Epimeric (20R,20S)-Verazine Isolated from Veratrum maackii: Two-Dimensional NMR Studies and Total Assignment of 1H- and 13C-Resonances

Discovery of steroidal alkaloid glycosides from the bulbs of Fritillaria unibracteata with anti-inflammatory activities using an in vivo zebrafish model

Nine undescribed steroidal alkaloid glycosides, unibrasolanosides A-F, unibraverazosides A-B, and unibratomatoside A, were isolated from the bulbs of Fritillaria unibracteata P. K. Hsiao & K. C. Hsia (Liliaceae). Their structures were elucidated by HRESIMS and 1D and 2D NMR data analyses as well as chemical methods and single-crystal X-ray diffraction analyses. Further investigation revealed that eight steroidal alkaloid glycosides displayed moderate anti-inflammatory activity in vivo in a CuSO4-induced transgenic zebrafish model.

Review: Veratrum californicum Alkaloids

Veratrum spp. grow throughout the world and are especially prevalent in high mountain meadows of North America. All parts of Veratrum plants have been used for the treatment of ailments including injuries, hypertension, and rheumatic pain since as far back as the 1600s. Of the 17-45 Veratrum spp., Veratrum californicum alkaloids have been proven to possess favorable medicinal properties associated with inhibition of hedgehog (Hh) pathway signaling. Aberrant Hh signaling leads to proliferation of over 20 cancers, including basal cell carcinoma, prostate and colon among others. Six of the most well-studied V. californicum alkaloids are cyclopamine (1), veratramine (2), isorubijervine (3), muldamine (4), cycloposine (5), and veratrosine (6). Recent inspection of the ethanolic extract from V. californicum root and rhizome via liquid chromatography-mass spectrometry has detected up to five additional alkaloids that are proposed to be verazine (7), etioline (8), tetrahydrojervine (9), dihydrojervine (10), 22-keto-26-aminocholesterol (11). For each alkaloid identified or proposed in V. californicum, this review surveys literature precedents for extraction methods, isolation, identification, characterization and bioactivity to guide natural product drug discovery associated with this medicinal plant.

Steroidal alkaloids isolated from Veratrum grandiflorum Loes. as novel Smoothened inhibitors with anti-proliferation effects on DAOY medulloblastoma cells

Constitutive activation of Hedgehog (Hh) pathway is intimately related with the occurrence and development of several malignancies, such as medulloblastoma (MB) and other tumors. Therefore, small molecular inhibitors of Hh pathway are urgently needed. In this study, three new steroidal alkaloids, ⊿⁵ (20R, 24R) 23-oxo-24-methylsolacongetidine, ⊿⁵ (20S, 24R) 23-oxo-24-methylsolacongetidine and veralinine 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-D-glucopyranoside, together with six known alkaloids, 20-epi-verazine, verazine, protoverine 15-(l)-2'-methylbutyrate, jervine, veramarine and β1-chaconine, were isolated and determined from Veratrum grandiflorum Loes. The dual-luciferase bioassay indicated that all compounds exhibited significant inhibitions of Hh pathway with IC₅₀ values of 0.72-14.31 μM against Shh-LIGHT 2 cells. To determine whether these Hh pathway inhibitors act with the Smoothened (Smo) protein, which is an important oncoprotein and target for this pathway, BODIPY-cyclopamine (BC) competitive binding assay was preferentially performed. Compared with BC alone, all compounds obviously reduced the fluorescence intensities of BC binding with Smo in Smo-overexpression HEK293T cells through fluorescence microscope and flow cytometer. By directly interacting with Smo, it revealed that they were actually novel natural Smo inhibitors. Then, their anti-tumor effects were investigated against the human MB cell line DAOY, which is a typical pediatric brain tumor cells line with highly expressed Hh pathway. Interestingly, most of compounds had slight proliferation inhibitions on DAOY cells after treatment for 24 h same as vismodegib, while β1-chaconine showed the strongest inhibitory effect on the growth of DAOY with IC₅₀ value of 5.35 μM. In conclusion, our studies valuably provide several novel natural Smo inhibitors for potential targeting treatment of Hh-dependent tumors.

New Steroidal Alkaloids from Solanum Hypomalacophyllum

Two new steroidal alkaloids (1-2) have been isolated from the leaves and roots of Solanum hypomalacophyllum Bitter, respectively. Their structures have been elucidated as deacetoxysolaphyllidine-3- O-β-D-glucopyranoside (1) and 4-keto-5,6-dihydro-(20 S)-verazine (2). Furthermore, two known steroidal alkaloids, 20 R-verazine and 20 S-verazine, and the common secondary metabolites oleanolic acid and β-sitosterol were isolated from the roots, whereas deacetoxysolaphyllidine was obtained from the leaves.

Chemistry, bioactivity and geographical diversity of steroidal alkaloids from the Liliaceae family

Plants belonging to the Liliaceae family have been the topic of research in many phytochemical and pharmacological laboratories because they contain structurally complex and biologically fascinating steroidal alkaloids. This review, citing 153 references, summarises the chemistry, bioactivity and geographical diversity of steroidal alkaloids isolated from Veratrum and Fritillaria species, so as to illustrate the chemo-diversity and biological significance of these alkaloids, along with their geographical distribution where this is discernible.