TNF-α Production Modulated by Aloe Vera Gel Extract and its Fractions in Candida Albicans Infected Macrophages

Aloes have been used as medicinal plants for centuries. The immunomodulatory effect of Aloe vera has previously been shown. Meanwhile, TNF-α, as an inflammatory cytokine, plays an essential role in defense against invading pathogen. In the present study, the effects of A. vera extract gel and its fractions were investigated on the TNF-α production by macrophages against Candida albicans as an opportunistic microorganism in humans. TNF-α was measured using Enzyme-Linked Immunosorbent Assay according to the instructions of the manufacturer (Biosource, Switzerland). The results showed that TNF-α level was increased by A. vera gel extract and some isolated fractions dose dependently. The A. vera gel extract in dilutions of 1:2, 1:5, 1:10 and 1:50 significantly increased the production of TNF-α. Likewise, R100 and R30 fractions of A. vera caused significant increase in TNF-α production. However, R10 and R5 fractions caused a reduction in TNF-α production as compared with that in control group. These results showed that A. vera gel extracts and its fractions induce both immunostimulating and immunosuprressive effects on the production of TNF-α against Candida albicans. The efficacy of immunomodulatory of this herb is dose-dependent.