Absolute configuration of labdane diterpenoids from Physalis nicandroides

Pseudoamaolide P, a 1,2:3,4:9,10:9,19-tetraseco-cycloartane triterpene spiroketal lactone from seeds of Pseudolarix amabilis

A 1,2:3,4:9,10:9,19-tetraseco-cycloartane triterpene spiroketal lactone, pseudoamaolide P (1), two new labdane-type diterpenoids, pseudoamains A and B (2-3), and four known cembrane-type diterpenoids (4-7) were isolated from the seeds of Pseudolarix amabilis. The structures of these compounds were elucidated by spectroscopic analyses, including HRESIMS, 1D-, and 2D-NMR. The anti-inflammatory activities of the compounds were evaluated by suppressing the transcription of the NF-κB-dependent reporter gene in LPS-induced 293 T/NF-κB-luc cells. All compounds do not show potent activity.

Withanolide-Type Steroids from Physalis nicandroides Inhibit HIV Transcription

The aim of the present study is to report the isolation, structural elucidation, and antiviral evaluation of four new withanolide-type steroids, named nicansteroidins A-D (1-4), together with nine related known compounds (5-13) isolated from the aerial parts of Physalis nicandroides. Their structures were established based on an extensive spectroscopic analysis, including 1D and 2D NMR techniques. Outstandingly, nicansteroidins A and B possess an unusual side chain with an exocyclic double bond on the δ-lactone system, whereas nicansteroidins C and D have an uncommon cycloperoxide functionality in ring A as distinct structural motifs. Their biological evaluation as inhibitors of human immunodeficiency virus type 1 replication revealed that two compounds from this series, 7 and 13, displayed strong inhibition of HIV-1 replication with IC₅₀ values lower than 2 μM. Moreover, cellular mechanism experiments showed that the main target of these compounds in the HIV replication cycle is viral transcription. This study is the first report of withanolide-type steroids as HIV inhibitors and provides insight into their potential as candidates for further preclinical studies.

Labdanes, Withanolides, and Other Constituents from Physalis nicandroides

Chemical investigation of the aerial parts (except fruits and calixes) of Physalis nicandroides var. attenuata led to the isolation of a series of new labdane-type diterpenoids, including the closely related compounds 1-3, the labdane glucosides 4 and 5, a mixture of the epimeric alcohols 6 and 7, and one labdanetriol, isolated as its tri-O-acetyl derivative 9. In addition, three new withanolides (14-16) and six known compounds were isolated. The structures of these compounds were elucidated by analysis of their spectroscopic data and chemical transformations, and those of compounds 1, 4, and 16 were confirmed by X-ray diffraction analysis of the natural product (1) and of the corresponding acetyl derivatives 4a and 16a. Fourteen of these compounds were assayed for their in vitro inhibitory activity against yeast α-glucosidase and acetylcholinesterase enzymes. The results were negative in both cases, except for compound 3a that marginally inhibited the activity of acetylcholinesterase with an IC₅₀ value of 64.4 μM.

Antiplasmodial Diterpenoids from Psiadia arguta

An ethyl acetate extract of Psiadia arguta leaves showed in vitro antiplasmodial activity against Plasmodium falciparum with IC₅₀ values of 12.3 ± 2.4 μg/mL (3D7 strain) and 13.5 ± 3.4 μg/mL (W2 strain). Phytochemical investigation led to the isolation and characterization of 16 compounds including four new diterpenoids: labdan-8α-ol-15-yl-(formate) (1), labdan-8α-ol-15-yl-(2-methylbutanoate) (2), labdan-8α-ol-15-yl-(3-methylpentanoate) (3), and labdan-8α-ol-15-yl-(labdanolate) (4). The latter compounds were characterized by spectroscopic methods (1D and 2D NMR, HRMS, and IR). The in vitro antiplasmodial activities of all compounds were evaluated. The known compounds labdan-13( E)-en-8α-ol-15-yl acetate (5), labdan-8α-ol-15-yl acetate (6), 13- epi-sclareol (7), labdan-13( E)-ene-8α,15-diol (8), and (8 R,13 S)-labdane-8α,15-diol (9) exhibited antiplasmodial effects, with IC₅₀ values of 29.1, 33.2, 35.0, 36.6, and 22.2 μM, respectively.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, pimaranes, abietanes, kauranes, cembranes and their cyclization products. The literature from January to December, 2015 is reviewed.

Anti-inflammatory labdane-type diterpenoids from Physalis angulata

Twelve new labdane-type diterpenoid glycosides were isolated from the stems and leaves of P. angulata.