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.

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 IC 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.

Hypolipidemic effect of Portulaca oleracea L. seed extract and its fractions have been studied on streptozotocin (STZ) at dose 75 mg/kg b.wt. After fractionation of the alcoholic extract; petroleum ether fraction was the most active fraction that decreased different hyperlipidemia biochemical parameters. After chromatographic analysis; oleamide, ethylpalmitate, β-amyrin, stigmasterol and β-sitosterol were identified. The GLC analysis of unsaponifiable matter revealed the presence of; lignoceric acid as a major constituent in the most bioactive fraction. In conclusion, petroleum ether fraction possessed a hypolipidemic effect in STZ-induced diabetic rats, which may be attributed to its phytosterols, fatty acid and amide compounds. The finding of the present investigation strongly demonstrates the potential of non-polar fraction of P. oleracea L. seed in combating hyperlipidemia in diabetic condition. So the petroleum ether fractions and its constituents can be used as hypolipdemic supplement in the developing countries towards the development of new therapeutic agents.

No abstract

No abstract