Highly modified cephalotane-type diterpenoids from Cephalotaxus fortunei var. alpina and C. sinensis

Cephalotanes are a rare class of diterpenoids occurring exclusively in Cephalotaxus plants. The intriguing structures and promising biological activities for this unique compound class prompt us to investigate C. fortunei var. alpina and C. sinensis, leading to the isolation of six undescribed cephalotane-type diterpenoids and/or norditerpenoids, ceforloids A-F (1-6). Their structures were elucidated by comprehensive analysis of spectroscopic data, including ECD and single-crystal X-ray diffraction studies, as well as quantum chemical calculations. Compound 1 possesses an unprecedented norditerpenoid skeleton featuring an unusual acetophenone moiety, and originated putatively from a disparate biogenetic pathway. Compounds 4 and 5 incorporate a unique 12,13-p-hydroxybenzylidene acetal motif. Compound 6 is a rare cephalotane-type diterpenoid glycoside. Immunosuppressive assays showed that compounds 2 and 6 exhibited mild suppressive activity against the activated T and B lymphocytes proliferation. These findings not only expanded the structural diversity of this small group of diterpenoids, but also explored their potential as novel structures for the development of immunosuppressive agents.

Molecular Networking Accelerated Discovery of Biflavonoid Alkaloids from Cephalotaxus sinensis

Four undescribed biflavonoid alkaloids, sinenbiflavones A-D, were isolated from Cephalotaxus sinensis using a MS/MS-based molecular networking guided strategy. Their structures were elucidated by series of spectroscopic methods (HRESIMS, UV, IR, 1D, and 2D NMR). Sinenbiflavones A-D are the first examples of amentoflavone-type (C-3'-C-8'') biflavonoid alkaloids. Meanwhile, sinenbiflavones B and D are the unique C-6-methylated amentoflavone-type biflavonoid alkaloids. Sinenbiflavone D showed weak SARS-CoV-2 3CLpro inhibitory activity with 43% inhibition rate at 40 μM.

[Two novel cephalotaxine-type alkaloids from Cephalotaxus sinensis]

Silica gel, octadecyl-silica(ODS), Sephadex LH-20, and semi-preparative high performance liquid chromatography(HPLC) was performed to isolate nine cephalotaxine-type alkaloids from Cephalotaxus sinensis: 8-oxodeoxyharringtonine(1), 8-oxonordeoxyharringtonine(2), cephafortunine A(3), 8-oxocephalotaxine(4), deoxyharringtonine(5), acetylcephalotaxine(6), cephalotaxine(7), epicephalotaxine(8), and cephalotaxinone(9). Compounds 1 and 2 were identified for the first time and their structures were determined by high-resolution-electrospray ionization-mass spectrometry(HR-ESI-MS), nuclear magnetic resonance(NMR), and electronic circular dichroism(ECD). Compounds 1-3 and 5 significantly inhibited the transcription of nuclear factor kappa B(NF-κB), with the half-maximal inhibitory concentration(IC_(50)) of(3.91±0.70),(2.99±0.45),(7.84±0.51), and(1.46±0.17) μmol·L~(-1), respectively.

Attenuation of Biochemical Parameters in Streptozotocin-induced Diabetic Rats by Oral Administration of Extracts and Fractions of Cephalotaxus sinensis

Cephalotaxus sinensis (C. sinensis) large size, evergreen tree common in China and utilized for numerous effective pharmacological applications in Chinese traditional medicine. The hepato-renal effects of C. sinensis were evaluated in vivo using Streptozotocin (STZ)-induced diabetic rats as an tentative model. Animals were orally treated with 80% EtOH extract (aq.EE), H(2)O extract (WtE) and ethylacetate (EaF)/butanol fractions (BtF) of C. sinensis (200 mg/kg, b.w.) for 28 days whereas control received vehicle merely. The degree of fortification was measured by using biochemical parameters like serum transaminases (ALT and AST), alkaline phosphatase (ALP), creatinine, urea and urine sugar. Meanwhile, the histopathological studies were conducted out to support the above parameters. Administration of C. sinensis aq.EE/BtF (p<0.05) and EaF (p<0.01) patently prevented STZ-induced elevation levels of serum ALT, AST, ALP, creatinine, urea, urine sugar and increase body weight respectively, which were comparable with the standard drug tolbutamide, while WtE did not show any significant effect (p>0.05). Phytochemical studies revealed the presence of saponins, terpenes, sterols and flavonoids in C. sinensis which could be responsible for the possible hepato-renal protective action. The results sustain the fact that the extract/fractions of C. sinensis have an immense potential to be developed further into a phytomedicine.