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Studi scientifici sull'Aloe Arborescens



Antiallergico

Inhibitory mechanism of aloe single component (alprogen) on mediator release in guinea pig lung mast cells activated with specific antigen-antibody reactions.

Ro JY, Lee BC, Kim JY, Chung YJ, Chung MH, Lee SK, Jo TH, Kim KH, Park YI. Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea. JYRO426@yumc.yonsei.ac.kr

We previously reported that the glycoprotein extracted from aloe strongly inhibited the mediator releases caused by the activation of guinea pig lung mast cells. Therefore, this study aimed to purify a single component that has an antiallergic effect from crude aloe extract and then to assess the effects of aloe single component (alprogen) on the mechanism of mediator releases caused by the mast cell activation. We purified aloe extracts by using various columns. We also purified mast cells from guinea pig lung tissues by using enzyme digestion, rough and discontinuous density Percoll gradient. Mast cells were sensitized with IgG(1) (anti-ovalbumin) and challenged with ovalbumin. Histamine was assayed by using a fluorometric analyzer and leukotrienes by radioimmunoassay. [Ca(2+)](i) level was analyzed by using a confocal laser scanning microscope. Protein kinase activity was determined by the protein phosphorylated with [gamma-(32)P]ATP. The phospholipase D activity was assessed by the labeled phosphatidylalcohol. The amount of mass 1,2-diacylglycerol (DAG) was measured by the [(3)H]DAG produced when prelabeled with [(3)H]myristic acid. Phospholipase A(2) activity was determined by measuring the lyso-phosphatidylcholine released from the labeled phospholipids. Alprogen significantly decreased histamine and leukotriene releases and blocked completely Ca(2+) influx during mast cell activation. The protein kinase C and phospholipase D activities were decreased by alprogen in dose-dependent manner. Alprogen inhibited mass DAG formation and the phospholipase A(2) activity during mast cell activation. The data suggest that alprogen purified from aloe inhibits multiple signals as well as blocking Ca(2+) influx caused by mast cells activated with specific antigen-antibody reactions and that then the inhibition of histamine and leukotriene release follows. PMID: 10604937

Analgesico e antiinfiammatorio

Initial characterization of the effects of Aloe vera at a crayfish neuromuscular junction.

Friedman RN, Si K. Section of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana 46202-5112, USA. rfriedma@iupui.edu

This study examines the effects of Aloe vera on neurotransmission processes in a well-established invertebrate neuromuscular junction preparation. We studied concentration-response relationships of an Aloe vera extract on excitatory junctional potentials (EJPs) at the opener muscle of the dactyl in the first and second walking limbs of crayfish (Procambarus clarkii and simulans). We observed concentration-dependent depolarizations of the muscle fibre membrane resting potential, depression of EJP amplitudes and an increase in latency to onset of the EJP following electrical stimulation of the isolated excitatory axon in the meropodite. These effects occurred with Aloe concentrations within the 1%-10% (wt-vol) range. Effects of lower concentrations, ranging to a minimum of 0.01% were equivocal. The effects of Aloe were at least partially, and in a majority of cases totally, reversible. EJPs reduced by Aloe could be restored by increasing the nerve stimulation amplitude. This, along with the latency increase, suggests a depression of action potential generation and conduction. The results provide a preliminary characterization of the effects of Aloe vera on the neurotransmission process and suggest that these effects may at least partially account for Aloe's analgesic and antiinflammatory effects. This study shows that the crayfish NMJ preparation should be useful for further elucidating the location(s) and mechanism(s) of action of Aloe on the nervous system. Copyright 1999 John Wiley & Sons, Ltd. PMID: 10548750

Antiinflammatory activity of Muktashukti bhasma.

Chauhan O, Godhwani JL, Khanna NK, Pendse VK. Department of Pharmacology and Experimental Therapeutics, Dr. Sampurnanand Medical College, Jodhpur, India.

Muktashukti bhasma (MSB), an Ayurvedic compound, consisting of pearl, Aloe vera and vinegar, inhibited acute and subacute inflammation in albino rats as induced by subplanter injection of carrageenan, histamine, 5-HT, nystatin and subcutaneous implant of cotton pellets. In all the test procedures the antiinflammatory response of 1000 mg/kg MSB was comparable to the response observed with 300 mg/kg acetylsalicylic acid (ASA). Oral premedication with MSB delayed castor oil-induced diarrhoea in rats, indicating its prostaglandin inhibitory activity. The antiinflammatory activity of the compound is attributed to its ability to cause inhibition of prostaglandins, histamine and 5-HT and also by stabilization of the lysosomal membranes. The antiinflammatory activity of MSB seems one third to half as potent as ASA. PMID: 10356960

Antiinflammatory activity of extracts from Aloe vera gel.

Vazquez B, Avila G, Segura D, Escalante B. Laboratory of Pharmacology, Escuela Nacional de Estudios Profesionales Iztacala (E.N.E.P-I), Universidad Nacional Autonoma de Mexico, Tlalnepantla, Mexico.

We studied the effects of aqueous, chloroform, and ethanol extracts of Aloe vera gel on carrageenan-induced edema in the rat paw, and neutrophil migration into the peritoneal cavity stimulated by carrageenan. We also studied the capacity of the aqueous extract to inhibit cyclooxygenase activity. The aqueous and chloroform extracts decreased the edema induced in the hind-paw and the number of neutrophils migrating into the peritoneal cavity, whereas the ethanol extract only decreased the number of neutrophils. The antiinflammatory agents indomethacin and dexamethasone also decreased carrageenan-induced edema and neutrophil migration. The aqueous extract inhibited prostaglandin E2 production from [14C]arachidonic acid. The chemical tests performed in the aqueous extract for anthraglycosides, reductor sugars and cardiotonic glycosides were positive. In the ethanol extract, the chemical tests performed for saponins, carbohydrates naftoquinones, sterols, triterpenoids and anthraquinones were also positive. In the chloroform extract, the chemical tests performed for sterols type delta 5, and anthraquinones were positive. These results demonstrated that the extracts of Aloe vera gel have antiinflammatory activity and suggested its inhibitory action on the arachidonic acid pathway via cyclooxygenase. PMID: 9121170

Antiinflammatory C-glucosyl chromone from Aloe barbadensis.

Hutter JA, Salman M, Stavinoha WB, Satsangi N, Williams RF, Streeper RT, Weintraub ST. Department of Pharmacology, Research Imaging Center, University of Texas Health Science Center at San Antonio, 78284-7760, USA.

A new antiinflammatory agent identified as 8-[C-beta-D-[2-O-(E)-cinnamoyl]glucopyranosyl]-2- [(R)-2-hydroxypropyl]-7-methoxy-5-methylchromone (1) has been isolated from Aloe barbadensis Miller. At a dose of 200 microg/mouse ear, 1 exhibited topical antiinflammatory activity equivalent to 200 microg/ear of hydrocortisone. There was no reduction in thymus weight caused by treatment with 1 for any of the doses tested, while 200 microg/ear of hydrocortisone resulted in a 50% decrease in thymus weight. PMID: 8778246

Isolation of a stimulatory system in an Aloe extract.

Davis RH, Parker WL, Samson RT, Murdoch DP. Pennsylvania College of Podiatric Medicine, Philadelphia 19107.

The authors' previous work on a 50% ethanol extract of Aloe vera was done to evaluate anti-inflammatory activity using the croton oil-induced ear swelling assay. The anti-inflammatory activity was found in the supernatant fraction. The supernatant fraction decreased inflammation, when applied topically, by 29.2%, and the precipitate decreased inflammation by 12.1%. However, in the present work, the precipitate fraction decreased the wound diameter by an average of 47.1% (stimulatory system). Little or no wound healing activity was found in the supernatant. Aloe vera appears to act as a modulatory system toward wounds and inflammation and is a potentially valuable tool for managing lower extremity conditions. PMID: 1748962

The isolation of an active inhibitory system from an extract of aloe vera.

Davis RH, Parker WL, Samson RT, Murdoch DP. Pennsylvania College of Podiatric Medicine, Philadelphia 19107.

An Aloe vera extract was prepared with 50% ethanol. The resultant supernatant and precipitate were tested for anti-inflammatory activity using the croton oil-induced ear-swelling assay. The supernatant fraction decreased inflammation, when applied topically, by 29.2%, and the precipitate decreased inflammation by 12.1%. The authors have shown that the anti-inflammatory activity (inhibitory system) resides in the supernatant of a 50% ethanol extract. PMID: 2061823

Antibatterico

Phenolic constituents of Cassia seeds and antibacterial effect of some naphthalenes and anthraquinones on methicillin-resistant Staphylococcus aureus.

Hatano T, Uebayashi H, Ito H, Shiota S, Tsuchiya T, Yoshida T. Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Okayama University, Japan.

Thirteen phenolic glycosides including six new compounds were isolated from seeds of Cassia tora (Leguminosae). The structures of the new compounds, rubrofusarin triglucoside (7), nor-rubrofusarin gentiobioside (9), demethylflavasperone gentiobioside (10), torachrysone gentiobioside (11), torachrysone tetraglucoside (12) and torachrysone apioglucoside (13), were elucidated on the basis of spectroscopic and chemical evidence. The effects of the phenolic glycosides, their aglycones and several other compounds structurally related to them on Escherichia coli K12, Pseudomonas aeruginosa PAO1 and some strains of Staphylococcus aureus were then examined. Among them, torachrysone (15), toralactone (16), aloe-emodin (18), rhein (19) and emodin (20) showed noticeable antibacterial effects on four strains of methicillin-resistant Staphylococcus aureus with a minimum inhibitory concentration of 2-64 micrograms/ml. On the other hand, the phenolic compounds tested did not show strong antibacterial effects on E. coli and P. aeruginosa. PMID: 10478467

Aloe-emodin effects on arylamine N-acetyltransferase activity in the bacterium Helicobacter pylori.

Wang HH, Chung JG, Ho CC, Wu LT, Chang SH.

Arylamine N-acetyltransferase (NAT) activities with p-aminobenzoic acid (PABA) and 2-aminofluorene (AF) were determined in H. pylori collected from peptic ulcer patients. Cytosols or suspensions of H. pylori with or without different concentrations of aloe-emodin co-treatment showed different percentages of AF and PABA acetylation. The data indicate that there was decreased NAT activity associated with increased aloe-emodin in H. pylori cytosols. Inhibition of growth study from H. pylori demonstrated that aloe-emodin elicited dose-dependent growth inhibition in H. pylori cultures. The report is the first finding of aloe-emodin inhibition of arylamine NAT activity in a strain of H. pylori. PMID: 9525111

Funghi e candida

Antifungal activity of anthraquinone derivatives from Rheum emodi.

Agarwal SK, Singh SS, Verma S, Kumar S. Central Institute of Medicinal and Aromatic Plants, P.O.-CIMAP, Lucknow 226 015, India.

Rhein, physcion, aloe-emodin and chrysophanol isolated from Rheum emodi rhizomes exhibited antifungal activity against Candida albicans, Cryptococcus neoformans, Trichophyton mentagrophytes and Aspergillus fumigatus (MIC 25-250 microg/ml). PMID: 10967452

Antifungal effects of different plant extracts and their major components of selected aloe species.

Ali MI, Shalaby NM, Elgamal MH, Mousa AS. Botany Department, Faculty of Science, Cairo University, Giza 12613, Egypt.

Different extracts of both fresh and dry leaves of Aloe eru A. Berger, A. vera L. Webb & Berth and A. arborescens Mill. were screened for their antifungal activity against Aspergillus niger, Cladosporium herbarum and Fusarium moniliforme. The toxicity of the isolated pure components were evaluated on the tested fungi. A comparative chromatographic study was performed to differentiate between natural components existing in various fractions and extracts of Aloe species and specific spray reagents were used for the detection of anthraquinones in the isolated components. Copyright 1999 John Wiley & Sons, Ltd. PMID: 10441780

Saprophytic and cycloheximide resistant fungi isolated from golden hamster.

Bagy MM, el-Shanawany AA, Abdel-Mallek AY. Department of Botany, Faculty of Science, Assiut University, Egypt.

Healthy hair samples from golden hamsters were examined for the presence of dermatophytes and non-dermatophytes using baiting technique and direct inoculation. Thirty-four species and 2 varieties attributed to 17 genera were recovered. Paecilomyces variotii (isolated from 84.4% of the examined hair) and Aspergillus niger (81.3%) were the more frequent isolates on Sabouraud's dextrose agar (SDA) without cycloheximide. Our results have clearly demonstrated that the hair of hamster was free from true dermatophytes. Using the dilution plate method many fungal species were isolated from cage material (7 genera and 10 species + 1 variety); from faeces (10 genera and 17 species); from standard chow (3 genera and 6 species) of hamster. P. variotii which was the most frequent fungus in the preceding 3 substrates was completely absent in the presence of cycloheximide in SDA. The present study has demonstrated for the first time the isolation of Trichophyton rubrum from hamster faeces. Also, several saprophytic and cycloheximide resistant fungi were isolated. In the air of hamster cage Cladosporium cladosporioides, Penicillium chrysogenum, Alternaria alternata and Scopulariopsis brevicaulis were the most dominant species on SDA with or without cycloheximide. Using the agar diffusion method, Aloe sap, onion oil, garlic bulb extract and aqueous leaf extracts of Andropogon citratus, Euphorbia sp. and Ruta graveolens were tested for their antifungal activity on 10 fungal species. It was observed that onion oil exhibited a high inhibitory effect against most of the tested fungi. PMID: 9768288

Upregulation of phagocytosis and candidicidal activity of macrophages exposed to the immunostimulant acemannan.

Stuart RW, Lefkowitz DL, Lincoln JA, Howard K, Gelderman MP, Lefkowitz SS. Department of Biological Sciences, Texas Tech University, Lubbock 79409, U.S.A.

Previous studies by these investigators have shown that mannosylated bovine serum albumin (m-BSA) enhances the respiratory burst (RB), phagocytosis, and killing of Candida albicans by resident murine peritoneal macrophages (MO). Upregulation of the above MO functions was associated with binding of m-BSA to the MO-mannose receptor. The present study was done to determine if the immunostimulant, acemannan prepared from aloe vera, could stimulate MO in a similar manner. Resident peritoneal MO collected from C57BL/6 mice were exposed to acemannan for 10 min. The RB was measured using chemiluminescence and demonstrated approximately a two-fold increase above the media controls. In studies involving phagocytosis, MO were exposed to acemannan, washed and exposed to Candida at a ratio of 1:5. The percent phagocytosis and Candida killing were determined using fluorescence microscopy. There was a marked increase in phagocytosis in the treated cultures (45%) compared to controls (25%). Macrophages exposed to acemannan for 10 min resulted in ca 38% killing of Candida albicans compared with 0-5% killing in controls. If MO were incubated with acemannan for 60 min, 98% of the yeast were killed compared to 0-5% in the controls. The results of the present study indicate that short term exposure of MO to acemannan upregulates the RB, phagocytosis and candidicidal activity. Further studies are needed to clarify the potential use of this immunostimulant as an anti-fungal agent. PMID: 9278177

Afte

The effectiveness and acceptance of a medical device for the treatment of aphthous stomatitis. Clinical observation in pediatric age

Andriani E, Bugli T, Aalders M, Castelli S, De Luigi G, Lazzari N, Rolli GP. Servizio Medicina di Base, Istituto per la Sicurezza Sociale Repubblica di S. Marino.

BACKGROUND: To evaluate the efficacy of a new bioadhesive patch, Aloe vera hydrogel, for the treatment of aphthous stomatitis. METHODS: An open, not controlled study was performed in 31 pediatric out-patients, aged 6-14 years, affected by mouth ulcers were enrolled consecutively in the 3 Gps Depts+ of San Marino Republic. For each case, data on case history and clinical profile, patterns of the lesion, presence of spontaneous or provoked pain were collected at baseline, and a bioadhesive patch ("Alovex patch") was administered on the basis of a daily regimen of < or = 3 patches for 4 days. Data on modification of the above-mentioned parameters, with patients and physicians opinion on the therapeutical efficacy, were collected during a control visit (4 days later). Moreover, by means of a daily diary, patients recorded information on the course of the symptoms during the 4 days and were also asked to compare the current treatment with other previous therapies. RESULTS: At the control visit 77% of the patients have shown a marked resolution of spontaneous pain, while in the other patients, pain was significantly decreased to a "mild" or "moderate" level. No one child declared to suffer from severe pain. Also provoked pain resulted to be significantly decreased after treatment Global efficacy was judged positively, being the therapeutical effect in more than 80% of cases "evident or of absolute improvement" both by physicians and patients opinion. A positive improvement of symptomatology started within the 2nd day of treatment in 74% of the patients. The compliance (adhesivity, acceptability and palatability) of the formulation was judged largely favourable in more than 90% of the patients. CONCLUSIONS: The results of this study underline the good efficacy and compliance of the patch for the treatment of the aphtous stomatitis; also the limit of topical available therapies, linked to the "contact time", to develop their therapeutical action, seems not to be evinced on the basis of this study, so the application of this patch seems to be more easy and beneficial. PMID: 10829589

Antibiotico

Oxoaporphine alkaloids and quinones from Stephania dinklagei and evaluation of their antiprotozoal activities.

Camacho MR, Kirby GC, Warhurst DC, Croft SL, Phillipson JD.

Bioactivity-guided fractionation of Stephania dinklagei yielded six compounds including, two zwitterionic oxoaporphine alkaloids, N-methylliriodendronine, and 2-O,N-dimethylliriodendronine, two oxoaporphine alkaloids, liriodenine, and dicentrinone, one aporphine alkaloid, corydine, and one anthraquinone, aloe-emodin. Apart from corydine, the isolates have not been reported as constituents of S. dinklagei. N-Methylliriodendronine, and 2-O,N-dimethylliriodendronine are reported for the first time as natural products. All isolated compound were tested for antiprotozoal activity and cytotoxic activities in vitro. N-Methylliriodendronine was the most active against L. donovani amastigotes (IC50 = 36.1 microM). Liriodenine showed the highest activity against Leishmania donovani, and Plasmodium falciparum with IC50 values of 26.16 and 15 microM, respectively. Aloe-emodin was the only compound active (IC50 = 14 microM) against T. b. brucei. PMID: 10909274

Studio sulle proprietà antiossidanti dell'aloe

Isolation and identification of a phenolic antioxidant from Aloe barbadensis.

Lee KY, Weintraub ST, Yu BP. Department of Food and Nutrition, Ho Seo University, Asan, Chungmam, Korea.

A potent antioxidative compound has been isolated from a methanolic extract of Aloe barbadensis Miller using a combination of column and thin-layer chromatography. The antioxidant activity of this substance was similar to that of alpha-tocopherol as assessed in vitro using rat brain homogenates. On the basis of electrospray ionization and electron-impact ionization mass spectra in combination with reversed-phase, high-performance liquid chromatographic behavior, this compound has been identified as 8-C-beta-D-[2-O-(E)-coumaroyl]glucopyranosyl-2-[2-hydroxy]-propyl-7-methoxy-5-methylchromone. PMID: 11281293

Antioxidant and radical scavenging effects of anthraquinones and anthrones.

Malterud KE, Farbrot TL, Huse AE, Sund RB. Department of Pharmacognosy, University of Oslo, Norway.

The activity of seven anthraquinones and four anthrones against nonenzymatic and enzymatic lipid peroxidation in vitro and their ability to scavenge free radicals have been studied. In nonenzymatic peroxidation in rat hepatocytes induced by t-butyl hydroperoxide, dithranol and anthrone were the strongest antioxidants, having IC50 values of 8 +/- 1 and 24 +/- 5 mumol/l, respectively. Rhein (IC50 64 +/- 2 mumol/l) and aloe-emodin (IC50 65 +/- 3 mumol/l) showed the highest inhibitory activity against peroxidation of linoleic acid catalyzed by soybean 15-lipoxygenase. Anthrone (IC50 62 +/- 2 mumol/l), dithranol (IC50 72 +/- 1 mumol/l) and rhein anthrone (IC50 76 +/- 6 mumol/l) were the most effective radical scavengers of the diphenylpicrylhydrazyl radical. The antioxidant activities in hepatocytes and the radical scavenging activities were correlated, whereas the inhibition of enzymatic lipid peroxidation showed no correlation with the two other effects. PMID: 8234446

Chemomodulatory action of Aloe vera on the profiles of enzymes associated with carcinogen metabolism and antioxidant status regulation in mice.

Singh RP, Dhanalakshmi S, Rao AR. Cancer Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.

The effect of two doses (30 microl and 60 microl/day/mice daily for 14 days) of the fresh leaf pulp extract of Aloe vera was examined on carcinogen-metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of mice. The modulatory effect of the pulp extract was also examined on extrahepatic organs (lung, kidney and forestomach) for the activities of glutathione S-transferase, DT-diophorase, superoxide dismutase and catalase. The positive control mice were treated with butylated hydroxyanisole (BHA). Significant increases in the levels of acid soluble sulfhydryl (-SH) content, NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and glutathione reductase (GR) were observed in the liver. Aloe vera significantly reduced the levels of cytochrome P450 and cytochrome b5. Thus, Aloe vera is clearly an inducer of phase-II enzyme system. Treatment with both doses of Aloe caused a decrease in malondialdehyde (MDA) formation and the activity of lactate dehydrogenase in the liver, suggesting its role in protection against prooxidant-induced membrane and cellular damage. The microsomal and cytosolic protein was significantly enhanced by Aloe vera, indicating the possibility of its involvement in the induction of protein synthesis. BHA, an antioxidant compound, provided the authenticity of our assay protocol and response of animals against modulator. The pulp extract was effective in inducing GST, DTD, SOD and catalase as measured in extrahepatic organs. Thus, besides liver, other organs (lung, kidney and forestomach) were also influenced favorably by Aloe vera in order to detoxify reactive metabolites, including chemical carcinogens and drugs. PMID: 11185732

Studio sull'innocuità dell'aloe e sul fatto che non ha effetti tossici

Sennosides and aloin do not promote dimethylhydrazine-induced colorectal tumors in mice.

Siegers CP, Siemers J, Baretton G. Institutes of Toxicology, Medical University of Lubeck, FRG.

In a model of dimethylhydrazine-induced colorectal tumors in male mice aloin- or sennoside-enriched diets (0.03%) did not promote incidence and growth of adenomas and carcinomas after 20 weeks. Furthermore, in anthranoid-fed mice no significant changes in serum electrolytes as well as parameters of hepato- and nephrotoxicity were observed. PMID: 8234430

The genotoxicity status of senna.

Heidemann A, Miltenburger HG, Mengs U. CCR Cytotest Cell Research, Rossdorf, FRG.

Genotoxicity tests were performed by several laboratories with the drug fructus sennae, senna extract, sennosides, rhein and aloe-emodin. The drug fructus sennae, the sennosides and rhein did not increase mutation frequencies in the following test systems: bacterial systems (Salmonella reverse mutation test and/or Escherichia coli forward mutation test); mammalian cell cultures [hypoxanthine guanine phosphoribosyl transferase (HGPRT) test; mouse lymphoma test; chromosome aberration test with Chinese hamster ovary cells]; bone marrow (micronucleus test; chromosome aberration test); melanoblast cells (mouse spot test) of rodents. With aloe-emodin mutagenic effects were observed only in vitro in the chromosome aberration test with CHO cells and in the Salmonella reverse mutation test (frameshift mutations in strains TA 1537, TA 1538 and TA 98). In the in vitro gene mutation test with V79 cells (HGPRT test) no mutagenic potential of aloe-emodin was observed. In in vivo studies [micronucleus test with bone marrow cells of NMRI mice, chromosome aberration test with bone marrow cells of Wistar rats, mouse spot test (crossing DBA/2J x NMRI) no indication for a mutagenic activity of aloe-emodin was found. The relevance of the absence of a mutagenic potential in in vivo test systems was strengthened by the fact that aloe-emodin could be found in the blood serum after oral administration. Additional information on the interaction of aloe-emodin with DNA was obtained from an ex vivo unscheduled DNA synthesis test performed with hepatocytes of male Wistar rats: aloe-emodin did not induce unscheduled DNA synthesis as expression of DNA damage. PMID: 8234427



Cancro Chemioterapia