Two high-molecular-weight (>1000 kDa) water-soluble preparations were isolated from stems of Symphytum asperum and S. caucasicum. Their basic component was established as poly [oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene], analogous to that of high-molecular-weight (>1000 kDa) preparations from roots of these same plants, using IR and NMR spectral data.Keywords: caffeic acid, 3-(3,4-dihydroxyphenyl)glyceric acid, Symphytum asperum, Symphytum caucasicum, poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene] Caucasian species of comfrey from the genus Symphytum L. have been used since antiquity to treat wounds and fractures. It was found that they possess analgesic, antimicrobial, and anti-inflammatory activities. They are also used for contusions, hematomas, ulcers, gastrointestinal infections, neuralgia, parodontosis, arthritis, and rheumatism [1].Despite the popularity of these plants in folk medicine, literature data on their chemical composition and biological activity are rather scant.Total polysaccharide preparations from roots of rough comfrey (S. asperum Lepech.) and Caucasian comfrey (S. caucasicum Bieb.) (Boraginaceae) exhibited anticomplementary activity [2,3]. Both preparations were fractionated and monitored for activity in order to establish the active principle. Ultrafiltration on membrane filters (1000 kDa pores) followed by dissolution of high-molecular-weight components in veronal-salt buffer (pH 7.35) and gel-permeation chromatography removed most ballast polysaccharides and afforded water-soluble high-molecular-weight (>1000 kDa) fractions. Both fractions contained some residual carbohydrates (25.7 and 26.9%, respectively) and possessed high anticomplementary activities [2, 3]. One fraction from roots of S. asperum also exhibited antioxidant, antilipoperoxidant, and anti-inflammatory activities [4]. The UV spectra of both preparations contained absorption maxima at 252, 282 (sh), and 286 nm in veronal-salt buffer (pH 7.35) and at 213, 237, 282 (sh), and 286 nm in water. We demonstrated previously on the basis of IR and NMR spectral data that the principal component of both high-molecular-weight water-soluble preparations from roots of S. asperum and S. caucasicum was a regularly substituted polyoxyethylene, namely poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene] [5,6]. This previously unknown natural phenolic biopolymer was isolated for the first time, is a polymer derived from caffeic acid, and represents a new class of natural esters with 3-(3,4-dihydroxyphenyl)glyceric acid as the repeating unit.The goal of the present investigation was to isolate water-soluble high-molecular-weight (>1000 kDa) preparations from the total polysaccharides from stems of rough comfrey (TRC) and Caucasian comfrey (TCC) and to compare the structures of the principal structural units using IR and NMR spectroscopies.TRC and TCC were isolated from total polysaccharides of S. asperum and S. caucasicum stems using the previously reported method [2,3]. Table 1 gives the amount of residual total sugars, fructose, ur...
High molecular weight fractions (> 1000 kDal) from the leaves of Symphytum asperum and S. caucasicum had anticomplement activity, were able to inhibit luminol-and lucigenin-dependent chemiluminescence (CL lum and CL luc respectively) induced by human polymorphonuclear neutrophils (PMN) after stimulation with opsonized zymosan, and could decrease the CL luc signal induced by superoxide anion formation in a cell-free hypoxanthine/xanthine oxidase system. The anticomplement and antioxidant activities of the high molecular weight fractions (> 1000 kDal) from the leaves of Symphytum asperum and S. caucasicum indicate that they might be used as anti-inflammatory and wound-healing agents.
Some 5α-type steroidal derivatives of the steroidal sapogenin tigogenin were synthesized. The structures of the synthesized derivatives were characterized by spectral methods and elemental analysis. The antituberculosis activity of the compounds toward Mycobacterium tuberculosis strain H37Rv was studied in vitro (Microplate Alamar Blue Assay) in BACTEC 12B medium and was compared with that of isoniazide. Some of the synthesized compounds exhibited high (92-98%) antimycobacterial activity.Key words: antimycobacterial activity, 5α-steroidal hydrazones, 5α-aminosteroids.Changes of various social, medical, and economic factors at the end of the 1980s caused tuberculosis to start again to spread. The emergence of resistant strains of the disease that exposed the imperfection of the modern arsenal of drugs enhanced the rebound of tuberculosis [1]. The need arose to create new drugs that could be used in shorter treatment courses than existing drugs in order to treat resistant and latent forms of the disease.It was recently proposed that the mechanism of resistance to isoniazide, which remains to this day the first-line drug, is related to mutation or deletion of peroxidase catalase KatG and that antibacterial resistance to the drug can be overcome by synthesizing new isoniazide derivatives, in particular, by preparing biologically different forms of this drug, namely hydrazones. Nevertheless, isonicotinoylhydrazones (INH) themselves are viewed as compounds with potential antituberculosis activity [2].We reported previously on the antimycobacterial activity of some 5α-steroidal INH in vitro [3][4][5]. It was found that some of them were just as active toward M. tuberculosis as isoniazide. Taking this into account, we synthesized various new steroidal INH [6] and other derivatives. The goal of the present study was to compare the antimycobacterial activity of the previously and newly synthesized compounds.Starting ketosteroids (2-9) were prepared from tigogenin (1) that was isolated from Yucca gloriosa L. by the published method [3][4][5][6][7][8]. Steroidal hydrazones (10-18) were prepared by condensation of isoniazide [3, 5, 6], m-nitrobenzoic acid hydrazide, and m-bromobenzoic acid hydrazide with steroidal skeletons (2-9). An aminosteroid (19) was synthesized from epiandrosterone acetate (6) as before [7] (Scheme 1).The structures of the newly synthesized compounds 17 and 18 were confirmed by IR, MS, PMR, and 13 C NMR spectral data.IR spectra of 17 and 18 exhibited absorption bands in the range 3400-3360 cm −1 that were characteristic for NH. Bands at 2946-2924 were assigned to the aliphatic part. The absorption band of HNC=O appeared at 1736 and 1705, respectively. The C=N band in both instances appeared at 1641; the aromatic part, 1550. The IR spectrum of 17 showed absorption bands at 1518 and 1335 (Ar-NO 2 ); of 18, 750 (Ar-Br). Resonances of angular 18-and 19-methyls in PMR spectra of 17 and 18 were singlets at δ 0.82-0.88 ppm. The methyl of the C-3 acetyl resonated at 1.97; axial 3α-H of 3α-steroidal esters, as a...
Certain 17β-aminoderivatives of 5α-steroids based on tigogenin were synthesized and their antitumor activity was studied. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy and mass spectrometry.We previously reported the synthesis and biological activity of certain derivatives of 17-amino alcohols of the 5α-androstane type and demonstrated their effect on the CNS [1] and radioprotective properties [2]. We synthesized 17β-amino-5α-androstane, a compound known to have anti-inflammatory and fungicidal activity [3]. In order to explain the antitumor activity, we synthesized certain derivatives of 17-aminosteroids.The starting material for the synthesis of the amine derivatives of 5α-androstanes was tigogenin (1), which was isolated from Yucca gloriosa cultivated in Georgia. Tigogenin was transformed into epiandrosterone acetate (2) and then into the 17β-aminoderivatives (3-9) by the literature method [1-3]. Thus, 17β-amino-5α-androstan-3β-ol (3) was prepared from 2 by Leuckart-Wallach amination [4]; 17α-amino-5α-androstan-3β-ol (4), by a modified Streitweiser-Schaeffer method [5]. The product of the Leuckart-Wallach reaction was reduced by an excess of LiAlH 4 in THF to give the 17β-methylamino derivative (5) [1].3: R = OH, R 1 = NH 2 , R 2 = H; 4: R = OH, R 1 = H, R 2 = NH 2 ; 5: R = OH, R 1 = CH 3 N, R 2 = H 6: R = OH, R 1 = NHCOOCH 3 , R 2 = H; 7: R = OCOOCH 3 , R 1 = NHCOOCH 3 , R 2 = H 8: R = OH, R 1 = H, R 2 = NHCOOCH 3 ; 9: R = OCOOCH 3 , R 1 = H, R 2 = NHCOOCH 3 10: R = OH, R 1 = CH 3 NCH 2 CONH 2 , R = H; 11: R = OH, R 1 = CH 3 NCH 2 CH 2 NH 2 , R 2 = H 12: R = O; 13: R = NOH The carbamoyl derivatives 6-9 were synthesized by treatment of 3 and 4 with an excess of Cl(CO)OCH 3 in pyridine. The mixture formed by this of the mono-and diacylated compounds (6, 7, and 8, 9, respectively) was separated by chromatography over a silica-gel column with elution successively by mixtures of petroleum ether and ethylacetate (20:1 and 10:1) [1]. Diaminoderivative 11 was prepared by reaction of 17β-methylamine (5) with chloroacetamide in the presence of Na 2 CO 3 in DMF at 80-90°C with subsequent reduction of amide 10 by an excess of LiAlH 4 in 1,4-dioxane. We also synthesized 17β-amino-5α-androst-2-ene (14) according to the previously published scheme [3] from epiandrosterone acetate (2) by forming 5α-androst-2-en-17-one (12) and reduction of its oxime 13 by metallic Na in n-propanol.
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