RESUMEN
Three new galactomannan components designed as AANP-1, AANP-3, and AAAP-7 were isolated from previously purified Aloe arborescence polysaccharide fractions, using ion-exchange, gel filtration, and preparative chromatographic techniques. Based on Fourier transform-infrared, one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy, the main backbone of AANP-1 elucidated as (1 â 4)-linked_α-d-deoxyGalp, (1 â 4) d-Manp, and ß-d-2-glup. The sugar residue sequence of AANP-3 was (1 â 4)-linked ß-d-NHAC-GAlp with ß-d-AcManp side chain that attached to O-4 position. The AAAP-7 repeated units were (1 â 4) d-Manp linked with (1 â 4) d-Galp interspersed with (1 â 3)-α-Manp. The results of high performance size-exclusion chromatography indicated that the approximate molecular weights of AANP-1, AANP-3, and AAAP-7 were 4.2, 2.4, and 2.5 kDa, respectively. The cytokine modulation assay revealed that the isolated components promoted a remarkable release of interleukin (IL)-12 and tumor necrosis factor alpha in comparison with the negative control group, whereas potent significant induction of IL-2 and interferon gamma was detected more than the positive control phytohemagglutinin (P < .05). This is the first report for isolation galactomannans from Aloe arborescence. Moreover, this finding could provide new insights for exploring the biological modifier mechanism in correlation with the knowledge of structural configuration.
Asunto(s)
Aloe/química , Citocinas/metabolismo , Mananos/química , Mananos/farmacología , Secuencia de Carbohidratos , Células Cultivadas , Galactosa/análogos & derivados , Humanos , Leucocitos Mononucleares/efectos de los fármacosRESUMEN
Plant polysaccharides gained extended scientific attention for their immunomodulatory effect. However, few scientific studies structurally defined polysaccharides in relation to their biological modifier response. Therefore, the study explored the effect of structurally identified isolated macromolecules from Aloe arborescens against cytokine modulation (interferon [IFN-γ], interleukins [IL-2 and IL-12], and tumor necrosis factor [TNF-α]) in vitro. The structures were elucidated by GC, GPC, FT-IR spectroscopy, 1D NMR, COSY, HMBC, and HSQC. Two acetylated glucomannans (AANP4 and AAAP6), one deoxy-glucogalactan (AANP5), and one deoxy-N-acetyl-[1-4]-galactosamine (AANP2) were isolated. The results showed significant induction for all cytokines and the most potent component was AAAP6; acetylated phenolic glucomannan with a (1 â 3)-linked glucose-mannose and (1 â 4)-linked mannose backbone, which stimulated IL-12 by more than 10-fold compared with phytohemagglutinin (positive control). In conclusion, A. arborescens polysaccharides could be a landmark for development of effective immunotherapeutics against cancer and chronic inflammatory conditions.
Asunto(s)
Aloe/química , Galactosamina/química , Factores Inmunológicos/química , Polisacáridos/química , Acetilación , Estructura Molecular , Fitoquímicos/química , Hojas de la Planta/química , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Aloe arborescens Miller (Family Asphodelaceae) is a member of genus Aloe, which is used in traditional medicine to cure various diseases. The extracts of the plant have been reported to possess anticancer, immunomodulator, antidiabetic, anti-inflammatory and antioxidant activities. The phytochemical investigations have revealed diverse chemical constituents, including phenolics [anthraquinones, anthrones, pyrones, chromones and coumarins], polysaccharides [arborans [(1-4) linked glucomannans, polysaccharide (A, B and C): (A: a linear (1-6)-O-α-glucan, B: a branching (1-2)-O-l-arabinose with (1-2)-O-d-galactose linkages and C: (1-4)-O-ß-mannan with 18% acetyl group)]], glycoproteins and carboxypeptidase enzyme. There are many reports, describing the different methodologies developed to perform chemical analysis as well as, separation, detection and identification of these constituents. Different chromatographic techniques were applied such as gas chromatography (GC), high-performance liquid chromatography (HPLC), liquid chromatography-electrospray ionization coupled with mass spectroscopy (LC-ESI/MS/MS) and gel filtration chromatography. Also the isolated compounds were identified based on the spectroscopic analysis; ultraviolet-visible spectroscopy (UV-vis), infra-red spectroscopy (IR), mass spectroscopy (MS) and nuclear-magnetic resonance (NMR). This study aims to pinpoint the active components besides finding out new structural leads for future drugs. Therefore, the review is targeted to provide evidence reported in the relevant literature on qualitative and quantitative research to assist scientists in isolation and characterization of bioactive compounds in A. arborescens.
Asunto(s)
Aloe/química , Cromatografía de Gases/métodos , Cromatografía Líquida de Alta Presión/métodos , Extractos Vegetales , Glicoproteínas , Fenoles , Extractos Vegetales/análisis , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en TándemRESUMEN
Different polysaccharides were isolated from the leaves of Aloe arborescens using the gradient power of hydrogen followed by antitumor and immunomodulatory assay. The total polysaccharide content of different fractions, water-soluble polysaccharide (WAP), acid-soluble polysaccharide (ACP), and alkaline-soluble polysaccharide (ALP), was estimated using a phenol-sulfuric acid spectrophotometric method. WAP possessed a higher content of mannose and glucose than either ACP or ALP. In vitro antitumor activity was investigated in three different cancer cell lines, and in vitro immunomodulatory potential was assessed through phagocytosis and lymphocyte transformation assay. The results showed that WAP and ALP exhibited the most significant cytotoxicity against HepG2 human liver cancer cells, with IC50 values of 26.14 and 21.46 µg/mL, respectively. In contrast, ALP was able to enhance lymphocyte transformation, whereas WAP had the most potent phagocytic activity. Molecular weight, total sugar and uronic acid content, Fourier transform-infrared analysis, and linkage type of bioactive polysaccharides were investigated. These findings revealed that the potential antitumor activity of the natural agents WAP and ALP was through an immunomodulation mechanism, which verifies the use of the plant as adjuvant supplement for cancer patients suffering immunosuppression during chemotherapy.
Asunto(s)
Aloe/química , Factores Inmunológicos/farmacología , Extractos Vegetales/farmacología , Polisacáridos/farmacología , Línea Celular Tumoral , Humanos , Factores Inmunológicos/química , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/inmunología , Linfocitos/efectos de los fármacos , Linfocitos/inmunología , Monocitos/efectos de los fármacos , Monocitos/inmunología , Extractos Vegetales/química , Hojas de la Planta/química , Polisacáridos/químicaRESUMEN
Since ancient times, plants and herbal preparations have been used as medicine. Research carried out in the last few decades has verified several such claims. Aloe arborescens Miller, belonging to the Aloe genus (Family Asphodelaceae), is one of the main varieties of Aloe used worldwide. The popularity of the plant in traditional medicine for several ailments (antitumor, immunomodulatory, antiinflammatory, antiulcer, antimicrobial and antifungal activity) focused the investigator's interest on this plant. Most importantly, the reported studies have shown the plant effectiveness on various cancer types such as liver, colon, duodenal, skin, pancreatic, intestinal, lung and kidney types. These multiple biological actions make Aloe an important resource for developing new natural therapies. However, the biological activities of isolated compounds such as glycoprotein, polysaccharides, enzyme and phenolics were insufficient. Considering all these, this contribution provides a systematic review outlining the evidence on the biological efficacy of the plant including the pharmacology and the related mechanisms of action, with specific attention to the various safety precautions, and preclinical and clinical studies, indicating the future research prospects of this plant.