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Studi scientifici sull'Aloe Arborescens



Cura del fegato, tumori del fegato

Aloe-Emodin quinone pretreatment reduces acute liver injury induced by carbon tetrachloride.

Arosio B, Gagliano N, Fusaro LM, Parmeggiani L, Tagliabue J, Galetti P, De Castri D, Moscheni C, Annoni G. Department of Internal Medicine, Milano University Study and Hospital Maggiore IRCCS, Italy.

Aloe contains several active compounds including aloin, a C-glycoside that can be hydrolyzed in the gut to form aloe-emodin anthrone which, in turn, is auto-oxidized to the quinone aloe-emodin. On the basis of the claimed hepatoprotective activity of some antraquinones, we studied aloe-emodin in a rat model of carbon tetrachloride (CCl4) intoxication, since this xenobiotic induces acute liver damage by lipid peroxidation subsequent to free radical production. Twelve rats were treated with CCl4 (3 mg/kg) intraperitoneally and six were protected with two intraperitoneally injections of aloe-emodin (50 mg/kg; CCl4+aloe-emodin); six other rats were only aloe-emodin injected (aloe-emodin) and six were untreated (control). Histological examination of the livers showed less marked lesions in the CCl4+aloe-emodin rats than in those treated with CCl4 alone, and this was confirmed by the serum levels of L-aspartate-2-oxoglutate-aminotransferase (394+/-38.6 UI/l in CCl4, 280+/-24.47 UI/l in CCl4+aloe-emodin rats; P<0.05). We also quantified changes in hepatic albumin and tumour necrosis factor-alpha mRNAs. Albumin mRNA expression was significantly lower only in the liver of CCl4 rats (P<0.05 versus control) and was only slightly reduced in the CCl4+aloe-emodin rats. In contrast tumour necrosis factor-alpha mRNA was significantly higher (P<0.05) in the CCl4 than the control rats and almost equal in the CCl4+aloe-emodin, aloe-emodin and control groups. In conclusion, aloe-emodin appears to have some protective effect not only against hepatocyte death but also on the inflammatory response subsequent to lipid peroxidation. PMID: 11129503

Vitamin C and aloe vera supplementation protects from chemical hepatocarcinogenesis in the rat.

Shamaan NA, Kadir KA, Rahmat A, Ngah WZ. Department of Biochemistry and Microbiology, Universiti Putra Malaysia, Selangor, Malaysia.

The effects of vitamin C and aloe vera gel extract supplementation on induced hepatocarcinogenesis in male Sprague-Dawley rats (120-150 g) by diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) was investigated. The severity of the carcinogenesis process was determined by measuring gamma-glutamyl transpeptidase (GGT) and the placental form of glutathione S-transferase (GSTP) histochemically in situ and in plasma and liver fractions. In addition, plasma alkaline phosphatase (ALP) and liver microsomal uridine diphosphate glucuronyl transferase (UDPGT) activity were also determined. Administration of DEN/AAF caused an increase in the surface area and number of enzyme-positive foci (both GGT and GSTP) compared with control. Supplementation of vitamin C or aloe vera gel extract to the cancer-induced rats suppressed this increase significantly (P < 0.05; P < 0.001). Increases in liver UDPGT, GGT, and GSTP activities were also observed with cancer induction that were again suppressed with either vitamin C or aloe vera gel supplementation. Plasma GGT in the DEN/AAF rats were determined monthly for the duration of the experiment and found to be reduced as early as 1 mo with aloe vera gel supplementation and 2 mo with vitamin C supplementation. In conclusion, vitamin C and aloe vera gel extract supplementation were found to be able to reduce the severity of chemical hepatocarcinogenesis. PMID: 9834927

Decreased levels of 2-amino-3-methylimidazo[4,5-f]quinoline-DNA adducts in rats treated with beta-carotene, alpha-tocopherol and freeze-dried aloe.

Uehara N, Iwahori Y, Asamoto M, Baba-Toriyama H, Iigo M, Ochiai M, Nagao M, Nakayama M, Degawa M, Matsumoto K, Hirono I, Beppu H, Fujita K, Tsuda H. Chemotherapy Division, National Cancer Center Research Institute, Tokyo, Japan.

To assess mechanisms of chemoprevention of hepatocarcinogenesis by trans-beta-carotene (beta-C), DL-alpha-tocopherol (alpha-T), and freeze-dried whole leaves of Kidachi aloe (Aloe), formation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-DNA adducts was measured by 32P-post-labeling analysis, and CYP1A1 and CYP1A2 protein levels were analyzed by ELISA. Group 1 rats were fed diet containing 0.02% beta-C, 1.5% alpha-T or 30% Aloe over an 8-day period, while group 2 was given basal diet alone. On day 7, all animals were subjected to two-thirds partial hepatectomy (PH). Twelve hours after PH, they received a single dose of the carcinogenic food pyrolysate IQ (100 mg/kg) intragastrically, to initiate hepatocarcinogenesis. Rats were killed 6, 12, 24 and 48 h after IQ administration. The levels of adducts, expressed as relative adduct labeling values in rats treated with beta-C, alpha-T and Aloe, were decreased as compared with the control group at hour 24 (36 h after PH), with a significant difference in the case of the beta-C group (46.4% of the control value). Similarly, all showed a tendency for decrease at hour 48. Furthermore, the levels of CYP1A2, known to be responsible for activation of IQ, showed a significant reduction at hour 24. It is concluded that beta-C, and possibly also alpha-T and Aloe, have the potential to reduce IQ-DNA adduct formation, presumably as a result of decreased formation of active metabolites. The results may explain, at least in part, the previously observed inhibitory effects of these compounds on induction of preneoplastic hepatocellular lesions. PMID: 8641964

Inhibition of benzo[a]pyrene-DNA adduct formation by Aloe barbadensis Miller.

Kim HS, Lee BM. Division of Toxicology, College of Pharmacy, Sung Kyun Kwan University, Suwon City, Kyunggi-Do, South Korea.

The antigenotoxic and chemopreventive effect of Aloe barbadensis Miller (polysaccharide fraction) on benzo[a]pyrene (B[a]P)-DNA adducts was investigated in vitro and in vivo. Aloe showed a time-course and dose-dependent inhibition of [3H]B[a]P-DNA adduct formation in primary rat hepatocytes (1x10(6) cells/ml) treated with [3H]B[a]P (4 nmol/ml). At concentrations of 0.4-250 microg/ml aloe, the binding of [3H]B[a]P metabolites to rat hepatocyte DNA was inhibited by 9.1-47.9%. Also, in rat hepatocytes cultured for 3-48 h with aloe (250 microg/ml) and [3H]B[a]P (4 nmol/ml), [3H]B[a]P-DNA adducts were significantly reduced by 36% compared with [3H]B[a]P alone. Aloe also inhibited cellular uptake of [3H]B[a]P in a dose-dependent manner at a concentration of 0.4-250 microg/ml by 6.3-34.1%. After a single oral administration of B[a]P to male ICR mice (10 mg/mouse), benzo[a]pyrene diol epoxide I (BPDE-I)-DNA adduct formation and persistence for 16 days following daily treatment with aloe (50 mg/mouse) were quantitated by enzyme-linked immunosorbent assay using monoclonal antibody 8E11. In this animal model, BPDE-I-DNA adduct formation was significantly inhibited in various organs (liver, kidney, forestomach and lung) (P < 0.001). When mice were pretreated with aloe for 16 days before B[a]P treatment, inhibition of BPDE-I-DNA adduct formation and persistence was enhanced. Glutathione S-transferase activity was slightly increased in the liver but cytochrome P450 content was not affected by aloe. These results suggest that the inhibitory effect of aloe on BPDE-I-DNA adduct formation might have a chemopreventive effect by inhibition of B[a]P absorption. PMID: 9111213

The effect of a plants mixture extract on liver gluconeogenesis in streptozotocin induced diabetic rats.

al-Awadi F, Fatania H, Shamte U. Department of Biochemistry, Faculty of Medicine, Kuwait University, Safat.

We have previously reported on plant mixture extract comprising of Nigella sativa, Myrrh, Gum Olibanum, Gum Asafoetida and Aloe to have a blood glucose lowering effect. The present study with streptozotocin diabetic rats is focussed on the mechanism of action, specifically on a) hepatic gluconeogenesis b) activity of key gluconeogenic enzymes, pyruvate carboxylase (PC) and phosphoenol-pyruvate carboxykinase (PEPCK). Similar studies using a biguanide, phenformin, have been conducted to compare the mode of action of these two compounds. The blood glucose levels (mean +/- SEM) before and after treatment with the plants extract were (16.7 +/- 1.7 mmol/L and 8.5 +/- 1.3 mmol/L) and with phenformin (15.1 +/- 1.3 mmol/L and 10.7 +/- 1.5 mmol/L). The rate of gluconeogenesis in isolated hepatocytes as well as activity of PC and PEPCK in liver homogenates is significantly lowered following treatment with the plants extract. Although phenformin also lowers blood glucose, it does not affect hepatic gluconeogenesis under stated experimental conditions. It is concluded that the anti-diabetic action of the plants extract may, at least partly, be mediated through decreased hepatic gluconeogenesis. The extract may prove to be a useful therapeutic agent in the treatment of non-insulin dependent diabetes mellitus (NIDDM). PMID: 1842751

Tumori solidi incurabili, gastrointestinali, al seno, al cervello (glioblastoma)

Biotherapy with the pineal immunomodulating hormone melatonin versus melatonin plus aloe vera in untreatable advanced solid neoplasms.

Lissoni P, Giani L, Zerbini S, Trabattoni P, Rovelli F. Division of Radiation Oncology, San Gerardo Hospital, Monza, Milan, Italy.

The possibility of natural cancer therapy has been recently suggested by advances in the knowledge of tumor immunobiology. Either cytokines such as IL-2, or neurohormones, such as the pineal indole melatonin (MLT), may activate anticancer immunity. In addition, immunomodulating substances have also been isolated from plants, particularly from Aloe vera. Preliminary clinical studies had already shown that MLT may induce some benefits in untreatable metastatic solid tumor patients, whereas, for the time being, no clinical trial has been performed with aloe products. We have carried out a clinical study to evaluate whether the concomitant administration of aloe may enhance the therapeutic results of MLT in patients with advanced solid tumors for whom no effective standard anticancer therapies are available. The study included 50 patients suffering from lung cancer, gastrointestinal tract tumors, breast cancer or brain glioblastoma, who were treated with MLT alone (20 mg/day orally in the dark period) or MLT plus A. vera tincture (1 ml twice/day). A partial response (PR) was achieved in 2/24 patients treated with MLT plus aloe and in none of the patients treated with MLT alone. Stable disease (SD) was achieved in 12/24 and in 7/26 patients treated with MLT plus aloe or MLT alone, respectively. Therefore, the percentage of nonprogressing patients (PR + SD) was significantly higher in the group treated with MLT plus aloe than in the MLT gorup (14/24 vs. 7/26, p < 0.05). The percent 1-year survival was significantly higher in patients treated with MLT plus aloe (9/24 vs. 4/26, p < 0.05). Both treatments were well tolerated. This preliminary study would suggest that natural cancer therapy with MLT plus A. vera extracts may produce some therapeutic benefits, at least in terms of stabilization of disease and survival, in patients with advanced solid tumors, for whom no other standard effective therapy is available. PMID: 9789122

Tumori al pancreas

Chemopreventive effects of Aloe arborescens on N-nitrosobis(2-oxopropyl)amine-induced pancreatic carcinogenesis in hamsters.

Furukawa F, Nishikawa A, Chihara T, Shimpo K, Beppu H, Kuzuya H, Lee IS, Hirose M. Division of Pathology, Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.

The modification effects of freeze-dried aloe (Aloe arborescens) whole leaf powder during the initiation phase of carcinogenesis were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian hamsters were given four weekly subcutaneous injections of BOP at a dose of 10mg/kg and then given 0, 1 or 5% aloe in their diet for 5 weeks. At week 54 of the experiment, all surviving animals were sacrificed and development of neoplastic and preneoplastic lesions was assessed histopathologically. The incidences of pancreatic adenocarcinomas, atypical hyperplasias or total atypical hyperplasias plus adenocarcinomas were significantly (P<0.05) decreased with BOP+5% aloe, and that of adenocarcinomas were also significantly (P<0.05) reduced in the BOP+1% aloe as compared to the BOP alone group. Multiplicities of pancreatic adenocarcinomas, atypical hyperplasias or total lesions were also significantly (P<0.01 or P<0.05) lower in the BOP+5% aloe group than with the BOP alone. Quantitative data for neoplastic lesions in the lung, liver, gall bladder, kidney and urinary bladder of hamsters were not significantly different among the three groups. In a satellite experiment, pretreatment with aloe significantly (P<0.01) reduced the formation of O6-methyldeoxyguanosine in epithelial cells of pancreatic ducts as compared to the BOP alone value. Our results thus indicate that aloe prevents BOP-induced pancreatic neoplasia in hamsters in relation to decreased DNA adduct formation in the target tissue. PMID: 11867195

Antiulcera

The plant kingdom as a source of anti-ulcer remedies.

Borrelli F, Izzo AA. Department of Experimental Pharmacology, University of Naples 'Federico II', via D. Montesano 49, 80131 Naples, Italy.

Phytogenic agents have traditionally been used by herbalists and indigenous healers for the prevention and treatment of peptic ulcer. This article reviews the anti-acid/anti-peptic, gastro-protective and/or anti-ulcer properties of the most commonly employed herbal medicines and their identified active constituents. Botanical compounds with anti-ulcer activity include flavonoids (i.e. quercetin, naringin, silymarin, anthocyanosides, sophoradin derivatives) saponins (i.e. from Panax japonicus and Kochia scoparia), tannins (i.e. from Linderae umbellatae), gums and mucilages (i.e. gum guar and myrrh). Among herbal drugs, liquorice, aloe gel and capsicum (chilli) have been used extensively and their clinical efficacy documented. Also, ethnomedical systems employ several plant extracts for the treatment of peptic ulcer. Despite progress in conventional chemistry and pharmacology in producing effective drugs, the plant kingdom might provide a useful source of new anti-ulcer compounds for development as pharmaceutical entities or, alternatively, as simple dietary adjuncts to existing therapies. PMID: 11113992

Acemannan hydrogel dressing versus saline dressing for pressure ulcers. A randomized, controlled trial.

Thomas DR, Goode PS, LaMaster K, Tennyson T. Department of Internal Medicine, St. Louis University, MO, USA.

Aloe vera has been used for centuries as a topical treatment for various conditions and as a cathartic. An amorphous hydrogel dressing derived from the aloe plant (Carrasyn Gel Wound Dressing, Carrington Laboratories, Inc., Irving, TX) is approved by the Food and Drug Administration for the management of Stages I through IV pressure ulcers. To evaluate effectiveness of this treatment, 30 patients were randomized to receive either daily topical application of the hydrogel study dressing (acemannan hydrogel wound dressing) or a moist saline gauze dressing. Complete healing of the study ulcer occurred in 19 of 30 subjects (63%) during the 10-week observation period. No difference was observed in complete healing between the experimental and the control groups (odds ratio 0.93, 95% CI 0.16, 5.2). This study indicates that the acemannan hydrogel dressing is as effective as, but is not superior to, a moist saline gauze wound dressing for the management of pressure ulcers. PMID: 10326343




Cancro Chemioterapia