Recent advances in natural anti-HIV triterpenoids and analogs

The human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic is one of the world's most serious health challenges. Although combination antiretroviral therapy provides effective viral suppression, current medicines used against HIV cannot completely eradicate the infectious disease and often have associated toxicities and severe side effects in addition to causing drug resistance. Therefore, the continued development of new antiviral agents with diverse structures and novel mechanisms of action remains a vital need for the management of HIV/AIDS. Natural products are an important source of drug discovery, and certain triterpenes and their analogs have demonstrated potential as pharmaceutical precursors for the treatment of HIV. Over the past decade, natural triterpenoids and analogs have been extensively studied to find new anti-HIV drugs. This review discusses the anti-HIV triterpenoids and analogs reported during the period of 2009-2019. The article includes not only a comprehensive review of the recent anti-HIV agent development from the perspective of medicinal chemistry, but also discusses structure-activity relationship analyses of the described triterpenoids.

Structural determination of eleven new preschisanartane-type schinortriterpenoids from two Schisandra species and structural revision of preschisanartanin J using NMR computation method

Nineteen preschisanartane-type schinortriterpenoids (SNTs), among which eleven ones were previously undescribed, were isolated from two Schisandra species, S. sphaerandra and S. rubriflora. Their structures were determined using 1D and 2D NMR spectroscopic analyses, NMR data comparison, quantum chemical calculation of NMR parameters, electronic circular dichroism (ECD), X-ray single crystal diffraction, and chemical derivation. Furthermore, structural re-examination of a few previously reported preschisanartane-type SNTs led to the structural revision of preschisanartanin J. Besides, it is suggested that the reported structures of arisanlactone D and schilancidilactone W should be re-checked. Finally, a few isolated SNTs were found to possess neurite outgrowth-promoting activities, and protective activities against neural injuries.

Integrated X-Ray, NMR, ECD, and Computational Approaches to Assign the Stereochemistry of Nortriterpenoids

Highly oxygenated nortriterpenoids are the principle bioactive chemical constituents isolated from plants of the genera Schisandra and Kadsura. The stereochemistry of these molecules remains a highly challenging problem to solve. To establish the stereochemistry and develop a general nuclear magnetic resonance-electric circular dichroism-computational approach to solve these complex metabolites, we reviewed the published methods to solve the stereochemistry of these triterpenoids. A key goal of this review is to provide a protocol to solve the problems hampering the assignment of the relative absolute configurations of other members of this natural product class.

Triterpenoids

Covering: 2013. Previous review: Nat. Prod. Rep., 2015, 29, 1028-1065This review covers the isolation and structure determination of triterpenoids reported during 2013 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 350 references are cited.

Triterpenoids from the Schisandraceae family: an update

Plants from the Schisandraceae family produce architecturally interesting triterpenoids, including lanostanes, cycloartanes, and schinortriterpenoids. This review focuses on their structures, classifications, biogenetic pathways, syntheses, and bioactivities (from February 2008 to May 2014).