Reciprocal hybridisation of Aloe species (Aloe arborescens with A. vera) and their characterisation in a highland region of Venezuela

Research into antioxidants in plants has expanded greatly in recent years, to find the best posible antioxidants to prevent and even treat disease. This study represents the first comparative investigation of the antioxidant activity of these three Aloe species (Aloe vera, arborescens and brevifolia). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was used to assess the antioxidant activity of methanolic extracts of the three Aloe species. A calibration range of a standard antioxidant represents the positive control, Butylhydroxyanisol (BHA) (0-100 µg/ml). The results showed a significant difference in the free radical scavenging activity of the three Aloe species and the standard (BHA) for DPPH, with respective IC50 values from lowest to highest of 0.040 mg/ml for standard BHA, 0.100 mg/ml for Aloe vera, 0.270 mg/ml for Aloe arborescens and 0.370 mg/ml for Aloe brevifolia. The percentage of inhibition in Aloe vera is higher than in the other two species (Aloe arborescens and brevifolia). Aloe vera, which is very rich in active substances, showed high antioxidant potential comparable to that of the standard. Leaf extracts from Aloe arborescens and Aloe brevifolia also had a lower antioxidant potential than Aloe vera, but this was not negligible.

The effect of salt stress on the growth and development of three Aloe species in eastern Morocco

Identification and discrimination of three common Aloe species by high performance liquid chromatography-tandem mass spectrometry coupled with multivariate analysis.

Metabolomics is as an innovative technique for discriminating plant species. The objective of this study was to investigate the secondary metabolites of three different Aloe species, A. vera, A. arborescens, and A. saponaria profiled by 1 H-NMR analysis. Principal component analysis (PCA) derived from the 1 H-NMR spectra indicated a clear discrimination among the Aloe species, providing high predictability and good fitness of the PCA model (R2 = 0.928 and Q2 = 865). As observed in the PLS-DA score plot, discrimination was observed in the Aloe species with respect to primary metabolites including sugar and organic acid and secondary metabolites such as phenylpropanoids and carotenoids. A. vera was characterized by high levels of malate. On the other hand, as compared to the other Aloe species, A. arborescens was characterized by higher levels of aloenin and sugar metabolites such as sucrose and glucose. Furthermore, the secondary metabolites were quantitatively analyzed by HPLC, and the amounts of carotenoids including zeaxanthin, α- and β-carotene, and phenylpropanoids in A. arborescens were found to be significantly higher than those in the other Aloe species. In conclusion, we demonstrated that 1 H-NMR-based metabolomics with chemometric analysis can be used for the facile discrimination of Aloe species.

The genus Aloe comprises over 400 species of flowering succulent plants. Aloe leaves are used in the treatment of asthma, gastrointestinal ulcers, cardiovascular disease, tumors, burns, and diabetes. They are rich in anthraquinones, such as aloin, aloe-emodin, chrysophanol, aloinoside A, and aloinoside B. The various species of Aloe show chemical and morphological similarity and diversity, which depend on the genotype and environmental conditions. In a continuity to our interest in the genus Aloe, this study targets the authentication of eight different Aloe species, Aloe vera (A1), Aloe arborescens (A2), Aloe eru (A3), Aloe grandidentata (A4), Aloe perfoliata (A5), Aloe brevifolia (A6), Aloe saponaria (A7), and Aloe ferox (A8), grown in Egypt by using the technique of random amplified polymorphic DNA. Twelve decamer primers were screened in amplification with genomic DNA extracted from all species, of which five primers yielded species-specific reproducible bands. Out of 156 loci detected, the polymorphic, monomorphic, and unique loci were 107, 26, and 23, respectively. Based on a dendrogram and similarity matrix, the eight Aloe species were differentiated from each other and showed more divergence. Aloe species prevailed similarity coefficients of 54-70 % by which they could be classified into three major groups. Thus, this technique may contribute to the identification of these Aloe species that have great morphological similarity in the Egyptian local markets.

Although a vast number of Aloe species are known, only the Aloe vera and Aloe arborescens species are currently used by cosmetic and pharmaceutical industries. Therefore, the current study aims to complete the existent literature data with new information on the phytochemical composition of some lesser-known Aloe species, with the main focus on carotenoids and fatty acids. Among the analyzed species, Aloe aculeata and Aloe ferox had the highest content in carotenoids, the major pigments being lutein and β-carotene (according to HPLC analysis). The fatty acid profile of each Aloe species was analysed by GC–MS. Linolenic and linoleic acids were the major polyunsaturated fatty acids found in higher percent in Aloe ferox, Aloe spectabilis and Aloe marlothii. Instead, Aloe aculeata proved to have a distinct fatty acid profile, rich in monounsaturated fatty acids. Species such as Aloe arborescens and Aloe marlothii proved to have the highest antioxidant potential according to data of DPPH, ORAC, HPS assays, even if the richest one in vitamin C was found to be Aloe spectabilis. Though the scientific research is mainly focused on the common species Aloe barbadensis, the current data suggests that other Aloe species could receive more attention from industry part, being great sources of bioactive compounds.

Aloe arborescens Mill., family Asphodelaceae, is a pharmacopoeial plant, the raw material of which is used for the production of medicinal products for various therapeutic uses. The standardization of Aloe species in accordance with the requirements of the British, Japanese, European Pharmacopoeias and the United States Pharmacopoeia is carried out according to the barbaloin content by the spectrophotometric method. The methods are multistage, provide for preliminary acid hydrolysis in combination with the oxidation, liquid-liquid extraction of the formed aglycones and subsequent complexation with magnesium acetate. A mixture of isomers of aloin A and aloin B (barbaloin) and aloenin were isolated by chromatographic methods. It was determined that in all electronic spectra of the extracts and preparations from the leaves of Aloe arborescens Mill., a bathochromic shift of the long-wavelength band in the alkaline-ammonia solution is observed, which confirms the presence of anthracene derivatives. Under conditions of differential absorption, a maximum absorption is observed in the range of 412–416 nm, which indicates the advisability of using barbaloin in the analysis method, which has a maximum absorption at a wavelength of 412 nm. As a result of the study, there were developed methods for the quantitative determination of the total of anthracene derivatives in leaves and preparations of Aloe arborescens Mill. by using of the differential spectrophotometry calculated on barbaloin at an analytical wavelength of 412 nm. The content of total anthracene derivatives calculated on barbaloin was 0.60±0.03% in Aloe arborescens fresh leaves, 0.5±0.02% in freshly prepared juice, 0.135±0.006% in "Aloe juice" and 0.020±0.001% in "Aloe liquid extract", solution for subcutaneous administration, produced by ZAO "Vifitech" and OAO "Dalkhimpharm".

Plants of the genus Aloe have perhaps the longest recorded history of medicinal usage and are amongst the most widely used plants for traditional medicinal purposes worldwide. Aloe vera, Aloe ferox, Aloe arborescens and Aloe perryi are the best known and most widely used, but many other species are also used for their therapeutic properties. The Aloes have been used since ancient times, particularly for the treatment of microbial infections, gastrointestinal disorders and inflammatory conditions. In addition to their myriad uses in traditional therapeutics, the Aloes have also been used as components of cosmetic formulations, and in the food and beverage industries. Despite their wide acceptance, studies from different laboratories often report wide variations in the therapeutic bioactivities from within the same Aloe species, even when the same extraction procedures are used. Furthermore, leaves from individual Aloe plants within the same species may have widely varying levels of the bioactive phytochemicals. Phytochemical analyses have shown that many Aloe species contain various carbohydrate polymers (notably glucomannans) and a range of other low molecular weight phenolic compounds including alkaloids, anthraquinones, anthrones, benzene and furan derivatives, chromones, coumarins, flavonoids, phytosterols, pyrans and pyrones. There has been a wealth of information published about the phytochemistry and therapeutic potential of the Aloes (especially Aloe vera). Much of this has been contradictory. Intra- and interspecies differences in the redox state of the individual Aloe components and in the ratios of these components may occur between individual plants. These factors may all affect the physiological properties of Aloe extracts. Due to the structure and chemical nature of many of the Aloe phytochemicals, it is likely that many of the reported medicinal properties are due to antioxidant or prooxidant effects. The antioxidant/prooxidant activities of many Aloe phytochemicals depend not only on their individual levels, but also on the ratios between the various components and their individual redox states. Therefore, discrepancies between bioactivity studies are likely when using different crude mixtures. This report aims to summarise the phytochemistry of the Aloes and (a) examine how their constituents may be responsible for their medicinal properties and (b) some possible reasons for the wide variations reported for their medicinal properties and (c) their therapeutic mechanisms. Some future areas of research into the medicinal activities of this important genus are also highlighted.

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

Aloe gel is a medicinal raw material with proven pharmacological activity. The health-promoting properties of other species of Aloe upon topical application prompted us to develop a formulation for the topical application of A. arborescence species. As a result of the gel preparation from the aqueous lyophilized extracts of three-year-old leaves of A. arborescence, no changes in the composition of the content of aloins A and aloenin A were found. The potential to neutralize free radicals was tested using DPPH and CUPRAC techniques, which confirmed the anti-radical activity of the lyophilisate. Screening of the inhibition of enzymes, the hyperactivity of which is associated with adverse changes in the skin of a pro-inflammatory nature, was performed. Importantly, using the PAMPA SKIN model, the possibility of the penetration of selected extract compounds (aloin A and aloenin A) through the skin was proven. Then, two formulations were prepared based on sodium alginate and hydroxypropyl methylcellulose (HPMC) and the hydrogels were characterized (rheological analysis, drug release profiles, permeability, and stability studies). HPMC-based hydrogel was the one with a targeted release of active substances and greater stability. Aloe arborescens hydrogel matrices seem to be a promising treatment strategy for inflammatory surface damage based on “green technology” at the stage of extract preparation and development of the drug form for topical application.

Herbal medicine is being used around the globe and plays an essential role in several developed and developing countries as primary health care. The genus Aloe has about 400 species while some of them (A. Vera, A. greatheadi, Aloe ferox, and Aloe arborescens) are commercially used in homeopathic and Allopathic medicines for its remarkable pharmaceutical properties. These plants have potent natural sources which have health-promoting effect for mammals including human beings. Phytochemistry of the species of aloe plants reported more than 200 biologically active secondary metabolites with the ability of various biological activities like antidiabetic, antioxidant antidiabetic, hepatoprotective, and renoprotective activities. This review highlighted the diabetic properties of different species of genus Aloe.

Krantz aloe (Aloe arborescens) is one of two aloe species currently used for the extraction of active ingredients that can be useful in the cosmetic and pharmaceutical industries. However, krantz aloe plants have been frequently collected from the wild, which is threatening wild populations. In vitro tissue culture would allow the growth of krantz aloe under controlled conditions, optimizing the production of active ingredients without risk to wild populations. The establishment of cultures from krantz aloe plant explants has proved difficult as a result of the long response times of the explants and their release of polyphenols. Krantz aloe seeds are not commonly used as a means of propagation because of their low germination percentages. The objective of this study was to evaluate the effects of seed imbibition (SI) with water and the addition of smoke-saturated water (SSW) to the culture medium on the in vitro germination and initial seedling development of krantz aloe. Seeds were germinated in vitro in axenic conditions. The treatments used were the addition of 10% SSW to the culture media, SI, and a combination of both (10% SSW + SI). Daily germination was recorded and gross morphology was measured after 1 month of culture establishment. The maximum germination percentage (GP) was achieved when 10% SSW was in the medium (97.2%), followed by the combined application of 10% SSW + SI (96.6%), both of which were almost 30% greater and significantly different from that of the control (69.4%). SI had an 83.3% GP. No significant differences were observed among treatments in any of the observed development parameters (leaf and root length and number). Taken together, these findings show that the use of SSW improves the in vitro germination of krantz aloe without affecting seedling development, indicating preliminarily that SSW represents a useful in vitro germination promoter for this species.

Characterisation of gels from different Aloe spp. as antifungal treatment: Potential crops for industrial applications

Aloe species are valuable plants with great ornamental and medicinal value. Although micropropagation protocols have been developed to meet the increasing global demand, the effects of the series of events during micropropagation on the phytochemical and pharmacological efficacy of ex-vitro plants remains poorly understood. Thus, we evaluated the effects of cytokinin and rooting compounds used during the shoot regeneration and rooting phases respectively, on secondary metabolite production in greenhouse-grown in vitro-derived Aloe arborescens. Shoots derived from meta-methoxytopolin (MemT)-containing medium and rooted with either smoke–water (SW) or indole butyric acid (IBA) had higher levels of total phenolics and flavonoids than those rooted on plant growth regulator (PGR)-free medium. Iridoid content was significantly reduced in cytokinin-regenerated shoots rooted with IBA in comparison to PGR-free regenerated shoots rooted with IBA. Conversely, the use of SW for rooting in cytokinin-regenerated shoots significantly increased iridoid content when compared to PGR-free regenerated shoots rooted with SW. These findings suggest an antagonistic interaction between cytokinins used in this study and IBA as well as a possible synergistic or additive interaction of the cytokinins with SW on iridoid production. Significantly higher antioxidant activity was recorded in shoots regenerated from meta-topolin riboside (mTR) and MemT and rooted with IBA or SW when compared to those rooted without PGR. Overall, the type of cytokinin and rooting treatments individually and interactively had a significant carry-over effect on secondary metabolite production and antioxidant potential of tissue culture-derived A. arborescens. Therefore, when micropropagating plants for medicinal uses, it is prudent to select the right cytokinin and rooting compound for optimal production of secondary metabolites and ultimately the pharmacological efficacy of acclimatized plants.

The medicinal use and commercialisation of the plants Aloe ferox and Aloe greatheadii are primarily based on research done on Aloe vera and Aloe arborescens. Consequently, in this study we investigated the possible antidiabetic effects of ethanol extracts of A. ferox and A. greatheadii var. davyana leaf gel in a streptozotocin (STZ)-induced type 2 diabetes rat model. Fifty male Wistar rats, weighing 200 g – 250 g, were randomly divided into five groups of n = 10: normal control rats, diabetic control rats, diabetic rats receiving A. ferox leaf gel extract (300 mg/kg), diabetic rats receiving A. greatheadii leaf gel extract (300 mg/kg), and diabetic rats receiving glibenclamide (600 μg/kg). Diabetes was induced by a single intraperitoneal injection of STZ (40 mg/kg). Rats were sacrificed 5 weeks after injection, following a 12-hour fast, and blood and tissue samples were collected. Compared to the normal control group, STZ significantly increased relative liver and kidney weights, end-point plasma glucose, fructosamine, oxidative stress, liver enzymes, total cholesterol (TC), triglycerides, very low density lipoproteincholesterol and TC: high density lipoprotein-cholesterol (HDL-C) values and reduced serum insulin levels. Treatment with A. greatheadii moderately increased serum insulin and HDL-C levels and moderately reduced end-point plasma glucose and liver alkaline phosphatase (ALP) and significantly decreased TC:HDL-C ratios. A. ferox supplementation similarly resulted in moderately increased serum insulin, accompanied by slight corrections in ALP and HDL-C, without any change to end-point plasma glucose values. A. greatheadii and, to a lesser extent, A. ferox, resulted in a clinically relevant improved diabetic state (indicated by moderate to high effect sizes), suggesting that these Aloe species may show promise for treating diabetes.