Boswellia sacraessential oil manages colon cancer stem cells proliferation and apoptosis: a new perspective for cure

The journey of boswellic acids from synthesis to pharmacological activities

There has been a lot of interest in using naturally occurring substances to treat a wide variety of chronic disorders in recent years. From the gum resin of Boswellia serrata and Boswellia carteri, the pentacyclic triterpene molecules known as boswellic acid (BA) are extracted. We aimed to provide a detailed overview of the origins, chemistry, synthetic derivatives, pharmacokinetic, and biological activity of numerous Boswellia species and their derivatives. The literature searched for reports of B. serrata and isolated BAs having anti-cancer, anti-microbial, anti-inflammatory, anti-arthritic, hypolipidemic, immunomodulatory, anti-diabetic, hepatoprotective, anti-asthmatic, and clastogenic activities. Our results revealed that the cytotoxic and anticancer effects of B. serrata refer to its triterpenoid component, including BAs. Three-O-acetyl-11-keto-BA was the most promising cytotoxic molecule among tested substances. Activation of caspases, upregulation of Bax expression, downregulation of nuclear factor-kappa B (NF-kB), and stimulation of poly (ADP)-ribose polymerase (PARP) cleavage are the primary mechanisms responsible for cytotoxic and antitumor effects. Evidence suggests that BAs have shown promise in combating a wide range of debilitating disease conditions, including cancer, hepatic, inflammatory, and neurological disorders.

Improved antimicrobial activities of Boswellia sacra essential oils nanoencapsulated into hydroxypropyl-beta-cyclodextrins

Natural antimicrobials have recently gained increasing interest over synthetic antimicrobials to overcome foodborne pathogens and food microbial contamination. Essential oils (EOs) obtained from Boswellia sacra resins (BO) were utilized for respiratory disorders, rheumatoid arthritis, malignant tumors, and viral infections. Like other EOs, the therapeutic potential of BO is hindered by its low solubility and bioavailability, poor stability, and high volatility. Several studies have shown excellent physicochemical properties and outstanding therapeutic capabilities of EOs encapsulated into various nanocarriers. This study extracted BO from B. sacra resins via hydrodistillation and encapsulated it into hydroxypropyl-beta-cyclodextrins (HPβCD) using the freeze-drying method. The developed inclusion complexes of BO (BO-ICs) had high encapsulation efficiency (96.79 ± 1.17%) and a polydispersity index of 0.1045 ± 0.0006. BO-ICs showed presumably spherical vesicles (38.5 to 59.9 nm) forming multiple agglomerations (136.9 to 336.8 nm), as determined by UHR-TEM. Also, the formation and stability of BO-ICs were investigated using DSC, FTIR, FE-SEM, UHR-TEM, 1H NMR, and 2D HNMR (NOESY). BO-ICs showed greater thermal stability (362.7 °C). Moreover, compared to free BO, a remarkable enhancement in the antimicrobial activities of BO-ICs was shown against three different bacteria: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. BO-ICs displayed significant antibacterial activity against Pseudomonas aeruginosa with an MIC90 of 3.93 mg mL-1 and an MIC50 of 0.57 mg mL-1. Also, BO-ICs showed an increase in BO activity against Escherichia coli with an MIC95 of 3.97 mg mL-1, compared to free BO, which failed to show an MIC95. Additionally, BO-ICs showed a more significant activity against Staphylococcus aureus with an MIC95 of 3.92 mg mL-1. BO encapsulation showed significantly improved antimicrobial activities owing to the better stability, bioavailability, and penetration ability imparted by encapsulation into HPβCD.

Innovative microwave-assisted biosynthesis of copper oxide nanoparticles loaded with platinum(ii) based complex for halting colon cancer: cellular, molecular, and computational investigations

In the current study, we biosynthesized copper oxide NPs (CuO NPs) utilizing the essential oils extracted from Boswellia carterii oleogum resin, which served as a bioreductant and capping agent with the help of microwave energy. Afterwards, the platinum(ii) based anticancer drug, carboplatin (Cr), was loaded onto the CuO NPs, exploiting the electrostatic interactions forming Cr@CuO NPs. The produced biogenic NPs were then characterized using zeta potential (ZP), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction spectroscopy (XRD), and Fourier transform infrared spectroscopy (FTIR) techniques. In addition, the entrapment efficiency and release profile of the loaded Cr were evaluated. Thereafter, SRB assay was performed, where Cr@CuO NPs demonstrated the highest cytotoxic activity against human colon cancer cells (HCT-116) with an IC50 of 5.17 μg mL-1, which was about 1.6 and 2.2 folds more than that of Cr and CuO NPs. Moreover, the greenly synthesized nanoparticles (Cr@CuO NPs) displayed a satisfactory selectivity index (SI = 6.82), which was far better than the free Cr treatment (SI = 2.23). Regarding the apoptosis assay, the advent of Cr@CuO NPs resulted in an immense increase in the cellular population percentage of HCT-116 cells undergoing both early (16.02%) and late apoptosis (35.66%), significantly surpassing free Cr and CuO NPs. A study of HCT-116 cell cycle kinetics revealed the powerful ability of Cr@CuO NPs to trap cells in the Sub-G1 and G2 phases and impede the G2/M transition. RT-qPCR was utilized for molecular investigations of the pro-apoptotic (Bax and p53) and antiapoptotic genes (Bcl-2). The novel Cr@CuO NPs treatment rose above single Cr or CuO NPs therapy in stimulating the p53-Bax mediated mitochondrial apoptosis. The cellular and molecular biology investigations presented substantial proof of the potentiated anticancer activity of Cr@CuO NPs and the extra benefits that could be obtained from their use.

Unraveling the terpene synthase family and characterization of BsTPS2 contributing to (S)-( +)-linalool biosynthesis in Boswellia

Boswellia tree bark exudes oleo-gum resin in response to wounding, which is rich in terpene volatiles. But, the molecular and biochemical basis of wound-induced formation of resin volatiles remains poorly understood. Here, we combined RNA-sequencing (RNA-seq) and metabolite analysis to unravel the terpene synthase (TPS) family contributing to wound-induced biosynthesis of resin volatiles in B. serrata, an economically-important Boswellia species. The analysis of large-scale RNA-seq data of bark and leaf samples representing more than 600 million sequencing reads led to the identification of 32 TPSs, which were classified based on phylogenetic relationship into various TPSs families found in angiosperm species such as TPS-a, b, c, e/f, and g. Moreover, RNA-seq analysis of bark samples collected at 0-24 h post-wounding shortlisted 14 BsTPSs that showed wound-induced transcriptional upregulation in bark, suggesting their important role in wound-induced biosynthesis of resin volatiles. Biochemical characterization of a bark preferentially-expressed and wound-inducible TPS (BsTPS2) in vitro and in planta assays revealed its involvement in resin terpene biosynthesis. Bacterially-expressed recombinant BsTPS2 catalyzed the conversion of GPP and FPP into (S)-( +)-linalool and (E)-(-)-nerolidol, respectively, in vitro assays. However, BsTPS2 expression in Nicotiana benthamiana found that BsTPS2 is a plastidial linalool synthase. In contrast, cytosolic expression of BsTPS2 did not form any product. Overall, the present work unraveled a suite of TPSs that potentially contributed to the biosynthesis of resin volatiles in Boswellia and biochemically characterized BsTPS2, which is involved in wound-induced biosynthesis of (S)-( +)-linalool, a monoterpene resin volatile with a known role in plant defense.

Essential Oils Extracted from Boswellia sacra Oleo Gum Resin Loaded into PLGA-PCL Nanoparticles: Enhanced Cytotoxic and Apoptotic Effects against Breast Cancer Cells

This work aims to develop and optimize blended polylactide-co-glycolide (PLGA) and poly(ε-caprolactone, PCL) loaded with Boswellia sacra oil (BO) to improve BO's physicochemical properties and anti-breast cancer effects via enhancing apoptosis. In this context, BO was extracted from B. sacra oleo gum resins (BO) via hydrodistillation and chemically characterized by evaluating its essential oil's composition using gas chromatography-mass spectrometry. Then, BO/PLGA-PCL NPs were formulated using the emulsion (O/W) solvent evaporation technique using a PLGA-PCL mixture at five different ratios (1:1, 2:1, 3:1, 1:2, and 1:3, respectively). The optimized NPs had a spherical morphology with no agglomerations and the lowest hydrodynamic size (230.3 ± 3.7 nm) and polydispersity index (0.13 ± 0.03) and the highest ζ potential (-20.36 ± 4.89 mV), as compared to the rest of the formulas. PLGA-PCL NPs could entrap 80.59 ± 3.37% of the BO and exhibited a controlled, sustained release of BO (83.74 ± 3.34%) over 72 h. Encapsulating BO in the form of BO/PLGA-PCL NPs resulted in a lower IC₅₀ value as assessed by the MTT assay. Furthermore and upon assessing the apoptotic effect of both BO and BO/PLGA-PCL NPs, there was an increase in the percentage of apoptotic and necrotic cell percentages compared to the control and free BO. Encapsulation of BO in PLGA-PCL NPs doubled the percentage of apoptotic and necrotic cells exerted by free BO. These findings support the potential use of BO/PLGA-PCL NPs in treating breast cancer.

Nanomedicine as an Emerging Technology to Foster Application of Essential Oils to Fight Cancer

Natural prodrugs extracted from plants are increasingly used in many sectors, including the pharmaceutical, cosmetic, and food industries. Among these prodrugs, essential oils (EOs) are of particular importance. These biologically active volatile oily liquids are produced by medicinal and aromatic plants and characterized by a distinctive odor. EOs possess high anticancer, antibacterial, antiviral, and antioxidant potential but often are associated with low stability; high volatility; and a high risk of deterioration with exposure to heat, humidity, light, or oxygen. Furthermore, their bioavailability is limited because they are not soluble in water, and enhancements are needed to increase their potential to target specific cells or tissues, as well as for controlled release. Nanomedicine, the application of nanotechnology in medicine, may offer efficient solutions to these problems. The technology is based on creating nanostructures in which the natural prodrug is connected to or encapsulated in nanoparticles or submicron-sized capsules that ensure their solubility in water and their targeting properties, as well as controlled delivery. The potential of EOs as anticancer prodrugs is considerable but not fully exploited. This review focusses on the recent progress towards the practical application of EOs in cancer therapy based on nanotechnology applications.

Nano-Drug Delivery Systems Entrapping Natural Bioactive Compounds for Cancer: Recent Progress and Future Challenges

Cancer is a prominent cause of mortality globally, and it becomes fatal and incurable if it is delayed in diagnosis. Chemotherapy is a type of treatment that is used to eliminate, diminish, or restrict tumor progression. Chemotherapeutic medicines are available in various formulations. Some tumors require just one type of chemotherapy medication, while others may require a combination of surgery and/or radiotherapy. Treatments might last from a few minutes to many hours to several days. Each medication has potential adverse effects associated with it. Researchers have recently become interested in the use of natural bioactive compounds in anticancer therapy. Some phytochemicals have effects on cellular processes and signaling pathways with potential antitumor properties. Beneficial anticancer effects of phytochemicals were observed in both in vivo and in vitro investigations. Encapsulating natural bioactive compounds in different drug delivery methods may improve their anticancer efficacy. Greater in vivo stability and bioavailability, as well as a reduction in undesirable effects and an enhancement in target-specific activity, will increase the effectiveness of bioactive compounds. This review work focuses on a novel drug delivery system that entraps natural bioactive substances. It also provides an idea of the bioavailability of phytochemicals, challenges and limitations of standard cancer therapy. It also encompasses recent patents on nanoparticle formulations containing a natural anti-cancer molecule.

Taxonomical Investigation, Chemical Composition, Traditional Use in Medicine, and Pharmacological Activities of Boswellia sacra Flueck

Aromatic oleo-gum-resin secreted from B. sacra, reputed as frankincense, is widely used in traditional medicine to treat Alzheimer’s disease, gastric disorders, hepatic disorders, etc. Frankincense is also used in the cosmetic, perfume, and beverage and food industries. Frankincense is a rich resource for bioactive compounds, especially boswellic acids and derivatives. Although several reports have described frankincense’s constituents and pharmacological activities, there is no comprehensive study that covers the valuable information on this species. Therefore, the current review will focus on the phytochemistry, traditional uses, and pharmacological activities of B. sacra.