The ASCO Post’s Integrative Oncology series is intended to facilitate the availability of evidence-based information on integrative and complementary therapies sometimes used by patients with cancer. In this installment, Gary Deng, MD, PhD, and Jyothirmai Gubili, MS, focus on the herbal extract boswellia, also known as Indian frankincense, which has shown anti-inflammatory activity and is of growing interest among many patients with cancer.

Scientific Names: Boswellia serrata

Common Names: Indian frankincense, Indian olibanum

Gary Deng, MD, PhD

Jyothirmai Gubili, MS

Overview

A tropical tree, Boswellia serrata is widespread in India, the Middle East, and North Africa. It is the source of “frankincense” or “olibanum,” a fragrant resin obtained from the bark. Frankincense is used in religious ceremonies in cultures around the world and is also valued for its medicinal properties. It is widely prescribed in Ayurveda (India’s traditional, holistic system of medicine) to treat diarrhea, dysentery, pulmonary disease, arthritis, coughs, sores, snakebite, ringworm, asthma, and for lowering cholesterol levels.

Boswellic acids, the major constituents of boswellia resin, have been reported to be responsible for many of the herb’s therapeutic effects. The supplemental form of boswellia is promoted for osteoarthritis, to maintain joint health, and to reduce inflammation. It is available in health food stores and online in the form of tablets, capsules, extracts, and as an ingredient in topical creams and ointments.

The Science

Preclinical studies have shown that boswellic acid, the bioactive constituent, has anti-inflammatory, antiarthritic,¹ cytotoxic,² and radio-enhancing properties.³ It also prevented intestinal tumorigenesis in a murine model,⁴ and may improve cognitive impairment and insulin resistance.⁵ The essential oil derived from boswellia demonstrated antimicrobial effects.⁶

Preliminary findings from small uncontrolled studies suggest the utility of boswellia for bronchial asthma,⁷ ulcerative colitis,⁸ mild irritable bowel syndrome,⁹ and osteomuscular pain.¹⁰ However, available data on boswellia’s effects against collagenous colitis are inconclusive,^11-13 and it did not confer a significant benefit in maintaining remission from Crohn’s disease.¹⁴

In a randomized trial involving patients (n = 75) with osteoarthritis, an enriched boswellic acid extract (100 mg or 250 mg taken daily for 90 days) affected significant reduction in pain and improved physical functioning when compared with placebo.¹⁵ An herbal formula comprising boswellia, Terminalia chebula, and turmeric (200 mg or 400 mg taken daily for 90 days) conferred similar benefits in 105 patients with osteoarthritis of the knee.¹⁶

Jun J. Mao, MD, MSCE

In addition, a combination of boswellic acid and curcumin (350 mg of curcuminoids, 150 mg of boswellic acid, taken three times daily for 12 weeks) was also reported to be more effective in alleviating osteoarthritic pain-related symptoms than curcuminoids alone or placebo in a three-arm parallel-group randomized study (n = 201).¹⁷ Larger well-designed studies are needed for clinical recommendation.¹⁸

Boswellia has been investigated for its potential anticancer effects as well. In a study of 44 patients with primary or secondary malignant cerebral tumors undergoing radiotherapy, those assigned to a boswellia preparation (4,200 mg/d) had greater reduction in cerebral edema than did patients on placebo (P = .023) after radiotherapy.¹⁹

In another trial, 144 patients with breast cancer undergoing adjuvant radiotherapy were randomly assigned to receive a topical boswellia cream (2%) or a placebo cream, applied twice daily. More patients in the placebo group had intense erythema (visual intensity) than did those who used boswellia cream (49% vs 22%; P = .009). Further, the treatment was also reported to be effective with concomitant chemotherapy (P = .018).²⁰

Supplementation with an oral formula containing 30% boswellia extract, betaine, and myo-inositol (one capsule, twice daily for 6 months) was also shown to significantly reduce mammary density in premenopausal women (n = 76) with high breast density in comparison to placebo (P < .001).²¹

Mechanistic studies revealed that boswellic acid exerts anti-inflammatory effects via inhibition of 5-lipoxygenase²² and cyclooxygenase-1.²³ It also inhibits nuclear transcription factor KappaB signaling, decreasing the production of tumor necrosis factor–alpha significantly.²⁴ The antiplatelet effects of boswellia gum resin extracts are attributed to inhibition of clotting factors Xa and Xia.²⁵

Data also show that boswellic acid exerts apoptotic effects in various cancer cell lines by inducing p21 expression through a p53-independent pathway^26-28 and by inducing endoplasmic reticulum stress.²⁹ Additional apoptotic mechanisms include early generation of nitric oxide and reactive oxygen species, which upregulate time-dependent expression of p53/p21/PUMA,³⁰ inhibition of ­microsomal prostaglandin E synthase-1, and decreased prostaglandin levels and its downstream targets.³¹

In other studies, acetyl-11-keto-beta-boswellic acid (AKBA), an active component of boswellia, was found to inhibit human prostate tumor growth via inhibition of VEGFR2-induced angiogenesis³²; a semisynthetic analog of boswellic acid, 3-alpha-butyryloxy-beta-boswellic acid, inhibited growth in Ehrlich ascites tumor, Ehrlich ascites carcinoma, and sarcoma 180 tumor models, via nuclear factor-KappaB downregulation and induction of poly (ADP-ribose) polymerase cleavage.³³

Adverse Reactions

• Use of a topical cream containing a Boswellia extract resulted in allergic contact dermatitis.³⁴
• Excessive intake of frankincense has been associated with a gastric bezoar (accumulation of vegetable fiber, hair, or other substances in the stomach or small intestine) in a 17-year-old girl with celiac disease. The symptoms, which included epigastric pain and vomiting, resolved after the bezoar was surgically removed.³⁵
• Mild stypsis was reported in patients with irritable bowel syndrome following supplementation with Casperome, a Boswellia extract.⁹

Herb-Drug Interactions

• OATP1B3: In vitro, KBA and AKBA were shown to modulate the activity of OATP1B3, a transporter that is responsible for the hepatic uptake of drugs and endogenous compounds.³⁶
• MRP2: In vitro, KBA and AKBA were also shown to modulate the activity of the multidrug-resistant protein MRP2.³⁶
• P-glycoprotein: A Boswellia extract and keto-boswellic acids were reported to inhibit the activity of P-glycoprotein in vitro and can potentially affect the transport of drugs mediated by this mechanism.³⁷
• Anticoagulant and/or antiplatelet drugs: Boswellia extracts can inhibit platelet aggregation and may increase the risk of bleeding when used with these drugs.²⁵

The clinical relevance of the previously mentioned interactions has yet to be determined.

Summary

Boswellic acid has shown anti-inflammatory activities in vitro. A few randomized controlled trials reported that formulations containing boswellia extract could reduce osteoarthritic pain, although the evidence is not definitive. A randomized controlled trial also showed that topical use of boswellia extract reduced radiation dermatitis. A few cases of mild adverse effects have been reported. Caution should be exercised when using boswellia in patients receiving anticoagulant or antiplatelet drugs. 

Dr. Deng is Medical Director, Attending Physician, and clinical member, Integrative Medicine Service, Memorial Sloan Kettering Cancer Center, New York. Ms. Gubili is Editor, Integrative Medicine Service, Memorial Sloan Kettering Cancer Center, New York.

DISCLOSURE: Dr. Deng and Ms. Gubili reported no conflicts of interest.

REFERENCES

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