A randomized placebo-controlled phase I clinical trial to evaluate the immunomodulatory activities of Atractylodes lancea (Thunb) DC. in healthy Thai subjects

Abstract

Background: Atractylodes lancea (Thunb) DC. (AL) and bioactive compounds β-eudesmol and atractylodin have been demonstrated in the in vitro and in vivo studies for their potential clinical use in cholangiocarcinoma. The study was a randomized, double-blinded, placebo-controlled phase I clinical trial to evaluate the immunomodulatory effect of AL in human subjects.

Methods: The modulatory effects of AL and β-eudesmol and atractylodin on TNFα and IL6 expression in PBMCs were measured using real-time PCR. Blood samples were collected from forty-eight healthy subjects following oral administration of a single or multiple dosing of capsule formulation of the standardized AL extract or placebo. Serum cytokine profiles, lymphocyte subpopulations (B lymphocytes, CD8⁺ cytotoxic T lymphocytes, CD4⁺ T-helper lymphocytes, and NK cells), and cytotoxic activity of PBMCs against the cholangiocarcinoma cell line CL-6 were evaluated using cytometric bead array (CBA) with flow cytometry analysis.

Results: AL extract at almost all concentrations significantly inhibited both TNFα and IL6 expression in Con A-mediated inflammation in PBMCs. β-Eudesmol at all concentrations significantly inhibited only IL6 expression. Atractylodin at the lowest concentration significantly inhibited the expression of both cytokines, while the highest concentration significantly inhibited only IL6 expression. The administration of AL at a single oral dose of 1000 mg appeared to decrease IFNγ and IL10 and increase B cell, while significantly increase NK and CD4⁺ and CD8⁺ cells. A trend of increasing (compared with placebo) in the cytotoxic activity of PBMCs at 24 h of dosing was observed. AL at multiple dosing of 1000 mg for 21 days tended to decrease the production of all cytokines, while significantly inhibited IL17A production at 24 h of dosing. In addition, a significant increase in CD4⁺ and CD8⁺ cells was observed. A trend of increase in the cytotoxic activity of PBMCs was observed at 24 h but terminated at 48 h of dosing.

Conclusions: The results confirm the immunomodulatory activity of AL in humans. This activity, in complementary with the direct action of AL on inducing cholangiocarcinoma cell apoptosis, suggests its potential role for CCA control.

Trial registration: Retrospectively registered on 17 October 2020 [Thai Clinical Trials Registry (TCTR: www.clinical trials.in.th ) Number TCTR20201020001 #].

Keywords: Atractylodes lancea; Atractylodin; Cholangiocarcinoma; Immunomodulatory activity; β-Eudesmol.

Fig. 1

Fold-changes of IL17A, IFNγ, TNFα, IL2, IL4, IL6, and IL10 compared with baseline levels in healthy Thai subjects following the administration of a single oral dose of 1000 mg of standardized AL extract (n = 20) and placebo (n = 4). Data are presented as median (range) values

Fig. 2

Fold-changes of IL17A, IFNγ, TNFα, IL2, IL4, IL6, and IL10 compared with baseline levels in healthy Thai subjects following the administration of daily oral doses of 1000 mg standardized AL extract (n = 20) and placebo (n = 4). Data are presented as median (range) values

Fig. 3

Fold-changes of CD4⁺, CD8⁺, B and NK cells compared with baseline levels in blood samples from healthy Thai subjects following the administration of a single oral dose of 1000 mg standardized AL extract (n = 16) and placebo (n = 4). Data are presented as median (range) values

Fig. 4

Fold-changes of CD4⁺, CD8⁺, B and NK cells compared with baseline levels in blood samples from healthy Thai subjects following the administration of daily oral doses of 1000 mg standardized AL extract (n = 20) and placebo (n = 4). Data are presented as median (range) values

Fig. 5

Fold-changes of cytotoxic activity of PBMCs against CL-6 cell compared with baseline levels in blood samples from healthy Thai subjects following the administration of (a) single oral dose of 1000 mg and (b) multiple oral doses of 1000 of standardized AL extract for 21 days (n = 20 for AL and n = 4 for each group). Data are presented as median (range) values