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Studi scientifici sull'Aloe Arborescens



Studio degli effetti dell'aloe contro il tifo

Efficacy of crude extract of Aloe secundiflora against Salmonella gallinarum in experimentally infected free-range chickens in Tanzania.

Waihenya RK, Mtambo MM, Nkwengulila G, Minga UM. Department of Zoology and Marine Biology, University of Dar Es Salaam, P.O. Box 35064, Dar Es Salaam, Tanzania

The ethnoveterinary use of Aloe species extract in free-range local chickens against fowl typhoid was investigated. Five-months-old local chickens, free of antibodies against fowl typhoid were used. The chickens were randomly assorted into five groups including pretreated and infected (G1, n=21), infected and untreated (G2, n=21), infected and treated (G3, n=21), untreated and uninfected (G4, n=10) and treated uninfected (G5, n=10). Groups 1, 2 and 3 were inoculated with 5.0x10(8) c.f.u/ml of Salmonella gallinarum, following which the chickens were monitored for 15 days. There was a delay on the occurrence of the clinical signs and reduced severity of the disease in the Aloe treated chickens (G1 and G3). The mortality rates were 23.8% (5/21) in G1 (pretreated and infected), 42.8% (9/21) in G2 (infected and untreated) and 14.2% (3/21) in G3 (infected and treated). Antibody levels were raised among the infected and untreated group (G2) while they remained relatively low in the Aloe treated groups (G1 and G3). However, there was a sharp increase in the levels of interleukin 6 (IL-6) in the Aloe treated groups (G1 and G3) as compared to the untreated group (G2) until day 9 post-infection. The results of this work indicate that the extract of Aloe secundiflora may be used in the control of fowl typhoid in chickens. Studies to determine the active ingredients of the plant extract are in progress. PMID: 11849835

Studio degli effetti dell'aloe contro i virus

Evaluation of the efficacy of the crude extract of Aloe secundiflora in chickens experimentally infected with Newcastle disease virus.

Waihenya RK, Mtambo MM, Nkwengulila G. Department of Zoology and Marine Biology, University of Dar es Salaam, PO Box 35064, Dar es Salaam, Tanzania

Two replicate experiments were carried out to verify the efficacy of Aloe species (Aloaceae) as used for the control of Newcastle disease (ND) in rural poultry in free-range systems among several communities in Tanzania. Four months old local chickens free of Newcastle disease antibodies were used. Following inoculation with ND virus, body weights, clinical signs, antibody levels and mortality were monitored. Results showed that there was reduced mortality rate and the severity of clinical signs during the acute phase of the infection in Aloe treated chickens compared with the non-treated ones. However, there was no significant effect of the Aloe on the antibody levels that were attributed to the recovery of the surviving chickens. The findings of this study suggest that Aloe secundiflora could be a potential candidate on the management of Newcastle disease in chickens. Further studies are in progress to identify the active ingredients of A. secundiflora against Newcastle disease virus. PMID: 11849832

Aloe polymannose enhances anti-coxsackievirus antibody titres in mice.

Gauntt CJ, Wood HJ, McDaniel HR, McAnalley BH. Department of Microbiology, University of Texas Health Science Center at San Antonio Texas, 7703 Floyd Curl Drive, San Antonio, TX 78284-7758, USA.

Aloe polymannose (AP), a high mannose biological response modifier (BRM) purified from the Aloe barbadensis Miller plant, was tested for activity in enhancing antibody titres against coxsackievirus B3 (CVB3) and CVB3-induced myocarditis in murine models of the disease. Inoculation of mice with AP over a range of three nontoxic doses and in varying schedules did not reduce virus titres in heart tissues or ameliorate virus-induced cardiopathological alterations during acute disease. However, this BRM was found to significantly enhance titres of anti-CVB3 antibodies produced during acute infection of three strains of mice with CVB3. Simultaneous intraperitoneal inoculation of AP at a dose of 0.5 mg/kg body weight per mouse with purified CVB3 significantly increased ELISA titres of anti-CVB3 antibodies and the proportion of mice with these titres, compared with similar parameters in mice inoculated only with CVB3. The data conclusively show that AP can immunopotentiate antibody production against capsid protein epitopes of a nonenveloped picornavirus and suggest this BRM (AP) might be of benefit in enhancing antibody titres against other enteroviruses during a natural infection and poliovirus vaccine strains. Copyright 2000 John Wiley & Sons, Ltd. PMID: 10861969

Lichen planus--report of successful treatment with aloe vera.

Hayes SM.

Lichen planus is a disease that involves the skin and mucous membranes. It is characterized by unique eruptions. The cause of this disease is unknown, but has been linked to emotional stress, and has also been attributed to viral infections. A case is described of a successful treatment of lichen planus. PMID: 10687438

The action of an aqueous extract of Aloe barbadensis Miller in an in-vitro culture of Trichomonas vaginalis]

Rojas L, Matamoros M, Garrido N, Finlay C. Instituto de Medicina Tropical Pedro Kouri.

The antiparasitic action of an aqueous extract of Aloe barbadensis Miller against and in vitro culture of Trichomonas vaginalis was studied for the first time. Three strains of this parasite were used for the study. Taking an initial concentration of 400 mg/mL of the extract, double serial dilutions were performed, and final concentrations based on the dried weight of the extract were 10.4, 20.8, 41, 83, and 160 mg/mL. Within 24 hours, percentages of inhibition greater than 50% were obtained from concentrations of 20.8 micrograms/mL. Similar results were obtained at 48, and 72 hours, with a lower concentration, the inhibition of growth was greater than 50%. PMID: 9813472

Inactivation of enveloped viruses by anthraquinones extracted from plants.

Sydiskis RJ, Owen DG, Lohr JL, Rosler KH, Blomster RN. Department of Microbiology, University of Maryland, Baltimore 21201.

To determine the extent of antiviral activity present in a number of plant extracts, hot glycerin extracts were prepared from Rheum officinale, Aloe barbadensis, Rhamnus frangula, Rhamnus purshianus, and Cassia angustifolia and their virucidal effects were tested against herpes simplex virus type 1. All the plant extracts inactivated the virus. The active components in these plants were separated by thin-layer chromatography and identified as anthraquinones. A purified sample of aloe emodin was prepared from aloin, and its effects on the infectivity of herpes simplex virus type 1 and type 2, varicella-zoster virus, pseudorabies virus, influenza virus, adenovirus, and rhinovirus were tested by mixing virus with dilutions of aloe emodin for 15 min at 37 degrees C, immediately diluting the sample, and assaying the amount of infectious virus remaining in the sample. The results showed that aloe emodin inactivated all of the viruses tested except adenovirus and rhinovirus. Electron microscopic examination of anthraquinone-treated herpes simplex virus demonstrated that the envelopes were partially disrupted. These results show that anthraquinones extracted from a variety of plants are directly virucidal to enveloped viruses. PMID: 1810179

Proprietą immunostimolanti (attivazione dei macrofagi) per virus e tumori in genere

In vivo macrophage activation in chickens with Acemannan, a complex carbohydrate extracted from Aloe vera.

Djeraba A, Quere P. INRA, Virologie Aviaire et Oncologie, Station de Pathologie Aviaire et Parasitologie, 37 380, Nouzilly, France.

Acemannan (ACM 1), a beta-(1,4) -acetylated mannan isolated from Aloe vera, can be used as an effective adjuvant in vaccination against some avian viral diseases. Our results demonstrate a quick and lasting in vivo priming effect of ACM 1 on macrophage response after intramuscular inoculation in chickens (500 &mgr;g per 2-month-old bird). In response to IFN-gamma in vitro, monocytes from ACM 1-treated chickens exhibited a strong enhancement of NO production from 3 to 9 days p.i., but a weaker effect on MHC II cell surface antigen expression on day 3 p.i. A stimulating effect of ACM 1 treatment was also observed on spontaneous and inducible NO production for splenocytes only on day 3 p.i. By that time, splenocytes exhibited a strong higher capacity to proliferate in response to the T cell-mitogen PHA. At the same time, the in vivo capacity to produce NO, measured by the (NO(-)(2)+NO(-)(3)) serum level after intravenous LPS injection, increased greatly from 3 to 9 days p.i. In conclusion, ACM 1 was able efficiently and durably to increase the activation capacity of macrophages from the systemic immune compartment (in particular from the blood and spleen after an intramuscular injection) in chickens, especially for NO production. These findings provide a better understanding of the adjuvant activity of ACM 1 for viral and tumoral diseases. PMID: 10708884

In vitro chemopreventive effects of plant polysaccharides (Aloe barbadensis miller, Lentinus edodes, Ganoderma lucidum and Coriolus versicolor).

Kim HS, Kacew S, Lee BM. Division of Toxicology, College of Pharmacy, Sungkyunkwan University, Changan-ku, Chunchun-dong, Kyunggi-do, Suwon 440-746, Korea.

A plant polysaccharide, Aloe gel extract, was reported to have an inhibitory effect on benzo[a]pyrene (B[a]P)-DNA adduct formation in vitro and in vivo. Hence, chemopreventive effects of plant polysaccharides [Aloe barbadensis Miller (APS), Lentinus edodes (LPS), Ganoderma lucidum (GPS) and Coriolus versicolor (CPS)] were compared using in vitro short-term screening methods associated with both initiation and promotion processes in carcinogenesis. In B[a]P-DNA adduct formation, APS (180 micrograms/ml) was the most effective in inhibition of B[a]P binding to DNA in mouse liver cells. Oxidative DNA damage (by 8-hydroxydeoxyguanosine) was significantly decreased by APS (180 micrograms/ml) and CPS (180 micrograms/ml). In induction of glutathione S-transferase activity, GPS was found to be the most effective among plant polysaccharides. In screening anti-tumor promoting effects, APS (180 micrograms/ml) significantly inhibited phorbol myristic acetate (PMA)-induced ornithine decarboxylase activity in Balb/3T3 cells. In addition, APS significantly inhibited PMA-induced tyrosine kinase activity in human leukemic cells. APS and CPS significantly inhibited superoxide anion formation. These results suggest that some plant polysaccharides produced both anti-genotoxic and anti-tumor promoting activities in in vitro models and, therefore, might be considered as potential agents for cancer chemoprevention. PMID: 10426820

Activation of a mouse macrophage cell line by acemannan: the major carbohydrate fraction from Aloe vera gel.

Zhang L, Tizard IR. Department of Veterinary Pathobiology, Texas A & M University College Station 77843, USA.

Acemannan is the name given to the major carbohydrate fraction obtained from the gel of the Aloe vera leaf. It has been claimed to have several important therapeutic properties including acceleration of wound healing, immune stimulation, anti-cancer and anti-viral effects. However, the biological mechanisms of these activities are unclear. Because of this wide diversity of effects, it is believed that they may be exerted through pluripotent effector cells such as macrophages. The effects of acemannan on the mouse macrophage cell line, RAW 264.7 cells were therefore investigated. It was found that acemannan could stimulate macrophage cytokine production, nitric oxide release, surface molecule expression, and cell morphologic changes. The production of the cytokines IL-6 and TNF-alpha were dependent on the dose of acemannan provided. Nitric oxide production, cell morphologic changes and surface antigen expression were increased in response to stimulation by a mixture of acemannan and IFN-gamma. These results suggest that acemannan may function, at least in part, through macrophage activation. PMID: 8956975

Nitric oxide production by chicken macrophages activated by Acemannan, a complex carbohydrate extracted from Aloe vera.

Karaca K, Sharma JM, Nordgren R. University of Minnesota, College of Veterinary Medicine, Department of Pathobiology, St Paul 55108, USA.

Cultures of normal chicken spleen cells and HD11 line cells produce nitric oxide (NO) in response to Acemannan, a complex carbohydrate derived from the Aloe vera plant. Neither cell type produced detectable amounts of NO in response to similar concentrations of yeast mannan, another complex carbohydrate. Nitric oxide production was dose dependent and inhibitable by the nitric oxide synthase inhibitor NG-methyl-L-arginine. In addition, the production of NO was inhibited by preincubation of ACM with concanavalin A in a dose-dependent manner. These results suggest that ACM-induced NO synthesis may be mediated through macrophage mannose receptors, and macrophage activation may be accountable for some of the immunomodulatory effects of ACM in chickens. PMID: 7558512

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



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