These results showed an immunomodulatory effect for the extract of P. oleracea. - GreenMedInfo Summary

Context: A large proportion of asthmatic patients use complementary and alternative medicine (CAM) for the treatment of their disease. Various pharmacological effects, including anti-inflammatory properties, have been described for Portulaca oleracea (P. oleracea).

Objective: The study intended to evaluate the effects of an extract of P. oleracea on interleukin 4 (IL-4) and interferon-gamma (INF-γ) and on the INF-γ /IL4 ratio, as an index for the balance of T helper 1 and 2 (Th1/Th2) cells, in bronchoalveolar lavage fluid (BALF) as well as on tracheal responsiveness (TR) in a rat model of asthma.

Design: The research team performed an animal study.

Animals: Forty-eight male Wistar rats, each weighing 220± 50 g, were included in the study.

Intervention: The rats were randomly divided into 6 groups: (1) a control group that was not induced with asthma and that received no treatments (C group), (2) a group induced with asthma that received no treatments (A group), (3) an intervention group induced with asthma and treated with one mg/ml of P. oleracea extract (PO 1 group), (4) an intervention group induced with asthma and treated with 2 mg/ml of P. oleracea extract (PO 2 group), (5) an intervention group induced with asthma and treated with 4 mg/ml of P. oleracea extract (PO 4 group), and (6) a positive control group induced with asthma and treated with 1.25μg/ml dexamethasone (D group). The asthma was induced using ovalbumin (OVA).

Outcome Measures: Tracheal responsiveness and the BALF levels of IL-4 and INF-γ and the INF-γ/IL4 ratio were measured.

Results: Tracheal responsiveness to methacholine in the A and PO 1 groups and to OVA in the A, PO 1, and PO 2 groups as well as the BALF levels of IL-4 in the A, D, PO 1, PO 2, and PO 4 groups were significantly higher than that of the C group. The BALF level of INF-γ and the INF-γ/IL4 ratio were significantly lower in the A, D, PO 1, PO 2, and PO 4 groups than in the C group. Only treatment with the 2 higher concentrations of the extract caused a concentration-dependent increase in the INF-γ/IL4 ratio (P<.001). The effects of the 2 higher concentrations of the extract on INF-γ and IL-4 and on the INF-γ/IL4 ratio were significantly greater than those of the dexamethasone treatment (P<.001).

Conclusions: These results showed an immunomodulatory effect for the extract of P. oleracea with regard to an increased INF-γ/IL4 ratio, as an index of Th1/Th2, as well as a preventive effect on tracheal responsiveness, which was more specific than the effects of dexamethasone on the Th1/Th2 balance.