Neutral Extracts Research Articles

Chios Mastic Gum Extract and Isolated Phytosterol Tirucallol Exhibit Anti-Inflammatory Activity in Human Aortic Endothelial Cells

Chios mastic gum (CMG) is a white, semitransparent, natural resin that is obtained as a trunk exudate from mastic trees. Triterpenic compounds and phytosterols like tirucallol are among its major components. CMG has been associated with cardiovascular protection, exerting its effect mainly through increasing the antioxidant defense system, and effectively lowering the levels of serum cholesterol in human subjects. However, data on its anti-inflammatory effect on endothelium are scarce. Attachment of leukocytes to the vascular endothelium and the subsequent migration of cells into the vessel wall are early events in atherogenesis, and this process requires the expression of endothelial adhesion molecules. In this study, we examined the effect of CMG neutral extract (25-200 microg/ml) and tirucallol (0.1-100 microM) on the following: 1) the expression of adhesion molecules (VCAM-1 and ICAM-1) by Cell ELISA and 2) the attachment of monocytes (U937 cells) in TNF-alpha stimulated Human Aortic Endothelial Cells (HAEC) by Adhesion assay. The impact of treatment with CMG neutral extract and tirucallol in NFkB phosphorylation was also examined by a cell-based ELISA kit. Both CMG extract and tirucallol inhibit significantly VCAM-1 and ICAM-1 expression in TNF-alpha-stimulated HAEC. They also inhibit significantly the binding of U937 cells to TNF-alpha-stimulated HAEC and attenuate the phosphorylation of NFkB p65. This study extends existing data regarding the cardioprotective effect of CMG, expands the spectrum of known phytosterols with potent antiatheromatic activity, provides new insight into the mechanisms underlying the beneficial effect of CMG on endothelial function, and may aid in design of new therapy for intervention in atherosclerosis.

Consumo e digestibilidade de nutrientes de dietas com silagens de grãos úmidos de milho ou sorgo, em ovinos

Avaliaram-se o consumo, a digestibilidade e o teor de nutrientes digestíveis totais (NDT) de dietas contendo silagens de grãos úmidos de milho e de sorgo, com ou sem inoculante microbiano, em ovinos. O volumoso utilizado foi feno de capim-braquiária (Brachiaria brizantha cv. Marandu). Doze animais foram distribuídos em quatro tratamentos: (1) feno+silagem de grão úmido de milho, (2) feno+silagem de grão úmido de sorgo; (3) feno+silagem de grão úmido de milho com inoculante microbiano e (4) feno+silagem de grão úmido de sorgo com inoculante microbiano. Não houve diferença entre tratamentos quanto aos consumos de matéria seca, de matéria orgânica, de proteína bruta, de fibra em detergente neutro, de carboidratos totais e de carboidratos não estruturais. O consumo de extrato etéreo diferiu em função do tipo de grão. Não houve diferença entre tratamentos quanto à digestibilidade dos nutrientes. Não houve efeito do grão e da inoculação para o NDT estimado das silagens de grãos úmidos de milho e de sorgo, com médias de 77,6% e 79,5%, respectivamente. O uso de inoculante microbiano em silagens de grãos úmidos não se fez necessário. O grão de milho úmido pode ser substituído pelo de sorgo sem prejuízos ao aproveitamento de nutrientes em ovinos adultos.

Phosphatidic Acid and N-Acylphosphatidylethanolamine Form Membrane Domains in Escherichia coli Mutant Lacking Cardiolipin and Phosphatidylglycerol

The pgsA null Escherichia coli strain, UE54, lacks the major anionic phospholipids phosphatidylglycerol and cardiolipin. Despite these alterations the strain exhibits relatively normal cell division. Analysis of the UE54 phospholipids using negativeion electrospray ionization mass spectrometry resulted in identification of a new anionic phospholipid, N-acylphosphatidylethanolamine. Staining with the fluorescent dye 10-N-nonyl acridine orange revealed anionic phospholipid membrane domains at the septal and polar regions. Making UE54 null in minCDE resulted in budding off of minicells from polar domains. Analysis of lipid composition by mass spectrometry revealed that minicells relative to parent cells were significantly enriched in phosphatidic acid and N-acylphosphatidylethanolamine. Thus despite the absence of cardiolipin, which forms membrane domains at the cell pole and division sites in wild-type cells, the mutant cells still maintain polar/septal localization of anionic phospholipids. These three anionic phospholipids share common physical properties that favor polar/septal domain formation. The findings support the proposed role for anionic phospholipids in organizing amphitropic cell division proteins at specific sites on the membrane surface.

Appraisal of ingestion and digestibility in growing rabbits using near infrared reflectance spectroscopy (NIRS) of feeds and faeces

The aim of this work was to examine whether faecal profiling using NIRS could be profitable for promote the Best Available Techniques (BAT) in the rational feeding of rabbits. A set of 51 feed samples, taken from 12 experimental diets, and of 66 dried grouped faeces samples, belonging to four nutrition experiments, with 130 ad libitum registered feed intakes (CV=25%), were submitted to a UV-Vis-NIRS scan (350-2500 nm) in order to calibrate the chemical composition and nutritional parameters, the ingestion aptitude and digestibility. A chemometric system has made it possible to contemporary use the spectrum of the input diet concatenated together with the spectra of the related output pool of the dried faeces. The daily measured feed intake, in absolute or in relative terms as ingestion per unit of metabolic weight, obtained a good resolution for the spectra of the feeds (R2cv=0.80 and 0.75, respectively), for the faeces (0.81 and 0.80) and for the joint evaluation of the concatenated spectra (0.87 and 0.81). The intake was positively correlated to the mineral, insoluble ash, protein, gross energy, crude fiber and acid detergent fiber (ADF) content in the feeds, and negatively correlated to the N-free extract, lignocellulose and all the digestibility coefficients, except crude fiber. Very significant improvements, on average equal to 0.20 R2 points, were also provided to the digestibility coefficients when using the concatenated method; in decreasing order: neutral detergent fiber (R2cv=0.00, 0.18 and 0.50 for the feeds, faeces and concatenated, respectively), ADF (0.00, 0.45 and 0.62), ether extract (0.53, 0.52 and 0.86), crude protein (0.53; 0.53 and 0.75), and gross energy (0.61; 0.74 and 0.83). The results corroborate previous knowledge and show the possibility of using NIRS faecal profiling in rabbit nutrition, which together with the NIRS of the feeds, could contribute to nitrogen monitoring.

Effect of solvation by neutral extractants on the separation of metal cations of different charges during cation-exchange extraction

The effect of additions of neutral extractants on the cation-exchange separation of metal cations of different charges is analyzed. It is shown and confirmed experimentally that, during nonspecific and exhaustive solvation, an increase in the concentration of the solvating addition is favorable to the extraction of low-charge metal cations into the organic phase.

Chios mastic gum neutral extract and isolated tirucallol exhibit anti-inflammatory activity in human aortic endothelial cells

Pistacia lentiscus var. Chia of the Anacardiaceae family is grown almost exclusively in the southern part of Chios island, a Greek island in the Aegean. Chios mastic gum (CMG) and essential oil are natural antimicrobial and antioxidant agents that have found extensive uses in Mediterranean and Middle Eastern countries, both as a dietary supplement and as a herbal remedy since ancient years. The CMG's cardioprotective effect, via its antioxidant capacity is known, however data on its anti-inflammatory effect on endothelium are scarce. The neutral fraction of CMG (CMGNF) consists of several triterpenic compounds, among which the phytosterol tirucallol. In this study, we examined the hypothesis that CMGNF and tirucallol exert anti-inflammatory effects and could inhibit the expression of adhesion molecules (VCAM-1 and ICAM-1) in Human Aortic Endothelial cells (HAECs). CMGNF (25–200µg/ml) and tirucallol (1–100µM) were incubated with HAECs for 18h and then the cells were stimulated for 6 further hours with TNF-α (1ng/ml). α-Tocopherol was used as positive control. After incubation the cells were fixed and finally the expression of VCAM-1 and ICAM-1 was quantified using a microplate ELISA reader. CMGNF (100, 200µg/ml) caused a significant decrease in VCAM-1 and ICAM-1 expression (p<0.001, p<0.01), compared to TNF-α-treated HAECs. Tirucallol (10, 100µM), also inhibited significantly VCAM-1 and ICAM-1 expression (p<0.001, p<0.01). Concluding, CMGNF has a noticeable anti-inflammatory potential that can be attributed, at least in part, to tirucallol. Our data extend existing data regarding the cardioprotective effect of CMG and provide a further molecular mechanism underlying the beneficial effect of CMG on endothelial function.

Evaluation of Ammonium Bicarbonate–Diethylene Triamine Penta Acetic Acid as a Multinutrient Extractant for Acidic Lowland Rice Soils

Simultaneous extraction of nutrients using ammonium bicarbonate–diethylene triamine penta acetic acid (ABDTPA) extractant has been successful for highland soils, but its potential for lowland soils is still uncertain. This study evaluated the suitability of ABDTPA extractant to determine available phosphorus (P), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) in lowland rice soils of Sri Lanka. Available nutrients were analyzed both by conventional and ABDTPA methods, using the original ABDTPA (1∶2 soil–extractant) method as well as a modified (1∶4 soil–extractant) method. Conventional methods tested were Olsen, Bray 1, and FeO strip for available P; neutral NH4OAc extraction for exchangeable Ca, Na, K, and Mg; and DTPA extraction for available Zn, Cu, Fe, and Mn. Nutrient content and uptake by plants were determined by a pot experiment with rice (Oryza sativa). Nutrients extracted by the conventional methods and ABDTPA methods correlated well, in general, for all nutrients. Highly significant correlations were observed between plant uptake and extractable nutrients by 1∶2 and 1∶4 ABDTPA methods for P (r=0.85***and 0.73***, respectively), K (r=0.79*** and 0.66***, respectively), Na (r=0.86*** and 0.78***, respectively), Zn (r=0.66*** and 0.60***, respectively), Mn (r=0.72*** and 0.84***, respectively), and Fe (r=0.74*** and 0.68***, respectively). Calcium and Mg extracted by ABDTPA showed a poor relationship with their respective plant uptake. The ABDTPA method was as effective as or even better than the conventional methods in evaluating fertility status of lowland rice soils with respect to most nutrients. Replacing the conventional methods by the single ABDTPA multielement extractant will reduce the time and cost of soil analysis.

Technical Note: Degradation of Phenanthrene and Anthracene by Pseudomonas Strain, Isolated From Coastal Area

ABSTRACT A bacterial strain was isolated from a Mumbai coastal area. It was dosed with anthracene and phenanthrene, and, after 14 days of incubation, it had degraded 90% and 93% of the anthracene and phenanthrene, respectively. The metabolites were extracted and identified by ultraviolet (UV)-visible light absorption, high-performance liquid chromatography, mass spectrometry, and by comparing with actual compounds and data. Neutral extracts from anthracene showed four metabolites, viz 1,2-dihydroxyanthracene, 6,7-benzocoumarin, 1-methoxy-2-hydroxyanthracene, and 9,10 anthraquinone. When Pseudomonas were grown in the presence of phenanthrene, two metabolites, viz 9,10-dihydroxyphenanthrene and 3,4-dihydroxyphenanthrene were identified.

Pesticide Residue Analysis of a Dietary Ingredient by Gas Chromatography/Selected-Ion Monitoring Mass Spectrometry Using Neutral Alumina Solid-Phase Extraction Cleanup

A sample cleanup procedure has been developed to remove coextractives that interfere with pesticide residue analysis of a dietary ingredient (Product B), an extract consisting of Scutellaria baicalensis and Acacia catechu. Samples were extracted using 1% acetic acid in acetonitrile, followed by solid-phase extraction and analysis by capillary gas chromatography with mass spectrometry in the selective-ion monitoring mode. Neutral alumina (alumina N) was found to be the most effective sorbent to remove coextractives from Product B; other materials that were tested but failed to remove interference were graphitized carbon black/primary-secondary amine (PSA), octadecylsilane (C18), Florisil, Oasis MCX, and strong anion exchange-PSA. The method was specifically developed for Product B, which was spiked with 41 organochlorine and organophosphorus pesticides, and resulted in the recovery of 80 to 120% at U.S. Pharmacopeia limits (0.06 to 4 microg/g) for the majority of the pesticides.

Digestibilidade de dietas a base de grão úmido de milho ou de sorgo ensilados

In vivo digestibility of diets with high moisture sorghum substituting corn was studied in 12 female bovines. Experimental design was completely randomized with three treatments, substituting high moisture corn by sorghum at 0, 50 and 100% levels. Diets contained high moisture corn or sorghum, soybean, urea, oat hay ( Avena sativa sp.), minerals and monensin. In situ degradability of corn and sorghum in cracking, grinding and silage processes was evaluated. There was no difference in apparent digestibility of crude protein, crude fiber, neutral detergent fiber and ethereal extract. Negative lineal effect was observed (P < 0,05) for apparent digestibility of starch with sorghum inclusion. Processing interacted with grain when effective degradation of dry matter was concerned (P < 0,01). Corn had the highest degradation in high moisture silage; the worst degradation occurred with cracked; an intermediate degradation occurred in grinding (P < 0,01). Degradation in silage was similar as that of cracked degradation in sorghum; it was worst in grinding (P < 0,01).

Consumo e digestibilidade do feno de capim-braquiária em bovinos de corte sob suplementação com mistura contendo sulfato de amônio, caseína e uréia

Avaliaram-se o consumo e a digestibilidade dos nutrientes de dietas contendo feno de capim-braquiária (Brachiaria brizantha cv. MG4) de baixa qualidade e de diferentes níveis protéicos. Os tratamentos avaliados foram: controle (somente feno) e feno com adição crescente, via infusão ruminal, da mistura sulfato de amônio, caseína e uréia (0,5:1,0:4,5) de modo a elevar em +2, +4, +6 e +8% o nível de PB das dietas. Os dados foram analisados em delineamento quadrado latino, com cinco níveis de suplementação, cinco animais e cinco períodos. A adição de quantidades crescentes de nitrogênio não-protéico (NNP) à dieta teve efeito quadrático sobre os consumos de matéria seca (MS), matéria orgânica (MO), fibra em detergente neutro (FDN) e extrato etéreo (EE). O maior consumo de MS foi observado com o nível de 10,5% PB. Não foram observados efeitos dos níveis de PB sobre os coeficientes de digestibilidade de MS, MO, FDN e EE. Houve efeito linear crescente sobre o coeficiente de digestibilidade da PB, que apresentou valores de 57,4; 66,9; 73,6; 77,3 e 81,7% nos níveis de PB de 6,3; 8,5; 10,5; 12,63 e 14,8%, respectivamente. O nível de 10,5% de PB foi o ponto crítico para a obtenção de resposta máxima para os consumos de MS (7,7 kg/dia) e MO (7,2 kg/dia). A suplementação com compostos nitrogenados em quantidades que permitam elevar o nível protéico da dieta a 10,5% otimiza o uso de forragens de baixa qualidade.

Selection criteria of Eucalyptus globulus Labill. for production of chemithermomechanical pulps (CTMP)

Abstract Utilization of rapidly growing trees, such as eucalypts, for high-yield mechanical pulps is limited by low brightness owing to high contents of alkali and neutral extractives. Wood supply problems have developed in many areas of the world and new sources of high-yield pulp are needed. Ten Eucalyptus globulus trees were selected from two plantation sites to evaluate suitability as raw material for high-quality and high-yield pulp. Chemithermomechanical pulp (CTMP) was prepared from tree chips pretreated with sodium sulfite prior to refining. Characteristics of the CTMP were correlated with chemical and physical properties of the wood. There was a linear relationship between the content of alcohol-benzene extractives in wood and CTMP brightness. Klason lignin content in wood was inversely correlated with pulp sheet density, which is an important characteristic affecting the physical properties of pulp. The content of alkali extractives were inversely correlated with pulp yields. Color reversion was tested by exposing CTMP sheets to heat and light. Heat-induced yellowing of CTMP was of a low level and satisfied requirements for printing paper. The rate of yellowing was inversely associated with extractives and can be reduced by antioxidants.

Diterpenoid alkaloids from Delphinium gracile

Two highly oxygenated hetisine-type diterpenoid alkaloids, delphigraciline (1), 14-hydroxyhetisinone N-oxide (2), and the norditerpenoid alkaloid 8-methoxykarakoline (3), were isolated from a neutral extract of Delphinium gracile. Their structures were elucidated on the basis of spectroscopic data and by comparison with previously reported spectroscopic data of similar alkaloids. Their antiparasitic and insecticidal activities are also discussed.

Studies on Reactive Extraction of Meta‐Aminophenol Using Trialkylphosphine‐Oxide

Distribution of meta‐aminophenol (MAP) between water and trialkylphosphine oxide (TRPO), dissolved in different diluents (1‐octanol and kerosene), as well as a comparison with the extraction equilibrium of pure diluent alone has been studied. The influence of the pH value of aqueous solutions, the TRPO concentration and diluents on the distribution ratio D has been discussed. The results indicate that the pH value and the TRPO concentration are the key factors that affect D. The non‐polar diluent (kerosene) is favorable for extracting MAP when TRPO is used as extractant. MAP can be extracted with both acidic and neutral extractants (Di(2‐ethylhexyl)phosphoric and TRPO) efficiently in kerosene while the basic one (Alamine 336) in 1‐octanol, and their efficient pH region is 2.5–3.5, 4.5–6.5, and 6.5–7.8, respectively. The extraction ability shows the order of TRPO/kerosene ≥Di(2‐ethylhexyl)phosphoric/kerosene>Alamine 336/1‐octanol. The best selection is TRPO/kerosene with initial pH at 5.5–9.5.

Solute-induced dissolution of hydrophobic ionic liquids in water

Significant solubilization of ostensibly water-immiscible ionic liquids (ILs) in acidic aqueous phases is induced by the presence of any of a variety of neutral extractants, the apparent result of the formation of the protonated form of the extractant and its subsequent exchange for the cationic component of the IL. The extent of this solubilization is shown to diminish with increasing hydrophobicity of the IL cation and decreasing extractant basicity. These observations raise concerns as to the viability of ILs as “drop in replacements” for traditional organic solvents in the solvent extraction of metal ions.

New method to discriminate between cathepsin B and cathepsin L in crude extracts from fish muscle based on a simple acidification procedure

SummaryA new and simple method to distinguish between cathepsin B and cathepsin L in crude extracts of herring (Clupea harengus) muscle has been established. An acid treatment of crude extracts (exposed to pH 3 for 5 min) activated a latent form of cathepsin L and inactivated cathepsin B. Furthermore, in neutral crude extract, the hydrolysis of benzyloxycarbonyl‐l‐phenylalanyl‐l‐arginyl‐4‐methylcoumarine (Z‐Phe‐Arg‐MCA) (cathepsin B and cathepsin L substrates) was between 0% and 15% of the hydrolysis of benzyloxycarbonyl‐l‐arginyl‐l‐arginyl‐7‐amino‐4‐methylcoumarine (Z‐Arg‐Arg‐MCA; cathepsin B substrate). Cathepsin B activity is measured in neutral extract using the specific cathepsin B substrate Z‐Arg‐Arg‐MCA and cathepsin L activity is measured in acid‐treated extract with Z‐Phe‐Arg‐MCA as substrate. The specific cathepsin B inhibitor, CA‐074, did not inhibit the Z‐Arg‐Arg‐MCA significantly without affecting the Z‐Phe‐Arg‐MCA activity. An acid treatment of the crude extract is therefore a more advantageous approach to discriminate between cathepsin B and cathepsin L activities.

Synergistic Extraction of Zirconium(IV) and Hafnium(IV) with 4‐Acylbis(1‐phenyl‐3‐methyl‐5‐pyrazolones) in the Presence of Neutral Organophosphorus Extractants

Various 4‐acylbis(1‐phenyl‐3‐methyl‐5‐pyrazolones), namely, 4‐adipoylbis(1‐phenyl‐3‐methyl‐5‐pyrazolone) (H2AdBP), 4‐sebacoylbis(1‐phenyl‐3‐methyl‐5‐pyrazolone) (H2SbBP) and 4‐dodecandioylbis(1‐phenyl‐3‐methyl‐5‐pyrazolone) (H2DdBP) were synthesized and examined with regard to the solvent extraction behavior of zirconium(IV) and hafnium(IV) from hydrochloric acid solutions. The results demonstrate that Zr(IV) and Hf(IV) extracted into chloroform with 4‐acylbis(1‐phenyl‐3‐methyl‐5‐pyrazolones) (H2X), as ZrO(HX)2 and HfO(HX)2, respectively. The equilibrium constants (K ex) of the extracted complexes follow an order H2SbBP>H2AdBP>H2DdBP. The synergistic extraction of Zr(IV) and Hf(IV) was also investigated with mixtures of H2SbBP and tri‐n‐butylphosphate (TBP), tri‐n‐octylphosphine oxide (TOPO), and trialkylphosphine oxide (TRPO), where the complexation strength follows the order TOPO>TRPO>TBP. The equilibrium constants of the synergistically extracted complexes have been correlated with the donor ability of the phosphoryl oxygen of the neutral organophosphorus extractants in terms of their 31P NMR chemical shifts and their basicity values (KH =nitric acid uptake constant).

Estrogenic Activity of Isoflavonoids fromOnobrychis ebenoides

Fractionation of the neutral extract of Onobrychis ebenoides (Leguminosae) yielded a new isoflavone, named ebenosin (1), in addition to the known ones, afrormosin (2), formononetin (3) and daidzein (4). Although the relative binding affinities of 1 - 4 for estrogen receptor alpha (ERalpha) were nearly comparable and matched those of 1-3 for ERbeta, that of 4 for the latter receptor was significantly higher than any of the other. Compounds 1 - 4 induced cell proliferation and gene expression in breast and endometrial cancer cells in an ER-dependent manner. Nonetheless, the rank order of induction potencies ( 4 > 3 >or= 2 >or= 1) matched better that of affinities for ERbeta ( 4 > 3 >or= 2 >or= 1) rather than ERalpha ( 4 >or= 3 >or= 2 >or= 1). While the antiestrogen ICI 182,780 could inhibit the induction of proliferation of ER-positive breast cancer cells by 1-4, it could not prevent 1 from exhibiting significant ER-independent cytotoxicity at 10 microM. By contrast, 1 was much less cytotoxic and only weakly estrogenic for ER-positive endometrial adenocarcinoma cells. In conclusion, our data suggest that the C-8 isoprenyl substituent of 1 renders it cytotoxic and/or estrogenic in a cell-dependent manner.

Antioxidant and antimicrobial activities of the methanol extracts from pummelo (Citrus grandis Osbeck) fruit albedo tissues

The present study was conducted to evaluate the antioxidant and antimicrobial properties of methanol (100 and 80% aqueous) extracts of pummelo fruits albedo (Citrus grandis Osbeck). The antioxidant and antibacterial activity for crude extracts and isolated compounds were evaluated using free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Paper disc diffusion method. A 100% Methanol (MeOH) extract was steeped in water at different pH levels and partitioned with ethyl acetate (EtOAc) to give basic, acidic, neutral, and phenolic fractions. The neutral extract was found to possess maximum antioxidant and antibacterial activity. Thereafter, neutral extract was carried out on a silica gel column and eluted with hexane:EtOAc:acetone and preparative TLC (PTLC) to give oil buntan compound, linoleic acid methyl ester, β-sitosterol, sigmasterol, limonin, nomilin and meranzin hydrate were isolated. While, 80% MeOH extract was fractionated also using a silica gel column and PTLC to give isomeranzin hydrate, p-coumaric acid and caffeic acid compound. The extract concentration providing 50% inhibition (IC50) was as follows; oil buntan compound 95 μg/mL, caffeic acid 45 μg/mL, p-coumaric acid 105 μg/mL, limonin + nomilin (mixture) 135 μg/mL was lower than that of synthetic antioxidant butylated hydroxyanisole (BHA) 40 μg/mL. The inhibitory zone (mm) of bacteria tested was 2.9–4.1 mm caffeic acid and 11.6–15.1 mm p-coumaric acid.

Binding of complement subcomponent C1q to Streptococcus pyogenes: evidence for interactions with the M5 and FcRA76 proteins.

Binding of C1q, the first component of the complement system, to some human pathogens has been earlier reported. In the present study, direct binding of C1q to group A streptococci (GAS) of various serotypes as well as some other Gram-positive and Gram-negative species was demonstrated. The interaction between C1q and GAS was investigated more in detail. In hot neutral extracts of a number of GAS strains two components of 64 and 52 kDa, respectively, bound C1q; alkaline and SDS extracts yielded the 52 kDa component as the main C1q-binding substance. Trypsin treatment of the SDS extracts of two GAS strains suggested the C1q-binding component(s) to be of protein nature. C1q-binding material purified from the SDS extract of an avirulent strain, type T27, was separated in 12% SDS-PAGE and probed in Western blot with human C1q and fibrinogen, conjugated to horse radish peroxidase (HRP) as well as rabbit IgG antibodies complexed to HRP (PAP system). The 52 kDa component was non-reactive with fibrinogen or rabbit IgG. However, C1q-binding components purified from the alkaline extracts of two M-positive strains revealed strong binding of either fibrinogen (type M5) or both fibrinogen and rabbit IgG (type M76); the molecular mass of these components. 55 kDa and 43-40 kDa, respectively, was in agreement with the reported molecular mass of the M5 and FcRA76 proteins. Our findings suggest that C1q may interact with GAS through certain M-family proteins as well as by a so far unidentified surface factor of protein nature occurring in most GAS strains. The involvement of M-family proteins, regarded as virulence factors of these organisms, may suggest the interaction of GAS with C1q as biologically important.