Study of the interaction of antiplasmodial strychnine derivatives with the glycine receptor

Strychnine and its mono- and dimeric analogues: a pharmaco-chemical perspective

Covering: up to November 2021Since its isolation in 1818, strychnine has attracted the attention of a plethora of chemists and pharmacologists who have established its structure, developed total syntheses, and examined its complex pharmacology. While numerous reviews on structure elucidation and total synthesis of strychnine are available, reports on structure-activity relationships (SARs) of this fascinating alkaloid are rare. In this review, we present and discuss structures, synthetic approaches, metabolic transformations, and the diverse pharmacological actions of strychnine and its mono- and dimeric analogues. Particular attention is given to its SARs at glycine receptors (GlyRs) in light of recently published high-resolution structures of strychnine-GlyR complexes. Other pharmacological actions of strychnine and its derivatives, such as their antagonistic properties at nicotinic acetylcholine receptors (nAChRs), allosteric modulation of muscarinic acetylcholine receptors as well as anti-cancer and anti-plasmodial effects are also critically reviewed, and possible future developments in the field are discussed.

In vitro antiprotozoal, antimicrobial and antitumor activity of Pavetta crassipes K. Schum leaf extracts

AIM OF THE STUDY

To study the potential benefit of the traditional medicinal plant Pavetta crassipes K. Schum (Rubiaceae), which is widely distributed throughout West Africa, the methanol and dichloromethane extracts were isolated from the plant leaves to determine if they exhibited antiprotozoal, antibacterial, antifungal or antitumor activity in vitro.

MATERIALS AND METHODS

The methanol and dichloromethane extracts and their specific fractions were obtained using bioassay-guided fractionation and investigated for antiproliferative activity in vitro in microorganisms (Staphylococcus aureus, Escherichia coli and Candida albicans), protozoans (Trypanosoma cruzi, Trypanosoma brucei, Leishmania infantum and Plasmodium falciparum), and cancer (U373, PC3, MXT and A549) and normal cell lines (NHDF and MRC-5).

RESULTS

Most of the alkaloid fractions investigated exhibited antiproliferative activity in all the cancer cell lines, microorganisms and protozoans studied.

CONCLUSIONS

The benefit of Pavetta crassipes as a traditional medicinal remedy was confirmed using antiprotozoal and cytotoxicity assays in vitro. These analyses revealed that the components present in the alkaloid extract of Pavetta crassipes are responsible for its antiprotozoal and cytotoxic efficacy.