Sesquiterpenes and Sesquiterpene Derivatives from Ferula: Their Chemical Structures, Biosynthetic Pathways, and Biological Properties

Ferula is a genus of flowering plants known for its edible and medicinal properties. Since ancient times, many species of Ferula have been used in traditional medicine to treat various health issues across countries, such as digestive disorders, respiratory problems, and even as a remedy for headaches and toothaches. In addition, they are also used as a flavoring agent in various cuisines. As the main active ingredients in Ferula, sesquiterpenes and their derivatives, especially sesquiterpene coumarins, sesquiterpene phenylpropanoids, and sesquiterpene chromones, have attracted the attention of scientists due to the diversity of their chemical structures, as well as their extensive and promising biological properties, such as antioxidative, anti-inflammatory, antibacterial properties. However, there has not been a comprehensive review of sesquiterpenes and their derivatives from this plant. This review aims to provide an overview of the chemical structures, biosynthetic pathways, and biological properties of sesquiterpenes and sesquiterpene derivatives from Ferula, which may help guide future research directions and possible application methods for this valuable edible and medicinal plant.

Sesquiterpene Coumarin Ethers with Selective Cytotoxic Activities from the Roots of Ferula huber-morathii Peşmen (Apiaceae) and Unequivocal Determination of the Absolute Stereochemistry of Samarcandin

Ancient physicians frequently used the resin of Ferula species to treat cancer. Today, some folkloric recipes used for cancer treatment also contain the resin of Ferula species. The dichloromethane extract of the roots of Ferula huber-morathii exhibited cytotoxic activities against COLO 205 (colon), K-562 (lymphoblast), and MCF-7 (breast) cancer cell lines (IC₅₀ = 52 µg/mL, 72 µg/mL, and 20 µg/mL, respectively). Fifteen sesquiterpene coumarin ethers with cytotoxic activity were isolated from the dichloromethane extract of the roots of F. huber-morathii using bioactivity-directed isolation studies. Extensive spectroscopic analyses and chemical transformations have elucidated the structures of these sesquiterpene coumarin ethers as conferone (1), conferol (2), feselol (3), badrakemone (4), mogoltadone (5), farnesiferol A (6), farnesiferol A acetate (7), gummosin (8), ferukrin (9), ferukrin acetate (10), deacetylkellerin (11), kellerin (12), samarcandone (13), samarcandin (14), and samarcandin acetate (15). The absolute configuration of samarcandin (14) was unequivocally determined by the X-ray crystallographic analysis of the semi-synthetic (R)-MTPA ester of samarcandin (24). Conferol (2) and mogoltadone (5) were found to be the most potent cytotoxic compounds against all three cancer cell lines; furthermore, these compounds exhibit low cytotoxic activity against the non-cancerous human umbilical vein epithelial cells (HUVEC) cell line. Investigation of the biological activity mechanisms of mogoltadone (5) revealed that while suppressing the levels of Bcl-XL and procaspase-3 in the COLO 205 cancer cell line, it did not have a significant effect on the Bcl-XL, caspase-3, and β-catenin protein levels of the HUVEC cell line, which may explain the cytotoxic selectivity of mogoltadone (5) on cancer cell lines.

Effective Synthesis and Biological Evaluation of Functionalized 2,3-Dihydrofuro[3,2-c]coumarins via an Imidazole-Catalyzed Green Multicomponent Approach

For the first time, an eco-friendly and efficient one-pot green multicomponent approach has been described to synthesize functionalized trans-2,3-dihydrofuro[3,2-c]coumarins (DHFCs). In this synthesis, imidazole and water were used as the catalyst and solvent, respectively, under mild conditions. Applications of the developed catalytic process in a water medium revealed the outstanding activity, productivity, and broad functional group tolerance, affording a series of newly designed DHFC and derivatives in excellent yields (72-98%). Moreover, the human serum albumin (HSA) binding ability of the synthesized DHFC derivatives has been uncovered through the detailed in silico and in vitro-based structure-activity analysis. The ability to bind HSA, the most abundant serum protein, in the low micromolar ranges unequivocally reflects the suitable absorption, distribution, metabolism, and elimination profile of the synthesized compounds, which may further be envisaged for their therapeutic usage endeavors.

Spasmolytic, Gastroprotective and Antioxidant Activities of Dry Methanol Extract of Ferula heuffelii Underground Parts

Dry MeOH extract of Ferula heuffelii (Apiaceae) underground parts was tested for spasmolytic, gastroprotective and antioxidant activities. HPLC analysis revealed that chlorogenic acid (CGA; 34.6 mg/g) was its main constituent. Extract in vitro exhibited notable total antioxidant activity (FRAP value=1.0 μmol Fe²⁺ /mg), and scavenging of DPPH (SC₅₀ =62.5 μg/ml) and ^• OH radicals (49.5 % at 20 μg/ml in 2-deoxyribose assay). In vitro on isolated rat ileum, extract exhibited significant spasmolytic activity, i. e., it showed 124.6 % of maximal atropine effect on spontaneous contractions (at 100 μg/ml), and reduced spasmogenic effect of KCl (80 mm) to 44.4 % (at 60 μg/ml) and of highest applied concentration of ACh to 26.3 % (at 120 μg/ml). In parallel experiments, spasmolytic effect of CGA was also demonstrated. In acute EtOH-induced gastric ulceration model in rats, extract (100 mg/kg p.o.) showed significant gastroprotective effect (gastric damage score 0.50), similar to ranitidine (20 mg/kg p.o.). Obtained results showed that tested F. heuffelii polar extract represents new herbal preparation with potential use against some gastrointestinal complaints.

A multi-omics study of the anti-cancer effect of a ferulic acid derivative FA-30

The active ingredients of Traditional Chinese Medicine are an important source of bioactive molecules and play an important role in the research and development of innovative drugs.

Penisarins A and B, Sesquiterpene Coumarins Isolated from an Endophytic Penicillium sp

Penisarins A (1) and B (2), sesquiterpene coumarins with an unusual tricyclic sesquiterpene system, were isolated from endophytic Penicillium sp. KMU18029. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compound 2 showed significant cytotoxicities against two human cancer cell lines, HL-60 and SMMC-7721, with IC₅₀ values of 3.6 ± 0.2 and 3.7 ± 0.2 μM, respectively.

Translational role of natural coumarins and their derivatives as anticancer agents

Natural coumarins and their derivatives isolated from various plants or microorganisms have inherent antioxidant, antibacterial, antifungal, antiviral and anticancer properties among many biological activities. Some of these coumarins and their derivatives lead to self-programmed cancer cell death (apoptosis) via different mechanisms, which will be discussed. The link between bacterial and viral infections to cancer compels us to highlight fascinating reports from coumarin isolation from microorganisms; comment on the recent bioavailability studies of natural or derived coumarins; and discuss our perspectives with respect to bioisosterism in coumarins, p-glycoprotein inhibition and covalent modification, and bioprobes. Overall, this review hopes to stimulate and offer in particular medicinal chemists and the reader in general an outlook on natural coumarins and their derivatives with potential for cancer therapy.