摘要:

AbstractInsect antifeedants are the substances that play a significant role in host plant selection by phytophagous insects. Extensive work has been done on natural antifeedants and a large number of these compounds have been identified belonging to different classes during the past decade. The present article deals with various chemical and biological aspects of insect antifeedants and with their possible role in insect pest management.

ISSN:0951-418X    

DOI:10.1002/ptr.2650070502

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of chalcones and flavanone isolated from licorice roots (Glycyrrhiza inflataBat.) on human polymorphonuclear neutrophil (PMN) degranulation were investigated. Licochalcone A (2‐methoxy‐4,4′‐dihydroxy‐5‐α,α‐dimethylallylchalcone) and licochalcone B (2‐methoxy 3,4,4′‐trihydroxychalcone), at concentrations of 10−6M to 10−3M, inhibited calcium ionophore A 23187 (A 23187)‐, leukotriene B4(LTB4) plus cytochalasin B (cyto B)‐, platelet activating factor (PAF) plus cyto B‐ and N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) plus cyto B‐induced lysosomal enzyme release from human PMNs. Isoliquiritigenin, isoliquiritin, liquiritigenin and liquiritin had no effects on PMN degranulation induced by various stimuli. In addition, licochalcones A and B, at high concentrations (10−4M–10−3M), increased cyclic AMP in human PMNs. Furthermore, licochalcones A and B, at concentrations of 10−6M to 10−3M, reduced the elevation of cytosolic free calcium concentration induced by calcium io

ISSN:0951-418X    

DOI:10.1002/ptr.2650070503

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of six flavonoids isolated from Sinkiang Licorice roots (lichochalcones A and B, isoliquiritigenin, isoliquiritin, liquiritigenin and liquiritin) on arachidonate metabolism and aggregation in human platelets were studied. Licochalcones A and B at concentrations of 10−5M to 10−3M inhibited the formation of 12‐hydroxy‐5,8,10‐heptadecatrienoic acid (HHT) and thromboxane B2(TXB2), does‐dependently. Furthermore, isoliquiritigenin and liquiritigenin at higher concentrations (10−4M–10−3M) inhibited the formation of HHT and TXB2, while they increased the formation of 12‐hydroxy‐5,8,10,14‐eicosatetraenoic acid (12‐HETE). However, isoliquiritin and liquiritin had no effect on arachidonate metabolism. Licochalcones A and B inhibited thrombin‐induced platelet aggregation at concentrations of 2 × 10−5M to 2 × 10−4M. Isoliquiritigenin, liquiritigenin, isoliquiritin and liquiritin had no effects on the thrombin‐induced aggregation. To clarify the inhibitory effects of flavonoids in licorice roots on the formation of HHT and TXB2and thrombin‐induced aggregation, we studied the effects of flavonoids on cytosolic free calcium concentrations ([Ca2+]i) induced by thrombin. The results showed that licochalcones A and B inhibited the elevation of [Ca2+]i

ISSN:0951-418X    

DOI:10.1002/ptr.2650070504

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractInvestigations were undertaken on the antiviral action of an hydroalcoholic extract fromHaemanthus albiflosbulb, reported here as an efficient agent against RNA viruses. Poliovirus propagated on HeLa cells with different concentrations of the extract was used in the assays. The effect on cellular RNA, DNA and protein synthesis as well as on viral RNA synthesis was evaluated by measuring the radioactivity incorporated using labelled precursors.A 0.2 μL/mL concentration of the plant extract showed an inhibition of cellular RNA, DNA and protein synthesis compared with the control of 44%, 40% and 52%, respectively. At the same concentration a 90% decrease of the viral RNA synthesis was observed over 210 min

ISSN:0951-418X    

DOI:10.1002/ptr.2650070505

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe methanol fraction of the extract ofPluchea indicaroots exhibited significant hepatoprotective activity against experimentally induced hepatotoxicity by carbon tetrachloride in rats and mice. The extract caused significant reduction of the elevated serum enzyme levels (AST, ALT, LDH and serum alkaline phosphatase) and serum bilirubin content in acute liver injury. A significant increase of reduced serum total protein, albumin and albumin/globulin ratio was also observed on extract treatment. The extract significantly reduced the prolonged pentobarbitone‐induced sleeping time and also caused a significant reduction of plasma prothrombin time in comparison with CCl4‐treated animals. The extract caused significant reduction of the increased bromosulphalein retention by CCl4‐treatment. These findings are suggestive of a potent hepatoprotective effect of the extract under investig

ISSN:0951-418X    

DOI:10.1002/ptr.2650070506

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractExperiments were designed to examine the analgesic and anti‐inflammatory activities of the crude hydroalcoholic extract (CE) ofHymenaea martiana. The CE ofH. martiana(25‐200 mg/kg, i.p.) caused a graded inhibition of hindpaw oedema induced by carrageenan, PAF‐acether (PAF), serotonin (5‐HT), dextran and histamine (HIS). However, the CE given orally up to 500 mg/kg had no effect on the agonist‐induced hindpaw oedema. The CE given intraperitoneally, but not orally, caused a graded and pronounced inhibition of His, 5‐HT, bradykinin (BK) and PAF‐induced increase of vascular permeability. When the CE was given orally (300 mg/kg) once a day for 15 days it caused a significant increase of agonist‐induced increase of vascular permeability. The CE given either by p.o. or by i.p. routes (100‐800 mg/kg) dose‐dependently inhibited arachidonic acid (AA)‐induced ear oedema in mice, being significantly more potent when it was given by the latter route. In contrast, CE at the same doses, failed to inhibit croton‐oil‐induced ear oedema in mice. The CE ofH. martianagiven by either i.p. or p.o. routes caused a marked and dose‐dependent antinociceptive activity as revealed by its antagonistic action against acetylcholine, acetic acid or AA‐induced writhing responses in mice, being more effective when given intraperitoneally. These results, and those previously reported with the CE ofH. martianain the isolated preparations, provide strong experimental support which argues in favour of the beneficial use of this plant extract in folk medicine. The exact mechanism that underlies its analgesic and anti‐inflammatory profiles remains unclear, but may result from its ability to inhibit the generation of lipoxygenase and/or cyclooxygenase products

ISSN:0951-418X    

DOI:10.1002/ptr.2650070507

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThree preparations ofSatureja montanasubsp. montana leaves were tested for diuretic activity in rats: an infusion, a water‐alcohol extract and essential oil. In 1‐day experiments, the cumulative volume of urine was collected during the first 5 h after oral administration of 5 mL/100 g body weight of plant preparation. It was established that all the preparations tested initially caused a decrease in diuresis and subsequently a mild stimulation of diuresis. 0.1% solution of essential oil was considered to be a therapeutic dose, whereas 0.5% and 1% solutions caused toxic symptoms in the animals. A further experiment involving treatment of rats for 3 days with a 10% drug infusion and 0.1% essential oil solution demonstrated the considerable diuretic activity of winter sav

ISSN:0951-418X    

DOI:10.1002/ptr.2650070508

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA crude polysaccharide fraction (F‐5) from ‘Juzen‐Taiho‐To’ (TJ‐48), a Kampo (Japanese herbal) medicine prepared by decocting a prescription of 10 herbs, enhanced the production of interleukin‐2 (IL‐2) by mouse spleen cells stimulated with concanavalin‐A (Con‐A). When F‐5 was fractionated by cetavlon precipitation, the neutral polysaccharide fraction (F‐5‐5) enhanced IL‐2 production, and also showed anticomplementary activity. Anion‐exchange chromatography and gel filtration indicated that F‐5‐5 contained at least seven kinds of polysaccharides with anticomplementary activity or IL‐2 production enhancing activity. Among these polysaccharides relatively higher molecular weight polysaccharides (F‐5‐5IIa‐1‐1, IIa‐2‐1, IIb‐1 and IIc‐1) showed only anticomplementary activity, whereas relatively lower molecular weight polysaccharides (F‐5‐5IIb‐3A, IIb‐3C and IIc‐2A) enhanced only IL‐2 production of the spleen cells. These immunomodulating polysaccharides consisted of neutral sugars such as arabinose, galactose and galacturonic acid, and the IL‐2 production enhancing polysaccharides also contained a relatively large proportion of protein. Pronase digestion of F‐5‐5 failed to decrease the enhancement of IL‐2 production, whereas the activity significantly decreased by chemical degradation of the carbohydrate moiety or uronic acid with periodate or lithium. Methylation analysis before and after base‐catalysed β‐elimination suggested that the anticomplementary polysaccharides were grouped into pectic polysaccharides, and that the most potent IL‐2 production enhancing polysaccharide (F‐5‐5IIc‐2

ISSN:0951-418X    

DOI:10.1002/ptr.2650070509

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractOral administration of an essential oil obtained fromHelichrysum picardiiBoiss.&Reuter at doses of 13 and 26 mg/kg to normal rats produced a significant choleretic activity. A quantitative determination of the total bile acid concentration was carried out using an enzymatic kit prepared with purified 3‐α‐hydroxysteroid dehydrogenase. The essential oil induced in bile secretion but it did not produce an enhancement in the bile con

ISSN:0951-418X    

DOI:10.1002/ptr.2650070510

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractDifferent samples of essential oil fromHelichrysum picardiiBoiss.&Reuter (Compositae) collected at the beginning of each season from the same locality have been tested for their cytostatic and antimicrobial activity. All the oil samples showed a strongerin vitroactivity against HEp‐2 cells than a 6‐mercaptopurine solution used as a positive control. Gram‐positive bacteria as well as the fungusCandida albicanswere sensitive to the action of the essential oil, whereas none of the samples showed activity against the gram‐negative b

ISSN:0951-418X    

DOI:10.1002/ptr.2650070511

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY