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

Background: 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. Materials and Methods: TNF-α was measured using Enzyme-Linked Immunosorbent Assay according to the instructions of the manufacturer (Biosource, Switzerland). Results: 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. Conclusion: 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.