Terpenoids fromCroton regelianus

The Corey-Seebach Reagent in the 21st Century: A Review

The Corey-Seebach reagent plays an important role in organic synthesis because of its broad synthetic applications. The Corey-Seebach reagent is formed by the reaction of an aldehyde or a ketone with 1,3-propane-dithiol under acidic conditions, followed by deprotonation with n-butyllithium. A large variety of natural products (alkaloids, terpenoids, and polyketides) can be accessed successfully by utilizing this reagent. This review article focuses on the recent contributions (post-2006) of the Corey-Seebach reagent towards the total synthesis of natural products such as alkaloids (lycoplanine A, diterpenoid alkaloids, etc.), terpenoids (bisnorditerpene, totarol, etc.), polyketide (ambruticin J, biakamides, etc.), and heterocycles such as rodocaine and substituted pyridines, as well and their applications towards important organic synthesis.

anti-HCoV: A web resource to collect natural compounds against human coronaviruses

BACKGROUND

A novel coronavirus, the SARS-CoV2, was revealed to be the cause of COVID19, the pandemic disease that already provoked more than 555.324 deaths in the world (July 10, 2020). No vaccine treatment has been defined against SARS-CoV2 or other human coronaviruses (HCoVs), including those causing epidemic infections, neither appropriate strategies for prevention and care are yet officially suggested.

SCOPE AND APPROACH

We reviewed scientific literature on natural compounds that were defined as potentially effective against human coronaviruses. Our desk research identified non-chemically modified natural compounds that were shown (in vitro) and/or predicted (in silico) to act against one or more phases of human coronaviruses cell cycle.We selected all available information, merged and annotated the data to define a comprehensive list of natural compounds, describing their chemical classification, the source, the action, the specific target in the viral infection. Our aim was to collect possible compounds for prevention and care against human coronaviruses.

KEY FINDINGS AND CONCLUSIONS

The definition of appropriate interventions against viral diseases need a comprehensive view on the infection dynamics and on necessary treatments. Viral targeting compounds to be exploited in food sciences could be of relevant interest to this aim.We collected 174 natural compounds showing effects against human infecting coronaviruses, providing a curated annotation on actions and targets.The data are available in anti-HCoV, a web accessible resource to be exploited for testing and in vivo trials. The website is here launched to favour a community based cooperative effort to call for contribution and expand the collection. To be ready to fight.

Aleuritin, a novel dinor-diterpenoid from the twigs of Aleurites moluccanus with an anti-lymphangiogenic effect

A phytochemical investigation of Aleurites moluccanus yielded one novel dinor-diterpenoid, aleuritin (1), along with a rare diterpenoid, aleuritone (2). Compound 1 has an unprecedented skeleton with a 6/6/5-fused tricyclic ring system. Compound 2 possesses a rare 6/6/5/3-fused tetracyclic skeleton, which is probably an artifact formed photochemically by the Norrish reaction. The structures of 1 and 2 were determined by spectroscopic methods (ECD, IR, mass, and NMR) and confirmed by single-crystal X-ray diffraction analyses. A plausible biogenetic pathway of 1 is proposed. Pharmacological study showed that these two compounds possessed mild in vitro anti-lymphangiogenic activity, which suppressed tube formation with IC50 values of 48.1 ± 1.8 and 34.2 ± 0.8 μg mL-1, respectively.

Chemical Constituents from Croton Species and Their Biological Activities

The genus Croton belongs to the Euphorbiaceae family, which comprises approximately 1300 species. Many Croton species have been used as folk medicines. This review focuses on the chemical constituents from Croton species and their relevant biological activities, covering the period from 2006 to 2018. A total of 399 new compounds, including 339 diterpenoids, were reported. Diterpenoids are characteristic components of the Croton species. These isolated compounds exhibited a broad spectrum of bioactivities, including cytotoxic, anti-inflammatory, antifungal, acetylcholinesterase inhibitory, and neurite outgrowth-promoting properties. The present review provides a significant clue for further research of the chemical constituents from the Croton species as potential medicines.

Advances in the chemistry and pharmacological potential of coumarinolignans

Coumarinolignans (CLs) are a group of non-conventional lignans having coumarins and phenyl propanes as two C₆C₃ units linked commonly through a dioxane bridge. The research findings during Jan 2008-May 2018 on this group of secondary metabolites describing their occurrence, structural characteristics, large-scale preparation, synthesis, derivatives, pharmacological activities, and structure-activity relationship are presented in this review. Around 38 CLs have been isolated from 40 plant species belonging to 20 different families during the review period. Reports on the syntheses of CL derivatives are also discussed. The majority of the reported CLs have shown potential anti-inflammatory activities, especially against pro-inflammatory cytokines. The other pharmacological effects exhibited by CLs such as hepatoprotective, anticancer, etc., are also covered in this review comprehending the lacunae in their development into drugs. This article is a continuation of our earlier work on coumarinolignans (Begum SA, Sahai M, Ray AB (2010) Non-conventional lignans: coumarinolignans, flavonolignans, and stilbenolignans. In: Kinghorn AD, Falk H, Kobayashi J (eds) Progress in the chemistry of organic natural products, Springer, Verlag/Wien, p 1-70).