Structural characterizations andα-glucosidase inhibitory activities of four Lepidium meyenii polysaccharides with different molecular weights

Four polysaccharides(MCPa,MCPb,MCPc,MCPd)were obtained from Lepidium meyenii Walp.Their structures were characterized by chemical and instrumental methods including total sugar,uronic acid and protein content determi-nation,UV,IR and NMR spectroscopy,as well as monosaccharide composition determination and methylation analy-ses.Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa,and shared a similar backbone chain consisting of(1→4)-glucose linkages with branches attached to C-3 and C-6.Furthermore,bioactivity assay showed that MCPs had concentration-dependent inhibitory activity onα-glucosidase.MCPb(Mw=10.1 kDa)and MCPc(Mw=5.62 kDa)with moderate molecular weights exhibited higher inhibitory activ-ity compared with MCPa and MCPd.

Four undescribed pyrethrins from seeds of Pyrethrum cinerariifolium and their aphidicidal activity

Four undescribed pyrethrins C-F(1-4)as well as four known pyrethrins(5-8)were isolated from seeds of Pyrethrum cinerariifolium Trev.The structures of compounds 1-4 were elucidated by UV,HRESIMS,and NMR(^(1)H and ^(13)C NMR,^(1)H-^(1)H COSY,HSQC,HMBC and ROESY),among which the stereostructure of compound 4 was determined by calcu-lated ECD.Furthermore,compounds 1-4 were evaluated for their aphidicidal activities.The insecticidal assay results showed that 1-4 exhibited moderate aphidicidal activities at the concentration of 0.1 mg/mL with the 24 h mortality rates ranging from 10.58 to 52.98%.Among them,pyrethrin D(2)showed the highest aphidicidal activity,with the 24 h mortality rate of 52.98%,which was slightly lower than the positive control(pyrethrin II,83.52%).

New alkaloids from the fruiting bodies of Ganoderma sinense

Four new alkaloids,sinensines B-E(1-4),together with one known alkaloid,sinensine(5),were isolated from the fruiting bodies of Ganoderma sinense.Their structures were elucidated on the basis of 1D and 2D NMR spectra analysis.The structure of sinensine E was confirmed by X-ray crystallographic analysis of its acetyl product(4a).

Six New 9,19-Cycloartane Triterpenoids from Cimicifuga foetida L.

Six new 9,19-cycloartane triterpene derivatives,as well as 3 known analogues(7–9),were isolated from the roots of Cimicifuga foetida L.Their structures were established on the basis of extensive spectroscopic analyses(IR,UV,ORD,HRESIMS,1D and 2D NMR).

Progress on the Chemical Constituents Derived from Glucosinolates in Maca(Lepidium meyenii)

Maca(Lepidium meyenii Walp.),a famous food supplement,has drawn an unprecedented international interest over the last two decades.It was assumed that glucosinolates,macamides,macaenes,and alkaloids are the main bioactive components of Maca before.Recently,a series of novel thiohydantoins which generally exhibit a variety of activities have been isolated from Maca.This review focuses on the progress on the main bioactive components of Maca and their biosynthetic pathway,which indicates that macamides,thiohydantoins,and some alkaloids may originate from glucosinolates.Interestingly,thiohydantoins from Maca are the first type of thiohydantoin derivatives to be found from a natural source and may contribute to some significant effects of Maca.

New Dammarane Triterpenoids,Caffruones A–D,from the Cherries of Coffea arabica

In present study,four new dammarane-type triterpenoids,namely caffruones A–D(1–4),were isolated from the cherries of Coffea arabica.Their structures were elucidated by extensive spectroscopic analysis including 1D,2D NMR(HSQC,HMBC,^(1)H–^(1)H COSY,and ROESY),HRMS and IR spectra.This is the first time that tetracyclic triterpenes have been reported in genus Coffea.

Lactam Triterpenoids from the Bark of Toona sinensis

Three new limonoid-type triterpenoids,namely toonasins A–C(1–3)with a rare lactam E ring,along with six known compounds(4–9)were isolated from the barks of Toona sinensis.The structures of new compounds were elucidated by interpretation of spectroscopic data,and the relative configuration of compound 1 was further characterized by X-ray crystallographic analyses.The isolated compounds were evaluated for their cytotoxic activities against five human tumor cell lines(HL-60,SMMC-7721,A-549,MCF-7 and SW480),and compounds 3 and 5 showed weak cytotoxicities.

Characterization of New Ent-kaurane Diterpenoids of Yunnan Arabica Coffee Beans

Five new ent-kaurane diterpenoids,named mascaroside Ⅲ–Ⅴ(1–3),and 20-nor-cofaryloside Ⅰ–Ⅱ(4–5),together with seven known diterpenoids,were isolated from methanol extracts of the green coffee beans of Yunnan Arabica Coffee.Their chemical structures were elucidated by extensive spectroscopic analyses.Meanwhile,cytotoxicity assay against HL-60,A-549,SMMC-7721,MCF-7 and SW480 cell lines showed that they have not evident inhibition of cytotoxicity.

Triterpenoids and Sterols from the Leaves and Twigs of Melia azedarach

Two new triterpenoids(1 and 2)and a new sterol(3),together with six known constituents(4–9),were isolated from the leaves and twigs of Melia azedarach.Their chemical structures were elucidated on the basis of spectroscopic analysis.

Cucurbitane-Type Triterpene Glycosides from Momordica charantia and Their α-Glucosidase Inhibitory Activities

Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).

Applanoids A—E as the First Examples of C-15/C-20 Michael Adducts in Ganoderma Triterpenoids and Their PXR Agonistic Activity

Ganoderma triterpenoids(GTs),a class of major active constituents of Ganoderma fungi,possess diverse structures and remarkable activities.In the present study,nine new GTs,namely applanoids A—I(1—9),were isolated from the medicinal fungus of Ganoderma applanatum.Their structures including absolute configurations were established by comprehensive spectroscopic analyses and ECD calculation.Applanoids A—E(1—5)represent the first example of GTs with 6/6/5/6/5 pentacyclic system and the formation of the ether ring between C-15 and C-20 involves Michael addition reaction.Furthermore,compounds 1—8 were evaluated for their human pregnane X receptor(hPXR)agonistic activity using dual-luciferase reporter gene assay,and the results showed that compounds 1,2 and 4 can dose-dependently activate hPXR.This investigation further illustrated the structural diversity of GTs and provided new insights for searching PXR agonists from GTs.

Lepithiohydimerins A-D:Four Pairs of Neuroprotective Thiohydantoin Dimers Bearing a Disulfide Bond from Maca(Lepidium meyenii Walp.)

Main observation and conclusion An HPLC-UV-guided separation was performed and four pairs of unprecedented macathiohydantoin dimers,lepithiohydimerins A—D(1—4)bearing a rare disulfide bond were isolated from the tubers of Maca.Their structures were unambiguously confirmed by NMR spectroscopic,X-ray crystallographic and electronic circular dichroism(ECD)analyses.At the concentration of 20μmol/L,compounds 2-1,2-2,and 4-1 increased the viability of PC12 cells with the cell viability at(72.06±1.14)%,(72.64±1.49)%,and(70.93±1.22)%,respectively.Furthermore,the serial concentration experiment showed that they can protect PC12 cells in a dose-dependent manner.