Studies on Chemical Constituents of Salix Matsudana

Two new phytane‐type diterpene‐γ‐lactones named Hanliuin III ( 3 ) and Hanliuin IV ( 4 ), together with two previously reported diterpenes, six known flavonoids and five other known compounds were isolated from Salix matsudana. The structures of two new compounds were deduced from spectroscopic methods and 2D NMR techniques.     

Chemical Constituents from Strychnos Cathayensis

Secostrychnosin ( 1 ), a new secoiridoid, as well as seven compounds never before isolated from nature: 4‐tert‐butyl‐2‐oxazolidinone ( 2 ), 3‐acetoxyindole ( 3 ), indole‐2‐carboxylic acid ( 4 ), benzocaine ( 5 ), 3‐acetylindole ( 6 ), butylparaben ( 7 ) and 2‐hydroxy‐3‐methoxybenzaldehyde ( 8 ), together with fifty other known compounds, have been isolated from the stem of Strychnos cathayensis. These compounds include twenty‐three alkaloids, twelve benzenoids, four steroids, three flavonoids, three iridoids, two triterpenoids, two secoiridoids, two fatty acids, one lignan, one acetophenone, one coumarin, one chromane, one tetraterpenoid, one tannin, and one organic acid. The structures of these compounds were determined by means of spectralanalyses.     

Isocassiaoccidentalin B,A New C‐Glycosyl Flavone Containing a 3‐Keto Sugar,and Other Constituents from Cassia nomame

A new C‐glycosyl flavone containing a 3‐keto sugar, isocassiaoccidentalin B ( 1 ), was isolated from whole Cassia nomame (Sieber ) Honda plants, along with eleven known compounds, including two flavonoids ( 2 and 3 ), five flavonoid glycosides ( 4  –  8 ), two chalcones ( 9 and 10 ), and two phenylpropanoids ( 11 and 12 ). The chemical structures of all compounds were determined via 1D‐ and 2D‐NMR, and ESI‐MS. Among these, compounds 2 , 3 , 7 , and 8 were found to be the most potent in inhibiting nitric oxide release. Compounds 1 , 2 , 4 , 8 , 9 , and 10 showed significant free‐radical scavenging activity.     

On the liquid chromatography and identification of the flavonoids,present in the “sumach tannic acid” extracted fromRhus coriaria

Summary The leaves ofRhus coriaria contain about 15–20% polyphenolic compounds. These are mostly hydrolysable tannins, with a central glucose unit, to which several gallic acid rests are bound depsidically. 5 to 10% of the total polyphenolic fraction however, consists of condensed tannins or flavonoids. This work studies the identity and the liquid chromatographic behaviour of these flavonoids. The presence of the dimeric flavonoids agathisflavone, amenthoflavone and hinokiflavone is proved. A new dimeric flavanoid (Sumaflavone) is tentatively identified.     

Specific Deuteration in Patuletin and Related Flavonoids via Keto–Enol Tautomerism: Solvent‐ and Temperature‐Dependent 1H‐NMR Studies

An H/D exchange process in patuletin ( 1 ) and its derivatives in D‐donor solvents (e.g., CF₃COOD), which occurs regioselectively at C(8) was observed for the first time during NMR studies. The effect of substituents and temperature on the deuteration of various flavonoids (see Fig. 1) which include apigenin, chrysin, galangin, kaempferol, luteolin, morin, myricetin, patuletin, patulitrin, and quercetin, as well as derivatives of patuletin was examined extensively under NMR conditions. The rate constant of deuteration at C(8) of patuletin ( 1 ) and two flavones, luteolin ( 3 ) and apigenin ( 12 ), was also determined in CF₃COOD. The D‐atom was introduced into the flavonoids via a keto–enol tautomerism (Scheme 1). During these studies, monodeuterated patuletin was also obtained as a new compound. The examined flavonoids have been reported to possess significant pharmacological activities, and their deuterated derivatives would be of importance for the identification and quantification of these compounds in biological matrices.     

Two New Flavonoids from Derris eriocarpa How

Two new flavonoids, 1 and 2 , together with two known flavonoids, tephrosin ( 3 ) and 12a‐hydroxy‐α‐toxicarol ( 4 ), were isolated from the whole herb of Derris eriocarpa How . The structures and absolute configurations of the new compounds were elucidated on the basis of their MS, NMR, and ECD data. The structures of the known compounds were established by extensive spectroscopic (MS, 1D‐ and 2D‐NMR) analyses and comparison with the literature data. All compounds were isolated from D. eriocarpa for the first time. Compound 3 showed modest inhibitory activities against the growth of human cancer cells HEL and A549 with the IC₅₀ values of 15.03 ± 0.62 and 13.27 ± 0.39 μm , respectively.     

A practicable strategy for enrichment and separation of four minor flavonoids including two isomers from barley seedlings by macroporous resin column chromatography,medium‐pressure LC,and high‐speed countercurrent chromatography

Separation of minor compounds especially with similar polarities and structures from complex samples is a challenging work. In the present study, an efficient method was successfully established by macroporous resin column chromatography, medium‐pressure liquid chromatography, and high‐speed countercurrent chromatography for separation of four minor flavonoids from barley seedlings. Macroporous resin column chromatography and medium‐pressure liquid chromatography were used for enrichment of these four flavonoids. High‐pressure liquid chromatography analysis showed the total content of these four flavonoids increased from 2.2% in the crude extract to 95.3% in the medium‐pressure liquid chromatography fraction. It was indicated that the combination of macroporous resin column chromatography and medium‐pressure liquid chromatography could be a practicable strategy for enrichment of minor compounds from complex sample. Then, high‐speed countercurrent chromatography was employed for separation of these four flavonoids using ethyl acetate/n‐butanol/water (0.1% glacial acetic acid) (4:1:5, v/v/v) as solvent system. As a result, four flavonoids including two isomers with purities higher than 98% were obtained. Interestingly, two flavonoids existing in one high‐pressure liquid chromatography peak were also successfully separated. All these indicated high‐speed countercurrent chromatography had great potential for separation of compounds with similar structures and polarities. This study provides a reference for efficient enrichment and separation of minor compounds from complex sample.     

Chemical Constituents from the Root Bark of Rodgersia Sambucifolia

A new demethylacetovanillochromene glycoside, 2,2‐dimethyl‐2H‐(8‐hydroxy‐6‐acetyl)‐[2,3‐b] pyran‐8‐O‐β‐D‐apiofuranosyl‐(1 →6)‐β‐D‐glucopyranoside ( 1 ), together with twenty‐three known compounds, have been isolated from the root bark of Rodgersia sambucifolia. These known compounds include two diterpenoids, three flavonoids, two catechins, four lignans, two benzenoids, two isocoumarins, two steroids and six monoterpene glycosides, which were determined by means of spectral analyses.     

Chemical Constituents from the Root Bark of Formosan Zanthoxylum Ailanthoides

Two new N‐isobutylamides, hydroxy lanyuamide I ( 1 ) and hydroxy lanyuamide II ( 2 ), together with one hundred and ten known compounds, have been isolated from the root bark of Formosan Zanthoxylum ailanthoides. These known compounds include twenty coumarins, twenty‐one benzo[c]phenanthridines, ten quinoline derivatives, one aporphine, one purine, seven amides, twelve benzenoids, one lactone, four flavonoids, nine lignans, eight steroids, two chlorophylls, eleven terpenoids and three other compounds, which were determined by means of spectral analyses.     

Nuclear magnetic resonance-based solvent system selection for counter-current chromatography separation of compounds present in the same high-performance liquid chromatography peak: Flavonoids in barley seedlings as an example

Partition coefficient is a key parameter for counter-current chromatography separation. High-performance liquid chromatography (HPLC) is the most commonly used tool for the screening of partition coefficients. However, HPLC technology is not applicable to the compounds present in the same chromatographic peak. Nuclear magnetic resonance (NMR) technology could easily distinguish compounds according to their characteristic absorption even if they exist in the same HPLC peak. In this study, two flavonoids present in the same HPLC peak were successfully purified by counter-current chromatography with a solvent system screened by NMR to show the great potential of NMR technology in the screening of the partition coefficient of co-efflux compounds. Through NMR screening, an optimized ethyl acetate/n-buthanol/water (7:3:10, v/v/v) system was applied in this study. As a result, two flavonoids, including 4.8 mg of 3′-methoxyl-6′’’-O-feruloylsaponarin and 9.8 mg of 6′’’-O-feruloylsaponarin were separated from 15 mg of the mixture. There is only one methoxy group difference between the two flavonoids. This study provides a new strategy for the screening of counter-current chromatography solvent systems and broadens the application scope of counter-current chromatography.     

A New Megastigmane Glucoside and Three New Flavonoid Glycosides from Spiraea prunifolia var. simpliciflora

A new megastigmane glucoside, simplicifloranoside ( 1 ), and three new flavonol glycosides, prunifolianosides A–C ( 2 – 4 , resp.), were isolated from the aerial parts of Spiraea prunifolia var. simpliciflora. In addition, fifteen known compounds, including five phenolic acids, three lignans, four flavonoids, one eugenol glycoside, and two alkyl‐primeverosides, were also identified. Their structures were elucidated on the basis of detailed spectroscopic analyses and acid hydrolysis.     

Two new diprenylated flavanones from Derris laxiflora Benth

Abstract

Phytochemical reinvestigation on the whole plants of Derris laxiflora Benth. afforded two new diprenylated flavanones, derriflavanones B and C (1–2), together with thirty-two known compounds, including sixteen flavonoids (3–18), eleven aromatic compounds (19–29), and five chlorophylls (30–34). All known compounds were first isolated from this plant. The structures of these compounds were determined by analysis of the NMR spectroscopy, mass data, IR spectra, UV spectra, optical rotation and by comparison with literature data.     

Two New Diterpenoid Glucosides from Clerodendrathus spicatus

Two new diterpenoid glucosides, clerodendranthusides B and C ( 1 and 2 , resp.), together with 16 known compounds, comprising four lignans, five miscellaneous phenylpropanoids, two flavonoids, one sesquiterpenoid glycoside, two triterpenoid glycosides, one megastigmane, as well as one anthraquinone, were isolated from the 50% EtOH extract of the whole plants of Clerodendrathus spicatus. Their structures were elucidated by chemical and spectroscopic methods.     

Labdane Diterpenes and Flavonoids from Leonurus japonicus

Chemical investigation of the aerial part of Leonurus japonicus led to the isolation and characterization of a new labdane‐type diterpene, named 3α‐acetoxy‐15‐O‐methylleopersin C ( 3 ), and a new acylated rutin derivative, named 2′′′‐syringylrutin ( 9 ), along with seven known compounds, including a labdane‐type diterpene and six flavonoids. The structures of the new compounds were established by spectroscopic methods.     

Chemical constituents from the fruits of Psoralea corylifolia and their protective effects on ionising radiation injury

Two new flavonoids, corylifol F (1) and corylifol G (2), together with 19 known compounds, were isolated from the fruits of Psoralea corylifolia L.. The structures of these compounds were determined by interpretation of spectroscopic data and comparison with literature properties. The radioprotective effects of the isolated compounds against ionising radiation damage were also evaluated in vitro. The results showed that corylifol A exhibited radioprotective effects in both HBL-100 and MCF-7 cells, while psoralen, isopsoralen, corylifol C and bakuchiol showed obvious selective action to protect HBL-100 cells against damage caused by ionising radiation.     

Additional Constituents of Hypericum Subalatum

The whole herb of Hypericum subalatum Hayata contains three flavonoids, caffeic acid esters, a pyranoxanthone, and three xanthines, in addition to the previously reported xanthonolignoids. Among these compounds, 2,7-dihydroxy-3,4-dimethoxyxanthone has not been described in the literature before. The co-occurrence of xanthone derivatives and flavonoids in this plant is of chemotaxonomic significance.     

Quantitative determination of flavonoids in some representatives of the family Fabaceae

The quantitative composition of the combined flavonoids in the epigeal parts of eight representatives of the family Fabaceae (four species ofOnobrychis, two ofAstragalus, and two ofTrifolium) have been studied. For the quantitative estimation of the flavonoids we used a spectrophotometric method permitting the determination of flavonols and isoflavones when they are present simultaneously. A comparatively high content of flavonoids (from 2.37 to 4.13%) was found. The sum of the flavonoid compounds from the species ofOnobrychis, Astragalus, andTrifolium investigated possesses a hypolipidemic activity.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 43–45, January–February, 1984.     

Nonsteroidal Constituents from Solanum Incanum L.

Sixteen compounds were isolated from the aerial parts of Solanum incanum L. These compounds included ten flavonoids ( 1‐10 ), chlorogenic acid ( 11 ), adenosine ( 12 ), benzyl‐O‐β‐D‐xylopyranosyl(1→2)‐β‐D‐glucopyranoside ( 13 ), and three phenylalkanoic acids ( 14‐16 ). The structures were determined from their physical and spectral data. Among these compounds, kaempferol 3‐O‐(6″′‐O‐2,5‐dihydroxycinnamoyl)‐β‐D‐glucopyranosyl (1→2) β‐D‐glucopyranoside ( 10 ) was identified as a new compound.     

A new potent immunosuppressive isoflavanonol from Campylotropis hirtella

Four new flavonoids were isolated from Campylotropis hirtella and these are a chromone and a 2H-chromene, an isoflavone and an isoflavanonol. The structures of these compounds were elucidated by extensive spectroscopic measurements. All of the compounds were assessed for immunosuppressive activity. Compound 4 showed very strong T lymphocyte suppression activity (IC₅₀: 0.13 μM) and potent B lymphocyte suppression activity (IC₅₀: 0.26 μM). Due to its potent immunosuppressive activity and lower cytotoxicity, further structure–activity studies will be pursued on this compound.     

Lignans,flavonoids and coumarins from Viola philippica and their α-glucosidase and HCV protease inhibitory activities

Two lignans including a new one, five flavonoids and five coumarins were isolated from the whole plant of Viola philippica (synonymised as Viola yedoensis Makino). The new compound was structurally determined as (7R,8S,8′S) -3,3′-dimethoxy- 4,4′,9-trihydroxy- 7,9′-epoxy-8,8′-lignan 9-O-rutinoside by analysis of its NMR, MS and CD spectroscopic data. The known compounds were characterised by comparing their NMR and MS data with those reported. Among the known compounds, 5-hydroxy-4′-methoxyflavone-7-O- rutinoside, 6,7-di-O-β-D- glucopyranosylesculetin, and 7R,8S-dihydrodehydrodiconiferyl alcohol 4-O-β-D- glucopyranoside were isolated and identified from this genus for the first time. Of these compounds, 5-hydroxy-4′-methoxyflavone-7-O-rutinoside and (7R,8S,8′S) -3,3′-dimethoxy- 4,4′,9-trihydroxy- 7,9′-epoxy-8,8′-lignan 9-O-rutinoside were potently active against α-glucosidase, while the two dimeric coumarins, 5, 5′-bi (6, 7-dihydroxycoumarin) and 6,6′,7,7′-tetrahydroxy-5,8′-bicoumarin potently inhibited HCV protease.