Written by Gabriele Dennert and the CAM-Cancer Consortium.
Updated October 27, 2011

Boswellia spp

Abstract and key points

  • Boswellia subspecies are branching trees found in Asia and Africa. For medicinal purposes mainly the resin is used.
  • No firm conclusions can be drawn on the effect of orally administered Boswellia extracts on peritumoural brain oedema, brain tumours, brain metastases or any other cancer in women, men or children.
  • Reported adverse effects mainly affected the gastrointestinal system and the skin.

Boswellia subspecies are trees in Asia and Africa. Medicinal dry extracts of different Boswellia trees are traded as phytopharmaceuticals for oral administration. Boswellia extracts are claimed to be inhibitors of inflammation processes, with efficacy against perifocal oedema in brain tumour patients and antitumour activity.

No certain conclusions can be drawn on the effect of orally administered Boswellic acids or Boswellia extracts on peritumoural brain oedema or brain tumours in humans. Findings from two clinical trials and two case series suggest a beneficial effect for Boswellia extracts on perifocal brain oedema in some of the study participants. The applicability of these findings to other patients, however, is limited due to methodological constraints.

In-vitro experiments have found an anti-inflammatory and antiproliferative effect at high concentrations in some animal and human malignant cell lines. However, the opposite effect was seen for low concentrations of Boswellia extracts. Only very little pharmacokinetic data is available for humans to date.

Adverse effects mainly affected the gastrointestinal system and the skin.

What is it?

Names

Boswellia subspecies are trees (family: Burseraceae) found in India, Northern Africa and the Middle East 1. Frankincense is the hardened gum resin extruded from incisions in the trunk of several Boswellia species, including Boswellia carterii (African frankincense) and Boswellia serrata (Indian frankincense). The gummy oleo-resin is also known as olibanum (Boswellia carterii) and Salai Guggal (Boswellia serrata) 2.

Medicinal dry extracts from the gummy resin are traded under names such as "H15 Ayurmedica" or "Olibanum" and referred to as “Boswellia extracts” throughout this summary.

Ingredients

Boswellia resin is a mixture containing more than 200 different substances 3, for instance: resin, long-chain sugar compounds, essential oils, proteins, and inorganic compounds 4. Boswellic acids (BAs) have been identified as the putative active principle of the gum resin. BAs are pentacyclic triterpenes with different functional groups in position 3 and 11 of their carbon rings. The most important BAs are:

  • alpha-Boswellic acid
  • beta -Boswellic acid
  • Acetyl-beta-Boswellic acid
  • Acetyl-alpha-Boswellic acid
  • 11-Keto-beta-Boswellic acid (KBA)
  • Acetyl-11-beta-beta-Boswellic acid (AKBA).

Boswellia preparations vary naturally in terms of their content of the different BAs. Medicinal dry extracts are manufactured following standardised procedures to minimise sources of variation within the production process 1. However, even in standardised products a natural variation occurs.

Application and dosage

Boswellia extracts are administered orally as capsules or tablets usually with a content around 400 mg of Boswellia extract. Providers recommend a daily dosage of 4 to 6 grams per day for adults in the treatment of perifocal brain oedema.

Mechanisms of action

Findings with healthy male volunteers indicated a possible initial fast gastric resorption, followed by intestinal resorption 5 depending on concomitant food intake 6. Gastrointestinal resorption of BAs was increased when taken with a high-fat meal. The concentration peak was seen after approximately 4.5 hours. Elimination half time was 6 hours in the mean and varied considerably with concomitant food intake. BAs were found to have a high volume of distribution.

A number of in-vitro molecular targets of boswellic acids were described, such as 5-lipoxygenase (5-LO), leukocyte elastase 11 or topoisomerase 1 and 2 24. The exact mechanisms remain unclear to date.

BAs selectively inhibit the key enzyme of leucotrien synthesis 5-LO 4 and reduce leukotrien biosynthesis in a concentration-dependent manner 10. Among the investigated BAs, AKBA showed the strongest inhibitory efficacy. When multicomponent extracts that contain several BAs (like all Boswellia gum resin extracts) were tested in in-vitro experiments, the composition and dose of the different Boswellic acids has been found to influence the observed effect. Inhibition of leukotrien synthesis could only be seen at higher concentrations; at lower concentrations an increased synthesis of leukotriens was observed.

History

Boswellia preparations have been used in Indian Ayurvedic medicine for the treatment of inflammatory diseases 4. It was also occasionally mentioned in European medical traditions from the Middle Ages to modern times 7. Current research is being conducted on the anti-inflammatory properties of Boswellia extracts and their use in chronic inflammatory diseases like Morbus Crohn or asthma bronchiale.

Claims of efficacy and alleged indications

Boswellia products sold in Europe are very reserved in describing alleged efficacy and indications of Boswellia extracts. This might be due to the fact that Boswellia products are traded as “dietary supplements” and European Union (EU) law forbids medicinal claims for dietary supplements.

Complementary medicine internet sites describe Boswellia products as inhibitors of inflammation processes, with efficacy against perifocal oedema in brain tumours or brain metastases. They are recommended for the treatment of brain oedema as an alternative to glucocorticoids and are claimed to improve accompanying clinical conditions like headache, pareses, dysphasia/aphasia and the overall wellbeing 8. Participants of internet forums and newsgroups for cancer patients regularly allege an antitumour activity for Boswellic extracts and also discuss the use of Boswellia products in other than brain tumours 9.

Prevalence of use

There is no data on the prevalence of use of Boswellia products in tumour or brain tumour patients.

Legal issues and providers

H 15 Ayurmedica is a registered Ayurvedic medication in India (Gufic, Mumbay, India). Its manufacturer also holds a partial license for Switzerland, but is not licensed within the EU. However, it can be imported to the EU for use in individual patients under specific circumstances and for use in clinical studies. Additionally, some companies sell Boswellia extracts as “dietary supplements” in the EU.

Cost(s) and expenditures

Costs for Boswellia extracts amount to between €40 to 60 per month (depending on the daily dose) when ordered via the internet (plus shipping).

Does Boswellia work?

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.

Is it safe?

Adverse effects

Several of the above mentioned clinical investigations reported the presence or absence of side effects of Boswellia extracts 4,17-18,20. In 134 cancer patients receiving BAs, 11 cases of possible adverse effects were reported: nausea/emesis WHO III (one patient), skin rash WHO II (two patients), gastrointestinal pain (two patients), loss of appetite and heartburn (six patients). In the former three patients with nausea/emesis and skin rash, Boswellia administration had to be terminated.

Contraindications

Pregnancy and lactation; nothing is known about teratogenicity and possible effects of Boswellia extracts on breast-fed infants. There is no information available on mutagenic effects of Boswellia extracts in women and men or long-term carcinogenicity.

Further known contraindications are any previous allergic reactions to Boswellia extracts or components of these extracts.

Interactions

Interactions with drugs, supplements or other herbs and herbal extracts might occur both on a pharmacokinetic and on a pharmacodynamic level, but have so far not been thoroughly studied. No conclusions can currently be drawn on possible pharmacokinetic or pharmacodynamic interactions in humans.

Citation

Gabriele Dennert, CAM-Cancer Consortium. Boswellia spp [online document]. http://www.cam-cancer.org/layout/set/print/CAM-Summaries/Herbal-products/Boswellia-spp. October 27, 2011.

Document history

Last updated and revised in October 2011 by Gabriele Dennert.
Fully updated and revised in November 2009 by Gabriele Dennert.
First published in November 2005, authored by Gabriele Dennert.

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