimentation of Macromolecules and Viruses in a Density Gradient

Abstract: Rotating a solution for a sufficient period of time in an ultracentrifuge gives rise to a sedimentation-diffusion equilibrium. The denser component in the solution sediments in the direction of the field, and back-diffusion occurs in response to the non-uniform concentration. At equilibrium the concentration of the solute increases with distance from the center of rotation and gives rise, along with the compression, to a density gradient. In conventional sedimentation equilibrium experiments described by Svedberg and Pedersen (68), and by Schachman (56), performed with low concentrations of solute, the density gradient is small. However, when a concentrated solution of an appropriate low-molecular weight solute is used, a large density gradient may be established. Because the system is at equilibrium, the density gradient at any position in the liquid is stable and reproducible, and depends only on the angular velocity, distance, temperature, and the molecular and solution parameters of the system.

Hydrolyzable tannins and related polyphenols.

Abstract: Recent advances in isolation and structure elucidation of several hundred of new polyphenolic compounds of the tannin class using new techniques (1) have altered the definition of a tannin, at least that of a hydrolyzable tannin. Thus the term tannin now includes all polyphenolic compounds of defined chemical structure as well as the whole group of compounds whose chemical structures and properties are those of tannins. Tannins by the new definition are thus similar to other classes of natural products, such as alkaloids, terpenoids etc.