Hepatoprotective Activity of 6-Heptadecylcyclohex -3-ene-1 Carboxylic Acid Isolated from the Methanol Extract of Dichrostachys cinerea Wight & Arn. Stem Bark

Aim of the Study: The phytoconstituent 6-heptadecylcyclohex 3-ene-1 carboxylic acid isolated from the methanol extract of Dichrotachys cinerea Wight. stem bark was evaluated for hepatoprotective activity against CCl4 induced toxicity. Materials and Methods: The constituent 6-heptadecylcyclohex 3-ene-1 carboxylic acid isolated from the methanolic extract of D. cinerea and the structure was confirmed by spectroscopic studies. Hepatoprotective property was screened in male wistar strain rats. The parameters studied were estimation of liver function serum markers such as serum total bilirubin, total protein, alanine transaminase, aspartate transaminase, alkaline phosphatase and histological profile of the liver tissue. Results: The LD50 of methanolic extract and constituent, 6-Heptadecylcyclohex -3-ene-1 carboxylic acid were evaluated and found to be 500 and 100 mg/kg body weight respectively. The hepatoprotective activity of constituent was more significant as similar to the standard hepatoprotective drug silymarin. The histological profile of the liver tissue showed the presence of normal hepatic cords, absence of necrosis and fatty infiltration as similar to the controls. Conclusion: The methanolic extract of D. cinerea stem bark and the phytoconstituent 6-heptadecylcyclohex-3-ene-1 carboxylic acid showed significant protection from CCl4 induced liver damage.

Analysis method optimization and stability test of related substances of chloral hydrate / 药学实践杂志

Objective To establish a quality control method for detecting impurities in chloral hydrate raw materials, improve the quality standards and control limits of raw materials. Methods The determination methods of chloroform and halogenated carboxylic acid in chloral hydrate were established to monitor the change of impurities in chloral hydrate through stability. Results The research and establishment of chloroform and halogenated carboxylic acid methods met the requirements of relevant regulations for analytical methodology verification, which could accurately detect four impurities in raw materials and preparations by one method. Conclusion The study provides technical support for the improvement and optimization of the quality standards of chloral hydrate and preparations. It is very necessary to implement the impurity monitoring in preparation research and production process by the chloral hydrate impurity detection and the stability comparison of this product at high temperature and light, which could largely promote the safety of medication.

Design, synthesis, antibacterial and antitumor activities of novel pyrazolo3,4-bpyridine-4-one-5-carboxylic acid derivatives / 药学学报

To discover new structural hits, based on the important role of pyrazole ring and fragment of pyridinone carboxylic acid in drug design, novel title pyrazolo[3,4-b]pyridine-4-one-5-carboxylic acid derivatives (10a-10p) were designed and synthesized, the structures were confirmed by spectral data and elemental analyses. The antibacterial and antitumor activities were evaluated by the measured minimum inhibitory concentration (MIC) values against the tested four strains and half inhibitory concentration (IC50) values against the tested four cancer cells, respectively. The results displayed markedly poor antibacterial activity and observably potent antitumor activity. In particularly, the title difluorophenyl (10d, 10e, 10f), pyridyl (10j), ethyl (10k) and cycloproyl (10l) compounds exhibited comparable activity against Capan-1 and A549 cells to that of the comparison doxorubicin. Thus, pyrazolo[3,4-b]pyridine-4-one-5-carboxylic acid derivatives as promising antitumor hits need to be developed.

Long-chain alkanol-alkyl carboxylic acid-based low-viscosity hydrophobic deep eutectic solvents for one-pot extraction of anthraquinones from Rhei Radix et Rhizoma / 药物分析学报

Natural long-chain alkanol and alkyl carboxylic acid were used to prepare novel hydrophobic deep eutectic solvents(HDESs).These HDESs are liquid at room temperature and have low viscosity(＜12.26 mPa-s),low polarity(lower than that of methanol,ChCl-based deep eutectic solvents and other reported HDESs),and low density(＜0.928 g/mL).A simple one-pot method based on a novel HDES-water two-phase extraction system was constructed for the extraction of weak-polarity bioactive components,anthraquinones,from Rhei Radix et Rhizoma.This HDES-based new extraction method does not consume hazardous organic solvents and can obtain a total anthraquinone yield of 21.52 mg/g,which is close to that obtained by the Chinese pharmacopoeia method(21.22 mg/g)and considerably higher than those by other reported HDESs-based extraction methods(14.20-20.09 mg/g,p＜0.01).The high extraction yield can be mainly attributed to the severe destruction of the RRR cell walls by the extraction system and the excellent dissolving ability of novel HDESs for anthraquinones.

Study on determination of 2-thioxothiazolidine-4-carboxylic Acid in urine by high performance liquid chromatography / 中华劳动卫生职业病杂志

Objective: To establish a high performance liquid chromatography method for the determination of 2-thioxothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: After acidification with hydrochloric acid, TTCA in urine was first extracted by ethyl acetate with excessive sodium chloride, then gradient separated by a symmetry C18 column and then detected by a diode array detector. The quantification was based on a working curve of external standard method. Results: The linear relationship of TTCA in urine was good in the range of 0.03-10.00 mg/L, and the correlation coefficient was 0.9999. The detection limit and minimum quantitative concentration of TTCA in urine were 0.008 mg/L and 0.027 mg/L. The intra-assay precision of the method was 0.9%-1.4%, the inter-assay precision was 1.3%-3.5%, and the average recovery was 85.0%-92.7% while the concentrations of TTCA in urine was 0.8, 2.0 and 8.0 mg/L, respectively (n=6) . Conclusion: The gradient elution high performance liquid chromatography method has simple operation and high sensitivity, and it is suitable for the determination of TTCA on a low level in urine for occupational workers exposure to carbon disulfide.

Determination of creatinine and 2-thiothiazolidine-4-carboxylic acid in urine by ultra high performance liquid chromatography tandem mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 μg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 μg/L. When the addition concentrations were 50.0, 150.0 and 450.0 μg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 μg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 μg/L. When the addition concentrations were 10.0, 40.0 and 160.0 μg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.

Production of carboxylic acids by metabolically engineered Yarrowia lipolytica: a review / 生物工程学报

Yarrowia lipolytica is a non-conventional yeast with unique physiological and metabolic characteristics. It is suitable for production of various products due to its natural ability to utilize a variety of inexpensive carbon sources, excellent tolerance to low pH, and strong ability to secrete metabolites. Currently, Y. lipolytica has been demonstrated to produce a wide range of carboxylic acids with high efficiency. This article summarized the progress in engineering Y. lipolytica to produce various carboxylic acids by using metabolic engineering and synthetic biology approaches. The current bottlenecks and solutions for high-level production of carboxylic acids by engineered Y. lipolytica were also discussed, with the aim to provide useful information for relevant studies in this field.

Chemical constituents from ethyl acetate extract of Eupatorium adenophorum / 中草药

Objective: To study the chemical constituents of the Eupatorium adenophorum. Methods: The chemical constituents were isolated and purified by silica gel chromatography repeatedly from the ethyl acetate extract of E. adenophorum, and their structures were identified by spectral analysis and chemical methods. Results: Fourteen compounds were isolated from E. adenophorum and identified as p-hydroxybenzoic acid ethyl ester (1), (1R,4R)-8aα-hydroxy-1-isopropyl-4,7-dimethyl- 1,2,3,4,6,8a-hexahydro-naphthalene-2,6-dione (2), daedalin A (3), 10-oxo-7-hydroxy-nordehydrotremetone (4), caffeoyl acetate (5), syringic acid (6), 3-hydroxy-4-(1-oxo-ethane)-benzoic acid (7), ferulic acid (8), p-hydroxyphenylethyl alcohol (9), protocatechuic acid ethyl ester (10), 4-hydroxy-3-isopropyl benzoic acid (11), balanophonin (12), indole-3-carboxylic acid (13), and 6-methoxy kaempferol (14). Conclusion: Compound 11 is obtained from natural products for the first time, compounds 1, 3, 6, 7, 9, 10, 12-14 are obtained from this genus for the first time, and compound 5 is obtained from this plant for the first time.

A new coumarin from flowers of Edgeworthia gardneri / 中草药

Objective: To study the chemical constituents from the flowers of Edgeworthia gardneri. Methods: The chemical constituents were isolated and purified by column chromatography on silica gel, AB-8 macroporous resin, sephadex LH-20, pre-HPLC. Their structures were determined on the basis of physicochemical properties and spectral analysis. Results: Four compounds were isolated from the flowers of E. gardneri and elucidated as gardnerol C (1), daphnoretin-5-O-β-D-glucopyranosyl- (1→2)-β-D-glucopyranoside (2), (3S)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (3), and dihydrokaempferol (4). Conclusion: Compound 1 is a new coumarin named gardnerol C, and compound 4 is obtained from the genus for the first time.

Chemical Constituents of Pericarps of Zanthoxylum bungeanum / 中国实验方剂学杂志

<b>Objective::To study the chemical constituents of pericarps of <italic>Zanthoxylum bungeanum</italic>. <b>Method::The dried pericarps of <italic>Z</italic>. <italic>bungeanum</italic> were smashed, and then extracted and concentrated in 95%ethanol to obtain the total extract. The total extract was loaded on a silica gel CC, eluted with different polar solvents in sequence, and then concentrated to obtain corresponding parts. The methylene chloride fraction and the <italic>n</italic>-butanol fraction were separated and purified by silica gel column chromatography, Sephadex LH-20 gel column chromatography, ODS column chromatography, semi-preparative HPLC, etc. And their structures were identified based on physicochemical properties and various spectroscopic methods. <b>Result::Fourteen compounds were isolated from the dichloromethane fraction and the n-butanol fraction of the <italic>Z</italic>. <italic>bungeanum</italic> and identified as(1<italic>S</italic>, 3<italic>S</italic>)-1-methyl-1, 2, 3, 4-tetrahydro-<italic>β</italic>-carboline-3-carboxylic acid(<bold>1</bold>), (3<italic>S</italic>)-1, 2, 3, 4-tetrahydro-<italic>β</italic>-carboline-3-carboxylic acid(<bold>2</bold>), apigenin-7, 4′-dimethyl ether(<bold>3</bold>), genkwanin(<bold>4</bold>), lcariside F₂(<bold>5</bold>), breyniaionoside A(<bold>6</bold>), 3-methoxyphenethyl alcohol-4-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-glucopynanoside(<bold>7</bold>), 1-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-glucopyranosyloxy-3-methoxy-5-hydroxybenzene(<bold>8</bold>), orcinol-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-glucopyranoside(<bold>9</bold>), syringin(<bold>10</bold>), 4-[(3<italic>S</italic>)-3-hydroxybutyl]-2-methoxyphenyl-<italic>β</italic>-<italic>D</italic>-glucopyranoside(<bold>11</bold>), (+ )-lyoniresinol-3a-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-glucopyranoside(<bold>12</bold>), 2-methylpropanyl-6-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-apiofuranosyl-<italic>β</italic>-<italic>D</italic>-glucopyranoside(<bold>13</bold>)and(<italic>E</italic>)-6-hydroxy-2, 6-dimethylocta-2, 7-dienoic acid(<bold>14</bold>). <b>Conclusion::All compounds were isolated from <italic>Z</italic>. <italic>bungeanum</italic> for the first time, and compounds <bold>1-4, 12</bold> and <bold>14</bold> were isolated from this genus for the first time.

Effects of combination of phenazine-1-carboxylic acid from Streptomyces kebangsaanensis with amphotericin B on clinical Fusarium solani species

Aim@#A novel endophyte, Streptomyces kebangsaanensis was isolated from the stem of a Malaysian ethnomedicinal plant, Portulaca oleracea in 2013. Studies on S. kebangsaanensis crude extract showed that it had antifungal activities and further work led to isolation of a novel compound, phenazine-1-carboxylic acid (PCA). This study investigated the combinatorial effect of PCA isolated from S. kebangsaanensis with amphotericin B on the growth of four clinical Fusarium solani isolates. @*Methodology and results@#Disk diffusion assay showed that the crude extract of S. kebangsaaneesis inhibited growth of all four F. solani isolates. Whereas, the compound PCA from this extract inhibited two of the tested F. solani isolates, UZ541/12, and UZ667/13 at minimum inhibitory concentration of 18.00 µg/mL Combinations of this compound with amphotericin B, reduced the minimum inhibitory concentration of amphotericin B for these two isolates from 8 to 0.13 µg/mL and 4 to 0.03 µg/mL respectively. Analysis of fractional inhibitory concentration index showed that a borderline synergism is present between the compound and amphotericin B. @*Conclusion, significance and impact of the study@#These results indicate PCA may be useful in improving actions of available drugs against antimicrobial resistant microorganisms.

The metabolic analysis of 11C-flumazenil in different specific radioactivity / 药学实践杂志

Objective To analyze the metabolic differences of 11C-flumazenil (11C-FMZ) with different specific radioactivity by detecting the percentage proportion of the main metabolites in vivo. Methods 5 male and 5 female volunteers with average age of (41.7±4.7) years and weight of (69.3±6.8) kg were selected from May to October 2019. 11C-FMZ with high and low specific radioactivity (268.3±57.2)×103 and (57.8±11.4)×103 Ci/mol was injected successively. The percentage of injected dose/liter of 11C-FMZ and its metabolites in the plasma at 1, 2, 3, 4, 5, 10, 15, 20, 30, 40 and 60 min after the injection was measured. Paired sample mean t test was used to calculate and compare the percentage of metabolites in the two groups. Results The percentage proportion of metabolites increased gradually with time, and reached the stable level after 15 min. The percentage proportion of low specific radioactivity group was higher than that of high specific radioactivity group with a significant statistical difference between 15 min and 60 min (P<0.05). Conclusion The metabolic rate of 11C-FMZ with different specific radioactivity was significantly different after injection and the specific radioactivity difference should be avoided if possible in clinical application.

Preparation and Characterization of Macroporous Hydrogels from Copolymers Networks

New hydrogels based on (MAA) and (NVP) copolymers crosslinked with (BAA), were prepared by free radical cross-linkingcopolymerization, with a NVP percent molar composition of 10, 47.5 and 85. These hydrogels have been characterized by(FTIR), (SEM), (TGA /DSC) coupling. The results show four steps of degradation. The degradation rate is inverselyproportional to the mole percent of NVP, and SEM shows that the hydrogels have a pore size between 7.14 to 13.33 μm.

Transformative hyaluronic acid-based active targeting supramolecular nanoplatform improves long circulation and enhances cellular uptake in cancer therapy

Hyaluronic acid (HA) is a natural ligand of tumor-targeted drug delivery systems (DDS) due to the relevant CD44 receptor overexpressed on tumor cell membranes. However, other HA receptors (HARE and LYVE-1) are also overexpressing in the reticuloendothelial system (RES). Therefore, polyethylene glycol (PEG) modification of HA-based DDS is necessary to reduce RES capture. Unfortunately, pegylation remarkably inhibits tumor cellular uptake and endosomal escapement, significantly compromising the antitumor efficacy. Herein, we developed a Dox-loaded HA-based transformable supramolecular nanoplatform (Dox/HCVBP) to overcome this dilemma. Dox/HCVBP contains a tumor extracellular acidity-sensitive detachable PEG shell achieved by a benzoic imine linkage. The and investigations further demonstrated that Dox/HCVBP could be in a "stealth" state at blood stream for a long circulation time due to the buried HA ligands and the minimized nonspecific interaction by PEG shell. However, it could transform into a "recognition" state under the tumor acidic microenvironment for efficient tumor cellular uptake due to the direct exposure of active targeting ligand HA following PEG shell detachment. Such a transformative concept provides a promising strategy to resolve the dilemma of natural ligand-based DDS with conflicting two processes of tumor cellular uptake and nonspecific biodistribution.

Chemical constituents of carboxylic acid and its derivatives in Cinnamomi Ramulus / 中草药

Objective To investigate the chemical constituents of Cinnamomi Ramulus. Methods Silica gel, Sephadex LH-20 column, and sp-HPLC chromatographies were applied to separate and purify the chemical constituents, followed by various spectral analyses to determine the chemical structures. Results Fifteen carboxylic acids and its derivatives were isolated, and their structures were identified as guizhi acid A (1), dihydrophaseic acid (2), rel-5-(3S,8S-dihydroxy-1R,5S-dimethyl-7-oxa-6-oxobicyclo [3,2,1]-oct- 8-yl)-3-methyl-2Z,4E-pentadienoic acid (3), vanillic acid (4), syringic acid (5), 4-hydroxybenzoic acid (6), E-cinnamic acid (7), E-o-hydroxycinnamic acid (8), erythro-guaiacylglycerol-8’-vanillic acid ether (9), salicylic acid (10), decumbic acid (11), hydroxyphenylpropionic acid (12), protocatechuic acid (13), E-melilotoside (14), and cryptamygin-B (15), respectively. Conclusion Fifteen compounds were successfully identified from Cinnamomi ramulus, among which 1 is a new compound and compounds 2, 3, 9-12 are isolated from the plant for the first time.

Cloning, space-time expression and bioinformatics analysis of ACS3 gene from different species of Lonicera macranthoides / 中草药

Objective To clone ACS3 gene from wild type and ‘Xianglei’ cultivar of Lonicera macranthoides, respectively, followed by bioinformatics analysis and detection of spatio-temporal expression pattern. Methods Unigene sequence which is highly homologous with ACS protein from the transcriptome database of L. macranthoides was screened, the primers were designed based on it to amplify the full length of the Unigene by qRT-PCR and RACE techniques; Bioinformatics tools were used to analyze and identify the physicochemical property, conserved domain and gene homology of ACS3 proteins; Finally, qRT-PCR technique was used to detect the gene expression patterns of different species of L. macranthoides. Results Lm-ACS3 (GenBank: MH724196) and Lm-XL-ACS3 (GenBank: MH724197) were isolated from wild type and ‘Xianglei’ cultivar of L. macranthoides, respectively. The length of open reading frame (ORF) were all 1 452 bp, encoding 483 amino acids, containing the conserved Aminotran_1_2 structural domain, which were highly similar to the ACC synthase of other plants; And qRT-PCR results showsed that the expression quantity of ACS3 gene in wild L. macranthoides changed significantly at different blossoming stages, the overall trend was upward from flowering stage 3, while the expression difference between the flowering stages was relatively small in “Xianglei” cultivar. Conclusion Lm-ACS3 and Lm-XL-ACS3 gene were separately obtained from L. macranthoides and L. macranthoides ‘Xianglei’ cultivar, the expression patterns of ACS3 in this two varieties were different; It’s speculated that ACS3 gene might be a possible functional gene that causing different phenotypes of two strains of L. macranthoides, it provides theoretical basis for further verifying the biological function of ACS3 gene in regulating flower’s bud duration and phenotype.

Influence of Glimepiride on Plasma Concentrations and Antihypertensive Effects of Losartan and Losartan Carboxylic Acid in the Patients with Type 2 Diabetes Mellitus Complicated with Hypertension / 中国药师

Objective:To assess the influence of glimepiride on the plasma concentrations and antihypertensive effects of losartan and its active metabolite losartan carboxylic acid(E-3174) in the patients with type 2 diabetes mellitus and hypertension. Methods:Pragmatic randomized controlled trial was used in the clinical study. Forty-five patients were enrolled and randomized into glimepiride group and the control group. Losartan was used as the antihypertensive drug in the two groups. After two-week interference,the plasma concentrations of losartan and its active metabolite E-3174 were determined using an LC-MS/MS method and the reduction of hyperten-sion was measured. Results:The plasma trough concentrations of losartan in glimepiride group was not higher than those in the control group,and those of E-3174 in glimepiride group was not lower than those in the control group. Additionally,the reduction of hyperten-sion was similar in the two groups. Conclusion: Glimepiride does not influence the plasma concentrations and the antihypertensive effects of losartan and its active metabolite E-3174 in the patients with type 2 diabetes mellitus and hypertension, suggesting no drug-drug interactions between them. Owing to the small sample,large clinical trial should be performed to confirm the above conclusion.

Ion Chromatography Method of Four Carboxylic Acids in Workplace Air / 中华劳动卫生职业病杂志

Objective@#To assess psychological acceptance and occupational stress of medical staff, analyze the relationship among personality, psychological acceptance and occupational stress and discuss the direct or indirect effects of personality to occupational stress.@*Methods@#The gaseous four kinds of carboxylic acids in the workplace air were simultaneously collected by silica gel tube, and then desorbed by deionized water and eluted by ion chromatograph. The the content was detected by conductivity detector.@*Results@#The linear relationship was good in the concentration range of about 0~140 mg/L. The correlation coefficient r>0.999, and the maximum detection limit was 4.5 μg/mL. The sampling efficiency of the four carboxylic acids ranges from 96.10%~100.27%. Through the sample added recovery experiments, the low and high content of the silicone tube samples were detected; and the range of desorption efficiency was 82.18%~100.12%; the range of precision was 0.70%~3.71%.@*Conclusion@#This method adopts deionized water to desorb samples, and the application of ion chromatography detection have reached the requirements of《Guidelines for the establishment of occupational health standards, Part 4: Determination of chemical substances in workplace air》, which can be used in four kinds of workplace air detection of carboxylic acid compounds.

Chemical constituent cluster of decoction of Sanguisorbae Radix by HPLC-IT-TOF/MS / 中草药

Objective: To analyze the chemical constituent cluster of decoction of Sanguisorba Radix systemically by HPLC-IT-TOF/MS. Methods: The samples were scanned by broad spectrum of DAD detector and ionized in negative and positive environment of electron spray ionization. Results: A total of 82 chemical constituents (include isomers) were identified based on exact molecular mass, fragment, ultraviolet spectrum as well as the combination of the database. The chemical constituent cluster was composed of 69 phenolics, 8 triterpenes, 3 flavonoids, an organic acid, and a monoterpene glycoside, of which citric acid, brevifolin carboxylic acid, methoxybenzoic acid methyl ester-5-O-sulfate, isorhamnetin-sulfate, and methylellagic acid-sulfate, et al were firstly found in Sanguisorba Radix. Conclusion: The systemical analysis of the chemical constituent cluster of decoction of Sanguisorba Radix was able to supply a clear material basis for the further study of efficacy and pharmaceutical metabolism of Sanguisorba Radix.

Bioassay-guided fractionation and antimicrobial and cytotoxic activities of Cassia bakeriana extracts

ABSTRACT The antimicrobial potential of extracts of bark and leaves of Cassia bakeriana Craib, Fabaceae, against aerobic and anaerobic oral bacteria was evaluated by the microdilution broth method. For crude ethanol extracts and organic fractions tested, the bark dichloromethane phase showed a significant antibacterial effect, with MIC values ranging from 12.5 to 100 µg/ml for most of the microorganisms tested. Thus, a bioassay-guided fractionation of this fraction was performed. This fractionation led to isolation of the 1,8-dihydroxy-anthraquinone-3-carboxylic acid, also known as cassic acid or rhein. It is the first time that this bioactive anthraquinone has been isolated from this plant. Rhein exhibited good selectivity and high activity against anaerobic microorganisms, with MIC values ranging between 3.12 µg/ml (11.0 µM) and 25 µg/ml (88.0 µM). These results were considered very promising since the most active samples and rhein showed greater selectivity against oral microorganisms than toxicity to Vero cells.