Bioactive cembrane diterpenoids from the gum resin of Boswellia carterii

Characteristic cembrane-type diterpenoids with nitric oxide inhibitory activity from the gum resin of Boswellia carterii Birdw

Five new characteristic cembrane-type diterpenoids (olibacartiols A-E, 1-5) were acquired from the gum resin of Boswellia carterii. The structures of these diterpenoids were characterized by detailed spectroscopic analysis, and compounds 1-3 were unambiguously confirmed by single-crystal X-ray diffraction experiments. The anti-inflammatory activities of the isolated compounds were evaluated using LPS-induced BV2 cell model and compounds 2-5 showed moderate NO inhibitory effects with IC50 values of 8.84 ± 1.02, 9.82 ± 1.95, 9.75 ± 2.24, and 7.39 ± 1.24 μM, respectively.

Chemical Constituents and Pharmacological Properties of Frankincense: Implications for Anticancer Therapy

The discovery of novel antitumor agents derived from natural plants is a principal objective of anticancer drug research. Frankincense, a widely recognized natural antitumor medicine, has undergone a systematic review encompassing its species, chemical constituents, and diverse pharmacological activities and mechanisms. The different species of frankincense include Boswellia serrata, Somali frankincense, Boswellia frereana, and Boswellia arabica. Various frankincense extracts and compounds exhibit antitumor, anti-inflammatory, and hepatoprotective properties and antioxidation, memory enhancement, and immunological regulation capabilities. They also have comprehensive effects on regulating flora. Frankincense and its principal chemical constituents have demonstrated promising chemoprophylactic and therapeutic abilities against tumors. This review provides a systematic summary of the mechanism of action underlying the antitumor effects of frankincense and its major constituents, thus laying the foundations for developing effective tumor-combating targets.

Medicinal plant resin natural products: structural diversity and biological activities

Covering: up to the mid of 2023Plants secrete defense resins rich in small-molecule natural products under abiotic and biotic stresses. This comprehensive review encompasses the literature published up to mid-2023 on medicinal plant resin natural products from six main contributor genera, featuring 275 citations that refer to 1115 structurally diverse compounds. The scope of this review extends to include essential information such as the racemic nature of metabolites found in different species of plant resins, source of resins, and revised structures. Additionally, we carefully analyze the reported biological activities of resins, organizing them based on the their structures. The findings offer important insights into the relationship between their structure and activity. Furthermore, this detailed examination can be valuable for researchers and scientists in the field of medicinal plant resin natural products and will promote continued exploration and progress in this area.

Guided discovery of hepatoprotective polyhydroxy cembrane-type diterpenoids from the gum resin of Boswellia carterii by MS/MS molecular networking

Seven previously undescribed polyhydroxy cembrane-type diterpenoids, olibanols A-G (1-7) were obtained from the gum resin of Boswellia carterii by means of MS/MS molecular networking. Compound 2 possessed four hydroxy groups, 1, 3, 4, 5, and 6 had three hydroxy groups, 7 with one hydroxy group, among which 1 and 4 were a pair of epimers with double bond at C-3 and hydroxy at C-8. Structures of these previously undescribed compounds were determined by NMR analysis and ECD calculations. All the polyhydroxy cembrane-type diterpenoids obtained were assayed for their hepatoprotective effects against the anti-tuberculosis drug-induced hepatic damage to the HRZ-induced HepG2 cells. As results indicated, compounds 3, 4, and 6 showed significant hepatoprotective effects against the hepatic damage via the Nrf2 signal pathway, which could be developed as potential hepatoprotective agents against the anti-tuberculosis drug-induced hepatic damage.

Cembrane diterpenoids: Chemistry and pharmacological activities

Cembrane diterpenoids (cembranoids), characterized by a 14-membered carbon ring and wide variety of functional groups, found in marine and terrestrial organisms. Many studies have shown that cembrane diterpenoids have cytotoxic and anti-inflammatory activities and are widely used in the development of new drugs. This review covered publications from 2011 to 2022 and classified the cembrane-type diterpenoids into isopropyl (ene) type, γ-lactone or unsaturated five-membered ring, δ-lactone or unsaturated six-membered ring, ε-lactone or unsaturated seven-membered ring, and other cembrane diterpenes. In addition, the biological activity and structure-activity relationship were summarized. This will provide guidance for new cembrane-type diterpenes as lead compounds to explore their potential application for treating cancer and inflammatory diseases.

Evaluation of antibacterial and wound-healing activities of alcoholic extract of Boswellia carterii, in vitro and in vivo study

BACKGROUND

Today, despite the existence of various chemical and physical treatments for wound healing, the use of traditional medicine including herbal medicine is still widely used in most developed and developing countries.

OBJECTIVES

To investigate the antimicrobial and wound-healing activities of alcoholic extract of Boswellia carterii (BC) plant.

METHODS

The BC extract was prepared using alcohol 70%. The chemical groups and extract compounds were determined using Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) analysis, respectively. The antimicrobial and wound-healing activities of different concentrations of BC extract and its combination with penicillin-streptomycin were assessed by agar well diffusion and infected wound model in albino rabbits, respectively.

RESULTS

FTIR revealed the presence of hydroxyl, amide, carboxyl, alkyl C-H stretches, aromatic C=C bends, and aromatic C-H bends in the BC extract. The HPLC revealed 14 different compounds including thujene (48.0%) as the most abundant ingredient. All BC concentrations showed antibacterial and wound-healing activities. The 10% concentration of BC extract had the strongest antibacterial effect. Also, the combination of penicillin-streptomycin with BC extract showed synergistic antibacterial effect. The 5% concentration of BC was the best wound-healing compound which healed the wound in 6 days and decreased the wound size 10 mm each day.

CONCLUSIONS

This study demonstrated the potential abilities of BC as an antibacterial and wound-healing medicinal plant. Further studies are required to justify the in vivo use of this plant.

Frankincense diterpenes as a bio-source for drug discovery

INTRODUCTION

Frankincense (Boswellia sp.) gum resins have been employed as an incense in cultural and religious ceremonies for many years. Frankincense resin has over the years been employed to treat depression, inflammation, and cancer in traditional medicines.

AREAS COVERED

This inclusive review focuses on the significance of frankincense diterpenoids, and in particular, incensole derivatives for establishment future treatments of depression, neurological disorders, and cancer. The authors survey the available literature and furnish an overview of future perspectives of these intriguing molecules.

EXPERT OPINION

Numerous diterpenoids including cembrane, prenylaromadendrane, and the verticillane-type have been isolated from various Boswellia resins. Cembrane-type diterpenoids occupy a crucial position in pharmaceutical chemistry and related industries because of their intriguing biological and encouraging pharmacological potentials. Several cembranes have been reported to possess anti-Alzheimer, anti-inflammatory, hepatoprotective, and antimalarial effects along with a good possibility to treat anxiety and depression. Although some slight drawbacks of these compounds have been noted, including the selectivity of these diterpenoids, there is a great need to address these in future research endeavors. Moreover, it is vitally important for medicinal chemists to prepare libraries of incensole-heterocyclic analogs as well as hybrid compounds between incensole or its acetate and anti-depressant or anti-inflammatory drugs.

Anti-inflammatory and hepatoprotective cembranoid alcohols from the Gum Resin of Boswellia carterii

Five undescribed cembranoid alcohols, boscartinols A-E (1-5) were discovered from the gum resin of Boswellia carterii. Their structures were elucidated by analyzing the spectroscopic data. Notably, all these five compounds preserved an isopropyl type cembranoid skeleton, featured the same groups of one epoxy ring at C₁-C₁₂ and one hydroxy group at C-11, as well as two double bonds migrating from C₃ to C₉ and one hydroxy group from C₃ to C₈ within the cembranoid structure. These cembranoids were evaluated for the hepatoprotective and anti-inflammatory activities using two cell models of APAP-induced HepG2 and LPS-induced RAW 264.7. For hepatoprotective activity, compounds 1 and 5 showed remarkable hepatoprotective activity (inhibition rate of 51.6% and 39.8%, respectively) at 10 μM, with the other three compounds of 2-4 showing less potently hepatoprotective. For anti-inflammatory activity, compounds 2-4 showed significant inhibitory effects on NO produced by LPS-induced RAW 264.7 cell (IC₅₀ values of 13.40 μM, 7.08 μM and 14.26 μM), with the other two compounds of 1 and 5 showing less potently anti-inflammatory activities.