Structure d'alcaloïdes indoliques doubles d'un type nouveau

Genome Assembly of the Medicinal Plant Voacanga thouarsii

The Apocynaceae tree Voacanga thouarsii, native to southern Africa and Madagascar, produces monoterpene indole alkaloids (MIA), which are specialized metabolites with a wide range of bioactive properties. Voacanga species mainly accumulates tabersonine in seeds making these species valuable medicinal plants currently used for industrial MIA production. Despite their importance, the MIA biosynthesis in Voacanga species remains poorly studied. Here, we report the first genome assembly and annotation of a Voacanga species. The combined assembly of Oxford Nanopore Technologies long-reads and Illumina short-reads resulted in 3,406 scaffolds with a total length of 1,354.26 Mb and an N50 of 3.04 Mb. A total of 33,300 protein-coding genes were predicted and functionally annotated. These genes were then used to establish gene families and to investigate gene family expansion and contraction across the phylogenetic tree. A transposable element (TE) analysis showed the highest proportion of TE in Voacanga thouarsii compared with all other MIA-producing plants. In a nutshell, this first reference genome of V. thouarsii will thus contribute to strengthen future comparative and evolutionary studies in MIA-producing plants leading to a better understanding of MIA pathway evolution. This will also allow the potential identification of new MIA biosynthetic genes for metabolic engineering purposes.

Tabernaesines A-I, Cytotoxic Aspidosperma-Aspidosperma-Type Bisindole Alkaloids from Tabernaemontana pachysiphon

Twenty-one aspidosperma-aspidosperma alkaloids, including the new tabernaesines A-J (1-9), were obtained from Tabernaemontana pachysiphon. The structures and absolute configurations were elucidated using HRMS and NMR experiments. Compounds 1-9 possessed a rare spiro heterocycle moiety between the monomeric units, while compounds 4 and 5 were characterized by an indole ring fused with an (N,N-diethyl)methyl amino group. Compounds 1, 5-7, 15, and 16 exhibited moderate cytotoxic potency against various human cancer cell lines at IC₅₀ 2.5-9.8 μM.

Constituents of Medicinal Plants of Lombok: A New Antibacterial Alkaloid from Voacanga Foetida (Bl.) Rolfe

A new, weakly antibacterial indole alkaloid, named lombine, together with the known alkaloid voacangine, have been isolated from the bark of Voacanga foetida (Bl.) Rolfe (Apocynaceae), a plant used on Lombok, Indonesia, for medicinal purposes. A combined chemo- and bio-rational strategy was developed to target this plant for investigation. Lombine was shown to be bactericidal against Staphylococcus aureus and Escherichia coli.

Chemistry and biology of the genus Voacanga

CONTEXT

Herbal remedies have been employed for the treatment and management of various ailments since the beginning of human civilization. Voacanga is an extensive genus of the family Apocynaceae and consists of small trees inhabiting the tropical and subtropical regions of Africa. Voacanga plants have been used in the treatment of leprosy, diarrhea, and generalized edema, convulsions in children as well as to treat cases of orchitis, ectopic testes and gonorrhea.

OBJECTIVES

The aim of this review is to present as much information as was established from the available scientific literature. The present review comprises the ethnopharmacological, phytochemical and therapeutic potential of the plant genus Voacanga.

METHODS

The present review reports on 111 natural products as found in 44 references compiled from the major databases, viz., Chemical Abstracts, Science Direct, SciFinder, PubMed, Dr. Dukes Phytochemical and Ethnobotany, CIMER, and InteliHealth.

RESULTS

An exhaustive survey of the literature revealed that indole alkaoids and steroids constitute the major classes of phytoconstituents of this genus. Pharmacological reports revealed that products derived from this genus have been used for the treatment of cancer, and for CNS, cardiotonic, antituberculosis, acetylcholinesterase (AChE), butyrylcholinesterase, antagonistic, anti-diarrheal activities.