Compendium of the most significant studies with reference to properties, intake, effects.

Chevrier MR, Ryan AE, Lee DY, Zhongze M, Wu-Yan Z, Via CS. Boswellia carterii extract inhibits TH1 cytokines and promotes TH2 cytokines in vitro. Clin Diagn Lab Immunol. 2005 May;12(5):575-80. doi: 10.1128/CDLI.12.5.575-580.2005. 

Abstract. Traditional herbal formulas used to treat inflammatory arthritis in China and India include Boswellia carterii or Boswellia serrata. They both contain boswellic acids (BAs) which have been shown to exhibit anti-inflammatory and antiarthritic properties. This study tests the hypothesis that mixtures of BAs derived from B. carterii have immunomodulatory properties. B. carterii plant resin obtained from China was prepared as an ethanol extract, and the presence of seven BAs was confirmed by column chromatography, high-performance liquid chromatography, and UV laser desorption/ionization tandem mass spectroscopy. The extract was then tested for its ability to alter in vitro production of TH1 cytokines (interleukin-2 [IL-2] and gamma interferon) and TH2 cytokines (IL-4 and IL-10) by murine splenocytes. Delivery of the resin extract using ethanol as a solvent resulted in significant cellular toxicity not seen with the addition of ethanol alone. By contrast, delivery of the resin extract using a sesame oil solvent resulted in a dose-dependent inhibition of TH1 cytokines coupled with a dose-dependent potentiation of TH2 cytokines. These results indicate that a purified mixture of BAs from B. carterii plant resin exhibits carrier-dependent immunomodulatory properties in vitro.

Safayhi H, Sailer ER, Ammon HP. Mechanism of 5-lipoxygenase inhibition by acetyl-11-keto-beta-boswellic acid. Mol Pharmacol. 1995 Jun;47(6):1212-6. 

Abstract. The formation of 5-lipoxygenase (EC 1.13.11.34) products from endogenous substrate by intact rat neutrophilic granulocytes and from exogenous arachidonic acid by rat granulocyte 105,000 x g supernatants and affinity chromatography-purified human leukocyte 5-lipoxygenase was inhibited by acetyl-11-keto-beta-boswellic acid (IC50 values of 1.5 microM, 8 microM, and 16 microM, respectively). With other pentacyclic triterpenes lacking the 11-keto function and/or the carboxyl function on ring A (e.g., amyrin and ursolic acid), no 5-lipoxygenase inhibition was observed. The presence of the noninhibitory pentacyclic triterpenes both in intact cells and in the cell-free system caused a concentration-dependent reversal of the 5-lipoxygenase inhibition by acetyl-11-keto-beta-boswellic acid, whereas the inhibitory actions of 5-lipoxygenase inhibitors from different chemical classes (MK-886, L-739,010, ZM-230,487, and nordihydroguaiaretic acid) were not modified. The inhibition by acetyl-11-keto-beta-boswellic acid and the antagonism by noninhibitory pentacyclic triterpenes were not due to nonspecific lipophilic interactions, because lipophilic four-ring compounds (cholesterol, cortisone, and testosterone) neither inhibited the activity of the 5-lipoxygenase nor antagonized the inhibitory action of acetyl-11-keto-beta-boswellic acid. Therefore, we conclude that acetyl-11-keto-beta-boswellic acid acts directly on the 5-lipoxygenase enzyme at a selective site for pentacyclic triterpenes that is different from the arachidonate substrate binding site.

Hoernlein RF, Orlikowsky T, Zehrer C, Niethammer D, Sailer ER, Simmet T, Dannecker GE, Ammon HP. Acetyl-11-keto-beta-boswellic acid induces apoptosis in HL-60 and CCRF-CEM cells and inhibits topoisomerase I. J Pharmacol Exp Ther. 1999 Feb;288(2):613-9. 

Abstract. Antiproliferative action of different pentacyclic triterpenes has repeatedly been reported, and some lipoxygenase inhibitors have been shown to induce cell death in various cell systems. Acetyl-11-keto-beta-boswellic acid (AKBA) is a pentacyclic triterpene that inhibits 5-lipoxygenase in a selective, enzymedirected, nonredox, and noncompetitive manner. To investigate a possible effect of AKBA on leukemic cell growth, proliferation of HL-60 and CCRF-CEM cells was assayed in the presence of AKBA and a structural analog without effect on 5-lipoxygenase, amyrin. Cell counts and [3H]thymidine incorporation were significantly reduced in a dose-dependent manner in the presence of AKBA (IC50 = 30 microM) but not amyrin. An additive effect of AKBA with the crosslinking of the CD95 receptor was also observed. Flow cytometric analysis of propidium iodide-stained cells indicated that the cells underwent apoptosis. This was confirmed by flow cytometric detection of sub-G1 peaks in AKBA-treated cells and by DNA laddering. However, because HL-60 and CCRF-CEM do not express 5-lipoxygenase mRNA constitutively, a mechanism distinct from inhibition of 5-lipoxygenase must account for the effect of AKBA. In a DNA relaxation assay with phiX174RF DNA, AKBA inhibited topoisomerase I from calf thymus at concentrations of >/=10 microM. A semiquantitative cDNA polymerase chain reaction approach was used to estimate the relative level of expression of topoisomerases in both cell lines. The data suggest that induction of apoptosis in HL-60 and CCRF-CEM by AKBA may be due to inhibition of topoisomerase I in these cells.

Ammon HP. Boswelliasäuren (Inhaltsstoffe des Weihrauchs) als wirksame Prinzipien zur Behandlung chronisch entzündlicher Erkrankungen [Boswellic acids (components of frankincense) as the active principle in treatment of chronic inflammatory diseases]. Wien Med Wochenschr. 2002;152(15-16):373-8. German. doi: 10.1046/j.1563-258x.2002.02056.x. 

Abstract. Preparations from the gum resin of Boswellia serrata have been used as a traditional remedy in Ayurvedic medicine in India for the treatment of inflammatory diseases. Compounds from the gum with genuine antiinflammatory effects are pentacyclic triterpenes of the boswellic acid type. Boswellic acids inhibit the leukotriene biosynthesis in neutrophilic granulocytes by a non-redox, noncompetitive inhibition of 5-lipoxygenase. The effect is triggered by boswellic acids binding to the enzyme. Moreover certain boswellic acids have been described to inhibit elastase in leukocytes, to inhibit proliferation, induce apoptosis and to inhibit topoisomerases of leukoma- and glioma cell lines. A series of chronic inflammatory diseases are thought to be perpetuated by leukotrienes. In clinical trials promising results were observed in patients with rheumatoid arthritis, chronic colitis, ulcerative colitis, Crohn's disease, bronchial asthma und peritumoral brains edemas.

Sibona M, Destefanis P, Agnello M, Lillaz B, Giuliano M, Cai T, Gontero P. The association of Boswellia resin extract and propolis derived polyphenols can improve quality of life in patients affected by prostatitis-like symptoms. Arch Ital Urol Androl. 2020 Jan 14;91(4):251-255. doi: 10.4081/aiua.2019.4.251. 

Abstract. Objectives: Chronic prostatitis syndrome is a bothering and poorly understood condition. Many patients report genitourinary pain and Lower Urinary Tract Symptoms as a main complaint. Many different pharmacological or behavioural therapies are prescribed in daily clinical practice, but efficacy data are still lacking. The aim of our study was to test the efficacy and safety of a transrectal delivered association of Boswellia resin extract and propolis derived polyphenols for the relief of prostatitis - like symptoms. Materials and methods: Patients affected by chronic/recurrent prostatitis - like symptoms were prospectively enrolled in our study from December, 2016 to December, 2018. Patients were screened at baseline through clinical examination and validated questionnaires administration: Chronic Prostatitis Symptom Index (CPSI), International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF). Inclusion criteria were: age ≥ 18; prostatitis symptoms persisting for at least 3 of the last 6 months; CPSI pain domain score ≥ 5; previous negative Meares-Stamey test. Treatment consisted on the administration of 1 suppository containing Boswellia resin extract and propolis derived polyphenols, once a day for 20 days. The primary endpoint of the study was the improvement of quality of life after treatment, defined by a reduction of ≥ 2 points, or ≥ 25%, of mean CPSI pain domain score, compared to baseline. Secondary endpoints were the improvement of post-treatment CPSI total score and the analysis of treatment - related adverse events. All patients were re-evaluated 1 month after treatment. Results: 40 patients were enrolled in our study. Median age (Inter - Quartile Range IQR) was 51.5 (41.5-63.2) years. Mean baseline CPSI scores were: 22.15 (total score), 9.67 (pain domain), 5.15 (micturition domain) and 7.35 (quality of life domain), respectively. No significant adverse events were reported. At 1 month follow-up, CPSI scores appeared modified as follows: 16.40 (total score, p = 0.001); 6.92 (pain domain; p = 0.001; 4.02 (micturition domain, p = 0.09); 5.45 (quality of life domain, p = 0.002). Mean CPSI pain domain score reduction was -2.75 points (-28.5%). Mean CPSI total score reduction was -5.75 points (-26%). Conclusions: The association of Boswellia resin extract and propolis derived polyphenols can reduce genitourinary pain and then improve quality of life of men affected by bothersome prostatitis - like symptoms.

Badria FA, Mikhaeil BR, Maatooq GT, Amer MM. Immunomodulatory triterpenoids from the oleogum resin of Boswellia carterii Birdwood. Z Naturforsch C J Biosci. 2003 Jul-Aug;58(7-8):505-16. doi: 10.1515/znc-2003-7-811.

Abstract. The immunomodulatory bioassay-guided fractionation of the oleogum resin of frankincense (Boswellia carterii Birdwood) resulted in the isolation and identification of 9 compounds; palmitic acid and eight triterpenoids belonging to lupane, ursane, oleanane, and tirucallane skeleta were isolated form the resin. These triterpenoids are lupeol, beta-boswellic acid, 11-keto-beta-boswellic acid, acetyl beta-boswellic acid, acetyl 11-keto-beta-boswellic acid, acetyl-alpha-boswellic acid, 3-oxo-tirucallic acid, and 3-hydroxy-tirucallic acid. The structures of the isolated compounds were deduced based on spectroscopic evidences. The lymphocyte transformation assay of the isolated compounds proved that the total extract retained more activity than that of any of the purified compounds.

Mertens, M., Buettner, A., & Kirchhoff, E. (2009). The volatile constituents of frankincense–a review. Flavour and Fragrance Journal, 24(6), 279-300.

Abstract. The smell of frankincense resin and powder, as well as burned frankincense, has been linked to a series of health effects since ancient times. Additionally, frankincense and its fumes are used as a means to induce positive psychophysical effects and well-being, not only in an ecclesiastical setting but also in traditional medical applications. This review aims to provide an overview of current knowledge of the volatile constituents of frankincense, with explicit consideration concerning the diverse Boswellia varieties. Altogether, more than 300 volatiles in frankincense have been reported in the literature. In particular, a broad diversity has been found in the qualitative and quantitative composition of the volatiles with respect to different varieties of Boswellia. A detailed discussion of the various analytical approaches applied to isolating and analysing the volatile fractions of frankincense is also presented. Copyright © 2009 John Wiley & Sons