Bioactive Lignans from Hypoestes aristata

Hypopurolides A - G, Labdane Diterpenoids from Hypoestes purpurea and Their Nitric Oxide Inhibitory Activity

Seven new labdane diterpenoids, hypopurolides A-G (1-7) were discovered from the aerial part of Hypoestes purpurea, along with one known analog, hypopurin D (8). The structures of 1-7 were characterized based on ¹ H-, ¹³ C-, and 2D-NMR, and HR-ESI-MS spectra. The absolute configurations of 1-7 were defined by single-crystal X-ray diffraction and electronic circular dichroism (ECD) data. Compounds 1-8 were tested for their nitric oxide (NO) inhibitory and cytotoxic effects. Compound 6 displayed moderate inhibitory effect toward LPS-induced NO release in RAW 264.7 cells with an IC₅₀ value of 41.50 μM.

The Cloke-Wilson rearrangement of aroyl-substituted donor-acceptor cylopropanes containing arylethyl donors

The chemistry of donor-acceptor (D-A) cyclopropanes containing alkyl donors has been scantily investigated. In the present work, we have synthesized new D-A cyclopropanes containing arylethyl donors and explored their reactivity in the presence of Lewis acids. Upon treatment with SnCl₄, these cyclopropanes underwent the Cloke-Wilson rearrangement to yield 3,4,5-trisubstituted γ-butyrolactones in good yields with high diastereoselectivity.

Phytochemical Profiling and Isolation of Bioactive Compounds from Leucosidea sericea (Rosaceae)

In the study, ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4-6, seven pentacyclic triterpenoids 7-13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16-22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC₅₀ values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.

Isolation and structural elucidation of bioactive obovatol dimeric neolignans from the bark of Magnolia officinalis var. biloba

(+)/(-)-Diobolignans A-F, six pairs of enantiomeric obovatol dimeric neolignans, were isolated from the bark of Magnolia officinalis var. biloba. (+)/(-)-Diobolignans A to C possessed a dioxane ring between the benzene ring and the propyl side chain, while (+)/(-)-diobolignans D to F possessed a furan ring. Meanwhile, (+)/(-)-diobolignans B and C, as well as (+)/(-)-diobolignans E and F, were two epimeric pairs of enantiomers, respectively. Their structures were determined by extensive analyses of HRESIMS, UV, IR, NMR and electronic circular dichroism (ECD) calculations. The bioassay showed (+)-diobolignan A displayed cytotoxic activities against human cancer cell lines HGC27 and HT29 with the IC₅₀ values of 9.43 and 9.45 μM, respectively. In addition, (-)-diobolignan A and (±)-diobolignan E showed neuroprotective effect on glutamic acid-induced cellular damage in SK-N-SH cell.

Dolominol a and B, two new neolignans from Dolomiaea souliei (Franch.) C.Shih

Two new neolignans, dolominol A (1) and dolominol B (2), together with 12 known lignans, erythro-(7S,8R)-guaiacyl-glycerol-β-O-4'-dihydroconiferyl ether (3), threo-(7R,​8R)-1-​(4-​hydroxy-​3-​methoxyphenyl)​-​2-{4-[(E)-​3-​hydroxy-​1-​propen​yl)​]-​2-​methoxyphenoxy}-1,​3-​propanediol (4), (-)-dihydrodehydrodiconiferyl alcohol (5), (-)-massoniresinol (6), vladinol D (7), syringaresinol (8), prinsepiol (9), medioresinol (10), (+)-pinoresinol (11), 2α-guaicyl-4-oxo-6α-catechyl-3,7-dioxabicyclo [3.3.0]octane (12), cycloolivil (13), isolariciresinol (14) were isolated from Dolomiaea souliei (Franch.) C.Shih. Their structures were determined by UV, CD, HR-ESI-TOFMS, 1 D and 2 D NMR experiments. Their hepatoprotective effect against LPS-induced L-02 cells injury was also studied. Result revealed that compound 4 showed best protective effect on LPS-induced L-02 cells.