The therapeutic properties and applications of Aloe vera: A review

Background There are many plants with interesting pharmaceutical activities but Aloe vera is probably the most applied medicinal plant worldwide. Since biblical times, aloe has been used for its purgative effect, skin disorders healing and beauty treatments. Scope and approach For this study, an extensive review on Aloe vera was carried out, including its main uses, components (both nutrients and bioactives), biological activities, and applications. Future trends were also assessed. Key findings and conclusions Aloe possesses numerous activities including, anticancer, antioxidant, antimicrobial, antiallergic, anti-inflammatory, immunomodulatory, hepatoprotective, antiulcer and antidiabetic. Some of these activities are due to the presence of polysaccharides (acemamman; glucomannan). A wide variety of commercial products based on Aloe vera are available on the market. However, the knowledge of the relationship between biological and therapeutic properties and its components has to be clearly defined in order to know the exact mechanism of action to develop effective new products, namely pharmaceuticals. The knowledge of the factors that affect Aloe vera variability, such as processing conditions, is also of great importance to be able to standardize the final products.

Aloe vera: Ancient knowledge with new frontiers

The aim of the present study was to analyse the effect of climate change on phytochemicals, total phenolic content (TPC) and antioxidant potential of methanolic extracts of Aloe vera collected from different climatic zones of the India. Crude methanolic extracts of A. vera from the different states of India were screened for presence of various phytochemicals, total phenolic content and in vitro antioxidant activity. Total phenolic content was tested by Folin–Ciocalteau reagent based assay whilst DPPH free radical scavenging assay, metal chelating assay, hydrogen peroxide scavenging assay, reducing power assay and β carotene-linoleic assay were used to assess the antioxidant potential of A. vera methanolic leaf extracts. Alkaloids, phenols, flavonoids, saponins, and terpenes were the main phytochemicals presents in all accessions. A significant positive correlation was found between TPC and antioxidant activity of different accessions. Extracts of highland and semi-arid zones possessed maximum antioxidant potential. Accessions from tropical zones showed the least antioxidant activity in all assays. It could be concluded that different agro-climatic conditions have effects on the phytochemicals, total phenolic content (TPC) and antioxidant potential of the A. vera plant. The results reveal that A. vera can be a potential source of novel natural antioxidant compounds.

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Effect of climate change on phytochemical diversity, total phenolic content and in vitro antioxidant activity of Aloe vera (L.) Burm.f.

// Uzma Saqib 1 , Sutripta Sarkar 2 , Kyoungho Suk 3 , Owais Mohammad 4 , Mirza S. Baig 5 and Rajkumar Savai 6, 7 1 Discipline of Chemistry, School of Basic Sciences, Indian Institute of Technology (IIT) Indore, MP, India 2 PostGraduate Department of Food & Nutrition, BRSN College (affiliated to WBSU), Kolkata, WB, India 3 Department of Pharmacology, Kyungpook National University School of Medicine, Joong-gu Daegu, South Korea 4 Interdisciplinary Biotechnology Unit, Aligarh Muslim University (AMU), Aligarh, UP, India 5 Discipline of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology (IIT), Indore, MP, India 6 Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus Liebig University, Giessen 35392, Germany 7 Max Planck Institute for Heart and Lung Research, Department of Lung Development and Remodeling, Member of the DZL, Bad Nauheim, Germany Correspondence to: Mirza S. Baig, email: msb@iiti.ac.in Rajkumar Savai email: rajkumar.savai@mpi-bn.mpg.de Keywords: Anti-inflammatory cytokines; inflammation; M1–M2 macrophages; natural compounds; pro-inflammatory cytokines Received: December 21, 2017      Accepted: February 25, 2018      Published: April 03, 2018 ABSTRACT Macrophages are critical mediators of the innate immune response against foreign pathogens, including bacteria, physical stress, and injury. Therefore, these cells play a key role in the “inflammatory pathway” which in turn can lead to an array of diseases and disorders such as autoimmune neuropathies and myocarditis, inflammatory bowel disease, atherosclerosis, sepsis, arthritis, diabetes, and angiogenesis. Recently, more studies have focused on the macrophages inflammatory diseases since the discovery of the two subtypes of macrophages, which are differentiated on the basis of their phenotype and distinct gene expression pattern. Of these, M1 macrophages are pro-inflammatory and responsible for inflammatory signaling, while M2 are anti-inflammatory macrophages that participate in the resolution of the inflammatory process, M2 macrophages produce anti-inflammatory cytokines, thereby contributing to tissue healing. Many studies have shown the role of these two subtypes in the inflammatory pathway, and their emergence appears to decide the fate of inflammatory signaling and disease progression. As a next step in directing the pro-inflammatory response toward the anti-inflammatory type after an insult by a foreign pathogen (e. g., bacterial lipopolysaccharide), investigators have identified many natural compounds that have the potential to modulate M1 to M2 macrophages. In this review, we provide a focused discussion of advances in the identification of natural therapeutic molecules with anti-inflammatory properties that modulate the phenotype of macrophages from M1 to M2.

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Phytochemicals as modulators of M1-M2 macrophages in inflammation

Many studies have proved that bioactive components of Aloe vera have an anti-inflammatory effect and support lipid and carbohydrate metabolism, helping to maintain normal sugar and cholesterol levels in blood and normal body weight. When aloe is applied externally, it accelerates the regeneration of the damaged skin. Aloe contains antioxidants, which may increase the shelf-life and nutritional value of food; therefore, it is widely used in cosmetic, pharmaceutical and food industry. An antioxidant activity was shown for leaf’s skin, flowers and gel of aloe. In this work the future of A. vera as effective antioxidants is primarily discussed and expected trends are summarised. Furthermore, the bioactive components and the health-promoting effects of A. vera are investigated.

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Aloe vera (L.) Webb.: Natural Sources of Antioxidants – A Review

https://cyberleninka.org/article/n/1017220.pdf

Nampoothiri P. Laxmipriya

Papers

Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review.