Artapilosines A and B, Unusual Phenanthrene Derivatives Related to Aporphine Alkaloids from Artabotrys pilosus

Monoterpenoid indole alkaloids from the stems and leaves of Tabernaemontana bovina and their potential antiproliferative activities

A phytochemical study on the stems and leaves of Tabernaemontana bovina led to the isolation and identification of a new monoterpenoid indole alkaloid, taberboviline (1), together with seven known monoterpenoid indole alkaloids (2-8). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their antiproliferative activities against five human cancer cell lines in vitro. Monoterpenoid indole alkaloids 1-8 exhibited notable antiproliferative activities against five human cancer cell lines with IC50 values ranging from 0.58 ± 0.05 to 26.19 ± 0.16 μM.

Total Synthesis of Artapilosine A and Artapilosine B

Artapilosines A and B, isolated from Artabotrys pilosus, demonstrated significant anti-HIV reverse transcriptase activity. In this work, we present the first asymmetric total synthesis of (-)-artapilosine A and of its enantiomer (+)-artapilosine A, achieved in 10 steps with overall yields of 0.9% and 0.7%, respectively, starting from commercially available piperonylic acid. The key step in this synthesis involved a pivotal photocyclization reaction, providing an efficient protocol for constructing the phenanthrene ring system common to many natural products. Additionally, using the same photocyclization strategy, we successfully synthesized artapilosine B in 10 steps with an overall yield of 2.1%.

2-Arylbenzofurans from the stems and leaves of Artocarpus tonkinensis and their potential antiproliferative activities

Phytochemical study on the stems and leaves of Artocarpus tonkinensis led to the isolation of a new 2-arylbenzofuran, artocartone (1), as well as seven known 2-arylbenzofurans (2-8). The chemical structure of 1 was established by means of comprehensive spectroscopic analyses and the known compounds were determined by comparing their MS and NMR data with those reported data in literature. The antiproliferative activities of all isolates 1-8 against five human cancer cell lines: HL-60, SMMC-7721, A-375, MCF-7 and SW480 in vitro were evaluated. As a result, compounds 1- 8 displayed notable antiproliferative activities against various human cancer cell lines with IC50 values in the range of 0.28 ± 0.05-26.89 ± 0.18 μM.

Synthesis of Phenanthrenes and 1-Hydroxyphenanthrenes via Aromatization-Assisted Ring-Closing Metathesis: toward Polynuclear Aromatic Hydrocarbons

This study presents an efficient synthetic strategy for phenanthrenes and 1-hydroxyphenanthrenes through aromatization-assisted ring-closing metathesis (RCM). It involves vinylation of 1-bromo-2-naphthaldehyde derivatives, Barbier allylation, and subsequent one-pot RCM/dehydration of the diene precursors to yield phenanthrene derivatives. Further, the corresponding keto analogues of diene precursors produce 1-hydroxyphenanthrenes through RCM and aromatization-driven keto-enol tautomerism. This pathway enables rapid access to a diverse array of functionalized phenanthrenes and 1-hydroxyphenanthrenes, including synthetically challenging derivatives containing both -OH and -OMe groups via the sequential construction of the terminal phenanthrene ring.

Natural products as potential lead compounds to develop new antiviral drugs over the past decade

Virus infection has been one of the main causes of human death since the ancient times. Even though more and more antiviral drugs have been approved in clinic, long-term use can easily lead to the emergence of drug resistance and side effects. Fortunately, there are many kinds of metabolites which were produced by plants, marine organisms and microorganisms in nature with rich structural skeletons, and they are natural treasure house for people to find antiviral active substances. Aiming at many types of viruses that had caused serious harm to human health in recent years, this review summarizes the natural products with antiviral activity that had been reported for the first time in the past ten years, we also sort out the source, chemical structure and safety indicators in order to provide potential lead compounds for the research and development of new antiviral drugs.

Xanthones with Potential Anti-Inflammatory and Anti-HIV Effects from the Stems and Leaves of Cratoxylum cochinchinense

Four new xanthones, cratocochinones A-D (1-4), together with eight known analogues (5-12), were isolated from the stems and leaves of Cratoxylum cochinchinense. The chemical structures of cratocochinones A-D (1-4) were elucidated by comprehensive spectroscopic analyses and the known compounds were identified by comparisons with the spectral data reported in the literature. All isolated compounds 1-12 were evaluated for their anti-inflammatory activities and anti-HIV-1 activities. Compounds 1-12 showed remarkable inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro, with IC50 values in the range of 0.86 ± 0.05 to 18.36 ± 0.21 µM. Meanwhile, compounds 1-12 exhibited significant anti-HIV-1 activities with EC50 which ranged from 0.22 to 11.23 µM. These findings indicate that the discoveries of these xanthones, isolated from the stems and leaves of C. cochinchinense, showing significant anti-inflammatory and anti-HIV-1 effects could be of great importance to the research and development of new natural anti-inflammatory and anti-HIV agents.

A world tour in the name of natural products

BACKGROUND

Names of natural products (NP) are usually given depending on the species of origin, be it a plant, a marine organism or a microbial species. In some cases, names have been given with reference to people, animals, music, foods or places. Many NP refer to countries, cities or specific places such as mountains, deserts, seas and oceans.

PURPOSE

On the basis of NP names, a world tour has been imagined referring to more than one hundred NP with names evocative of over 50 countries and regions.

RESULTS

The world tour goes from UK (britannin) to Italy (vaticanol) in Europe, from Uganda (ugandoside) to Senegal (senegalene, senegalenines) in Africa, from Brazil (brasilin) to Chile (santiaguine) in South America, from Utah (utahin) to Florida (floridanolide) in the US. It includes Central America (mexicanin, panamine) and the Caribbean islands (jamaicin, bahamaolides). It also crosses Alaska (alaskene) and Canada (quebecol, canadaline). The tour continues throughout Asia, from Thailand (thailandine) to China (Chinaldine) and Pakistan (pakistanamine), to finally reaches Oceania with Australia (australigenin) and Vanuatu (vanuatine), among other countries. This virtual journey, without bordure or wall, brings us to the highest mountains (himalayamine), the deepest oceans (pacificins) and the largest deserts (desertomycin).

CONCLUSION

In the current period of COVID-19 pandemia, with restricted opportunities for international travels, this NP name-based virtual journey offers a world tour to learn more from nature and to inspire scientists to contribute to the field of NP discovery and drug design. There are also limitations associated with the use of trivial names for NP. NP names can be further exploited for teaching and learning.