Distribution of sapogenins in morphological Medicago sativa L. parts: Comparison of various extraction techniques

Saponins in plant extracts were indirectly determined by estimation of the content of sapogenins. The first step of determination is extraction with high efficiency. One conventional extraction technique (maceration) and two modern ones (accelerated solvent extraction and supercritical fluid extraction) were compared. Methanol and ethanol were used as solvents or co‐solvents. The results were supported by statistical analysis. Saponins were extracted from leaves, roots, and sprouts of Medicago sativa. Acid hydrolysis, purification, and determination by high‐performance liquid chromatography with evaporative light scattering detector were used. The content of sapogenins was the highest in the roots. Smaller amounts of sapogenins were found in sprouts and the smallest ones in leaves. The main ingredient was medicagenic acid with mean concentration of 621.8 µg/g in roots, 456.7 µg/g in sprouts, and 471.3 µg/g in leaf extract. The highest content of sapogenins in extract was obtained after maceration with methanol; however, this method is nonselective in relation to biologically active compounds. Due to the possibility of using the obtained extracts with sapogenins in the cosmetic or pharmaceutical industry, the selection of extraction techniques and solvents is a very important aspect. Additionally, the chosen technique should be considered eco‐friendly and consistent with the assumptions of “green chemistry.”     

Isolation and determination of saponin hydrolysis products from Medicago sativa using supercritical fluid extraction,solid‐phase extraction and liquid chromatography with evaporative light scattering detection

Saponins are widespread secondary metabolites with various beneficial properties: fungicidal, antibacterial, antiviral, and anticancer. Alfalfa saponin molecules contain mainly: medicagenic acid, hederagenin, bayogenin, and soyasapogenol B. Structural diversity of saponins makes their determination in Medicago sativa extracts very difficult. The most popular determination technique is high‐performance liquid chromatography applied with evaporative light scattering detection. Qualitative and quantitative analysis of sapogenins from Medicago sativa by high‐performance liquid chromatography with evaporative light scattering detection required hydrolysis and purification of extracts obtained by supercritical fluid extraction. Hydrolysis of saponins with concentrated hydrochloric acid provided high concentration of medicagenic acid. In the purification process, satisfactory results were obtained for solid‐phase extraction using octadecyl. Recoveries were from 71 to 99% with a standard deviation from 2 to 8. Hydrolysis with concentrated hydrochloric acid was the only method that allowed identification of all four analyzed sapogenins. Moreover, it is characterized by a short time of preparation, simplicity of execution, a small amount of the sample and solvents. The hydrolysis and purification methods coupled with high‐performance liquid chromatography and evaporative light scattering detection can be successfully used for qualitative and quantitative analysis of the main saponins present in Medicago sativa plant extracts obtained by supercritical fluid extraction.     

Spirostanol sapogenins from the underground parts of Tupistra chinensis

Chemical examination of the underground parts of Tupistra chinensis led to the isolation of two new 5beta-spirostane type steroidal sapogenins, tupichigenin B (1) and C (2), together with two known steroidal sapogenins, ranmogenin A (3) and delta25(27)-pentrogenin (4). The structures of 1 and 2 were established as spirost-25(27)-ene-1beta,3beta,4beta,5beta,6b eta-pentaol and 1beta,2beta,3beta,4beta,5beta-pentahydroxyspi rost-25(27)-en-6-one, respectively, on the basis of detailed analysis of their physical and spectral data.     

Synthesis of diamino-furostan sapogenins and their use as scaffolds for positioning peptides in a preorganized form

The synthesis of peptide-furostane conjugates from natural steroidal sapogenins is reported. The approach comprises the introduction of α-oriented amino groups into spirostanic sapogenins followed by reductive opening of the spiroketal chain, thus producing diamino-furostanic scaffolds suitable for further functionalization. Solid and solution-phase coupling processes were utilized for the incorporation of various α-amino acids and peptides into the furostanic skeletons. The attachment position depends on the steroidal sapogenin originally used, i.e., diosgenin or hecogenin. The resulting furostanic skeletons feature a trans A/B-ring fusion and hold the peptides in axial disposition. This characteristic ensures a preorganized alignment of the peptidic motifs, an important structural feature for future applications in molecular recognition and catalysis. A macrocyclic tripeptide-furostane conjugate was also produced by a combination of peptide coupling, Staudinger ligation, and a cyclization protocol. This work constitutes the first report on the use of furostanic sapogenins as scaffolds for positioning natural amino acids and (cyclo)peptides.     

Two new dammarane-type triterpene sapogenins from Chinese red ginseng

Two new dammarane-type triterpene sapogenins were isolated from the Chinese red ginseng. The new sapogenins were named as 24,26-dihydroxy-panaxdiol (1) and 24-hydroxy-panaxdiol (2). Their structures were elucidated by the combined analysis of NMR and mass spectrometry as 20(S),25(R)-epoxydammarane-3β,12β,24β,26-tetraol (1) and 20(S),25-epoxydammarane-3β,12β,24α-triol (2). The complete signal assignments of the two compounds were carried out by 2D NMR spectral and NOE differential spectroscopy analysis.     

Simple gas chromatographic method for the determination of medicagenic acid in alfalfa (Medicago sativa)

A gas chromatographic method for the determination of medicagenic acid in alfalfa leaves, stems, entire plant (tops) and roots and also in leaf protein concentrates is described. The method is based on extraction of lucerne saponins followed by hydrolysis of the triterpene glycosides. After derivatization of the liberated sapogenins to silylated products, the trimethylsilylated medicagenic acid was determined by gas chromatography. The sensitivity of the method permits the detection of 50 ng of medicagenic acid.     

Synthetic Steroidal Sapogenins. Part III1 23-Ketohecogenin and 23-Ketoisochiapagenin

The synthesis of the 23-keto analogues of the steroidal sapogenins hecogenin and isochiapagenin is described.     

Mercaptolysis of the E／F Rings of Steroidal Sapogenins： A Concise Synthesis of Δ^20（22）－Furostene－26－thioethers

Lewis acid catalyzed mercaptolysls of steroidal sapogenins was reinvestigated. Besides obtaining the reported 26-thioacetals 5 under milder conditions, a new type of compounds Δ^20(22)-furostene-26-thioethers 6 were also synthesized through the mercaptolysis of steroidal sapogenlns, which can be used to the synthesis of the steroidal molecule with side chains.     

Microdetermination of steroid and triterpene saponin glycosides in various plant materials I. Allium species

Summary From plant material (Allium sativum, Allium cepa, Allium porrum), extracts characterised by a high haemolytic activity were obtained. In the raw saponin preparation the percentage of saponins in garlic, onion and leek was determined, applying the densitometric method on thin layer chromatograms, previously proposed⁵. Purified crystalline or oil-like saponin preparations were hydrolysed or complexed with cholesterol. The isolated sapogenins were identified by mass spectrometry, IR, NMR and UV analysis. The following sapogenins were found: sitosterol, gitogenin, oleanolic acid and amyrin.

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Mikrobestimmung von Steroid- und Triterpen-Saponinen in verschiedenem Pflanzenmaterial

Summary Aus Allium sativum, Allium cepa und Allium porrum wurden Extrakte erhalten, die stark hämolytisch wirken. Die rohen Saponin-Präparate wurden auf Dünnschicht-Platten mit unserer densitometrischen Methode untersucht und ihr Saponingehalt bestimmt. Die gereinigten, kristallisierten oder öligen Saponinpräparate wurden einer Hydrolyse und einer Komplexierung mit Cholesterin unterzogen. Die isolierten Sapogenine wurden massenspektrometrisch, mit IR, NMR und UV geprüft. Folgende Sapogenine wurden gefunden: Sitosterol, Gitogenin, Oleanolsäure und Amyrin.

     

Two new isospirostanol sapogenins from Reineckia carnea

Two new isospirostanol sapogenins named(25R)-5β-spirostane-(1α,3α)-diol(1) and(25R)-5β-spirostane-(1α,2α,3α,4α)tetrol(2) were isolated from the whole herb of Reineckia camea(Andr.) Kunth.The structures of the sapogenins were elucidated bychemical and spectral methods.     

海星动物化学成份的研究-罗氏海盘车中的皂苷元

报导了从罗氏海盘车中分离得到二个甾体皂苷元;20(R)-5α-孕甾-9(11)-烯-3β,6α,20-三醇和5α-孕甾-9(11)-烯-3β,6α-二醇-20-酮,并测定了它们的结构.     

The unexpected course of the reaction of steroid sapogenins with diacetoxyiodobenzene and BF3·Et2O in formic acid

The reaction of steroid sapogenins of both the 25R and 25S series with diacetoxyiodobenzene and BF₃·Et₂O in formic acid produced a mixture of an equatorial 23-formyloxysapogenin, a 16β,23:23,26-diepoxy-22-one and a bisnorcholanic lactone. The outcome of this reaction, that drastically differs from the same reaction in acetic acid, opens up new possibilities for the transformation of the side chain of steroid sapogenins.     

On reactions of spirostane sapogenins with benzeneseleninic anhydride

Direct dehydrogenation of spirostane sapogenins with benzeneseleninic anhydride/iodoxybenzene afforded the Δ²² derivatives in low yields. The reactions catalyzed by BF₃/Et₂O produced the 23-oxo-sapogenins in addition to their 22-oxo-23-spiro-isomers. The reactions of sapogenins with benzeneseleninic anhydride carried out in the presence of TiCl₄ afforded products chlorinated at C23.     

Russell Earl Marker and the Beginning of the Steroidal Pharmaceutical Industry

A biographical essay is presented on the chemical research of Russell E. Marker (1902–1995). The biography begins in 1925 with Marker's decision to forgo a Ph.D. in chemistry because he did not wish to complete the course requirements at the University of Maryland. Marker then took a position at the Ethyl Gasoline Company where he helped develop the octane rating for gasoline. He then moved to the Rockefeller Institute where he studied the Walden inversion, and then to Penn State College where his already prolific publication record soared to even greater heights. In the 1930s, Marker became fascinated with steroids and their potential as pharmaceuticals and collected specimens from plants in the southwest US and Mexico, discovering many sources of steroidal sapogenins. With his students at Penn State College, where he rose to full professor, he discovered the structure of these sapogenins and invented the “Marker degradation” that converted diosgenin and other sapogenins into progesterone. Together with Emeric Somlo and Federico Lehmann, he co-founded Syntex and began the manufacture of progesterone. Shortly thereafter, he left Syntex, began another pharmaceutical company in Mexico, then quit chemistry altogether. A discussion of Marker's legacies and the ironies in his professional career is provided.     

Simple and rapid characterization of soybean cultivars by perfusion reversed-phase HPLC: application to the estimation of the 11S and 7S globulin contents

A perfusion RP HPLC method enabling the separation of soybean proteins in an analysis time lower than 3 min has been used to obtain the chromatographic profiles of different soybean cultivars. The chromatograms obtained for each soybean variety presented clear differences that justified the potential use of this method for cultivar characterization. The area percentages obtained were employed as variables for cluster and principal components analysis of these soybeans. The application of these multivariate methods enabled the grouping of the soybeans in different categories. The protein fractions obtained from these soybeans by the application of a fractionation method were also analyzed. The chromatographic profiles obtained enabled the assignment of peaks to the main soybean proteins (7S and 11S globulins). These data were used for the estimation, for the first time, of the 7S and 11S globulin contents in soybean cultivars.     

Alkynes From Furans: A General Fragmentation Method Applied to the Synthesis of the Proposed Structure of Aglatomin B

Furans are versatile synthons in organic chemistry. Described is a general method for transforming furans into alkynes by dual C?C double‐bond cleavage. The reaction is proposed to proceed by sequential [4+2] cycloaddition between furan and singlet oxygen and a formal retro‐(3+2) fragmentation of the endoperoxide intermediate. A wide array of furans, including those derived from sapogenins, are amenable to this reaction, thus providing the corresponding alkynoic acids in up to 88 % yields. The synthetic utility was demonstrated by a seven‐step synthesis of the proposed structure of a pregnane natural product, aglatomin B, from a known intermediate.     

Thin-layer chromatographic detection and estimation of steroid sapogenins in fenugreek

Summary A thin-layer Chromatographic method was developed for the detection and estimation of the steroid sapogenins of fenugreek seeds and plant at its various stages of growth. It depends on the initial separation of the constituent sapogenins (diosgenin, tigogenin and gitogenin) effectively on silica gel and alumina chromatoplates (n-hexane/ethylacetate as solvent) followed by direct photometric estimation of each product separately with reference to a calibration curve. Errors of ± 6% were found with synthetic mixtures.

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Dünnschicht-chromatographischer Nachweis und Bestimmung von Steroidsapogeninen in BockshornkleeSteroidsapogenine. XIV

Zusammenfassung Das Verfahren wurde zur Untersuchung der Samen und der Pflanze (Trigonella foenum graecum L.) in verschiedenen Wachstumsstufen angewendet. Die Sapogenine (Diosgenin, Tigogenin und Gitogenin) wurden auf Dünnschichten aus Silicagel oder Aluminiumoxid mit Hilfe von n-Hexan/Äthylacetat-Gemischen getrennt und anschließend photometrisch mit Phosphormolybdänsäure direkt auf der Platte bestimmt. In synthetischen Gemischen wurden Fehler von ± 6% gefunden.

     

速收除草剂在大豆及土壤中的残留动态

 采用 Zorbax SIL色谱柱、以二氯甲烷 -甲醇为流动相的高效液相色谱法 ,测定了速收除草剂在大豆田土壤和大豆上的残留动态 ,建立了样品前处理方法和分析方法。速收在土壤、青豆和大豆籽粒的添加回收率分别为84.82 %～ 85 .63 % ,88.79%～ 94.0 0 %和 93 .70 %～ 94.48%。速收在土壤中的半衰期 (t1 / 2 )为 1 0 .0～ 1 0 .5 d,降解速度较慢 ,但在收获期的土壤、青豆 (用药后 80～ 85 d)和大豆籽粒中均未检出 ,说明其残留污染性很小 ,可以在大豆田安全使用。     

Synthesis of the aglycon of aspafiliosides E and F via a spiroketal-forming cascade

A facile synthesis of C17α-OH-tigogenin, the aglycon of aspafiliosides E and F, is described. The crucial step is the spiroketal-forming cascade, which forms the rings EF in one step and provides a new strategy for spiroketal ring closure in steroidal sapogenins and other substrates. This synthesis minimizes redundant oxidation-reduction manipulations of previous syntheses.     

海洋生物中具有生物活性的多羟基甾醇及甾体皂苷

综述了近几年来对海洋生物中具有生物活性的多羟基甾醇及其皂苷研究的新进 展，报道了以新化合物为主的80个具有生理活性化合物的结构，并部分地阐述了其 构效关系。