LC-ESI-MS analysis of taxoids from the bark of Taxus wallichiana

LC-ESI-MS analysis was carried out for taxoid profiling of partially purified methanol extracts of the stem bark of Taxus wallichiana growing in different regions of the Himalayas (Kashmir, Himachal Pradesh, UP hills, Sikkim and Arunachal Pradesh). Cone voltage fragmentation of the protonated, ammonium or sodium cationized molecular species resulted in diagnostic fragment ions. Thus, information about the number and nature of substituents and the taxane skeleton (whether it is normal or rearranged) was readily available from the LC-ESI-MS spectra. The rearranged 11(15-->1)-abeo-taxanes showed a characteristic elimination of the hydroxyisopropyl along with an acetoxy group. The identification of the taxoids was achieved by comparison of the ESI mass spectra with those of the authentic taxoids available to us or by interpreting the ESI mass spectra. The results were also corroborated by MS/MS analysis of the partially purified extract injected directly into the ESI source. Paclitaxel, its analogues and their xylosides are present in samples from all the regions. An interesting observation is the detection of a large number of basic taxoids having nitrogen-containing side chains.     

Two ring opened oxetane taxoids containing a C-20 benzoyloxy group from the roots of Taxus wallichiana Zucc.

Two new taxanes, named wallitaxane G (1) and H (2), were isolated from the roots of Taxus wallichiana (Taxaceae), together with nine known compounds (3?11). Their structures were elucidated on the basis of NMR spectroscopic analysis and the relative configurations of 1 and 2 were determined based on NOESY data. Wallitaxane H (2) showed the most potent α-glucosidase inhibitory activity, with an IC₅₀ value of 16.1 μM. Plausible biosynthetic pathways for the formation of 1 and 2 were proposed based on oxetane ring-opening and benzoyl migration.     

Taxumairols X--Z,new taxoids from Taiwanese Taxus mairei

In addition to 19-dydroxybaccatin III, 1beta-hydroxy-5 alpha-deacetylbaccatin I, taxayuntin G and 13-O-deacetyltaxumairol Z (4), three new taxane diterpenoids, taxumairols X (1), Y (2), Z (3) have been isolated from extracts of the Formosan Taxus mairei (LEMEE & LEVL.) S. Y. HU. Compounds 1-2 belong to the 11(15-->1)-abeo-taxane system, having a tetrahydrofuran ring at C-2, C-3, C-4 and C-20. The new compound 3 and 4, which was misidentified previously are derivatives of 11(15-->1)-abeo-taxane with an intact oxirane system. The structures of compounds 1-4 were elucidated on the basis of extensive two dimensional (2D)-NMR analysis.     

Analysis of taxol and major taxoids in Himalayan yew, Taxus wallichiana.

A reversed-phase column liquid chromatography method for the analysis of taxol, 10-deacetylbaccatin III, baccatin IV, 1-hydroxybaccatin I, 2-acetoxybrevifoliol, brevifoliol, 2'-deacetoxydecinnamoyltaxinine J and 2'-deacetoxytaxinine J in yew needles has been developed using a Nova-Pak Phenyl column and a binary gradient profile. The various aspects of analysis such as extraction efficiency, detection limits, reproducibility and peak purity were validated using UV-Vis as well as photodiode array detection.     

Three new taxoids from the leaves of the Japanese yew, Taxus cuspidata

Three new taxane diterpenoids were isolated from the leaves of the Japanese yew, Taxus cuspidta. Their structures were established as 5 alpha,13 alpha-diacetoxy-taxa-4(20),11-diene-9 alpha,10 beta-diol (1), 7 beta,13 alpha-diacetoxy-5 alpha-cinnamyloxy-2(3-->20)-abeo-taxa-4(20),11-diene-2 alpha,10 beta-diol (2), and 2 alpha,10 beta,13 alpha-triacetoxy-taxa-4(20),11-diene-5 alpha,7 beta,9 alpha-triol (3) respectively on the basis of 1D and 2D NMR data.     

A new carbamic acid from Dryopteris wallichiana

A new carbamic acid, (1,7a-dihydro-1H-inden-2(7aH)-ylidene)methylcarbamic acid (1), along with three known ones, 12-ursen-28-oic acid-3-O-β-D-glucopyranoside (2), 12-ursen-3-O-β-D-glucopyranoside (3), and 3,7,11,15-tetramethyl-2-hexadecen-1-ol (4), was isolated and identified from Dryopteris wallichiana.     

Two new diacetylene glycosides: bhutkesoside A and B from the roots of Ligusticopsis wallichiana

Two new diacetylene glycosides: bhutkesoside A (1) and B (2), along with 10 known compounds, i.e. falcarindiol (3), chlorogenic acid (4), 5-O-p-coumaroyl-quinic acid (5), 3,5-di-O-caffeoyl-quinic acid (6), 4-hydroxy-7-methoxy-phenylethanol (7), ferulic acid (8), dehydrodiconiferyl alcohol-4-O-β-d-glucopyranoside (9), 5,7-dihydroxy-2-methylchromone-7-O-rutinoside (10), schumanniofioside B (11) and marmesinin (12) were isolated from the roots of Ligusticopsis wallichiana (DC) Pimenov & Kljuykov (Apiaceae), commonly known as ‘Bhutkesh’ in Nepal. The structures were determined on the basis of spectroscopic data. Compounds 4 and 6 showed potent antioxidant activity on DPPH free radical scavenging assay.     

Two New Taxoids from Taxus Yunnanensis

Sincethediscoveryofthefamousanticanceragentpaclitaxel(Taxol@)',muchattentionhasbeenpaidbecauseofitsuniquetubulinactivity',aswellasitsnovelstructure3.Duetothescarcityofpaclitaxel,manykindsofmeasuresincludingsemisynthesis"',totalsynthesis"'andcellculture8havebeentaken.Searchingforpaclitaxelanalogsandprecursorsisthereforeanecessaryinvestigation.ThisledtotheisolationofnumeroustaxoidsfromvariousTaxusspecies'.Asacontinuationofourpreviousstudies"""",wehaveinvestigatedthebarkofTaxusyunnanensis,Cheng…     

Two New Lignans from Taxus yunnanensis

The phytochemical investigation on the ethanolic extracts of the barks of Taxus yunnanensis (Taxaceae) led to the isolation of two new neo-lignans, named taxuyunins A (1) and B (2), along with the known diterpenolignan, brevitaxin (3). Their structures were elucidated on the basis of spectroscopic and chemical evidences. Compound 1 is a neo-lignan xyloside while compound 2 belongs to the rare neo-lignan possessing a ramified C3 side chain.     

Two New Taxane Diterpenoids from Taxus Chinensis

Taxuschinensisrpilger)RChd.istheuniqueTaxUsspeciesgrownonlyinChina.AsPartofourongoingsearchfortaxanediterpenoidstoprovideprecursorsforthesemiSynthesisofanalogsoftheanticancerdrugpaclitaXel(4,=taxol),l,2wehaveinvestigatedthedonorconstitUentsofthestembarkofTaxuschinensis,andidenhfiedseveralaroids.Inthispapef,wereporttwOnew~ecliterpenoids,2deacetoxy-7,9-dideacetyltaxndneJ(1)and2-deacetoxy-taXinineB(3),isolatedfromT.chinensis.PreviousstlldiesonTchinensishaveresultedintheisolahonofpaclitaxela…     

4-Deacetylbaccatin III: a proposed biosynthetic precursor of paclitaxel from the bark of Taxus wallichiana

4-Deacetylbaccatin III was isolated and characterized from the bark of Taxus wallichiana Zucc. It was previously identified as an intermediate during the synthesis of paclitaxel and was proposed as a precursor for the biosynthesis of paclitaxel. Existence of 4-deacetylbaccatin III in T. wallichiana is strong evidence for the previously proposed biosynthetic pathway of paclitaxel via 4-deacetylbaccatin III.     

Separation and purification of flavonoid from Taxus remainder extracts free of taxoids using polystyrene and polyamide resin

An efficient separation process of flavonoid from Taxus wallichiana var. mairei remainder extracts free of taxoids was developed in this study. AB‐8 macroporous resin and polyamide resin offered the fine adsorption capacity, and its adsorption rate at 30°C fitted well to the Langmuir and Freundich isotherms. Resin dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from T. wallichiana var. mairei remainder extracts free of taxoids. The optimum parameters for adsorption by AB‐8 resin were as follows: (1) the concentration of flavonoids in a sample solution of 5.61 mg/mL with a processing volume of 2 bed volume (BV) (60 mL); (2) for desorption, ethanol–water (80:20, v/v), with 6 BV as an eluent at a flow rate of 2 BV/h. After a one‐run treatment with AB‐8 resin, the content of flavonoids was increased 5.10‐fold from 4.05 to 20.65%. The optimum parameters for adsorption by polyamide resin were as follows: processing volume of 2 BV (30 mL); for desorption, ethanol–water (70:30, v/v), with 8 BV as an eluent at a flow rate of 2 BV/h. After one‐run treatment with polyamide resin, the content of total flavonoids increased from 20.65 to 65.21%. The method will provide a potential approach for large‐scale separation and purification of flavonoid for its wide pharmaceutical use.     

Preparative separation and enrichment of four taxoids from Taxus chinensis needles extracts by macroporous resin column chromatography

An environment‐friendly method was established for the preparative separation and enrichment of four taxoids, namely 10‐deacetylbaccatin III (10‐DAB III), 7‐xylosyl‐10‐deacetyltaxol (7‐xyl‐10‐DAT), cephalomannine and paclitaxel from Taxus chinensis needles extracts. Characteristics of seven widely used macroporous resins for four taxoids were compared, AB‐8 resin offered better adsorption and desorption capacities than others. AB‐8 resin column chromatography was used to study the desorption process for four taxoids. The optimum parameters for desorption were 30% ethanol 5 RV for removing impurities, following 15 RV for 10‐DAB III, after the desorption of impurities with 35% ethanol 10 RV, 45% ethanol 30 RV for 7‐xyl‐10‐DAT, then 65% ethanol 10 RV for cephalomannine and paclitaxel, the flow rate was 6 RV/h. After separation on AB‐8 resin column chromatography, the contents of 10‐DAB III, 7‐xyl‐10‐DAT, cephalomannine and paclitaxel in the product reached 4.58, 13.17, 1.36 and 3.08%, respectively, which were 7.63‐, 3.68‐, 6.18‐ and 6.55‐fold to those in T. chinensis needles extracts. The recovery yields were 94.96, 77.32, 88.09 and 95.25%. In general, the AB‐8 resin column chromatography has the advantages of lower cost, high efficiency and simple procedure. Therefore, it may provide scientific references for the preparative separation and enrichment of taxoids from other T. species.     

A new rearranged chamigrane sesquiterpene from Laurencia okamurai

A new rearranged chamigrane sesquiterpene,named laurenokamurin,was isolated from the marine red alga Laurencia okamurai.Its structure was determined on the basis of spectroscopic methods.     

高效液相色谱指纹图谱法分析南方红豆杉药材的氯仿提取物

建立了南方红豆杉药材氯仿提取物的高效液相色谱(HPLC)指纹图谱分析方法。采用Eurospher 100 C18色谱柱(250 mm×4 mm, 5 μm),以甲醇和水为流动相进行梯度洗脱,流速为1 mL/min,检测波长为232 nm,柱温为30 ℃。以10-脱乙酰巴卡亭III(10-DABIII)为参照物,在相同的色谱条件下测定了10批不同产地的南方红豆杉药材氯仿提取物的指纹图谱,获得了11个共有指纹峰,并利用主成分分析法(PCA)对指纹图谱进行统计分析。结果表明南方红豆杉药材的质量与种植区域有关。该方法稳定、可靠,可用于南方红豆杉药材的质量控制。     

Analysis of cell cultures of Taxus wallichiana using direct analysis in real-time mass spectrometric technique

The applicability of a new mass spectrometric technique, DART (direct analysis in real time) has been studied in the analysis of the calli of Taxus wallichiana. The intact callus samples were directly analyzed by holding them in the gap between the DART source and mass spectrometer for measurements. Five C-14 oxygenated taxoids were characterized from the analysis of the calli of the Taxus wallichiana almost instantaneously. The confirmation of the structures of the identified taxoids was made through their accurate molecular formula determinations.     

A new rearranged dolabellane diterpene from the soft coral Clavularia inflata

A new dolabellane type diterpene 1 has been isolated through its acetate 1a. The structure of 1a was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry. The structure of 1 was deduced by comparison of its NMR spectral data with those of 1a, while its relative stereochemistry was deduced by NOESY. The absolute stereochemistry of C-7 was determined by analyses of 1 separately esterified with R and S O-mandelic acids.