Boswellic acids inhibit glioma growth: a new treatment option?

Conventional malignant glioma therapy (surgery, radiation therapy and chemotherapy) does not yield satisfying results. The prognosis of the glioma patient depends more on the histological grading of the tumor and patient's age than on the therapy. Especially the adjuvant chemotherapy failed to date to influence survival time in glioma patients significantly. To improve results in malignant glioma therapy additional therapeutic regimes are necessary. In an earlier study we were able to show a significant reduction on perifocal edema by an extract from gum resin (EGR) accompanied with a clinical improvement in patients with malignant glioma. Also a decrease of urinary LTE4-excretion as a metabolite of leukotriene synthesis in brain tumors was observed. Furthermore we had found a proliferation inhibiting activity of the extract form EGR, the boswellic acids in cell cultures. The purpose of this experimental study was to elucidate the effects of the boswellic acids, which are constituents of an extract from gum resin on tumor growth in vivo. Female wistar rats weighing 200-250 g were treated with the drug 14 days after inoculation of C6 tumor cells into their right caudate nucleus and randomization into 4 groups. The treatment groups received different dosages and were compared to a control group without any additional treatment. Survival time of the rats in the highest dosage group (3 x 240 mg/kg body weight) was more than twice as long as in the control group (P < 0.05). In a second experiment the inhibition of tumor cell proliferation was examined. The C6 tumor cells were implanted into the caudate nucleus. Drug treatment was started immediately after implantation and stopped after 14 days. The animals were sacrificed and the brains were examined microscopically. Comparing low and high dosage of EGR treatment a significant difference in tumor volume was detected (P < 0.05). The proportion of apoptotic tumor cells in animals with high dose treatment was significantly larger than in the low dose (treatment) group (P < 0.05). These data demonstrate an influence of EGR in rat glioma growth and might represent a new therapeutic option on glioma treatment in man in future. Further experimental work on human gliomas is needed to definitively answer this question.