An updated review of the genus Rhododendron since 2010: Traditional uses, phytochemistry, and pharmacology.

Rhododendron, the largest genus of Ericaceae, consists of approximately 1000 species that are widely distributed in Europe, Asia, and North America but mainly exist in Asia. Rhododendron plants have not only good ornamental and economic value but also significant medicinal potential. In China, many Rhododendron plants are used as traditional Chinese medicine or ethnic medicine for the treatment of respiratory diseases, pain, bleeding and inflammation. Rhododendron is known for its abundant metabolites, especially diterpenoids. In the past 13 years, a total of 610 chemical constituents were reported from Rhododendron plants, including 222 diterpenoids, 122 triterpenoids, 103 meroterpenoids, 71 flavonoids and 92 other constituents (lignans, phenylpropanoids, phenolic acids, monoterpenoids, sesquiterpenoids, coumarins, steroids, fatty acids). Moreover, the bioactivities of various extracts and isolates, both in vitro and in vivo, were also investigated. Our review summarized the research progress of Rhododendron regarding traditional uses, phytochemistry and pharmacology in the past 13 years (2010 to December 2022), which will provide new insight for prompting further research on Rhododendron application and drug development.

Structurally diverse lanostane triterpenoids from medicinal and edible mushroom Ganoderma resinaceum Boud.

Ganoderma resinaceum is a multi-purpose herbal medicine that is homologous to functional food that has long been used for enhancing health and treating chronic hepatopathy in Traditional Chinese Medicine. In a search program to discover the key bioactive composition of G. resinaceum, sixteen new lanostane-type triterpenoids (1-16), and twenty known analogues (17-36) were isolated from the fruiting bodies of G. resinaceum. Spectroscopic analyses and X-ray crystallography were used to determine the new structures. Furthermore, the spectroscopic properties of 15ß-hydroxy-4,4,14α- trimethyl-3,7,11,20-tetraoxo-5α-pregn-8-ene (15) and 15α-hydroxy-4,4,14α-trimethyl- 3,7,11,20-tetraoxo-5α-pregn-8-ene (34) indicated a potential structural misassignment of their analogues, lucidone E and lucidone H, reported previously. To probe this hypothesis, ROESY experiments and single-crystal X-ray diffraction analysis were conducted. These results undoubtedly reassigned the structure of lucidone E and lucidone H. Biological evaluation of the selected compounds disclosed that compounds 3, 4, 7/21, 11, 12, 13/14, 17, 18, 24/25, 27, 30, 31, and 35 had significant hepatoprotective activities, due to their remarkable in vitro inhibitory activities against the increase of ALT and AST levels in HepG2 cells induced by H2O2.

Lactam ent-Kaurane Diterpene: A New Class of Diterpenoids Present in Roasted Beans of Coffea arabica.

Seven new lactam ent-kaurane diterpenoids, cafemides A-G (1-7), were isolated from roasted beans of Coffea arabica. Their structures were elucidated by extensive spectroscopic analysis including 1D, 2D NMR (heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), 1H-1H correlation spectroscopy (COSY), and rotating frame Overhauser effect spectroscopy (ROESY)), high-resolution electrospray ionization mass spectrometry (HRESIMS), and IR spectra. They were divided into subtype I-III according to the structure. Further, with the aid of liquid chromatography-tandem mass spectrometry (LC-MS/MS) based molecular network, seven (8-14) subtype II diterpenoids were successfully identified. In addition, a variety of other subtypes of N-containing diterpenoids have been proven in roasted coffee. Compounds 1, 2, 3, 5, and 7 showed a moderate inhibitory effect on α-glucosidase with an IC50 value of 8.28 ± 0.62 µM, 38.23 ± 8.87 µM, 28.94 ± 1.42 µM, 12.44 ± 1.37 µM, and 22.2 ± 5.34 µM, respectively. To the best of our knowledge, this is the first time that N-containing diterpenoids have been reported in coffee.

Lanostane triterpenoids with anti-inflammatory activities from Ganoderma lucidum.

Ganoderma lucidum is one of the most famous medicinal fungi and is traditional Chinese medicine with various biological activities in Asian countries. To clarify its pharmacodynamic material basis, 15 lanostane triterpenoidswere obtained from the fruiting bodies of G. lucidum, including 8 previously undescribed lanostanoids. Their structures, including absolute configuration, were established based on ultraviolet, infrared, high-resolution electrospray ionisation mass spectrometry, 1D and 2D nuclear magnetic resonance, and X-ray crystallographic analysis. Ganoluciduone A was an unusual octonorlanostane, which was isolated from Ganoderma for the first time. In addition, the anti-inflammatory activities of all isolates were evaluated by observing their inhibitory effects on nitric oxide production in RAW264.7 cells activated by a lipopolysaccharide. Ganoluciduone B exhibited moderate inhibitory activity on nitric oxide production, with an inhibition rate of 45.5% at a concentration of 12.5 µM.

C30 and C31 Triterpenoids and Triterpene Sugar Esters with Cytotoxic Activities from Edible Mushroom Fomitopsis pinicola (Sw. Ex Fr.) Krast.

Fomitopsis pinicola (Sw. Ex Fr.) Krast has been commonly used as a health food source and antitumor agent. To uncover bioactive key composition of F. pinicola, in our study, we investigated the chemical constituents of a methanol extract of F. pinicola and thirty-five lanostane-type tritetpenoids; 13 new compounds (1-13) and twenty-two known analogues (14-35) were isolated. Among them, compounds 1-9 were C30 lanostane triterpenoids and triterpene sugar esters, while compounds 10-13 were C31 triterpenoids and triterpene sugar esters. Their structures and absolute configurations were elucidated by extensive 1D, 2D NMR, MS, and IR spectra. Furthermore, cytotoxic activities of all isolates against five human tumor cell lines (HL-60, A549, SMMC-7721, MCF-7, and SW480) were evaluated. The results showed that compounds 12, 14, 17, 18, 22, and 23 displayed cytotoxic effects against five human tumor cell lines with IC50 values ranging from 3.92-28.51 µM. Meanwhile, compounds 9 and 35 exhibited selected inhibitory activities against HL-60, SMMC-7721, and MCF-7 with IC50 values in the range of 13.57-36.01 µM. Furthermore, the flow cytometry analysis revealed that compounds 17, 22, and 35 induced apoptosis in HL-60 cell lines. Their structure-activity relationships were preliminarily reported. These findings indicate the vital role of triterpenoids and their glycosides in explaining antitumor effects of F. pinicola and provide important evidence for further development and utilization of this fungus.

[Study on chemical constituents of seeds of Croton tiglium and their cytotoxicities].

Seven compounds were isolated from the seeds of Croton tiglium by preparative TLC, semi-preparative HPLC, and column chromatography over silica gel, MCI, and Sephadex LH-20, etc. Their structures were elucidated by spectroscopic data analysis as bis(2,3-dihydroxypropyl) nonanedioate (1), 12-O-(α-methyl)butyrylphorbol-13-decanoate (2), 12-O-tiglylphorbol-13-decanoate (3), (9S,10R,11E,13R)-9,10,13-trihydroxyoctadec-11-enoic acid (4), methyl (9S,10R,11E,13R)-9,10,13-trihydroxyoctadec-11-enoate (5), 4(1H)-quinolinone (6), and 5-hydroxy-2-pyridinemethanol (7). Compound 1 was a new compound and compounds 4-7 were isolated from family Euphorbiaceae for the first time. Compounds 2 and 3 showed cytotoxic activities against human lung cancer cell line A549 with IC50 values of 47.8 and 7.0 µmol•L ⁻¹, respectively, and against human hepatocarcinoma cell line HepG2 with IC50 values of 71.4 and 44.0 µmol•L ⁻¹, respectively.