Aglycone Of Compound Research Articles

Arvensic acids K and L, components of resin glycoside fraction from Convolvulus arvensis

Alkaline hydrolysis of the resin glycoside fraction of the whole plants of Convolvulus arvensis gave two new glycosidic acids, named arvensic acids K and L (1 and 2). Their structures were characterized on the basis of spectroscopic data as well as chemical evidence. They possessed a same pentasaccharide chain, composed of one D-fucose, three D-glucose and one L-rhamnose units. The aglycone of compound 1 was identified to be rarely existing 11S-hydroxyheptadecanoic acid, while compound 2 possessed 11S-hydroxyhexadecanoic acid as the aglycone. Their cytotoxic and anti-migration activities were also evaluated.

A new triterpenoid saponin from Pulsatilla cernua predicted by NMR-based mosaic method

A saponin (1) with gypsogenin as aglycone was isolated from the roots of Pulsatilla cernua. The aglycone of compound 1 was considered as gypsogenin which was rarely found in this genus. Its structure was predicted by NMR-based “mosaic” method rapidly, and further confirmed on the basis of spectroscopic data, including 2D NMR spectra and chemical evidence. This work suggested that NMR-based mosaic method is suitable for most of saponins from common species of genus Pulsatilla.

Two new C21 steroidal glycosides isolated from Cynanchum komarovii

The present study was designed to further investigate the C21 steroidal glycosides in Cynanchum plants. Two new steroidal glycosides based on a 13, 14:14, 15-disecopregnane-type aglycone, komaroside P (1) and komaroside Q (2), together with three known compounds (3–5) were isolated from the whole herbs of Cynanchum komarovii. The aglycones of compounds 1 and 2 were two new disecopregnane. Their structures were elucidated on the basis of 1D, 2D NMR spectroscopic data and acid hydrolysis. All the compounds (1–5) showed potent inhibitory activities against human leukemia cell lines (HL-60) with IC50 values ranging from 16.6 to 26.3 μmol·L−1, compared to the positive control 5-fluorouracil (6.4 μmol·L−1).

Furostane Series Asterosaponins and Other Unusual Steroid Oligoglycosides from the Tropical Starfish Pentaceraster regulus.

Seven new asterosaponins, pentaregulosides A-G (1-7), including two furostane-type steroid oligoglycosides (2, 3), along with four previously known compounds (8-11) were isolated from the ethanolic extract of the starfish Pentaceraster regulus, collected off the coast of Vietnam. The structures of 1-7 were elucidated by extensive NMR and ESIMS techniques as well as chemical transformations. The aglycons of compounds 1 and 3 have not previously been observed in starfish steroid oligoglycosides, while the aglycons of compounds 2 and 4-6 are very rare for this structural group. Compound 1 exhibited cytotoxic activity with an IC50 value of 6.4 ± 0.3 μM against RAW 264.7 murine macrophages. In contrast, nontoxic asterosaponins 3, 4, and 5 showed a potential immunomodulatory action at a concentration of 5 μM, reducing by 40%, 28%, and 55%, respectively, reactive oxygen species formation in the RAW 264.7 cells, co-stimulated with the pro-inflammatory endotoxic lipopolysaccharide from E. coli.

The cytotoxic and tyrosine kinase inhibitory properties of C21 steroids and iridoids from the tubers of Alocasia cucullata.

Ten steroids and iridoids were isolated from the tubers of Alocasia cucullata (Lour.) G. Don. Among them, alocasgenin A (1) and alocasgenoside B-C (2-3) were new compounds and the aglycone of compound 1, obtained from the acid hydrolysis of 1, was named alocasgenol (1a). Also, for the first time, tenacigenin B (4), 17β-tenacigenin-B (5), 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-tenacigenin C (6), marsdenoside A-B (7-8) and tenacigenoside A-B (9-10) were isolated from the genus Alocasia. The chemical structures were elucidated by the extensive analysis of spectral data and compared with the literature. By evaluation of the cytotoxic and tyrosine kinase inhibition, compounds 1-10, 1a and compound 2 showed significant growth inhibition against two tumour cell lines, MGC-803 and HT-29, while compounds 1, 1a, 3, 6 and 8 presented moderate inhibition. Furthermore, compound 2 had the inhibitory property against the enzyme activity biochemically.

Structure-activity relationships of 3-O-β-chacotriosyl oleanane-type triterpenoids as potential H5N1 entry inhibitors

A series of 3-O-β-chacotriosyl oleanolic acid analogs have been designed, synthesized and evaluated as H5N1 entry inhibitors based on a small molecule inhibitor saponin 1 previously discovered by us. Detailed structure-activity relationships (SARs) studies on the aglycone of compound 1 indicated that the subtle modification of oleanolic acid as an aglycon has key influences on the antiviral activity. These results suggested that either the introduction of a disubstituted amide structure at the 17-COOH of OA or alteration of the C-3 configuration of OA from 3β-to 3α-forms can significantly improve the selective index while maintaining their antiviral activities in vitro. Compound 8 was selected for further mechanistic study because of its distinguished inhibition activity and good selective index. Molecular simulation study and surface plasmon resonance analysis confirmed that compound 8 stabilized HA2 subunit of hemagglutinin (HA) by binding with amino acid residues LYS-26, ASN-53, ASN-27 and ASN-50, therefore may prevent HA from conformational rearranging, which is a critical step for viral entry.

Cycloartane and oleanane-type glycosides from Astragalus pennatulus

Four new cycloartane and one new oleanane-type glycosides were isolated from Astragalus pennatulus along with five known cycloartane-type glycosides. The structures of the new compounds were established as 3-O-β-D-xylopyranosyl-6-O-β-D-glucopyranosyl-3β,6α,16β-trihydroxy-24-oxo-20(R),25-epoxycycloartane (1), 3-O-[β-D-glucuronopyranosyl-(1→2)-β-D-xylopyranosyl]-3β,16β,24α-trihydroxy-20(R),25-epoxycycloartane (2), 3-O-[β-D-glucuronopyranosyl-(1→2)-β-D-xylopyranosyl]-3β,16β,25-trihydroxy-20(R),24(S)-epoxycycloartane (3), 3,25-di-O-β-D-glucopyranosyl-6-O-β-D-xylopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), 29-O-α-L-rhamnopyranosyl-abrisapogenol B (5) by 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. The aglycone of compound 1, 3β,6α,16β-trihydroxy-24-oxo-20(R),25-epoxycycloartane, is reported for the first time. The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. None of the tested compounds caused a significant reduction of the cell number.

Structure–activity relationships of 3-O-β-chacotriosyl ursolic acid derivatives as novel H5N1 entry inhibitors

A series of methyl ursolate 3-O-β-chacotrioside analogs have been designed, synthesized and evaluated as H5N1 entry inhibitors based on a small molecule inhibitor saponin 3 previously discovered by us. Detailed structure–activity relationships (SARs) studies on the aglycone of compound 3 indicated that both the type of pentacyclic triterpene and the subtle modification of ursolic acid as an aglycon had key influences on the antiviral activity. These results suggested that either the introduction of a disubstituted amide structure at the 17-COOH of ursolic acid or alteration of the C-3 configuration of ursolic acid from 3β-to 3α-forms was helpful to significantly improve the selective index while keeping their antiviral activities.

Steroidal saponins with induced platelet aggregation activity from the aerial parts of Paris verticillata

In order to utilize and protect the resources of Rhizoma Paridis rationally, we carried out a phytochemical investigation on the non-medicinal (aerial) parts of Paris verticillata that led to the isolation of fifteen steroidal saponins. Among them, three are new spirostanol saponins, named parisverticosides A–C (1–3), as well as one new cholestane glycoside, named parisverticoside D (4). Their structures were elucidated by extensive spectroscopic analysis and acid hydrolysis. The aglycone of compound 1 is a new spirostane and identified as (23S,24S,25S)-spirost-5-en-1β,3β,23, 24-tetraol. The selected isolates were evaluated for induced platelet aggregation activity and compound 5 showed 62% maximal platelet aggregation rate at the concentration of 300μg/mL.

Chemical constituents from the fibrous root of Ophiopogon japonicus, and their effect on tube formation in human myocardial microvascular endothelial cells

In an effort to identify novel active constituents on the cardiovascular system, a systematic study on macroporous resin adsorption of extracts from the fibrous root of Ophiopogon japonicus was performed in a human myocardial microvascular endothelial cell line (HMMEC) based assay. One novel spirostan, named ophiogenin (1), together with six known spirostans (4–8, 10), and one new sesquiterpene glycoside, named ophioside A (2), together with one known monoterpene glycoside (9) were isolated from the active fractions, and the aglycone of compound 2 that was a new natural compound was obtained from the acid hydrolysis of 2, named ophiopogonol (3). Their structures were determined by spectral and chemical analyses. Furthermore, their effect on HMMEC tube formation was also determined. Our results indicated that compounds 4 and 8 could significantly improve the tube formation and 2 showed moderate increasing effect, while compound 5 exhibited potent inhibitory effect.

Steroidal Glycosides from the Rhizomes ofAnemarrhena asphodeloidesand Their Antiplatelet Aggregation Activity

Five new steroidal glycosides, timosaponin J ( 1), timosaponin K ( 2), (25 S)-karatavioside C ( 5), timosaponin L ( 6), and (25 S)-officinalisnin-I ( 8), together with eight known steroidal saponins, timosaponin E (1) ( 3), purpureagitosid ( 4), timosaponin BII ( 7), timosaponin B III ( 9), anemarrhenasaponin I ( 10), anemarrhenasaponin III ( 11), anemarrhenasaponin A (2) ( 12), and timosaponin A III ( 13), were isolated from the rhizomes of Anemarrhena asphodeloides. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The aglycones of compounds 1 and 2 are new aglycones. Compounds 1- 13 were evaluated for their platelet aggregation activities, and compound 13 exhibited the strongest inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation.

Isolation and characterization of structurally novel antimutagenic flavonoids from spinach (Spinacia oleracea).

Thirteen compounds, isolated from spinach (Spinacia oleracea), acted as antimutagens against the dietary carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline in Salmonella typhimurium TA 98. The antimutagens were purified by preparative and micropreparative HPLC from a methanol/water (70:30, v/v) extract of dry spinach (commercial product) after removal of lipophilic compounds such as chlorophylls and carotenoids by solid-phase extraction (SPE). Pure active compounds were identified by instrumental analysis including FT-IR, (1)H and (13)C NMR, UV-vis spectroscopy, and mass spectrometry. All of these compounds were flavonoids and related compounds that could be attributed to five groups: (A, methylenedioxyflavonol glucuronides) 5,3'-dihydroxy-4'-methoxy-6,7-methylenedioxyflavonol 3-O-beta-glucuronide (compound 1), 5,2',3'-trihydroxy-4'-methoxy-6,7-methylenedioxyflavonol 3-O-beta-glucuronide (compound 2), 5-hydroxy-3',4'-dimethoxy-6,7-methylenedioxyflavonol 3-O-beta-glucuronide (compound 3); (B, flavonol glucuronides) 5,6,3'-trihydroxy-7,4'-dimethoxyflavonol 3-O-beta-glucuronide (compound 4), 5,6-dihydroxy-7,3',4'-trimethoxyflavonol 3-O-beta-glucuronide (compound 5); (C, flavonol disaccharides) 5,6,4'-trihydroxy-7,3'-dimethoxyflavonol 3-O-disaccharide (compound 6), 5,6,3',4'-tetrahydroxy-7-methoxyflavonol 3-O-disaccharide (compounds 7 and 8); (D, flavanones) 5,8,4'-trihydroxyflavanone (compound 9), 7,8,4'-trihydroxyflavanone (compound 10); (E, flavonoid-related compounds) compounds 11, 12, and 13 with incompletely elucidated structures. The yield of compound 1 was 0.3%, related to dry weight, whereas the yields of compounds 2-13 ranged between 0.017 and 0.069%. IC(50) values (antimutagenic potencies) of the flavonol glucuronides ranged between 24.2 and 58.2 microM, whereas the flavonol disaccharides (compounds 7 and 8), the flavanones (compounds 9 and 10), and the flavonoid-related glycosidic compounds 11-13 were only weakly active. The aglycons of compounds 7 and 8, however, were potent antimutagens (IC(50) = 10.4 and 13.0 microM, respectively).

Anti-AIDS agents, 21. Triterpenoid saponins as anti-HIV principles from fruits of Gleditsia japonica and Gymnocladus chinensis, and a structure-activity correlation.

Gleditsia saponin C [1] and gymnocladus saponin G [2] were isolated from Gleditsia japonica and Gymnocladus chinensis, respectively, as anti-HIV principles. Compounds 1 and 2 demonstrated inhibitory effects against HIV replication in H-9 cells with EC50 values of 1.1 and 2.7 microM, respectively. Evaluation of the anti-HIV activities of the prosapogenins of 1 and 2 suggested that the unusual monoterpenyl moieties in 1 and 2 are essential for their anti-HIV activity. Derivatives of echinocystic acid [8], the aglycone of compound 1, were also prepared and evaluated for inhibitory activity against HIV replication. 3,16-Di-O-acetylechinocystic acid [12] was shown to be an anti-HIV agent with an EC50 value of 2.3 microM.

Developmental aspects of flavonoid patterns in Brassica campestris var. oleifera: a preliminary study

Field-grown plants of Brassica campestris L. var. oleifera (summer turnip rapeseed) were harvested at various growth stages from seedling through to maturity. Cotyledons, roots, hypocotyls, leaves, stems, and flowers were sampled as available and freeze-dried prior to extraction. Chlorophyll-free, unhydrolysed alcoholic extracts were subjected to two-dimensional chromatography on polyamide thin layers to establish flavonoid patterns. Major aglycones of compounds were tentatively identified on the basis of mobility, colour reactions with a diphenylboric acid ethanolamine spray, and co-chromatography with standards. Each organ was found to have a pattern characteristic to itself which changed little with age. The greatest variety of compounds was present in leaf tissues. Only two compounds, presumably highly glycosylated derivatives of quercetin, were common to all tissues.