Introduction: Macrophages are one of the key phagocytes against various pathogenic fungi, particularly Candida species killed by various mechanisms such as nitric oxide (NO) agents. The purposes of this research were to investigate the anti-Candida and immunomodulatory effects of the extracts from Allium jesdianum on mouse peritoneal macrophages.
Methods: The antifungal assay of amphotericin B and nystatin, as well as hydroalcoholic extract from A. jesdianum was carried out using disk diffusion and broth macrodilution methods against Candida albicans (ATCC 10231). Furthermore, microculture tetrazolium (MTT) and nitrite assays (Griess test) were applied to study the influence of the aqueous extract from A. jesdianum on macrophage viability indices and NO production, respectively.
Results: The results showed inhibition zone values of 8, 16, 28 mm for A. jesdianum, amphotericin B and nystatin against the organism tested, respectively. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of A. jesdianum were found to be 330 and 663 μg/mL, respectively. Aqueous extract of A. jesdianum induced a significant decrease (2.8-fold at a concentration of 5 mg/mL and 4.3-fold at concentration of 10 mg/mL) in macrophage viability indices in comparison with the control group (P < 0.001) but there was no toxic effect at 1 and 0.5 mg/mL. In addition, the aqueous extract of A. jesdianum resulted in a significant increase in NO production at non-toxic concentrations (77.6 μM nitrite at concentration of 1 mg/mL and 79.4 μM at concentration of 0.5 mg/mL) by macrophages (P < 0.01).
Conclusion: The extract of A. jesdianum showed an in vitro anti-C. albicans and NO stimulatory effect. More studies with purified immunomodulatory components of A. jesdianum should be performed in future to shed light on the exact mechanisms of this activity.