Isolation and structure elucidation of alkaloids from the bulb of Fritillaria wabuensis

Cevanine-type alkaloids from the bulbs of Fritillaria unibracteata var. wabuensis and their antifibrotic activities in vitro

Steroidal alkaloids are the main bioactive components of the bulbs of Fritillaria, which have been used as traditional Chinese medicine, known as "Beimu", for the treatment of cough for thousands of years in China. Cough and dyspnea are the most common symptoms observed in patients with pulmonary fibrosis. However, the antifibrotic activity of steroidal alkaloids has not been reported yet. In this study, two previously unreported cevanine-type steroidal alkaloids (1 and 2), four previously undescribed cevanine-type alkaloid glycosides (3-6), and 19 known steroidal alkaloids (7-25) were isolated from the bulbs of Fritillaria unibracteata var. wabuensis. The structures of these compounds were elucidated by comprehensive HRESIMS and NMR spectroscopic data analysis, as well as DP4+ NMR calculations. The biological evaluation showed that compounds 2, 7-10, 14, 15, and 17 downregulated fibrotic markers induced by transforming growth factor-β (TGF-β) in MRC-5 cells. Moreover, compounds 14 and 17 dose dependently inhibited TGF-β-induced epithelial-mesenchymal transition in A549 cells, alleviated TGF-β-induced migration and proliferation of fibroblasts, and decreased the expression of fibrotic markers, fibronectin, and N-cadherin in TGF-β-induced MRC-5 cells. The research showed the potential of cevanine-type alkaloids as a class of natural antifibrotic agents.

Alkaloids from Fritillaria przewalskii Bulbs and Their Anti-Alzheimer's Disease Activities

Three undescribed isosteroidal alkaloids, przewalskines A-C (1-3), as well as seven known alkaloids (4-10) were obtained from Fritillaria przewalskii bulbs. Their structures were deduced by extensive HRESIMS, 1D NMR, and 2D NMR analyses, and their bioactivities were evaluated involving the anti-inflammatory and inhibitory potencies on AChE, BChE, and Aβ aggregation. Compound 4 revealed the potent effect on inhibiting Aβ aggregation activity with IC50 value of 33.1 μM, AChE activity with IC50 value of 6.9 μM, and also showed NO release inhibitory acitivity with IC50 value of 32.6 μM. These findings contribute new multi-.target anti-AD agents and embody the chemical diversity of F. przewalskii.

Antitussive, expectorant and anti-inflammatory activities of four alkaloids isolated from Bulbus of Fritillaria wabuensis

ETHNOPHARMACOLOGICAL RELEVANCE

Bulbus Fritillaria Cirrhosae (BFC), known by the Chinese name "Chuan-Bei-Mu", is used as an antitussive, antiasthmatic and expectorant drug for more than 2000 years in China, and Bulbus of Fritillaria wabuensis S. Y. Tang & S. C. Yueh (BFW) was recorded in the 2010 edition of China Pharmacopoeia as one of sources for BFC. The primary objective of this study was to evaluate the antitussive, expectorant and anti-inflammatory effects of alkaloids - imperialine, imperialine-β-N-oxide, isoverticine, and isoverticine-β-N-oxide, which were isolated from BFW, and to provide experimental evidence for its traditional use.

MATERIALS AND METHODS

The alkaloids were isolated using phytochemical methods, and their structures were determined by spectroscopic analysis. Their antitussive effects were measured using murine model of ammonia induced cough, the expectorant effects were evaluated by measuring mice's tracheal phenol red output, and the anti-inflammatory effects were assessed by using the murine model of xylene induced ear edema.

RESULTS

The structures of the four alkaloids - imperialine, imperialine-β-N-oxide, isoverticine, and isoverticine-β-N-oxide isolated from BFW were confirmed. The four alkaloids significantly inhibited cough frequency and increased latent period of cough in mice induced by ammonia. Imperialine and isoverticine showed obviously antitussive activities in a dose-dependent manner. Besides, the four alkaloids markedly enhanced mice's tracheal phenol red output in expectorant assessment and significantly inhibited the development of ear edema in anti-inflammatory evaluation assay. Moreover, significant differences were found between the structure-activity relationships of the four alkaloids.

CONCLUSIONS

The four alkaloids exhibited significant antitussive, expectorant and anti-inflammatory activities. We suggest that they may be the active ingredients of BFW. The results of the present study provided evidence for BFW to be used as an antitussive and expectorant Traditional Chinese Medicine (TCM).

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.