Cleistanthane diterpenes from the seed of Caesalpinia sappan and their antiausterity activity against PANC-1 human pancreatic cancer cell line

Naturally Occurring Cleistanthane Diterpenoids and Their Biological Activities

Cleistanthane diterpenoids, an important class of active natural products, are characterized by a 6/6/6 tricycle system and contain a variety of functional groups. Studies have shown that cleistanthane diterpenoids are widespread in various higher plants and endophytic fungi and exhibit a wide range of biological activities. This review provides extensive coverage of naturally occurring cleistanthane diterpenoids discovered from 1973 to 2024 and sheds light on the sources, structures, biological effects, and primary molecular mechanisms of them and provides a useful reference for the further study and development of these compounds.

A new cassane diterpenoid from the seed of Caesalpinia sappan

In this study, a previously undescribed cassane diterpenoid, named caesalpinin JF (1), along with two known cassane diterpenoids caesanine C (2) and tomocinol B (3), was isolated from 95% EtOH extract of the seeds of Caesalpinia sappan Linn. Additionally, three known compounds including pulcherrin R (4), syringaresinol-4'-O-β-D-glucopyranoside (5) and kaempferol (6) were also identified. The structures of the isolated compounds were elucidated by comprehensive 1D and 2D NMR spectroscopic analyses. Additionally, electronic circular dichroism (ECD) calculation was used to identify the absolute structure of compound 1. Among the isolated compounds, compound 1 displayed a potent anti-neuroinflammation with an IC50 value of 9.87 ± 1.71 μM.

Naturally Occurring Norsteroids and Their Design and Pharmaceutical Application

The main focus of this review is to introduce readers to the fascinating class of lipid molecules known as norsteroids, exploring their distribution across various biotopes and their biological activities. The review provides an in-depth analysis of various modified steroids, including A, B, C, and D-norsteroids, each characterized by distinct structural alterations. These modifications, which range from the removal of specific methyl groups to changes in the steroid core, result in unique molecular architectures that significantly impact their biological activity and therapeutic potential. The discussion on A, B, C, and D-norsteroids sheds light on their unique configurations and how these structural modifications influence their pharmacological properties. The review also presents examples from natural sources that produce a diverse array of steroids with distinct structures, including the aforementioned A, B, C, and D-nor variants. These compounds are sourced from marine organisms like sponges, soft corals, and starfish, as well as terrestrial entities such as plants, fungi, and bacteria. The exploration of these steroids encompasses their biosynthesis, ecological significance, and potential medical applications, highlighting a crucial area of interest in pharmacology and natural product chemistry. The review emphasizes the importance of researching these steroids for drug development, particularly in addressing diseases where conventional medications are inadequate or for conditions lacking sufficient therapeutic options. Examples of norsteroid synthesis are provided to illustrate the practical applications of this research.

Turning weeds into feed: Ensiling Calotropis gigantea (Giant milkweed) reduces its toxicity and enhances its palatability for dairy cows

Calotropis gigantea (Giant milkweed, GM) has the potential to be utilized as a new feed additive for ruminants, however, the presence of unpalatable or toxic compounds decreases animal feed intake. This study aimed to valorize GM as a potential new feed resource through the chemical and microbial biotransformation of toxic compounds that will henceforth, make the plant palatable for cows. After GM's ensiling using fermentative bacteria, the plant was sampled for UHPLC-MS/MS to analyse the metabolomic changes. Illumina Miseq of the 16 S rRNA fragment genes and ITS1 were used to describe the microbial composition and structure colonizing GM silage and contributing to the biodegradation of toxic compounds. Microbial functions were predicted from metataxonomic data and KEGG pathways analysis. Eight Holstein dairy cows assigned in a cross-over design were supplemented with GM and GM silage to evaluate palatability and effects on milk yield and milk protein. Cows were fed their typical diet prior to the experiment (positive control). After ensiling, 23 flavonoids, 47 amino acids and derivatives increased, while the other 14 flavonoids, 9 amino acids and derivatives decreased, indicating active metabolism during the GM ensiling process. Lactobacillus buchneri, Bacteroides ovatus, and Megasphaera elsdenii were specific to ensiled GM and correlated to functional plant metabolites, while Sphingomonas paucimobilis and Staphylococcus saprophyticus were specific to non-ensiled GM and correlated to the toxic metabolite 5-hydroxymethylfurfural."Xenobiotics biodegradation and metabolism", "cancer overview" and "neurodegenerative disease" were the highly expressed microbial KEGG pathways in non-ensiled GM. Non-ensiled GM is unpalatable for cows and drastically reduces the animal's feed intake, whereas ensiled GM does not reduce feed intake, milk yield and milk protein. This study provides essential information for sustainable animal production by valorizing GM as a new feed additive.

Bioactive compounds from Vellozia pyrantha A.A.Conc: A metabolomics and multivariate statistical analysis approach

The chemical composition of V. pyrantha resin (VpR) and fractions (VpFr1-7 and VpWS) were assessed by LC-MS and NMR. Twenty-eight metabolites were identified, including 16 diterpenoids, seven nor-diterpenoids, one fatty acid, one bis-diterpenoid, one steroid, one flavonoid, and one triterpenoid. The pharmacological potential of VpR, VpFr1-7, and isolated compounds was assessed by determining their antioxidant, antimicrobial, and cytotoxic activities. VpFr4 (IC50 = 205.48 ± 3.37 μg.mL-1) had the highest antioxidant activity, whereas VpFr6 (IC50 = 842.79 ± 10.23 μg.mL-1) had the lowest. The resin was only active against Staphylococcus aureus (MIC 62.5 μg.mL-1) and Salmonella choleraesius (MIC and MFC 500 μg.mL-1), but fractions were enriched with antibacterial compounds. V. pyrantha resin and fractions showed great cytotoxic activity against HCT116 (IC50 = 20.08 μg.mL-1), HepG2 (IC50 = 20.50 μg.mL-1), and B16-F10 (12.17 μg.mL-1) cell lines. Multivariate statistical analysis was used as a powerful tool to pinpoint possible metabolites responsible for the observed activities.

Isolation and structure elucidation of two new cassane derivatives from the seed kernels of Caesalpinia sinensis

Two new cassane-type derivatives (1-2), together with three known compounds (3-5), were isolated from the seed kernels of Caesalpinia sinensis. Their structures were elucidated on the basis of interpretation of comprehensive spectroscopic data, including HRESIMS and 1D/2D NMR spectroscopy, and the absolute configuration were established by means of ECD calculation. Compound 2, possessing a 16-degradative cassane skeleton, was rarely encountered in cassane diterpenoids isolated from the genus Caesalpinia. All compounds were evaluated for their anti-inflammatory activities against the overproduction of NO in LPS-stimulated RAW 264.7 macrophages, and compounds 1-5 could inhibit production of NO at the concentration of 50 μM.

Network Pharmacology Study to Reveal the Potentiality of a Methanol Extract of Caesalpinia sappan L. Wood against Type-2 Diabetes Mellitus

Caesalpinia sappan L. (CS) is widely used to treat diabetic complications in south-east Asia, specifically in traditional Chinese medicine. This study intends to explain the molecular mechanism of how chemical constituents of CS interrelate with different signaling pathways and receptors involved in T2DM. GC-MS was employed to identify the chemical compounds from the methanol extract of CS wood (MECSW). Lipinski's rule of five was applied, and 33 bioactive constituents have been screened from the CS extract. After that, 124 common targets and 26 compounds associated with T2DM were identified by mining several public databases. Protein-protein interactions and compound-target network were constructed using the STRING database and Cytoscape tool. Protein-protein interactions were identified in 121 interconnected nodes active in T2DM and peroxisome proliferator-activated receptor gamma (PPARG) as key target receptors. Furthermore, pathway compound target (PCT) analysis using the merger algorithm plugin of Cytoscape revealed 121 nodes from common T2DM targets, 33 nodes from MECSW compounds and 9 nodes of the KEGG pathway. Moreover, network topology analysis determined "Fisetin tetramethyl ether" as the key chemical compound. The DAVID online tool determined seven signaling receptors, among which PPARG was found most significant in T2DM progression. Gene ontology and KEGG pathway analysis implied the involvement of nine pathways, and the peroxisome proliferator-activated receptor (PPAR) pathway was selected as the hub signaling pathway. Finally, molecular docking and quantum chemistry analysis confirmed the strong binding affinity and reactive chemical nature of fisetin tetramethyl ether with target receptors exceeding that of the conventional drug (metformin), PPARs agonist (rosiglitazone) and co-crystallized ligands, indicating that fisetin could be a potential drug of choice in T2DM management. This study depicts the interrelationship of the bioactive compounds of MECSW with the T2DM-associated signaling pathways and target receptors. It also proposes a more pharmaceutically effective substance, fisetin tetramethyl ether, over the standard drug that activates PPARG protein in the PPAR signaling pathway of T2DM.

Anticancer activity of Caesalpinia sappan by downregulating mitochondrial genes in A549 lung cancer cell line

Background: The standardization and mechanism of action of  Caesalpinia sappan as an anticancer agent are still lacking. This study aimed to understand the mechanism of action of  C,sappan extract as an anticancer agent. Methods: This study was conducted using the A549 lung cancer cell line to understand the mechanism of action of  C. sappan extract as an anticancer agent. The cytotoxicity activity, cell cycle progression, apoptosis, protein-related apoptosis (i.e., BCL-2and BAX protein) assays, and RNA sequencing were performed level were measured. Moreover, the antioxidant activity, total flavonoids, and phenolics of C.sappan were also assessed. Results: C.sappan has strong antioxidant activity (22.14 ± 0.93 ppm) total flavonoid content of (529.3 ± 4.56 mgQE/g), and phenolics content of (923.37 ± 5 mgGAE/g). The C.sappan ethanol extract inhibited cancer cell growth and arrested at G0/G1 phase of cell cycle, inducing apoptosis by increasing BAX/BCL-2 protein ratio in A549 lung cancer cell line. Furthermore, results from RNA sequencing analysis showed that C.sappan ethanol extract caused downregulation of genes acting on mitochondrial function including adenosine triphosphate (ATP) production and respiration. Conclusions: This study demonstrated that C.sappan has the ability to inhibit cancer cell growth by inducing apoptosis and mitochondrial dysfunction in A549 cells.

A pharmacognostic approach for mitigating pancreatic cancer: emphasis on herbal extracts and phytoconstituents

Background

Pancreatic cancer is studied as one of the most lethal cancers with currently no control of its lethality, mainly due to its late diagnosis and lack of foolproof treatment processes. Despite continuous efforts being made in looking for therapies to deal with cancer, it keeps on being a labyrinth for the researchers. Efforts like discovering new treatment options, repurposing existing drugs, are continuously made to deal with this cancer.

Main body

With the urge to get answers and the fact that nature has all roots of therapeutics, efforts are made in the direction of finding those answers for providing ministrations for pancreatic cancer from plant products. Plant products are used as treatment options either directly in the form of extracts or an alternative to them is individual phytochemicals that are either isolated from the plants or are commercially synthesized for various purposes. In this review, we put forward such pharmacognostic initiatives made in combating pancreatic cancer, focusing mainly on plant extracts and various phytochemicals; along with the mechanisms which they triggered to fulfill the need for cytotoxicity to pancreatic cancer cells (in vitro and in vivo).

Conclusion

This study will thus provide insights into new combination therapy that can be used and also give a clue on which plant product and phytoconstituent can be used in dealing with pancreatic cancer.

Graphical abstract

Panduratins Q-Y, dimeric metabolites from Boesenbergia rotunda and their antiausterity activities against the PANC-1 human pancreatic cancer cell line

A methanolic extract of the rhizomes of Boesenbergia rotunda showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient deficiency conditions with a PC₅₀ value of 6.6 μg/mL. Bioactivity-guided phytochemical investigation of the rhizomes of B. rotunda led to the isolation of nine undescribed dimeric metabolites, panduratins Q-Y. Their structures were elucidated based on NMR, MS, and ECD spectroscopic data interpretation. Panduratins Q-S and U-W exhibited potent cytotoxicity towards PANC-1 cell line with the PC₅₀ values ranging from 0.8 to 6.3 μM. Panduratin W, which possessed a cyclohexenylchalcone-linked flavanone skeleton, showed the most cytotoxicity with a PC₅₀ value of 0.8 μM under nutrient-deprived medium.

Two new cassane-type diterpenoids from the seeds of Caesalpinia sappan

A new cassane diterpenoid, caesappine A (1), and a new natural cassane diterpenoid, caesappine B (2) were isolated from the seeds of Caesalpinia sappan. The new structures of compounds 1 and 2 were elucidated by analysing their 1D NMR, 2D NMR and HR-ESI-MS spectra. Compounds 1 and 2 were evaluated for the cytotoxic activities on Hela and HepG-2 human cancer cell lines.

A new cytotoxic cardenolide from the roots of Calotropis gigantea

Bioactivity-guided isolation of the CHCl₃-soluble fraction of the roots of Calotropis gigantea was carried out to obtain a new cardenolide glycoside, caloside G. Its absolute structure was elucidated based on NMR and ECD spectroscopic data interpretation. Caloside G showed noteworthy cytotoxicity against the PANC-1 human pancreatic and HeLa human cervical carcinoma cell lines, with the submicromolar IC₅₀ values of 0.038 and 0.09 µM, respectively.

Synthesis of ent-Cleistanthane Diterpenoid Spruceanol: Construction of an Aromatic C Ring via Lewis Acid-Controlled Regioselective Diels-Alder Cycloaddition

The first synthesis of ent-cleistanthane-type diterpenoid spruceanol with significant anticancer activity is described. A chiral pool approach was employed with a linear sequence of 13 steps beginning from readily available and inexpensive andrographolide. The approach features the construction of an aromatic ring with hydroxyl and methyl groups at C-12 and C-13 of the target compound, respectively, via Lewis acid-controlled regioselective Diels-Alder cycloaddition and the regioselective removal of the primary hydroxyl group of the Diels-Alder adduct.

Calosides A-F, Cardenolides from Calotropis gigantea and Their Cytotoxic Activity

Phytochemical analysis of the roots of Calotropis gigantea led to the isolation of six new cardenolide glycosides, calosides A-F (1-6), and five known cardenolides (7-11). The structures of 1-6 were elucidated based on NMR and ECD spectroscopic data interpretation. Caloside D (4) is the first naturally occurring example of a cardenolide containing a C-8/C-19 oxygen bridge. In turn, calosides E (5) and F (6) represent the first naturally occurring 3-epi-cannogenol diglycosides having potent cytotoxicity against the PANC-1 cell line (IC₅₀, 0.081 and 0.070 μM, respectively) and HeLa (IC₅₀, both 0.17 μM) cells, under normoglycemic conditions.

Ancistrolikokine E3, a 5,8'-Coupled Naphthylisoquinoline Alkaloid, Eliminates the Tolerance of Cancer Cells to Nutrition Starvation by Inhibition of the Akt/mTOR/Autophagy Signaling Pathway

PANC-1 human pancreatic cancer cells are characterized by their ability to proliferate aggressively under hypovascular and hypoxic conditions in the tumor microenvironment, displaying a remarkable tolerance to nutrition starvation. The antiausterity strategy is a new approach in anticancer drug discovery aiming at the identification of potent agents that inhibit preferentially the survival of tumor cells during a limited supply of nutrients and oxygen. The new 5,8'-coupled naphthyldihydroisoquinoline alkaloid ancistrolikokine E₃ (4), isolated from the Congolese liana Ancistrocladus likoko, showed potent preferential cytotoxicity against PANC-1 cells under nutrient-deprived conditions, with a PC₅₀ value of 2.5 μM, without exhibiting toxicity in normal, nutrient-rich medium. The compound was found to induce dramatic alterations in cell morphology, leading to cell death. Moreover, it inhibited significantly PANC-1 cell migration and colony formation in a concentration-dependent manner. This study on 4 provides the first live evidence of the effect of a naphthyldihydroisoquinoline alkaloid against PANC-1 cells in nutrient-deprived medium. Mechanistic investigations conducted suggest that compound 4 is a potent inhibitor of the activation of the Akt/mTOR pathway. Furthermore, it inhibited the expression levels of the key autophagy regulators Atg5, Atg12, Beclin-1, LC3-I, and LC3-II. The results demonstrated that ancistrolikokine E₃ (4) is a potent early-stage inhibitor of the autophagy pathway in PANC-1 human pancreatic cancer cells. Ancistrolikokine E₃ (4) and related naphthylisoquinoline alkaloids are promising potential lead compounds for anticancer drug development based on the antiausterity strategy.

New isocoumarins, naphthoquinones, and a cleistanthane-type diterpene from Nectria pseudotrichia 120-1NP

Four new compounds, namely, nectriapyrones A (2) and B (3), nectriaquinone B (5), and zythiostromic acid C (8), were isolated from the brown rice culture of Nectria pseudotrichia 120-1NP together with four known compounds (1, 4, 6, and 7). To the best of our knowledge, this is the first report of 4 from a natural source. Their structures were determined on the basis of 1D/2D-NMR spectroscopy and HRESITOFMS data. In addition, the absolute configuration of secondary alcohols in 8 were determined using modified Mosher's ester method. All isolated compounds were evaluated for their antimicrobials activity, phytotoxicity, and cytotoxicity.

Chemical Constituents of Propolis from Vietnamese Trigona minor and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

The ethanol extract of propolis from the Vietnamese stingless bee Trigona minor possessed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells in nutrient-deprived medium, with a PC₅₀ value of 14.0 μg/mL. Chemical investigation of this extract led to the isolation of 15 cycloartane-type triterpenoids, including five new compounds (1-5), and a lanostane-type triterpenoid. The structures of the new compounds were elucidated on the basis of NMR spectroscopic analysis. Among the isolated compounds, 23-hydroxyisomangiferolic acid B (5) and 27-hydroxyisomangiferolic acid (13) exhibited the most potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 4.3 and 3.7 μM, respectively.

Diterpenes and Their Derivatives as Potential Anticancer Agents

As therapeutic tools, diterpenes and their derivatives have gained much attention of the medicinal scientists nowadays. It is due to their pledging and important biological activities. This review congregates the anticancer diterpenes. For this, a search was made with selected keywords in PubMed, Science Direct, Web of Science, Scopus, The American Chemical Society and miscellaneous databases from January 2012 to January 2017 for the published articles. A total 28, 789 published articles were seen. Among them, 240 were included in this study. More than 250 important anticancer diterpenes and their derivatives were seen in the databases, acting in the different pathways. Some of them are already under clinical trials, while others are in the nonclinical and/or pre-clinical trials. In conclusion, diterpenes may be one of the lead molecules in the treatment of cancer. Copyright © 2017 John Wiley & Sons, Ltd.

Constituents of the Rhizomes of Boesenbergia pandurata and Their Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Line

Human pancreatic cancer cell lines have a remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions represents a novel antiausterity strategy in anticancer drug discovery. In this investigation, a methanol extract of the rhizomes of Boesenbergia pandurata showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC₅₀ value of 6.6 μg/mL. Phytochemical investigation of this extract led to the isolation of 15 compounds, including eight new cyclohexene chalcones (1-8). The structures of the new compounds were elucidated by NMR spectroscopic data analysis. Among the isolated compounds obtained, isopanduratin A1 (14) and nicolaioidesin C (15) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 1.0 and 0.84 μM, respectively.

Chemical Constituents of Mangifera indica and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cell lines such as PANC-1 have an altered metabolism, enabiling them to tolerate and survive under extreme conditions of nutrient starvation. The search for candidates that inhibit their viability during nutrition starvation represents a novel antiausterity strategy in anticancer drug discovery. A methanol extract of the bark of Mangifera indica was found to inhibit the survival of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions with a PC50 value of 15.5 μg/mL, without apparent toxicity, in normal nutrient-rich conditions. Chemical investigation on this bioactive extract led to the isolation of 19 compounds (1-19), including two new cycloartane-type triterpenes, mangiferolate A (1) and mangiferolate B (2). The structures of 1 and 2 were determined by NMR spectroscopic analysis. Among the isolated compounds, mangiferolate B (2) and isoambolic acid (12) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under the nutrition-deprived condition with PC50 values of 11.0 and 4.8 μM, respectively.

Therapeutic Potential of Essential Oils Focusing on Diterpenes

Among all plant derivates, essential oils (EOs) have gained the attention of many scientists. Diterpenes, a family of components present in some EO, are becoming a milestone in the EOs world. The goal of this review is to describe a scenario of diterpenes taking into health-consumption deportment. Previous studies revealed that diterpenes have antioxidant, antimicrobial, antiviral, antiprotozoal, cytotoxic, anticancer, antigenotoxic, antimutagenic, chemopreventive, antiinflammatory, antinociceptive, immunostimulatory, organoprotective, antidiabetic, lipid-lowering, antiallergic, antiplatelet, antithrombotic, and antitoxin activities. In conclusion, diterpenes may be an immense featuring concern in pharmaceutical consumption from a drug discovery point of view. Copyright © 2016 John Wiley & Sons, Ltd.

A New Cassane-type Diterpene from the Seed of Caesalpinia Sappan

Phytochemical investigation of the CH2C12 extract of the Vietnamese medicinal plant Caesalpinia sappan Linn resulted in the isolation of a new cassane-type diterpene named tomocin I (1). Its chemical structure was determined by NMR spectroscopic and mass spectrometric analysis.

Cassane diterpenes from the seed kernels of Caesalpinia sappan

Eight structurally diverse cassane diterpenes named tomocins A-H were isolated from the seed kernels of Vietnamese Caesalpinia sappan Linn. Their structures were determined by extensive NMR and CD spectroscopic analysis. Among the isolated compounds, tomocin A, phanginin A, F, and H exhibited mild preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived condition without causing toxicity in normal nutrient-rich conditions.

Cytotoxic constituents from the seeds of Vietnamese Caesalpinia sappan

CONTEXT

Caesalpinia sappan Linn. (Leguminosae) has been used in folk medicines for the treatment of many diseases. The heartwood of this plant contains various phenolic components with interesting biological applications; however, the chemical and biological potentials of the seed of this plant have not been fully explored.

OBJECTIVE

This study identified the cytotoxic activity of compounds from the seeds of C. sappan.

MATERIALS AND METHODS

The methanol extract of the seed of C. sappan was suspended in H2O and then partitioned with CH2Cl2, EtOAc, and n-BuOH, successively. Diterpenoid compounds were isolated from the CH2Cl2-soluble fraction by silica gel column chromatography methods using organic solvents. The compound structures were determined by detailed analysis of NMR and MS spectral data. Cytotoxic activity was measured using a modified MTT assay against HL-60, HeLa, MCF-7, and LLC cancer cells. The activation of caspase-3 enzyme and western blotting assay were performed to confirm inhibitory mechanism of active compound.

RESULTS

Five cassane-type diterpenoids were isolated and identified as phanginin I (1), phaginin A (2), phanginin D (3), phanginin H (4), and phanginin J (5). Compounds 1-4 showed effective inhibition against HL-60 cells with the IC50 values of 16.4 ± 1.5, 19.2 ± 2.0, 11.7 ± 1.6, and 22.5 ± 5.1 μM. Compounds 1-3 exhibited cytotoxic activity against HeLa cells with the IC50 values of 28.1 ± 3.6, 37.2 ± 3.4, and 22.7 ± 2.8 μM. Treatment of HL-60 cell lines with various concentrations of 3 (0-30 μM) resulted in the growth inhibition and induction of apoptosis.

CONCLUSION

These findings demonstrate that compound 3 (phanginin D) is one of the main active components of the seed of C. sappan activating caspases-3 which contribute to apoptotic cell death.