Protective value of Aloe vera against some toxic effects of arsenic in rats

Concomitant oral supplementation of Aloe vera, (1, 2 or 5% w[sol ]v in drinking water) during arsenic exposure (0.2 mg[sol ]kg, intraperitoneally, once daily for 3 weeks) was investigated in rats for its protective value. Animals exposed to arsenic (III) showed a significant inhibition of delta-aminolevulinic acid dehydratase (ALAD) activity, a marginal decrease in glutathione (GSH) and an increase in zinc protoporphyrin (ZPP) level in blood. White blood corpuscles (WBC) level decreased while most of the other clinical blood parameters like red blood cells count, haemoglobin, MCV, MCH, MCHC ratio and platelet number, etc. remained unaltered on arsenic exposure. Hepatic reduced GSH, oxidized glutathione (GSSG) level remained unaltered, thiobarbituric acid reactive substance (TBARS) level increased significantly while the activity of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and catalase decreased on arsenic exposure. Renal GSH contents decreased while superoxide dismutase (SOD) activity decreased significantly on arsenic exposure. Concomitant administration of Aloe vera had remarkable protective action on inhibited blood ALAD activity and restored blood GSH level while most of the other blood biochemical parameters remained unchanged on Aloe vera supplementation. Interestingly, most of hepatic biochemical variables indicative of oxidative stress showed protection; no effect of Aloe vera on blood and liver arsenic concentration was noted. Also, no effect of Aloe vera on most of the altered renal biochemical parameters were noticed. The results thus lead us to conclude that simultaneous supplementation of Aloe vera protects against arsenic induced oxidative stress but does not influence the arsenic concentration in these organs.     

丛枝菌根在芦荟育苗中的应用

利用6种丛枝(AM)菌和1种AM菌剂对库拉索芦荟Aloe vera组培幼苗接种的结果表明:供试菌种或菌剂均可使幼苗形成丛枝菌根,感染率达96.67％～100%,感染指数达73.30～86.67;接种13个月的苗高比对照增加19.85％～51.91％;叶片长度比对照增加56.67％;芦荟幼苗经接种后,叶片汁液的干物质含量,比对照分别增加13.13％～150.96％。接种15个月的芦荟幼苗叶汁鲜重比对照增加60.87％～233.80％;折合有效成分的生药含量,比对照提高2.17倍～7.24倍。     

Preliminary evaluation: the effects of Aloe ferox Miller and Aloe arborescens Miller on wound healing

Aim of the study

Genus Aloe has been traditionally utilized for medicinal purpose for decades. Compared with Aloe vera gel, the qualitative assessment for the therapeutic effects of the other two Aloe species, Aloe ferox Miller and Aloe arborescens Miller, for their topical wound healing was less addressed. Therefore, the aim of present study is to provide the positive evidence for Aloe ferox Miller and Aloe arborescens Miller supporting their therapeutic properties for topical treatment of skin wounds.

Materials and methods

Two types of the whole-leaf juice prepared from either Aloe ferox Miller or Aloe arborescens Miller were used in this study. Incision wound healing was investigated using both the rat and rabbit model. The wound closure rate with and without the topical administration of the whole-leaf juice were monitored. The changes in wound characteristics were traced and wound severity was scored on different days. The anti-microorganism actions of each whole-leaf juice preparation were evaluated by measuring their inhibition growth effects on four bacterial strains and three fungal spores. The toxic influence owing to topical application of Aloe whole-leaf juice on intact and damaged skin was also assessed.

Results and Conclusions

Our results indicated that the two types of whole-leaf juice preparations exhibit the therapeutic properties, including facilitation of the healing process, selective inhibition of the microbial growth and zero side-effect on the skin, during the observation period. It is concluded that both of Aloe whole-leaf juice preparations have the positive potential for skin medicinal application.     

A Biochemical and Cellular Approach to Explore the Antiproliferative and Prodifferentiative Activity of Aloe Arborescens Leaf Extract

Aloe arborescens Miller, belonging to the Aloe genus (Liliaceae family), is one of the main varieties of Aloe used worldwide. Although less characterized than the commonest Aloe vera, Aloe arborescens is known to be richer in beneficial phytotherapeutic, anticancer, and radio‐protective properties. It is commonly used as a pharmaceutical ingredient for its effect in burn treatment and ability to increase skin wound healing properties. However, very few studies have addressed the biological effects of Aloe at molecular level. The aim of the research is to provide evidences for the antiproliferative properties of Aloe arborescens crude leaf extract using an integrated proteomic and cellular biological approach. We analysed the composition of an Aloe arborescens leaf extract by gas chromatography‐mass spectrometry analysis. We found it rich in Aloe‐emodin, a hydroxylanthraquinone with known antitumoral activity and in several compounds with anti‐oxidant properties. Accordingly, we show that the Aloe extract has antiproliferative effects on several human transformed cell lines and exhibits prodifferentiative effects on both primary and immortalized human keratinocyte. Proteomic analysis of whole cell extracts revealed the presence of proteins with a strong antiproliferative and antimicrobial activity specifically induced in human keratinocytes by Aloe treatment supporting its application as a therapeutical agent. Copyright © 2013 John Wiley & Sons, Ltd.     

Preliminary study of effectiveness of aloe vera in scabies treatment

In an open, non‐comparative study carried out between August and December 2002 at the Obafemi Awolowo University Teaching Hospitals Complex, Ile‐Ife, Nigeria, 5 patients with scabies were successfully treated with crude gel of Aloe vera; thereafter the efficacy of the extract was compared with that of benzoate lotion among 30 patients. Sixteen patients were treated with Aloe vera and 14 patients had benzyl benzoate lotion. Itching was still present in 3 patients in the benzyl benzoate group and in 2 patients in the Aloe vera group after 2 courses of treatment. The scabietic lesions virtually disappeared in all of them. None of these patients had any noticeable side effects. It is concluded that Aloe vera gel is as effective as benzyl benzoate in the treatment of scabies. Copyright © 2009 John Wiley & Sons, Ltd.     

The influence of long-term Aloe vera ingestion on age-related disease in male Fischer 344 rats

The effects of long-term Aloe vera ingestion on age-related diseases were investigated using male specific pathogen-free (SPF) Fischer 344 rats. Experimental animals were divided into four groups: Group A, the control rats fed a semi-synthetic diet without Aloe vera; Group B, rats fed a diet containing 1% freeze-dried Aloe vera filet; Group C, rats fed a diet containing 1% charcoal-processed, freeze-dried Aloe vera filet; and Group D, rats fed the control diet and given whole leaf charcoal-processed Aloe vera (0.02%) in the drinking water. This study demonstrates that life-long Aloe vera ingestion produced neither harmful effects nor deleterious changes. In addition, Aloe vera ingestion appeared to be associated with some beneficial effects on age-related diseases. Groups B exhibited significantly less occurrence of multiple causes of death, and a slightly lower incidence of fatal chronic nephropathy compared with Group A rats. Groups B and C rats showed the trend, slightly lower incidences of thrombosis in the cardiac atrium than Group A rats. Therefore, these findings suggest that life-long Aloe vera ingestion does not cause any obvious harmful and deleterious side effects, and could also be beneficial for the prevention of age-related pathology.     

Oral administration of Aloe vera and honey reduces walker tumour growth by decreasing cell proliferation and increasing apoptosis in tumour tissue

Cancer is diagnosed in approximately 11 million people and is responsible for almost 8 million deaths worldwide every year. Research in cancer control has shown the importance of co‐adjuvant therapies. Aloe vera may reduce tumour mass and metastasis rates, while honey may inhibit tumour growth. This study verified the influence of Aloe vera and honey on tumour growth and in the apoptosis process by assessing tumour size, the cell proliferation rate (Ki67‐LI) and Bax/Bcl‐2 expression at 7, 14 and 20 days after Walker 256 carcinoma implant in Wistar rats distributed into two groups: the WA group – tumour‐bearing rats that received a gavage with a 670 µL/kg dose of Aloe vera and honey solution daily, and the CW group – tumour‐bearing rats which received only a 0.9% NaCl solution. The effect of Aloe vera and honey against tumour growth was observed through a decrease in relative weight (%) and Ki67‐LI in tumours from the WA group compared with those from the CW group. The Bax/Bcl‐2 ratio increased in tumours from the WA group at all tested timepoints. These data suggest Aloe vera and honey can modulate tumour growth by reducing cell proliferation and increasing apoptosis susceptibility. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of Aloe vera leaves on blood glucose level in type I and type II diabetic rat models

Aloe vera (L.) Burm. fil. (= A. barbadensis Miller) (Liliaceae) is native to North Africa and also cultivated in Turkey. Aloes have long been used all over the world for their various medicinal properties. In the past 15 years, there have been controversial reports on the hypoglycaemic activity of Aloe species, probably due to differences in the parts of the plant used or to the model of diabetes chosen. In this study, separate experiments on three main groups of rats, namely, non-diabetic (ND), type I (IDDM) and type II (NIDDM) diabetic rats were carried out. A. vera leaf pulp and gel extracts were ineffective on lowering the blood sugar level of ND rats. A. vera leaf pulp extract showed hypoglycaemic activity on IDDM and NIDDM rats, the effectiveness being enhanced for type II diabetes in comparison with glibenclamide. On the contrary, A. vera leaf gel extract showed hyperglycaemic activity on NIDDM rats. It may therefore be concluded that the pulps of Aloe vera leaves devoid of the gel could be useful in the treatment of non-insulin dependent diabetes mellitus Copyright 2001 John Wiley & Sons, Ltd.     

Effects of Aloe vera ingestion in the rat. I. Growth,food and fluid intake and serum chemistry

This study was designed to examine the effects of long-term (1.5 and 5.5 months) Aloe vera (Aloe barbadensis) ingestion on the growth, food intake and serum chemistry of Fischer 344 male rats. Aloe vera powders, produced by two different methods, were mixed with rat chow at selected concentrations. Process A aloe was prepared from skinned aloe filets by homogenization followed by lyophilization and grinding to a fine powder; Process B aloe was prepared similarly except that the homogenate was charcoal filtered prior to lyophilization. Ingestion of Process A aloe at concentrations greater than 1% was associated with diarrhoea and a decrease in weight gain. Ingestion of 1% Process A and both 1% and 10% Process B aloe had no adverse effect on body weight gain, food intake, gastrointestinal transit time and gross pathology. Serum chemistry was minimally affected. The rats ingesting 10% Process B aloe exhibited a slight, but significant increase in fluid intake. The results indicate that, although high concentrations of aloe should be avoided, ingestion of moderate levels (1%) of aloe from either process causes no apparent adverse effects in the rat. © 1998 John Wiley & Sons, Ltd.     

Polypeptides of the Three Major Medicinal Aloes

Major polypeptide species of proteins have been identified and analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in fresh extracts of the gel portion of mature leaves of Aloe saponaria Haw, Aloe barbadensis Miller, and Aloe arborescens Miller var. natalensis Berger. Extracts of gel from freshly cut Aloe leaves were prepared by dissection, tissue disruption, ethanol extraction, differential centrifugation, and gel filtration methods. Comparisons of SDS-PAGE profiles of Aloe leaf gels showed that all three medicinal Aloes share five major common polypetides. Other results indicated that Aloe saponaria and Aloe barbadensis share the most major polypeptides, i.e. 11, and Aloe barbadensis and Aloe arborescens the least, i.e. 5, while Aloe arborescens had three individual polypeptides not found in the other two species. This is the first report to describe the nature and types of polypeptides detected in extracts of leaf gel portions of mature Aloe plants of these three medicinal species. Accordingly, this report may be of considerable value in helping to identify and characterize those Aloe substances of medicinal importance which are associated with each or all of these medicinal Aloes.     

Evaluation of the antipsoriatic activity of Aloe vera leaf extract using a mouse tail model of psoriasis

Aloe vera gel is used traditionally for the treatment of skin diseases, including psoriasis. An ethanolic extract of the gel was assessed for antipsoriatic activity using a mouse tail model of psoriasis. The extract produced a significant differentiation in the epidermis, as seen from its degree of orthokeratosis (85.07 ± 3.36%) when compared with the negative control (17.30 ± 4.09%). This was equivalent to the effect of the standard positive control, tazarotene (0.1%) gel, which showed a 90.03 ± 2.00% degree of orthokeratosis. The ethanolic extract of Aloe vera leaf gel also produced a significant increase in relative epidermal thickness when compared with the control group, whereas the standard tazarotene showed no change. Taken together, the extract showed an overall antipsoriatic activity of 81.95%, compared with 87.94 for tazarotene, in the mouse tail model for psoriasis.     

Lipid lowering activity of hydrosoluble chitosan and association with Aloe vera L. and Brassica olearaceae L

The lipid lowering activity of chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. has been studied in rats. In this study, rats were submitted to different treatments with hydrosoluble chitosan alone (4% diet), hydrosoluble chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. (1:4, 4% diet) for 35 days, to identify the formula with the highest hypolipaemic potential. The results showed that all treatments reduced blood lipid levels but that hydrosoluble chitosan associated with Brassica olearaceae L. proved most efficient, because it decreased the levels of total cholesterol, LDL-cholesterol, VLDL-cholesterol and triglycerides in blood serum. The overall results suggest that the hydrosoluble chitosan/Brassica olearaceae L. association is a therapeutic alternative for hyperlipidaemia, and in this way may contribute to the prevention of atherogenic processes.     

Evaluation of Bioactive Potential of an Aloe vera Sterol Extract

We prepared a crude gel material from Aloe vera succulent leaf tissues. The ethanolic extract of lyophilized A. vera gel was used for the GC‐MS analysis. Hexadecanoic acid (22.22%) was identified as major compound. Sitosterol and stigmasterol were found to be 2.89% and 2.1% in the extract. HPLC analysis was carried out to confirm the presence of stigmasterol. The concentration of sterol extract needed to scavenge DPPH free radical by 50% was calculated as 5.2 mg mL^?1. In the FRAP assay, the sterol extract showed significant hydroxyl radical scavenging in a dose‐dependent manner (IC₅₀ value 1.17 µg mL^?1). Concentration of the sample required to reduce lipid peroxidation was found to be 4.18 µg mL^?1, and the extract also possessed acetylcholinesterase activity (IC₅₀ ‐ 5.26 µg mL^?1). Catalase activity was 0.196 μM H₂O₂ decomposed min^?1 µg^?1 protein, whereas the peroxidase activity was 17.01 μM of pyragallol oxidized min^?1 µg^?1 protein. The extract recorded higher activity against growth of S. greseus and C. albicans in the experiments carried out to determine antibacterial and antifungal activity, respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

Toxicity studies on six plants used in the traditional Arab system of medicine

Toxicity studies were done on six plants used in the traditional Arab system of medicine, namely: Aloe vera, Ammi majus, Areca catachu, Citrullus colocynthis, Cuminum cyminum and Zizyphus spina-christi. During acute toxicity tests, observations were made for 24 h while the animals were treated for 3 months in chronic treatment. External morphological changes, visceral toxicity, haematological changes, and spermatogenic dysfunction, besides effects on average body weight and vital organ weight, were recorded. In the acute toxicity test, C. colocynthis showed a dose dependent toxic effect. On chronic treatment, per cent lethality was found to be significant in A. catachu, A. vera and C. colocynthis treated groups where haematological changes were also observed. The spermatogenic dysfunction was significant in A. vera and C. colocynthis treated animals. C. cyminum and Z. spina-christi on the other hand, reduced sperm abnormalities.     

Aloe vera as an herbal medicine in the treatment of metabolic syndrome: A review

Metabolic syndrome (MS) is a highly prevalent health problem worldwide and is associated with different risk factors, including hyperglycemia, dyslipidemia, hypertension, and obesity. This condition increases the risk of developing type II diabetes mellitus and cardiovascular problems. The MS is one of the most important health concerns in industrialized countries and mainly results from a sedentary lifestyle, high levels of subjective stress, and unhealthy diets. Nowadays, the identification of appropriate health care approaches, such as herbal medicines, with fewer side effects is more favorable, especially with regard to the adverse effects of chemical drugs. Aloe barbadensis Miller known as Aloe vera is a useful plant with two major parts, including leaves that contain high concentrations of anthraquinone compounds and a clear gel. The gel is used as a food with several beneficial properties, such as antiinflammatory, antioxidant, antiviral, antibacterial, and wound‐healing features. Other effects of A. vera, such as its lipid‐lowering, antihypertensive, antidiabetic, antiobesity, and cardioprotective impacts, have been demonstrated in several studies. The present study was conducted to review the evidence on the pharmacological effects of A. vera on the different components of MS.     

Caco‐2 Cell methodology and inhibition of the P‐glycoprotein transport of digoxin by Aloe vera Juice

The aims of this study were to carry out a thorough quality control setup for essential Caco‐2 cell characteristics in P‐glycoprotein (P‐gp) inhibition studies and to explore if Aloe vera juice (AVJ) inhibits the bidirectional transport of the P‐gp substrate digoxin (30 nm ). Seven AVJ concentrations (0.00001‐1.0 mg/mL), anticipated to cover a clinically relevant range, were tested and digoxin apparent permeability coefficients (Papp), net Papp values (Papp_Net) and net flux values (J_Net) were calculated. Relevant validation parameters for P‐gp inhibition studies in Caco‐2 cells are suggested to include, as a minimum, an assay linearity test with and without a known P‐gp inhibitor, cell cytotoxicity testing (MTT‐test) for substrates and inhibitors, and cell integrity testing by TEER and mannitol transport measurements. The question is also raised whether a minimum effect of a reference P‐gp inhibitor as verapamil should be demanded. Cell cytotoxicity was seen for digoxin at concentrations ≥3 µm and for AVJ at 10 mg/mL. AVJ did not inhibit the P‐gp transport of digoxin in any of the concentrations tested. This indicates that AVJ is no inhibitor of the P‐gp mediated transport of digoxin in vitro if AVJ is present in clinically relevant concentrations. Copyright © 2008 John Wiley & Sons, Ltd.     

Review of Clinical Pharmacology of Aloe vera L. in the Treatment of Psoriasis

Aloe vera L., is a plant used worldwide as folk remedy for the treatment of various ailments, including skin disorders. Its gel is present in cosmetics, medicinal products and food supplements. Psoriasis, an immune‐mediated chronic inflammatory disease, involving mainly the skin, affects about the 2–3% of general population. Conventional pharmacological treatments for psoriasis can have limited effectiveness and can cause adverse reactions. For this reason often psoriatic patients look for alternative treatments based on natural products containing Aloe vera. We conducted a systematic review of clinical trials assessing effectiveness and safety of aloe for the treatment of psoriasis. Clinical studies published in English were considered; a total of four clinical trials met inclusion criteria. Studies were also evaluated by using the Jadad scale and Consort Statement in Reporting Clinical trials of Herbal Medicine Intervention. Quality and methodological accuracy of considered studies varied considerably, and some crucial information to reproduce clinical results was missing. We conclude that administration of aloe as cutaneous treatment is generally well tolerated, as no serious side effects were reported. Results on the effectiveness of Aloe vera are contradictory; our analysis reveals the presence of methodological gaps preventing to reach final conclusions. Copyright © 2015 John Wiley & Sons, Ltd.     

芦荟保湿活性成分筛选及皮肤适应性研究

目的:优选芦荟的保湿活性成分,并对其进行皮肤适应性评价.方法:采用皮肤水合状态和经皮水分散失测试的方法,优选芦荟中的保湿活性成分;采用红细胞溶血、Franz扩散池体外透皮吸收以及人体斑贴试验,分别从生物相容性、皮肤渗透性与皮肤安全性3个方面综合评定保湿活性成分的皮肤适应特性.结果:芦荟的多糖成分有显著提高皮肤水合状态(P＜0.05),同时降低经皮失水(P＜0.05)的优良保湿功效;芦荟多糖液(2,20 g·L-1)对红细胞的溶血率均低于0.3％,远低于血液相容性的常规值,与人体相容度高;5％芦荟多糖皮肤渗透速率达到0.251 mg·h·cm-2,24 h累计渗透量达(4.152±0.046) mg· cm-2,具备较强的皮肤渗透力;人体皮肤斑贴试验中全部评定为0级反应,对人体高度安全.结论:库拉索芦荟活性多糖对皮肤具有显著的保湿功效以及优良的皮肤适应性,可作为保湿类化妆品或外用皮肤干燥症制剂中的优良添加剂在皮肤科中广泛应用.     

Hypoglycemic and Hypolipidemic Effects of Aloe vera Extract Preparations: A Review

Obesity is considered to be an epidemic disease, and it is associated with several metabolic disorders. Pharmacological treatments currently available are not effective for prolonged treatment duration. So, people are looking toward new therapeutic approach such as herbal ingredients. Since ancient periods, different herbs have been used for remedy purposes such as anti‐obesity, antidiabetes, and antiinflammatory. Among the several herbal ingredients, Aloe vera (Aloe barbadensis Miller) is widely used to curb the metabolic complications. Till date, reports are not available for the side effects of A. vera. Several researchers are used to different solvents such as aqueous solution, alcohol, ethanol, and chloroform for the A. vera extract preparations and studied their hypoglycemic and hypolipidemic effects in animal and human studies. Furthermore, little information was recorded with the active compounds extracted from the A. vera and their anti‐obesity and antidiabetic effects in clinical studies. In this review, we made an attempt to compile all the available literature by using different search engines (PubMed, Scopus, and Google Scholar) on the A. vera extract preparations and the possible mechanism of action involved in carbohydrate and lipid metabolism. Copyright © 2015 John Wiley & Sons, Ltd.     

Semi-purification and characterization of haemagglutinin substance from Aloe barbadensis Miller

Extracts of Aloe barbadensis Miller have been found to induce cell proliferation and haemagglutination effects. An ethanol extract of Aloe was found to be strongly haemagglutinating. The carbohydrate-agglutinin binding was observed to be glucosamine dependent and the site of recognition of this particular sugar has been identified. Characterizations of the haemagglutinin by different treatments have shown that it is pH sensitive and heat and trypsin resistant.