Cytotoxic alkaloids of Pachysandra terminalis

Two new pregnane alkaloids from Pachysandra terminalis Sieb. et Zucc. and their cytotoxic activities

Pactermines E and F (1 and 2), two new pregnane alkaloids were isolated from the whole plant of Pachysandra terminalis Sieb. et Zucc. Their structures were determined by physicochemical properties and spectroscopic methods including 1D, 2D NMR, IR, HR-ESI-MS data. Cytotoxic activities against three human cancer A549, HCT116 and SW620 cell lines of the isolated compounds were evaluated by CCK8 method. However, all compounds showed no significant activity against the three cancer cells (IC50>100 μM) except for compound 1, which showed inhibitory effects against HCT116 cells with IC50 values of 84.6 μM.

Chemistry and bioactivities of natural steroidal alkaloids

Steroidal alkaloids possess the basic steroidal skeleton with a nitrogen atom in rings or side chains incorporated as an integral part of the molecule. They have demonstrated a wide range of biological activities, and some of them have even been developed as therapeutic drugs, such as abiraterone acetate (Zytiga^®), a blockbuster drug, which has been used for the treatment of prostate cancer. Structurally diverse natural steroidal alkaloids present a wide spectrum of biological activities, which are attractive for natural product chemistry and medicinal chemistry communities. This review comprehensively covers the structural classification, isolation and various biological activities of 697 natural steroidal alkaloids discovered from 1926 to October 2021, with 363 references being cited.

3-Epipachysamine B suppresses proliferation and induces apoptosis of breast cancer cell via PI3K/AKT/mTOR signaling pathway

3-Epipachysamine B is a natural steroidal alkaloid isolated from Pachysandra terminalis Sieb. et Zucc. (known locally as Kunxianqi). Kunxianqi contains numerous compounds with demonstrated activity against breast cancer (BRCA). However, it is unknown whether 3-epipachysamine B also has anti-BRCA efficacy. In the present study, we employed network pharmacology technology to search and find potential molecular targets of 3-epipachysamine B. We applied cell proliferation, apoptosis, and western blotting assays to test the predicted key targets and the effects of 3-epipachysamine B against BRCA. Network pharmacology disclosed 80 potential BRCA-related targets of 3-epipachysamine B and assigned them to 75 signaling pathways. Of these, the most highly enriched was the PI3K/AKT signaling pathway. PIK3R1, AKT1, and mTOR had high degrees and betweenness centrality in protein-protein interaction network and are associated with PI3K/AKT signaling. Molecular docking and molecular dynamics simulation indicated strong binding between 3-epipachysamine B and PIK3R1, AKT1, and mTOR. 3-Epipachysamine B repressed the proliferation and induced the apoptosis of BRCA cells, as well as downregulated P-AKT/AKT, P-mTOR/mTOR, and P-PI3K/PI3K in the cells. The PI3K inhibitor LY294002 augmented these changes. Hence, 3-epipachysamine could also prove effective as an anticancer agent in future animal tumor model and human clinical breast cancer trials. Successful validation results could lead to a safe and effective new breast cancer treatment that improves patient prognosis and quality of life.

The Alkaloid-Enriched Fraction of Pachysandra terminalis (Buxaceae) Shows Prominent Activity against Trypanosoma brucei rhodesiense

In the course of our studies on antiprotozoal natural products and following our recent discovery that certain aminosteroids and aminocycloartanoid compounds from Holarrhena africana A. DC. (Apocynaceae) and Buxus sempervirens L. (Buxaceae), respectively, are strong and selective antitrypanosomal agents, we have extended these studies to another plant, related to the latter-namely, Pachysandra terminalis Sieb. and Zucc. (Buxaceae). This species is known to contain aminosteroids similar to those of Holarrhena and structurally related to the aminocycloartanoids of Buxus. The dicholoromethane extract obtained from aerial parts of P. terminalis and, in particular, its alkaloid fraction obtained by acid-base partitioning showed prominent activity against Trypanosoma brucei rhodesiense (Tbr). Activity-guided fractionation along with extended UHPLC-(+)ESI QTOF MS analyses coupled with partial least squares (PLS) regression modelling relating the analytical profiles of various fractions with their bioactivity against Tbr highlighted eighteen constituents likely responsible for the antitrypanosomal activity. Detailed analysis of their (+)ESI mass spectral fragmentation allowed identification of four known constituents of P. terminalis as well as structural characterization of ten further amino-/amidosteroids not previously reported from this plant.

Two new pregnane alkaloids from Pachysandra terminalis Sieb. et Zucc

Two new pregnane alkaloids, (20S)-20α-cinnamoylamino-3β-dimethylamino-5-en-pregnane (1) and (20S)-20α-cinnamoylamino-3β-dimethylamino-pregnane (2), and four known alkaloids (+)-(20S)-20-(dimethylamino)-3-(3'R-isopropyl)-lactam-5α-pregn-2-en-4-one (3), axillaridine A (4), pachysamine M (5) and 20α-dimethylamino-16β-hydroxy-3β-senecioylamino-pregn-5-ene (6) were obtained from the whole herb of Pachysandra terminalis Sieb. et Zucc. Their structures were determined by various spectral techniques and computed electronic circular dichroism (ECD) data. Compounds 1-4 were tested for cytotoxicity against three human tumor cell lines and a human umbilical vein endothelial cell (HUVEC) line. Compound 4 exhibited moderate cytotoxicity against MCF-7, U251 and A549 cells with IC₅₀ values of 15.01 ± 0.47 μM, 20.13 ± 1.34 μM and 20.04 ± 1.16 μM, respectively; compounds 1-3 showed weak cytotoxic activity against three tumor cells.

4-dehydroxyepisarcovagine A, a new steroidal alkaloid from Sarcococca pruniformis Lindl

A new steroidal alkaloid, 4-dehydroxyepisarcovagine A (1), along with seven known alkaloids, sarcovagine D (2), sarcovagenine C (3), epoxysarcovagenine D (4), Pachysamine L (5), Pachysamine E (6), sarcovagine A (7) and sarcovagine B (8), was isolated from the roots and stems of Sarcococca pruniformis Lindl. The structure of compound 1 was elucidated by means of spectroscopic analysis.

Terminamines K-S, Antimetastatic Pregnane Alkaloids from the Whole Herb of Pachysandra terminalis

Nine new pregnane alkaloids (1-9), together with eight known alkaloids (10-17), were isolated from the whole herb of Pachysandra terminalis. Their structures were elucidated on the basis of spectroscopic analyses. In addition, the isolates were examined for their ability to inhibit the migration of MDA-MB-231 cells induced by the chemokine epidermal growth factor (EGF). Alkaloids 1, 5, 7, 9, 12, and 17 presented significant anti-metastasis activities compared with the positive reagent, LY294002.

Therapeutic Potential of Steroidal Alkaloids in Cancer and Other Diseases

Steroidal alkaloids are a class of secondary metabolites isolated from plants, amphibians, and marine invertebrates. Evidence accumulated in the recent two decades demonstrates that steroidal alkaloids have a wide range of bioactivities including anticancer, antimicrobial, anti-inflammatory, antinociceptive, etc., suggesting their great potential for application. It is therefore necessary to comprehensively summarize the bioactivities, especially anticancer activities and mechanisms of steroidal alkaloids. Here we systematically highlight the anticancer profiles both in vitro and in vivo of steroidal alkaloids such as dendrogenin, solanidine, solasodine, tomatidine, cyclopamine, and their derivatives. Furthermore, other bioactivities of steroidal alkaloids are also discussed. The integrated molecular mechanisms in this review can increase our understanding on the utilization of steroidal alkaloids and contribute to the development of new drug candidates. Although the therapeutic potentials of steroidal alkaloids look promising in the preclinical and clinical studies, further pharmacokinetic and clinical studies are mandated to define their efficacy and safety in cancer and other diseases.

Structures, semisyntheses, and absolute configurations of the antiplasmodial α-substituted β-lactam monamphilectines B and C from the sponge Svenzea flava

Bioassay-guided fractionation of the Caribbean sponge Svenzea flava collected near Mona Island, off the west coast of Puerto Rico, led to the isolation of two isocyanide amphilectane-type diterpenes named monamphilectines B and C (2 and 3). Attached to the backbone of each of these compounds is the first α-substituted monocyclic β-lactam ring to be isolated from a marine organism. The molecular structures of 2 and 3 were established by spectroscopic methods and then confirmed unequivocally by chemical correlation and comparison of physical and chemical data with the natural products. The new β-lactams were successfully synthesized in one step, starting from the known diisocyanide 4, via parallel Ugi four-center three-component reactions (U-4C-3CR) that also established their absolute stereostructures. Interestingly, compounds 2 and 3 exhibited activities in the low nanomolar range against the human malaria parasite Plasmodium falciparum.

Alkaloids from Pachysandra terminalis inhibit breast cancer invasion and have potential for development as antimetastasis therapeutic agents

The aim of the present study was to identify potentially useful natural compounds for the development of novel therapeutic agents to inhibit metastasis. A phytochemical investigation of Pachysandra terminalis resulted in the isolation of seven new pregnane alkaloids, terminamines A-G (1-7), and seven known alkaloids (8-14). The structures of 1-7 were elucidated by 1D- and 2D-NMR spectroscopic and mass spectrometric methods. Compounds 1-5 and 8-14 inhibited the migration of MB-MDA-231 breast cancer cells induced by the chemokine epithelial growth factor. In addition, compound 1 inhibited phosphorylation of integrin β(1), which plays an important role in MB-MDA-231 cell adhesion and metastasis.