Ten undescribed cembrane-type diterpenoids from the gum resin of Boswellia sacra and their biological activities

Qualitative and quantitative analyses of the changes in the chemical composition of frankincense before and after stir-frying using GC-MS and LC-MS

Frankincense is a resin drug used widely in the medical field. Comprehensive qualitative and quantitative analyses of the differences in the chemical composition of frankincense, stir-fried frankincense and vinegar frankincense were done by combining GC-MS and LC-MS. GC-MS revealed six chemical compositions with high content in frankincense: β-ocimene, 1-octanol, acetic acid, octyl ester, nerolidol, lauric acid and incensole acetate. LC-MS revealed eight more widely studied chemical compositions: 11-keto-β-boswellic acid, β-elemolic acid, acetyl-11-keto-β-boswellic acid, β-elemonic acid, α-boswellic acid, β-boswellic acid, 3-O-acetyl-α-boswellic acid and 3-O-acetyl-β-boswellic acid. In addition, the chemical composition of frankincense was identified by the fragmentation information afforded by LC-MS.

Phytochemical Analysis and Pharmaceutical Applications of Monoterpenoids Present in the Essential Oil of Boswellia sacra (Omani Luban)

Due to its intricacy and long-term usefulness, traditional medicine continues to be practiced in several nations. Among the many medicinal plants found in the Dhofar region of Oman, the aromatic oleo-gum resin generated by Boswellia sacra, commonly referred to as frankincense, stands out for its medical and commercial significance. Resin-carrying ducts are unique to members of the Boswellia family. Boswellia sacra Flueck is one of the 29 species in the genus Boswellia (Burseraceae) and has long been cultivated for its aromatic gums and resins for use as incense. In addition to the resins (60%-80% alcohol soluble), gums (15%-20% water soluble), and essential oil (5%-7%), other components, including polysaccharides and polymeric compounds, also exist in smaller amounts. Physiochemical analyses indicate that Boswellia resin oil is made up of 42.5% diterpenes, 13.1% monoterpenes, and 1% sesquiterpenes. Traditional medicine makes extensive use of frankincense for the treatment of stomach diseases, Alzheimer's disease, and hepatic illnesses. The bioactive chemicals present in frankincense, particularly boswellic acids, are plentiful. The current review examines various compounds present in different species of Boswellia, especially Boswellia sacra, along with their structure.

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.

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.

Appraisal terpenoids rich Boswellia carterri ethyl acetate extract in binary cyclodextrin oligomer nano complex for improving respiratory distress

Boswellia carterii (BC) resins plants have a long historical background as a treatment for inflammation, as indicated by information originating from multiple countries. Twenty-seven diterpenoids have been identified in ethyl acetate and total methanol BC, comprising seventeen boscartins of the cembrane-type diterpenoids and ten boscartols of the prenylaromadendrane-type diterpenoids. Moreover, twenty-one known triterpenoids have also been found, encompassing nine tirucallane-type, six ursane-type, four oleanane-type, and two lupane-type. The cembrane-type diterpenoids hold a significant position in pharmaceutical chemistry and related industries due to their captivating biological characteristics and promising pharmacological potentials. Extraction of BC, creation and assessment of nano sponges loaded with either B. carterii plant extract or DEX, are the subjects of our current investigation. With the use of ultrasound-assisted synthesis, nano sponges were produced. The entrapment efficiency (EE%) of medications in nano sponges was examined using spectrophotometry. Nano sponges were characterized using a number of methods. Within nano sponges, the EE% of medicines varied between 98.52 ± 0.07 and 99.64 ± 1.40%. The nano sponges' particle sizes varied from 105.9 ± 15.9 to 166.8 ± 26.3 nm. Drugs released from nano sponges using the Korsmeyer-Peppas concept. In respiratory distressed rats, the effects of BC plant extract, DEX salt and their nano formulations (D1, D5, P1 and P1), were tested. Treatment significantly reduced ICAM-1, LTB4, and ILβ 4 levels and improved histopathologic profiles, when compared to the positive control group. Boswellia extract and its nano sponge formulation P1 showed promising therapeutic effects. The effect of P1 may be due to synergism between both the extract and the formulation. This effect was achieved by blocking both ICAM-1 and LTB4 pathways, therefore counteracting the effects of talc powder.

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.

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.

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.

Populusene A, an Anti-inflammatory Diterpenoid with a Bicyclo[8,4,1]pentadecane Scaffold from Populus euphratica Resins

Populusene A (1), an unprecedented carbon skeleton featuring a bicyclo[8.4.1]pentadecane nucleus and a bridgehead double bond (anti-Bredt system), and populusin A (2), a cembrane-type diterpenoid possessing an uncommon dioxatricyclo[6.6.1.12,5]hexadecane scaffold, were isolated from the exudates of Populus euphratica. Their structures were elucidated by spectroscopic, computational, and crystallographic methods. A plausible biosynthetic route for 1 and 2 was proposed. Compounds 1 and 2 were found to significantly inhibit the production of TNF-α and IL-6 and the expression of iNOS, COX-2, and p-NF-κB at 125 nM in RAW264.7 cells.

Cembranoids from Boswellia species

Frankincense of Boswellia species has long been used in traditional medicines, mainly for its interesting anti-inflammatory and anti-depressant properties of its di- and triterpenes. Boswellic acids (triterpenes) and cembranoids (diterpenes) are the major constituents of frankincense from all reported species which are responsible for the overall biological activity of frankincense. Boswellic acids have been thoroughly investigated for decades but cembranoids have attracted considerable attention only recently, and a good number of publications have highlighted the important role of these 14-membered rings in contributing to the superior anti-inflammatory activity of the sacred resin. Partial and total syntheses of some cembranoids from frankincense have been reported. Their therapeutic potential is not limited to the well proven anti-inflammatory activity but also to their recently reported anti-depressant properties. There is a considerable number of publications in the field of cembranoids of Boswellia species where we feel a review in this topic will be of interest to the readership of Phytochemistry. In this article we have discussed the chemistry (isolation and chemical structures as well as synthetic studies), biogenesis and bioactivity of the reported cembranoids of Boswellia species. The structural discrepancies due to wrongly assigned structures of some cembranoids have been highlighted and corrected. We have covered the related literature up to the end of 2020.

Prenylaromadendrane-type diterpenoids from the gum resin of Boswellia sacra flueck and their cytotoxic effects

Two new prenylaromadendrane-type diterpenoids, and three known analogues, were isolated from the ethanol extract of the gum resin of B. sacra Flueck. The structures of the new compounds were elucidated using 1 D and 2 D NMR spectroscopic analyses, mass spectrometric data, circular dichroism spectra, and comparison with the other compounds in the literature. One diterpenoid represents the first example of an acetoxyl-substituted prenylaromadendranoid in frankincense. All compounds exhibited notable cytotoxicity against human malignant glioma (U87-MG) cell line, with inhibitory rates exceeding that of the positive control 5-fluorouracil. However, nitric oxide inhibition induced by lipopolysaccarides was not observed in primary mouse peritoneal macrophages.

Sacraoxides A-G, Bioactive Cembranoids from Gum Resin of Boswellia sacra

Seven undescribed cembranoids, sacraoxides A–G (1, 3–8) were isolated from the gum resin of Boswellia sacra. Their structures were elucidated by extensive physicochemical and spectroscopic analysis, as well as ECD calculation, modified Mosher’s method and X-ray diffraction crystallography. Compounds 6 and 7 exhibited inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in RAW264.7 cells with IC₅₀ values of 24.9 ± 1.7 and 36.4 ± 2.9 μM.