摘要:

AbstractMajor polypeptide species of proteins have been identified and analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis in fresh extracts of the whole leaf, leaf gel, root and stalk portions ofAloe barbadensisMiller plants of immature, young and mature ages. Extracts of the freshAloeplant portions were prepared by dissection, tissue disruption, differential centrifugation and gel filtration methods. Extracted plant portions analysed by separation electrophoresis were also assayed by biochemical and immunological techniques for the presence of lectin associated reactions, i.e. agglutination or mitogenicity. Results of the separation electrophoresis analysis of extracts prepared from fresh whole leaves and leaf gel of matureAloe barbadensisMiller plants revealed 23 identifiable different polypeptides. Molecular weights of these polypeptides, calculated from sets of molecular weight reference standards, ranged from 70 000 for the largest to 3000 for the smallest. Electrophoresis profiles of commercially processed and freshly processedAloe barbadensisMiller andAloe saponariaHaw leaf gel extracts revealed similar patterns for major peptides. Treatment of mature wholeAloeleaf extracts with acidic and alkaline conditions revealed distinct changes in pH stability of ten peptides. Comparisons of separation electrophoresis profiles of fresh extracts ofAloewhole leaves and of leaf gel portions revealed marked differences in both molecular weights and concentrations of peptides found in extracts from mature, young or immature plants. This report is the first to describe the nature and types of polypeptides detected in extracts of whole leaf, leaf gel, stalk and root portions of immature, young and matureAloeplants. Accordingly, information in this report may be of considerable value in helping to identify and characterizeAloesubstances present during processing in extracts and in products.

ISSN:0951-418X    

DOI:10.1002/ptr.2650090602

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA chloroform extract of the seeds of the West African legumeMillettia thonningiihas been shown to kill the snails which transmit the schistosomiasis and also the larvae of the parasite itself. This study examines the bioactivity of the chloroform extract ofM. thonningiiin aqueous non‐sterile conditions. Suspensions of the extract in water maintained larvicidal activity for long periods. HPLC analysis showed that over a period of 4 weeks in aqueous suspension, degradation of two of the compounds present, the isoflavonoids alpinumisoflavone and 4′‐methylalpinumisoflavone, occurred and bioactivity was eventually lost, indicating that these compounds are probably responsible for the bioactivity. These isoflavonoids are thought to act via inhibition of electron tran

ISSN:0951-418X    

DOI:10.1002/ptr.2650090603

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe hexane extract of the Chinese medicinal plantAcorus gramineus(Araceae) has previously been shown to possess significant bioactivity towards a range of organisms inin vitrobioassays including digenean, nematode and arthropod targets. In the present study the principal active components inA. gramineuswere identified as the phenylpropanoids α‐ and β‐asarone by comparing TLC, HPLC, UV and bioassay data obtained using the hexane extract with those derived with commercially available pure compounds. The known mammalian toxicity and carcinogenicity of asarones means that they are unlikely to have any utility as lead compounds for the development of practical anthelmintics and insecti

ISSN:0951-418X    

DOI:10.1002/ptr.2650090604

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the present study the cytotoxicity of 16 proanthocyanidins was evaluated in GLC4, a human small cell lung carcinoma cell line, and in COLO 320, a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. With IC50values ranging from 18 to>200 μM following continuous incubation, the proanthocyanidins examined possess only moderate to low cytotoxicity. The highest cytotoxicity was found in a series of galloylated proanthocyanidins. An increase in the number of galloyl substituents increased cytotoxicity. Simple proanthocyanidins possess low cytotoxicity, that was independent of the stereochemistry. Compounds with doubly linked units had negligible cytotoxic effects, even at 200 μM, the highest concentration teste

ISSN:0951-418X    

DOI:10.1002/ptr.2650090605

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA series of flavonoids, able to inhibit non‐enzymic and enzymic lipid peroxidation, were investigated as inhibitors of cytochrome P‐450 mediated reactions (aminopyrine N‐demethylation and aniline hydroxylation) in rat liver microsomes. The most potent compounds were chrysin, luteolin, amentoflavone and eriodictyol (aminopyrine N‐demethylation) and apigenin, kaempferol and quercetin (aniline hydroxylation). Some structure‐activity relationships were established for inhibition of aminopyrine N‐demethylation and it was observed that the resorcinol configuration of the ring A is a determinant feature, whereas O‐glycosylation abolished the activity. Most of the compounds showed lower activity on aniline hydroxylation. The presence of these flavonoids during incubation of microsomes in a medium containing NADPH did not modify the cytochrome P‐450 concentration and protected against lipid peroxidation induced degradation of

ISSN:0951-418X    

DOI:10.1002/ptr.2650090606

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAt the maximum dose tested, 100 μg/plate, lucidin‐3‐O‐primveroside (LUC‐Prv) exhibited mutagenic potential inSalmonella typhimuriumTA100 without S9 mix but not with the addition of this preparation. When the pH of the tested system was reduced from 7.4 to 6.5, the same results were obtained. However, after hesperidinase treatment at pH 6.5, higher mutagenicity was demonstrated, and the mutagenicity of the hydrolysis product in TA100 decreased in the presence of S9 mix. When the preincubation time of the mixture was kept longer, i.e. 30, 60 and 120 min, the number of revertants in TA100 without S9 mix became higher. When the concentration of hesperidinase was varied from 5 × 10−5to 2.5 × 10−2unit, no change in the number of revertants was observed. In contrast, LUC‐Prv and its hydrolysis products demonstrated no mutagenicity in TA98 by the sa

ISSN:0951-418X    

DOI:10.1002/ptr.2650090607

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractCapsaicin (8‐methyl‐n‐vanillyl‐6‐nonenamide), caused a concentration dependent leakage of chromate through an egg lecithin (phosphatidyl choline) liposomal preparation. Capsaicin treatment of liposomal suspensions caused a maximum leakage of marker chromate at 20 min and then attained a plateau from 30 min onward. Treatment of liposomes with various concentrations of capsaicin (μg/mL loposomal suspensions) showed that lower concentrations of capsaicin (<0‐0.1 μg/mL) caused greater chromate leakage than higher concentrations (0.1‐0.5 μg/mL). This dual effect of capsaicin on liposome membrane was accompanied by an increased amount of malondialdehyde formed (an important end product of lipid peroxidation) at lower concentrations (<0.10 μg/mL) than at higher concentration

ISSN:0951-418X    

DOI:10.1002/ptr.2650090608

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe present study was undertaken to identify potential phytotherapeutic agents among the aqueous extracts of 151 herbal medicinal plants of Korea. Extracts were assayed for (1) binding potency to hepatitis B‐virus surface antigen (HBsAg), and (2) inhibition of serum hepatitis B‐virus DNA polymerase activity. Of the 151 aqueous plant extracts tested, 33 demonstrated a positive precipitation reaction with HBsAg+serum, and 15 of these specifically bound HBsAg in serum as well as recombinant HBsAg (Hepavax®). Nine extracts competitively inhibited>80% of anti‐HBsAg antibody binding to Hepavax® HBsAg. Furthermore, nine of these 15 plant extracts also exhibited greater than 25%—50% inhibition of hepatitis B‐virus (HBV) DNA polymerase activity, and also significantly stimulated production of the potent cytokine, tumour necrosis factor (TNF). None of the extract concentrations used altered liver function parameters of

ISSN:0951-418X    

DOI:10.1002/ptr.2650090609

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effects of anOlea europaeaL. dried leaf extract containing 3.2% of oleuropein were investigated on the rat isolated ileum and trachea. On basal tone rat isolated ileum,Olea europaeaL. extract was shown to produce a dual effect characterized by a contraction at low doses (10−7‐10−4g/mL) and a relaxation at high doses (3.10−4‐10−3g/mL). The extract induced contractile effect was found to involve at least histamine, 5‐hydroxytryptamine and thromboxane A2. On precontracted rat isolated ileum, the extract only induced a relaxation that was not modified by nifedipine, diltiazem, dipyridamone, verapamil or papaverine (10−6M). The effects of the extract were also studied on the rat isolated trachea. On basal tone organs,Olea europaeaL. extract did not produce any effect, whereas, when basal tone was raised by acetylcholine (ACh 10−3M), the drug caused a relaxation (maximal effect 39.01% ± 5.40%) of the response to theophylline; (3.10 ± 10−3Mn= 15). It is suggested that the induced relaxation is consecutive to an increase of in

ISSN:0951-418X    

DOI:10.1002/ptr.2650090610

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThis report investigates the antioxidant properties ofR. cordifoliaextract for protection against lipid peroxidation and reduced glutathione (GSH) content in rat liver homogenate compared with vitamin E and parabenzoquinone (PBQ).R. cordifoliaprotects against depletion of glutathione in a dose and time dependent manner, an inverse correlation was observed between reduced glutathione depletion and malondialdehyde (MDA) formation. Interestingly, parabenzoquinone showed a better response thanR. cordifoliaon cumene hydroperoxide (CHP) induced malon‐dialdehyde (MDA) release but there was no response in the rate of reduced glutathione (GHS) depletion. Thus it appears thatR. cordifoliais a potent antiperoxidative and antioxidant. The mechanism of action is different to that of vitamin E and parabenzoquinone (PBQ

ISSN:0951-418X    

DOI:10.1002/ptr.2650090611

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY