Effect of extracts from indigowood root (Isatis indigotica Fort.) on immune responses in radiation-induced mucositis.

OBJECTIVES

To evaluate the effect of indigowood root (Isatis indigotica Fort.) on acute mucositis induced by radiation.

DESIGN

The objective severity of mucositis, anorexia, and swallowing difficulty were measured before and after the treatment.

SETTINGS: Patients with head and neck cancer receiving radiotherapy at Tian Sheng Memorial Hospital, Taiwan were recruited for this trial.

SUBJECTS: Twenty (20) patients were randomized into two groups. Group 1 served as controls with only normal saline, and group 2 as the indigowood root (IR) group.

INTERVENTIONS: Prophylactic application of IR consisted of gargling and then swallowing the IR preparation on the irradiated oral mucosa.

OUTCOME MEASURES: Patients' characteristic distribution of gender, age, diagnosis, and mean radiation dose between the two arms were calculated by Fisher's exact test. We compared the mean of grade 1-4 mucositis, anorexia, difficulty in swallowing, and body weight change with the Mann-Whitney U test. p values less than 0.05 indicated statistical significance.

RESULTS

The clinical trial showed that application of IR can reduce the severity of radiation mucositis (p = 0.01), anorexia (p = 0.002), and swallowing difficulty (p = 0.002). Although patients' resting days did not show a significant difference (p = 0.06), complete radiotherapy was done without rest for 4 of 11 patients in the IR group versus 2 of 9 in controls. Hemoglobin level between both groups showed no significant difference. Serum interleukin-6 was significantly lower in the IR group during the first, fifth, and seventh weeks.

CONCLUSIONS

We confirmed that indigowood root has anti-inflammatory ability to reduce the mucosal damage caused by radiation. We postulate that indirubin may play a pharmaceutical role in improvement of radiation mucositis, anorexia, and difficulty in swallowing in our clinical trial. However, the exact mechanisms and pathways still need further analysis.