Antioxidant and Immune‐Modulatory Effects of Aloe vera Decolorized Leaf Juice vs. Inner Leaf Juice

The aloe vera ( Aloe vera ) plant has a long history of traditional therapeutic topical use. Its leaf and inner leaf juices are also ingested in various forms. Aloe vera leaf juice is made from macerated aloe leaves, and when it is intended for human ingestion, it is purified of latex constituents via a charcoal filtration process known as decolorization. Several publications have shown immunomodulatory effects, as well as antibacterial, antifungal and anti‐parasitic properties of aloe vera inner leaf juice, but limited information is available regarding these effects for aloe vera leaf juice after the decolorization process. The aim of this preliminary study was to compare biologically‐relevant antioxidant and immune‐modulatory effects of aloe vera inner leaf and decolorized leaf preparations using a variety of in vitro techniques. Methods Antioxidant activity of decolorized leaf (DL) and inner‐leaf (In‐L) aloe vera preparations were assessed for total antioxidant capacity by the Folin‐Ciocalteu method. Direct immune‐modulatory effects in the absence of an immune stimulant were assessed by treating human peripheral blood mononuclear cells (PBMCs) from three healthy donors with each aloe vera preparation for 24 hours, followed by multi‐parameter flow‐cytometry, which evaluated the activation status (as measured by expression of CD25 and CD69) of several immune cell populations [natural killer (NK) cells (CD3−/CD56+), CD3+/CD56+ immune cells (including NKT cells), and T lymphocytes (CD3+/CD56−)] that were identified by double‐staining with monoclonal antibodies specific for CD3 and CD56. To investigate potential immune modulatory effects of each aloe vera preparation in response to inflammatory stimulus, PBMCs were also pre‐treated with DL or In‐L and stimulated by either lipopolysaccharide (LPS) or polyinosinic:polycytidylic (poly I:C) acid to mimic bacterial and viral insults, respectively. Results DL showed higher total antioxidant capacity than In‐L, at 5 and 10 mg/ml concentrations (p<0.05). DL showed a significant increase in the activation of T lymphocytes and monocytes (p<0.01). DL also increased the expression of the glycoproteins CD25 and CD69 of NK cells (p<0.05). This increased expression was also observed when the cells were stimulated by poly I:C (p<0.01). The CD3+/CD56+ cell population also increased its expression of CD69, an activation marker, when pre‐treated with DL alone and also when the pre‐treated PBMCs were stimulated by poly I:C (p<0.01). In contrast, In‐L material showed a relatively limited immune modulatory activity, increasing the expression of CD69 only in T cells (p<0.01). Conclusion The decolorized aloe vera leaf preparation showed higher antioxidant and immune‐modulatory activity than the inner‐leaf preparation. The increase in immune cell activation markers representing activation status of the immune cells suggests that DL supports innate immunity, particularly through the sustained activation of NK cells, both in terms of direct effects, and in the context of a viral‐mimetic insult. Support or Funding Information This work was funded by Herbalife International of America, Inc., 950 W. 190th Street, Torrance, CA 90502