Termitomenins F and G,Two New Lignan Glucosides from Terminalia chebula var.tomentella(Kurz)C.B.Clarke

The extensive chemical investigation on the branches and leaves of Terminalia chebula var.tomentella(Combretaceae)led to the isolation of two new lignan glucosides with a furofuran skeleton,termitomenins F(1)and G(2).In addition,19 known compounds including five lignan glucosides(3-7),six hydrolyzable tannins(8-13)and eight simple phenolics(14-21)were also identified.Their structures were determined by comprehensive spectroscopic analyses.It is noted that 8 and 9 were C-glycosidic hydrolyzable tannins with one hexahydroxydiphenoyl and one gallagyl group linked to an open-chain glucosyl C-1/O-2/O-3 and O-4/O-6,respectively,which were rarely found in plants.Nine known compounds,6-9,13,and 18-21,were procured from the titled plant for the first time,while 3-5,10-12 and 14-17 were also found in the fruits.Notably,the known hydrolyzable tannins 8-13 exhibited strongerα-glucosidase inhibitory activities with IC_(50) values ranging from 0.10 to 3.12μM,than the positive control,quercetin(IC_(50)=9.38±0.33μM).

(4S,4'S)-2,2'-(4,6-Dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole]-Ni(Ⅱ)Complexes Catalyzed Highly Enantioselective Nitrile Imine Cycloaddition Reactions

The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented.This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cy-cloadducts bearing one or two contiguous stereocenters in good yields(up to 97%yield)with high regioselectivities(100%)and enantioselectivities(up to 97.5%ee).Following that,chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process,additionally,toward five kinds of derivatization reac-tions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.

Suadimins D—J,Monoterpenoid Indole-Quinoline and Bisindole Alkaloids from Melodinus suaveolens

Comprehensive Summary,Compounds 1—12,including seven complex monoterpenoid indole-quinoline and bisindole alkaloids,suadimins D—J(1—7)with previously unreported carbon-carbon linkages,were isolated and identified from the twigs and leaves of Melodinus suaveolens.Their structures were elucidated by a combination of diverse methods,especially the extensive spectroscopic data analysis and electric circular dichroism(ECD)calculations.The cytotoxicity of these compounds against three cancer cell lines was evaluated,some of which showed moderate activities with IC50 values ranging from 2.4 to 8.0μM.

Asponchimides A−E: new enantiomeric N-acetyldopamine trimers from Aspongopus chinensis

Five new racemic N-acetyldopamine (NADA) trimers, asponchimides A−E ( 1 − 5 ), were isolated from Aspongopus chinensis, a prominent traditional Chinese medicinal insect employed for alleviating pain, treating indigestion, and addressing kidney ailments. Compounds 1 − 5 were successfully resolved by chiral high-performance liquid chromatography (HPLC), yielding five pairs of enantiomers: (+)- and (−)-asponchimides A−E ( 1a / 1b − 5a / 5b ). Their structural identities were discerned by extensive spectroscopic analyses, including high-resolution mass spectrometry (HRMS), ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR), and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. Compounds 1 − 5 are pioneering instances of NADA trimers featuring a Δ7 double bond. When subjected to a series of bioassays, a majority of the compounds exhibited weak inhibitory activity against nitric oxide (NO) production in LPS-induced RAW 264.7 cells.

Lignans with NO inhibitory activity from Tinospora sinensis

Two new lignan glucosides,tinsinlignans A and B(1 and 2),two new oxyneolignans,tinsinlignans C and D(3 and 4),along with one known analogue(5),were isolated from the stems of Tinospora sinensis.The structures of the new compounds were elucidated based on analysis of spectroscopic data,and the absolute configuration of 1 was determined through electronic circular dichroism(ECD)calculation based on the time-dependent density functional theory(TD-DFT).Compounds 1−4 were evaluated for their inhibitory effects on nitric oxide(NO)production induced by lipopolysaccharide(LPS)in murine RAW264.7 macrophage cells and compounds 1 and 2 exhibited moderate inhibitory activities with IC50 values of 18.5±2.0 and 28.8±1.2μmol·L^(−1),respectively.

Hyperisampsins N and O,two new benzoylated phloroglucinol derivatives from Hypericum sampsonii

Twenty-one benzoylated phloroglucinol derivatives bearing homoadamantyl frameworks were isolated from the aerial parts of Hypericum sampsonii,including two new ones named hyperisampsins N and O（1 and 2）.The structures of 1 and 2 were elucidated by extensive NMR and mass spectrometric analyses.Their absolute configurations were further determined by using TDDFT ECD calculations.Compounds 2,7,and 8 were evaluated for their cytotoxic activities against five human cancer cell lines,of which,2 and 8 exhibited significant cytotoxic activities toward HL-60 cell and moderate activities against others cell lines.

Macleayine,a new alkaloid from Madeaya cordata

Macleayine （1）, a new natural occurring alkaloid with a unique spiro [furanone-piperidinedione] framework, was isolated from the aerial parts ofMacleaya cordata. Its unusual structure was established by extensive spectroscopic analyses, computer-assisted structure elucidation software （ACD/Structure Elucidator）, quantum chemistry calculations and ECD calculation. The result of virtual molecular docking predicted the compound can enhance the effects of insulin, and may be used to treat tvpe II diabetes.

Five new terpenoids from Viburnum odoratissimum var.sessiliflorum

Five new terpenoids,including two vibsane-type diterpenoids(1,2)and three iridoid allosides(3-5),together with eight known ones,were isolated from the leaves and twigs of Viburnum odoratissimum var.sessiliflorum.Their planar structures and relative configurations were determined by spectroscopic methods,especially 2D NMR techniques.The sugar moieties of the iridoids were confirmed asβ-D-allose by GC analysis after acid hydrolysis and acetylation.The absolute configurations of neovibsanin Q(1)and dehydrovibsanol B(2)were determined by quantum chemical calculation of their theoretical electronic circular dichroism(ECD)spectra and Rh2(OCOCF_(3))_(4)-induced ECD analysis.The anti-inflammatory activities of compounds 1,3,4,and 5 were evaluated using an LPS-induced RA W264.7 cell model.Compounds 3 suppressed the release of NO in a dose-dependent manner,with an IC_(50) value of 55.64μmol·L^(-1).The cytotoxicities of compounds 1-5 on HCT-116 cells were assessed and the results showed that compounds 2 and 3 exhibited moderate inhibitory activities with IC_(50) values of 13.8 and 12.3μmol·L^(-1),respectively.