Aloe vera leaf

It is suggested that aloe polysaccharides mediate skin-protectant effects in damaged skin, induced by internal or other external factors such as radiation, via inhibiting apoptosis of normal cell lines in vitro and thrombocytes in vivo. Following irradiation, aloe polysaccharides block the upregulation of pro-apoptotic p53, Bax, and Bad while blocking downregulating anti-apoptotic Bcl-2. In vivo, aloe polysaccharides may act as a scavenger for oxygen free radicals including DPPH, alkyl radicals, superoxides, and singlet oxygen and hydroxyl radicals that may also be generated by superoxides. Hydrogen peroxide, which is a weak initiate lipid peroxidation, may also be effectively scavenged by aloe polysaccharides. In a Fenton reaction system, aloe polysaccharides demonstrated a concentration-dependent scavenging activity against hydroxyl radical that were generated during the reaction. Aloe polysaccharides may also compete with oxygen to react with nitric oxide (NO), thereby inhibiting the generation of nitrite and peroxynitrite anions that act as free radicals.

Findings from a study investigating the effects of aloe polysaccharides on doxorubicin-induced oxidative stress suggest that aloe polysaccharides mediate potent antioxidant actions in vivo. Doxorubicin, known to generate reactive oxygen species such as superoxide and hydroxy radicals, was administered to albino rats. This led to myocardial oxidative stress and cardiac injury accompanied by leakage of LDH and CPK from cardiac myocytes and to serum due to lipid peroxidation of cardiac membranes, reduced levels of antioxidant coenzyme GSH, and increased levels of SOD from a compensatory and combative mechanism of oxidative stress. Treatment with aloe polysaccharides resulted in a significant decrease in serum LDH and CPK levels, indicating that aloe polysaccharides are capable in stabilizing cardiac membranes from peroxidative damage. Restored levels of endogenous GSH and SOD in a dose-dependent manner were also observed with the treatment of aloe polysaccharides, suggesting that aloe polysaccharides exhibit potent antioxidant properties.

In a study of rats with open cutaneous back wounds, treatment with aloe polysaccharides decreased the levels of matrix metalloproteinase-3 (MMP-3) and induced tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) during the early stage of wound repair, resulting in decreased collagen breakdown and increased preservation of collagen content in the injured area. A study proposes that acemannan, a common aloe polysaccharide, stimulates BMSC proliferation, ALPase activity, expression of VEGF, BMP-2, OPN, BSP, and mineralization leading to osteoblast differentiation and bone formation during socket healing.