Composition of boswellic acid derivatives as antitumor agents

Abstract

A pharmaceutical composition comprising a therapeutically effective amount of one or more structurally modified pentacyclic triterpenoid derivatives of 11-keto-β-boswellic acid (AKBA), wherein the derivatives are substituted at one or more positions selected from: a) a pentacyclic framework; b) a functional 11-keto group at the C-11 position c) an acetyl group in the C-3 hydroxyl position d) a carboxylic acid group in the C-24 position; and wherein the composition further comprises one or more pharmaceutically acceptable excipients, carriers or diluents; wherein the composition is formulated for administration selected from the group consisting of oral, topical, parenteral or transdermal routes; and wherein the composition is effective, particularly in triple negative breast cancer (TNBC), and exhibits selective cytotoxicity against malignant breast cancer cells such as the MDA-MB-231 cell line, while exhibiting reduced cytotoxicity against normal fibroblast cells such as 3T3-L1.

Description

[0001] The present invention relates to pharmaceutical compositions containing incensol and boswellic acid derivatives. More specifically, it concerns their use as effective antitumor agents for the treatment and management of various cancers. The invention further encompasses methods of formulation and therapeutic applications in oncology.

[0002] Cancer remains one of the leading causes of death worldwide, with existing treatments such as chemotherapy, radiation, and targeted therapies often associated with significant side effects, limited efficacy, and the development of drug resistance. Despite advances in oncology, there remains a need for safer and more effective therapeutics that target tumor cells without damaging normal tissue. The complexity of tumor biology and the ability of cancer cells to evade conventional therapies highlight the urgent need for novel agents with multicenter mechanisms of action.

[0003] Natural products have long been recognized for their therapeutic potential and provide a rich source of bioactive molecules with anticancer properties. Boswellic acids, derived from Boswellia species, and incensols have demonstrated anti-inflammatory, anti-proliferative, and apoptosis-inducing effects. However, their clinical application has been limited by factors such as poor bioavailability, low efficacy, and inconsistent therapeutic outcomes. This has led to research into derivatives and optimized compositions to enhance their anti-tumor potential.

[0004] The present invention addresses these challenges by providing a novel composition combining incensol and boswellic acid derivatives, specifically formulated to enhance bioactivity and therapeutic efficacy against tumors. By leveraging their complementary mechanisms—such as inhibition of tumor cell proliferation, induction of apoptosis, and modulation of key signaling pathways—the invention offers a promising, targeted approach for cancer therapy with improved safety and efficacy profiles over existing treatments.

[0005] The present disclosure provides a pharmaceutical composition containing 3-O-acetyl-11-keto-β-boswellic acid (AKBA) for the treatment of inflammatory diseases, autoimmune disorders and cancer, in particular triple negative breast cancer (TNBC).

[0006] Another object of the present disclosure is to provide an AKBA composition having improved bioavailability and solubility for improved therapeutic efficacy.

[0007] Another object of the present disclosure is to provide an effective formulation of AKBA with selective cytotoxicity against cancer cells while minimizing toxicity to normal, healthy cells.

[0008] Another object of the present disclosure is to provide a stable and patient-friendly delivery system of AKBA in various dosage forms, including oral, injectable and topical formulations.

[0009] Another object of the present disclosure is to provide a method for treating triple negative breast cancer by administering the AKBA-based composition, which is an alternative to conventional chemotherapy with fewer side effects.

[0010] Another object of the present disclosure is to provide a pharmaceutical composition in which AKBA is combined with pharmaceutically acceptable carriers, excipients or adjuvants to improve its stability and therapeutic performance.

[0011] The present invention generally relates to a novel pharmaceutical composition containing 3-O-acetyl-11-keto-β-boswellic acid (AKBA) as the primary active ingredient. AKBA is a pentacyclic triterpenoid derived from Boswellia serrata and is known for its potent anti-inflammatory, anticancer, and immunomodulatory activities. The invention provides a stable, bioavailable formulation of AKBA for therapeutic use in the treatment of various inflammatory diseases, autoimmune disorders, and cancer, particularly triple-negative breast cancer (TNBC). The composition was developed to improve the solubility and bioavailability of AKBA, thus ensuring effective administration and improved pharmacokinetic profiles compared to existing formulations.

[0012] Furthermore, the invention encompasses the combination of AKBA with suitable pharmaceutically acceptable excipients, carriers, or additional therapeutic agents to maximize its therapeutic potential while minimizing side effects. The composition can be administered orally, topically, or parenterally and can be offered in various dosage forms such as tablets, capsules, injectables, and emulsions. The invention exhibits selective cytotoxicity against cancer cells while sparing normal cells.

[0013] The present invention relates to a pharmaceutical anti-cancer composition containing at least one pentacyclic triterpenoid derivative of 11-keto-β-boswellic acid (AKBA) or its pharmaceutically acceptable salt, solvate, or prodrug. In particular, the invention discloses a composition in which the derivative is selected from compounds of formula I, a pentacyclic scaffold; an 11-keto functional group at the C-11 position; an acetyl group at the C-3 hydroxyl position; a carboxylic acid group at the C-24 position; wherein the compound is 3-O-acetyl-11-keto-β-boswellic acid (AKBA); and one or more pharmaceutically acceptable excipients, carriers, or diluents.

[0014] The main active ingredient in the present composition is 3-O-acetyl-11-keto-β-boswellic acid (Compound 1), a potent pentacyclic triterpenoid known for its anti-inflammatory and anticancer properties. Compound 1 possesses a hydroxyl group at the C-3 position and a keto group at the C-11 position, which contributes to its ability to induce apoptosis and inhibit tumor cell proliferation. The compound interferes with critical signaling pathways involved in cancer development, such as NF-κB and STAT3, thereby reducing tumor growth and metastasis. In the present invention, Compound 1 is used either as a standalone drug or in combination with other derivatives or complementary therapies to maximize anticancer efficacy.

[0015] In one embodiment, the pharmaceutical composition comprises compound 1 formulated with pharmaceutically acceptable carriers or excipients suitable for oral, injectable, or topical administration. The formulation may be designed to improve solubility and stability, for example, by encapsulation in nanoparticles, liposomes, or solid dispersions. The composition may also contain bioavailability enhancers or targeted delivery systems to ensure efficient accumulation of the active ingredient at tumor sites while minimizing systemic toxicity. The controlled-release profile of the formulation is intended to ensure sustained therapeutic concentrations of the active ingredient for prolonged anti-tumor activity.

[0016] The invention further discloses a method for treating various cancers, including, but not limited to, breast cancer, prostate cancer, lung cancer, colorectal cancer, and glioblastoma, by administering the described pharmaceutical composition. The method involves administering an effective amount of compound 1 or its derivatives to inhibit tumor growth, induce programmed cell death in cancer cells, and modulate immune responses against tumor progression. The invention also demonstrates the ability of compound 1 to overcome the multidrug resistance frequently observed with conventional chemotherapy, making it a valuable therapeutic option in oncology.

[0017] Furthermore, the invention encompasses methods for synthesizing the 11-keto-β-boswellic acid derivatives described in Formula I. These methods involve selective functionalization at specific positions of the triterpenoid backbone and ensure high purity and yield of the desired compounds. The synthesis may include steps such as esterification, acetylation, oxidation, halogenation, and conjugation with targeting ligands such as nitroimidazole moieties to increase selective cytotoxicity against hypoxic tumor cells. The invention ensures that the derivatives retain their structural integrity and biological activity during formulation and administration. EXAMPLE 1: Extraction and isolation

[0018] The air-dried powder of B. papyrifera resin (1.5 kg) was extracted with methanol (MeOH) at room temperature, performing three consecutive extractions lasting two days each. The combined extracts were evaporated under reduced pressure to yield a yellow, semi-solid MeOH residue (1.3 kg). This residue was subjected to column chromatography using varying ratios of ethyl acetate (EtOAc) and n-hexane (10%, 20%, 30%, and 50%), yielding eight major fractions (BPF1-8). Fractions BPF4-7 (40-70% EtOAc / n-hexane), determined by TLC analysis, were combined and further purified by column chromatography (20-30% EtOAc / n-hexane).This procedure yielded a mixture of three major compounds: 3-acetyl-11-keto-β-boswellic acid (AKBA), 11-keto-β-boswellic acid (KBA), and 11α-hydroxy-ABA, which were further purified by chloroform HPLC and eluted as UV-active compounds at a retention time of 42 minutes and a flow rate of 4 mL / min.

[0019] Fraction three (BSF3) from the first chromatography was further processed by silica gel chromatography with a 20% EtOAc / n-hexane gradient, yielding β-boswellic acid (β-BA) and 3-acetyl-β-boswellic acid (β-ABA), which were also purified by recycled chloroform HPLC. Subfraction BPSF2 was subjected to additional column chromatography to isolate serratol and isoserratol in a 5-10% EtOAc / n-hexane system. These compounds, along with other semipure isolates, were subjected to preparative HPLC.

[0020] In addition, incensole and incensole acetate were isolated and purified using a CHCl3-HPLC system stabilized with 0.6% EtOH and eluted as UV-inactive compounds with retention times of 44.7 and 46.0 minutes, respectively. Several benzyl derivatives were also synthesized from compounds 2 and 3 following known protocols. EXAMPLE 2: In vitro inhibition of carbonic anhydrase

[0021] The in vitro inhibitory activity against human carbonic anhydrase isoforms (CA-II and CA-IX) was investigated. The purified enzymes were dissolved in HEPES-Tris buffer (0.1 mg / mL; 20 mM, pH 7.4). The reaction mixture for each assay contained 140 µl of HEPES-Tris buffer, 20 µl of the enzyme solution, and 20 µl of the test compound prepared in DMSO. The mixture was pre-incubated for 15 minutes at 25 °C to allow for enzyme-inhibitor interaction.

[0022] After pre-incubation, the reaction was initiated by adding the substrate p-nitrophenyl acetate (P-NPA), prepared in methanol, at a concentration of 0.7 mM. The reaction was monitored in a 96-well plate using a molecular spectrometer, measuring absorbance at 400 nm every minute for 30 minutes. The assays were strictly maintained at 25°C and performed in triplicate to ensure accuracy and reproducibility. The percentage inhibition and IC50 values ​​were analyzed. EXAMPLE 3: In vitro cytotoxicity test

[0023] The in vitro cytotoxicity of the metal complexes was evaluated using the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). This assay was performed using the aggressive breast cancer cell line MDA-MB-231, an established model for triple-negative breast cancer widely used for in vitro and in vivo studies.

[0024] The 3T3-L1 fibroblast cell line served as a non-cancerous control in the study. Both cell lines were cultured in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% antibiotics (100 U / mL penicillin). The cells were plated in 96-well plates at a density of 1.0 × 10 4 Cells were seeded per well and incubated for 24 hours at 37 °C in a humidified atmosphere with 5% CO 2 After incubation, the culture medium was removed, and the cells were treated with different concentrations (12.6 µM / mL, 25 µM / mL, 50 µM / mL, and 100 µM / mL) of AKBA derivatives.

[0025] After 48 hours of treatment, 20 µL of MTT solution (5 mg / mL) was added to each well, and the cells were incubated for another 4 hours. After incubation, the medium was carefully discarded, and the purple formazan crystals formed by the viable cells were dissolved in dimethyl sulfoxide (DMSO). The absorbance in each well was measured at 570 nm using a microplate reader. All experiments were performed in triplicate to ensure reproducibility. Cytotoxicity was expressed as the percentage of cell viability compared to untreated control cells and calculated using the standard equation.

[0026] The cytotoxic potential of compound 1 was investigated using the MTT assay at concentrations of 12.6 µM / mL, 25 µM / mL, 50 µM / mL, and 100 µM / mL against the human breast cancer cell line MDA-MB-231. Compound 1 exhibited moderate cytotoxic activity with an IC50 value of 56.8 ± 0.5 µM. At the highest concentration tested (100 µM / mL), it demonstrated 62.4% inhibition of MDA-MB-231 cell viability. The cytotoxic effects of the compound were dose-dependent, with increasing concentrations resulting in a higher percentage of cell viability inhibition.

[0027] When tested with the non-tumorigenic fibroblast cell line 3T3-L1 at the same concentrations, Compound 1 exhibited significantly lower cytotoxicity, with an IC50 value exceeding 100 µM. At 100 µM / mL, inhibition of 3T3-L1 cell viability was limited to 21.5%, suggesting lower toxicity to normal cells. The selective cytotoxicity profile of Compound 1 underscores its potential as a therapeutic agent with preferential activity against cancer cells over healthy fibroblasts. Examples 1. A pharmaceutical composition comprising a therapeutically effective amount of one or more structurally modified pentacyclic triterpenoid derivatives of 11-keto-β-boswellic acid (AKBA), wherein the derivatives are substituted at one or more positions selected from: a) a pentacyclic framework; b) a functional 11-keto group at the C-11 position c) an acetyl group in the C-3 hydroxyl position d) a carboxylic acid group in the C-24 position; and wherein the composition further comprises one or more pharmaceutically acceptable excipients, carriers or diluents; wherein the composition is formulated for administration selected from the group consisting of oral, topical, parenteral or transdermal routes; and wherein the composition is effective, particularly in triple negative breast cancer (TNBC), and exhibits selective cytotoxicity against malignant breast cancer cells such as the MDA-MB-231 cell line, while exhibiting reduced cytotoxicity against normal fibroblast cells such as 3T3-L1.

Claims

[1] A pharmaceutical composition comprising a therapeutically effective amount of one or more structurally modified pentacyclic triterpenoid derivatives of 11-keto-β-boswellic acid (AKBA), wherein the derivatives are substituted at one or more positions selected from: a) a pentacyclic framework; b) a functional 11-keto group at the C-11 position c) an acetyl group in the C-3 hydroxyl position d) a carboxylic acid group in the C-24 position; and wherein the composition further comprises one or more pharmaceutically acceptable excipients, carriers or diluents; wherein the composition is formulated for administration selected from the group consisting of oral, topical, parenteral or transdermal routes; and wherein the composition is effective, particularly in triple negative breast cancer (TNBC), and exhibits selective cytotoxicity against malignant breast cancer cells such as the MDA-MB-231 cell line, while exhibiting reduced cytotoxicity against normal fibroblast cells such as 3T3-L1. [2] The pharmaceutical composition of claim 1, wherein the compounds include, but are not limited to, 3-O-acetyl-11-keto-β-boswellic acid.