Boswellia spp

Two prospective clinical studies, a retrospective and a prospective case series – all involving patients with brain tumours or metastases – as well as a case report of a female patient with brain metastases have been published.

Clinical trials

Preliminary findings from a randomised clinical trial with 44 patients suggest a positive effect of Boswellia serrata on brain oedema 29,30. Patients receiving irradiation of the brain for primary brain tumours or brain metastases of solid tumours were administered either 3 x 1400 mg/d Boswellia extracts during radiotherapy or placebo. In patients with brain metastases, a reduction of brain oedema (evaluated by MRI scans) of > 75% was seen in 67% in the Boswellia group and in 31 % in the placebo group at the end of radiotherapy. Reevaluation at 4 weeks after radiotherapy showed no differences between Boswellia and placebo groups, which might be attributable to the termination of Boswellia intake at the end of radiotherapy. No differences could be seen in patients with primary brain tumours (small number of participants).

A prospective clinical study with 29 glioma patients was conducted by Heldt 19 and Böker 20. Participants were non-randomly allocated to receive three different doses of Boswellia extracts (3 x 1200 mg/d, 3 x 800 mg/d, 3 x 400 mg/d) prior to surgical intervention. After seven days of intervention, the size of perifocal oedema was reduced in the CT scans of participants at 3 x 1200 mg/d and – to a lower degree – in participants at 3 x 800 mg/d. Improvement in clinical symptoms was found only in the group receiving the highest daily dose. These participants also had a reduced urinary excretion of leukotrien E4 (LTE4) (as a measurement of leukotrien synthesis in the body). No effect on the tumour size was observed. Due to the study design, it is unclear whether changes in oedema size or clinical improvement can be attributed to olibanum intake.

Case studies/series

Janssen 17 evaluated the use of H15 retrospectively in 17 female and male children (age 0.5 to 18 years) with different progressive or relapsed brain tumours. H15 was administered orally at 40 to 126 mg/kg body weight per day over 1 to 26 months with or without concomitant conventional therapy. Six patients reported an improvement of their clinical condition and subjective relief of symptoms. In two of these patients, and in two additional patients with no subjective changes, regression of prior neurological symptoms like pareses and ataxia was documented. Regression of the peritumoural oedema in one case and reduction of a tumour cyst in another case were documented by MRI. Under Boswellic acids, 4 children with malignant brain tumours in progression remained in stable disease over 3 to 8 months. In two additional patients an anti-tumoural treatment effect was seen, however, this was more likely to be the result of concomitant radio- and chemotherapy than of Boswellia extracts. In one case, a partial remission over 26 months with administration of H15 as monotherapy was considered questionable by study authors, as tumour relapse had only been documented radiologically without histological re-evaluation.

Streffer et al. 18 published a prospective case series of 12 adult patients with progressive cerebral oedema with or without overt tumour progression. Seven patients were treated for glioblastoma and five patients for leukencephalopathy (after conventional tumour therapy). All study participants had to be taken off steroids or on a stable dosage of steroids for at least four weeks. H15 was administered orally at 3 x 1200 mg/d. Three participants with glioblastoma reported a clinical improvement, in two of these three cases a reduction in perifocal oedema could be seen in MRI scan. All five participants with leukencephalopathy reported a clinical benefit. No tumour response was seen in any patient.

Both case series suggest that there might be a beneficial effect for Boswellia extracts on brain oedema in study participants with brain tumours or leukencephalopathy. The applicability of these findings to other patients, however, is limited due to selection of participants and study design.

Flavin 22 reported the favourable course of a 39-year old women with newly developed symptomatic multiple brain metastases of a mammacarcinoma, which were documented in a CT scan, one year after initial diagnosis. She received radiation therapy of the brain and capecitabine chemotherapy and also started with Boswellia serrata, 3 x 800 mg/d orally. After 10 weeks of treatment, brain metastases could no longer be seen in the CT scan. The patient was maintained on Boswellia serrata for another 4 years without signs of recurrent cerebral metastases, but newly developed bone metastases after that period.

However, it is not possible to attribute the long-term remission of her brain metastases to Boswellia extracts. Both radiotherapy and capecitabine treatment 23 have reportedly induced remission of CNS metastases and may have been the active treatment in this case. Nevertheless, a long-term remission of multiple CNS metastases is rare and all involved possibly beneficial interventions, including Boswellia extracts, deserve consideration in future investigations.

Pre-clinical data

Can Boswellia extracts have a direct effect on malignant cells and tumours? Some BAs – especially AKBA - have shown to reduce tumour cell proliferation and to induce apoptosis in several in-vitro experiments with animal 12,13 and human 10,12,14-15,25-28 malignant cell lines, as well as in animal studies 16. In one study, however, low concentrations of Boswellia extract resulted in an increased growth of human malignant cells 15,31.