New skeletons and new concepts in Amaryllidaceae alkaloids

The Amaryllidaceae alkaloids, represent a group of isoquinoline alkaloids, which are produced almost solely by members of the Amaryllidaceae family. The alkaloids of this family have attracted considerable amount of interest due to some important pharmacological activities they were shown to possess. In the last decade, our phytochemical studies on four Galanthus (Amaryllidaceae) species of Turkish origin have yielded quite a number of new alkaloids with diverse structures. Among these alkaloids, gracilines and plicamines constitute two new subgroups for the Amaryllidaceae alkaloids. The gracilines contain an incorporated 10b,4a-ethanoiminodibenzo[b,d]pyrane skeleton. The plicamines are dinitrogenous compounds, where the oxygen atom in position 7 of a tazettine skeleton is replaced by a nitrogen atom substituted by a pendant 4-hydroxyphenethyl moiety. One of the new alkaloids, galanthindole, which possesses a nonfused indole ring, unlike the already known subgroups of Amaryllidaceae alkaloids, may be considered as the prototype of a third new subgroup of the Amaryllidaceae alkaloids. Additionally, two known isoquinoline alkaloids which do not possess one of the established skeletons of the Amaryllidaceae alkaloids, namely ( − )-capnoidine and (+)-bulbocapnine, have been isolated from a Turkish Galanthus species. Totally, 21 new, 20 known alkaloids and 2 known lignans have been characterized. In this review, the isolation and structure elucidation of these compounds with interesting chemical structures are described.     

Mechanism of the Antiviral Activity Resulting from Sequential Administration of Complementary Homopolyribonucleotides to Cell Cultures

The antiviral activity of the double-stranded complex poly(rI) . poly(rC) in cell culture was restored or even surpassed if the constituent homopolymers were administered separately. Poly(rI) primed the cells for the antiviral activity of poly(rC) and poly(rC) primed for poly(rI), but neither poly(rI) nor poly(rC) primed the cells for the antiviral activity of noncomplementary homopolynucleotides. The priming effect of poly(rI) was significantly reduced if the poly(rI)-primed cells were treated with either T(1) ribonuclease or diethylaminoethyl (DEAE)-dextran before addition of poly(rC), and the priming effect of poly(rC) was significantly reduced if the poly(rC)-primed cells were treated with either pancreatic ribonuclease or DEAE-dextran before addition of poly(rI). (3)H-labeled poly(rC) bound more rapidly to poly(rI)-treated cells than to control cells. Cell-associated poly(rC) was markedly more resistant to pancreatic ribonuclease treatment if the cells had been incubated with poly(rI) before exposure to poly(rC). Our results clearly indicate that poly(rI) and poly(rC) added successively to cell cultures do not act independently but reunite at the cellular level, most likely at the outer cell membrane.     

The incorporation of [myo-2-3H] inositol into phosphatidyl inositol of stimulated rat pancreas

The 'phospholipid effect' involves agonist induced breakdown of phosphatidyl inositol (PI) or its phosphorylated derivates with increased incorporation of 32P or [myo-2-3H] inositol during resynthesis. In rat pancreas pancreozymin and bethanecol resulted in the standard dose dependent increased incorporation of 32P into PI which was paralleled by increased amylase secretion. By contrast the incorporation of [myo-2-3H] inositol into PI was significantly decreased by pancreozymin whereas bethanecol had no effect. However, pancreozymin caused a 30% decrease in labelled PI irrespective of whether it was prelabelled with 32P or [myo-2-3H] inositol. Thus in rat pancreas, pancreozymin resulted in the standard agonist induced breakdown of pre-labelled PI but inhibited the incorporation [2-3H-myo] inositol during the resynthetic phase.     

Castration cells in rat adenohypophysis after long-term alcohol consumption

Histological and ultrastructural changes of hypophyseal gonadotropic cells of rats which received a 15% solution of ethyl alcohol for 6 months were studied. Light microscopy revealed hyperplasia and hypertrophy of these cells; some contained a vacuole of varying size. Ultrastructural analysis showed that this vacuole originated from, and anastomosed with, dilated cisternae of the granulated endoplasmic reticulum. Vacuolated cells in the pituitary of alcoholized rats were identical with cells observed after surgical or chemical castration. The development of these alcohol-induced castration cells is achieved in four stages. The first stage was characterized by beginning hydropic degeneration and other still reversible alterations. Cells in the second and third stages seemed already irreversibly on their way to decay. The fourth stage was represented by typical signet-ring cells. Our results offer a morphological basis to the adoption of a biphasic effect of alcohol on gonadotropic secretion.     

Revisiting CCL-type chemokines in breast cancer and its milieu: prominent targetable chemokines,CCL8 and CCL21

The patterns of chemokine expression play a decisive role in both breast cancer prognosis and metastasis. In a recent article published in Bioscience Reports, ‘Bioinformatics identification of CCL8/21 as potential prognostic biomarkers in breast cancer microenvironment’, Chen et al. presented that expression of both CCL8 and CCL21 among CCL-type chemokines is prominent for prognosis of the breast cancer, metastasis and chemoresistance (Biosci Rep (2020) 40(11); DOI: 10.1042/BSR20202042). Identifying the sources of the CCL8 and CCL21 in the tumor microenvironment and developing targeting strategies for these chemokines to prevent tumor growth will improve both prognosis and therapeutic outcomes.     

Alkaloids from Galanthus rizehensis

Two new Amaryllidaceae alkaloid N-oxides, incartine N-oxide (1) and lycorine N-oxide (2) together with one β-carboline alkaloid, 1-acetyl-β-carboline (3) and six known alkaloids namely, incartine (4), N-trans feruloyltyramine (5), lycorine (6), O-methylnorbelladine (7), vittatine (8) and 11-hydroxyvittatine (9) were isolated from Galanthus rizehensis Stern (Amaryllidaceae). The structures of the alkaloids were elucidated by spectroscopic analyses (UV, IR, MS, 1D and 2D NMR). Acetylcholinesterase inhibitory activity potentials of the compounds were also determined.