Activity of the Phenolic Compounds of Plant Extracts in Reactions with Diphenylpicrylhydrazyl

Pharmaceutical Chemistry Journal -     

In vitro Inhibition of Prostaglandin Biosynthesis by Essential Oils and Phenolic Compounds1.]

Various essential oils used in the treatment of rheumatism and inflammation as well as some of their main constituents and phenolic compounds known for their irritant and pungent properties were screened for activity as inhibitors of prostaglandin biosynthesis. A newly developed combination of a prostaglandin-synthesizing cyclooxygenase system from sheep seminal vesicles and an HPLC separation technique for the metabolites of arachidonic acid was used as test system. Eugenol- and thymol/carvacrol-containing essential oils, the pure compounds eugenyl acetate, capsaicin, curcumin and carvacrol, as well as urushiol from TOXICODENDRON RADICANS (L.) Kuntze (poison ivy) exhibited the greatest inhibitory effect.     

白芷提取分离物体外对酪氨酸酶的抑制作用

目的:体外评价白芷提取分离物对酪氨酸酶的抑制作用.方法:白芷提取分离物采用薄层色谱法鉴别,HPLC法测定分离物中欧前胡素含量,多巴速率氧化法测定其对酪氨酸酶的抑制率.结果:白芷提取分离物主要为欧前胡素,含欧前胡素0.01,0.05,0.10 μg·ml-1分离物对酪氨酸酶的抑制率分别为(15.92±5.3)%、(25.34±3.94)%、(40.38±1.45)%.结论:白芷提取分离物对酪氨酸酶活性具有抑制作用.     

Phenolic and Terpenoid Constituents from the Sri Lankan Medicinal Plant Osbeckia aspera.

Abstract

A crude aqueous acetone extract of Osbeckia aspera. Blume (Melastomataceae), a plant from Sri Lanka used traditionally to treat liver disease, was fractionated by column and preparative paper chromatography, and the fractions were analyzed by high-performance liquid chromatography (HPLC) using diode array and mass spectrometric detection. Phenolic acids (gallic, protocatechuic, and ellagic acid), flavonol glycosides [quercetin 3-O.-β-galactopyranoside, quercetin 3-O.-β-glucopyranoside, kaempferol 3-O.-β-glucopyranoside, and kaempferol 3-O.-(6″-O.-p.-coumaroyl-β-glucopyranoside) (tiliroside)] and flavonol aglycones (quercetin and kaempferol) were identified by comparison of their retention times, UV and MS spectra with those of authentic standards. Five compounds from a methanol extract were identified by NMR spectroscopy as the flavonol glycosides, quercetin 3-O.-(3″-O.-acetyl-β-galactopyranoside) and kaempferol 3-O.-[2″,6″-di-O.-(E.,E.)-p.-coumaroyl-β-glucopyranoside], and the norsesquiterpenoids 6,9-dihydroxy-4,7-megastig-madien-3-one, 9-hydroxy-4,7-megastigmadien-3-one and 9-hydroxy-4-megastigmen-3-one. A crude water extract, 50% acetone extract and fractions from this extract, a 100% methanol extract, and three of the phenolic acids in the fractions were tested for in vitro. hepatoprotective activity against bromobenzene and 2,6-dimethyl-N.-acetyl p.-quinoneimine toxicity to HepG2 liver-derived cells. The crude water extract showed protective activity against both liver toxins, whereas the fractions and compounds were more protective against 2,6-dimethyl-N.-acetyl p.-quinoneimine than bromobenzene. Of the three phenolic acids present in the extracts that were tested, gallic and protocatechuic acids were more active at protecting the liver cells from the two toxic compounds than ellagic acid.     

Pharmacological Studies of Mentha longifolia Phenolic Extracts. II. Hepatoprotective Activity

The effects of Mentha longifolia crude ethanolic extract (F 1), rich in luteolin glycosides (F 2), apigenin glycosides (F 3) and phenolic acids (F 4), were studied on CCl 4 -induced liver injury in mice. Administration of CCl 4 -induced significant impairment in hepatic antioxidant status, decreasing the glutathione content and superoxide dismutase activity, and stimulating lipid peroxidation. Pretreatment with Mentha longifolia extracts significantly improved hepatic antioxidant status in mice, which was most pronounced in the reduction of CCl 4 -mediated lipid peroxidation. In addition, in pretreated animals, an increase in hepatic glutathione and superoxide dismutase activity, as well as a decrease of cytochrome P450, was found.     

Phenolic Constituents of Selaginella doederleinii

Eleven phenolic Compounds have been isolated from the ethanolic extract of SELAGINELLA DOEDERLEINII by a combination of Chromatographic techniques. These are five lignans: (-)-lirioresinol A, (-)-lirioresinol B, (+)-wikstromol, (-)-nortracheloside, (+)-matairesinol ( 1), two phenylpropanones: 3-hydroxy-1-(3-methoxy-4-hydroxyphenyl)-propan-1-one ( 2), 3-hydroxy-1-(3,5 -dimethoxy-4-hydroxyphenyl)-propan-1-one ( 3), and four biflavonoids: amentoflavone, 7,7'-di- O-methylamentoflavone, 7,4',7',4'-tetra- O-methylamentoflavone, and heveaflavone ( 4). Compounds 1, 2, and 3 are novel natural secondary metabolites. Their structures were deduced from their spectral data (mainly (1)H-NMR, mass, and CD). Lignans are described here for the first time in the family Selaginellaceae. Their cytotoxic activity against L 929 murine cells accounts for the use of the plant in traditional Chinese medicine as an anticancer agent.     

Pharmacological Study of Mentha longifolia Phenolic Extracts

The effect of M. longifolia crude ethanol extract (F1), as well as fractions rich in luteolin glycosides (F2), apigenin glycosides (F3) and phenolic acids (F4) on intestine motility, spontaneous motility, pentobarbital induced sleep and bile secretion have been investigated. The crude ethanol extract was effective only on intestinal motility, apigenin and luteolin glycosides active on spontaneous motility. Phenolic acids were found to possess significant spasmodic, choleretic and CNS stimulative effects.     

Inhibition of cryptosporidium parvum in vitro by 9-(alkylthio)acridine derivatives

The synthesis of several acridinic thioethers is described. Compounds prepared were tested in vitro as potential drugs against the opportunistic infection known as cryptosporidiosis. With a view to predict activity, the quantitative structure-activity relationships were investigated. Correlations between experimental data and either log P or pKa are discussed.     

Inhibition of thrombin by iopromide in vitro

Iopromide is a nonionic, iodinated, monomeric, radiographic contrast agent used in various indications, including coronary angiography and visceral and peripheral arteriography. Nonionic contrast media have been postulated to increase thrombogenicity when compared with ionic contrast media. The goal of this study was to characterize the interaction of iopromide with thrombin, specifically to determine the rate, extent, specificity, and reversibility of the thrombin inhibition by iopromide, the integrity of the thrombin-iopromide complex, and the inhibitory potency of iopromide using a validated assay methodology. Iopromide was mixed with purified thrombin or pooled serum from healthy male and female donors. The final concentrations of iopromide in the presence of estimated physiologic concentrations of thrombin (1 nmol/L) were 0-184 mmol/L. After incubation for defined time intervals, the activity of thrombin was determined by adding substrate and measuring the absorbance of the generated chromophores at 405 nm. The possible inhibition of the protease trypsin by iopromide was investigated to evaluate the specificity of thrombin inhibition by iopromide. Iopromide was compared with Thromstop, a known thrombin inhibitor, to assess the relative potency of iopromide. The inhibition of thrombin by iopromide was immediate, rapidly reversible, and proportionate to the iopromide concentrations. The minimum inhibitory concentration of iopromide was 50 mmol/L. At the highest iopromide concentration tested, 184 mmol/L, the mean inhibition of thrombin activity was 44.5%. The mean concentration of iopromide associated with a 50% inhibition was 206 mmol/L. The inhibitory potency of iopromide was 4 x 10(6) times smaller than that of Thromstop. The inhibition of thrombin by iopromide is specific, because trypsin was not inhibited by iopromide. The results indicate that in vitro iopromide at clinically relevant concentrations partially inhibits thrombin activity. However, the in vitro model used does not consider other factors that may be relevant for the overall coagulation response in vivo.     

Inhibition of Staphylococcus Aureus Mediated by Extracts from Iranian Plants

In order to find new antibacterial agents effective against Staphylococcus aureus, ethanolic extracts of 10 plants were tested. S. aureus (489 samples) were isolated either from healthy carriers (nose and throat) or clinical samples. Out of 489 isolates tested, 98.6% were sensitive to trimethoprim-sulfamethoxazole which was used as the reference antibiotic. From the plant extracts screened for antibacterial activity, Myrtus communis L. (leaves) had the greatest activity, inhibiting the growth of 99% of the isolates. Glycyrrhiza glabra L., Eucalyptus globolus Labill and Menta viridis L., were also active against the isolates inhibiting the growth of 90, 59.5 and 48.7% of the isolates, respectively. All of these extracts were active against the reference strains of S. aureus tested. Saturia hortensis L., Teucrium polium L., and Achillea santolina L., had very little antibacterial activity, while Trigonella foenum graecum L., Echium amoenum Fisch & Mey (flowers) and Juglans regia L. (leaves), had no antibacterial activity against the bacterial isolates.     

Qualitative and Quantitative Analysis of the Phenolic Constituents from Orthosiphon aristatus

ORTHOSIPHON ARISTATUS (Orthosiphonis folium DAB 9) was studied with regard to its phenolic constituents. Twenty compounds were isolated and identified on the basis of their spectral characteristics. The compounds included nine lipophilic flavones, two flavonol glycosides, and nine caffeic acid derivatives. The presence of the recently reported methylripariochromene A could not be confirmed. All compounds identified were quantified by HPLC. The caffeic acid derivatives including the major compounds rosmarinic acid and 2,3-dicaffeoyltartaric acid (67% of total identified phenolics) predominated over the flavones (33%) in an aqueous MeOH extract. The predominance of the caffeic acid derivatives was even more pronounced in a hot water extract (94.5% of total identified phenolics) that was comparable to a herbal tea.     

UPLC-Q-TOF-MS分析罗汉果叶醇提物中化学成分

目的建立超高效液相色谱-四极杆串联飞行时间质谱(ultra performance liquidchromatography-quadrupole time-of-flight mass spectrometry,UPLC-Q-TOF-MS)对罗汉果叶醇提取物溶液进行快速定性的方法。方法色谱条件：色谱柱为ACQUITY UPLC BEH C₁₈(2.1 mm×100 mm,1.8μm);进样体积为5μL;流速为0.3 mL·min^-1,流动相为0.1%甲酸水溶液(A)-乙腈溶液(B)进行梯度洗脱;质谱条件：电喷雾离子源(ESI),检测范围m/z 50～1 000,分别采用正、负离子进行MSE模式采集,基于高分辨分子量和质谱碎片信息,结合数据库匹配对质谱数据进行分析。结果从罗汉果叶醇提取物中共表征出64个化合物,其中黄酮类7个,酸类14个,酯类12个,三萜类10个,酮类4个,醇类4个以及其他类13个。结论UPLC-Q-TOF-MS技术为罗汉果叶中化学成分的分析提供了简便、高效、精确的参考方法。     

Growth Inhibition of Asexual Erythrocytic Forms of Plasmodium falciparum and P. berghei in vitro by Naphthylisoquinoline Alkaloid-Containing Extracts of Ancistrocladus and Triphyophyllum Species

Naphthylisoquinoline alkaloid-containing extracts [1–20] of four species of the genus Ancistrocladus (A. barteri, A. heyneanus, A. robertsoniorum, and A. tectorius) and of Triphyophyllum peltatum have been examined for their antiplasmodial activity against asexual erythrocytic forms of Plasmodium falciparum (NF 54, clone A1A9) and P. berghei (Anka) in vitro. Incorporation of 3 H-hypoxanthine was measured in the presence of the test substances. The above mentioned plant species are used in several countries of the pantropical area against fevers and malaria. Five of the examined extracts displayed high growth inhibiting activity in the P. falciparum system : CH 2 Cl 2 /NH 3 bark extract of T. peltatum [20], EtOH leaf extract of A. barteri [4], CH 2 Cl 2 leaf [14] and CH 2 Cl 2 /NH 3 bark [15] extracts of A. tectorius, and CH 2 Cl 2 leaf [17] extract of T. peltatum). These extracts (IC 50 < 1 µg/ml) [4, 14, 15, 17, and 20] were further examined in the P. berghei system. Two of them (the CH 2 Cl 2 /NH 3 bark extracts of A. tectorius [15] and T. peltatum [20]) were proven to be highly active in both test systems. These findings confirm that extracts of species belonging to the Ancistrocladaceae and the Dioncophyllaceae have a considerable antiplasmodial capacity.     

Inhibition of glutamate decarboxylase by salicylate in vitro

Salicylate inhibits the activity of glutamate decarboxylase from Escherichia coli by a reversible mechanism, but high concentrations of the drug denature the enzyme protein Salicylate inhibits the activity of glutamate decarboxylase prepared from Escherichia coli and rat brain (Gould, Huggins & Smith, 1963; Gould & Smith, 1965). It was suggested that the mechanism of inhibition involved an irreversible combination of the drug with the enzyme protein. This mechanism has not been confirmed in the present work. High concentrations of salicylate denature, and lower concentrations cause a reversible inhibition of the bacterial enzyme.     

Antimicrobial Activity and Phytochemical Constituents of Leaf Extracts of Cassia auriculata

Plants produce a wide variety of phytochemical constituents, which are secondary metabolites and are used either directly or indirectly in the pharmaceutical industry. ‘For centuries, man has effectively used various components of plants or their extracts for the treatment of many diseases, including bacterial infections. In the present study methanol, chloroform and aqueous extracts of Cassia auriculata leaf were subjected for antimicrobial activity by well-diffusion method against six bacterial strains namely Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis. The results revealed that the methanol and chloroform extracts exhibited strong inhibitory activity against all the tested organisms (zone of inhibition of 12-20 mm), except Pseudomonas aeruginosa (zone of inhibition 10 mm or nil). The aqueous extracts showed moderate activity by ‘Zone of inhibition ≤12 or nil). The extracts were screened for their phytochemical constituents by standard protocols’ and were shown to contain carbohydrates, proteins, alkaloids, flavonoids, steroids, saponins and tannins. The antibacterial activity of these extracts is possibly linked to the presence of flavonoids, steroid, saponins and/or tannins. Further studies are needed to determine the precise active principles from Cassia auriculata.     

Inhibition of uterine contractions by rolipram in vitro

The human myometrium contains two different forms of phosphodiesterase (PDE). One form is characterized by its lack of substrate specificity and its calcium-calmodulin dependence. The other one is selective for cyclic adenosine monophosphate (cAMP). Rolipram (4-[3-(cyclopentyloxy)-4-methoxyphenyl]-2-pyrrolidinone, ZK 62711) is a specific cAMP-PDE inhibitor. The physiological significance of the two forms of PDE is still unknown, particularly the role of the cAMP-specific form in the control of uterine motility. The latter form largely occurs in myometrium of pregnant women near term and is also present during the third trimester of pregnancy. Using isolated guinea-pig uteri it has been shown that rolipram in the concentration of 9 x 10(-4) mol/l caused the organ to remain insensitive to the stimulatory action of oxytocin. 9 x 10(-6) mol/l rolipram led to immediate relaxation of the uterus when it was added to the organ bath after the maximum concentration was reached following oxytocin stimulation. A new drug like rolipram effecting uterine motility in a not receptor-mediated manner might have advantages in comparison to beta-mimetics for the treatment of premature labor.