Anti-inflammatory chromone alkaloids and glycoside from Dysoxylum binectariferum

New cycloartane triterpenoids from Dysoxylum malabaricum and their cytotoxic evaluation

The cytotoxic dichloromethane-methanol bark extract of Dysoxylum malabaricum was subjected to bioassay-guided fractionation, followed by systematic dereplication to focus on the identification of new compounds. From the bark of Dysoxylum malabaricum, two new cycloartane-type triterpenoids were isolated in addition to two previously known triterpenoids. The structures and absolute configurations of the isolated compounds were elucidated unambiguously via NMR, HRESIMS data, and electronic circular dichroism calculations. The isolated compounds were tested for their cytotoxic potential against the panel of breast, lung, and hypopharynx cancer cell lines and displayed notable cytotoxicity against breast cancer cell lines. Compound 3 exhibited the most potent cytotoxic effect with an IC50 14 µM against MCF-7 cell lines and induced cell cycle arrest. Through western blot and cell cycle analysis, it was revealed that compound 3 halts the G0/G1 phase of the cell cycle by inhibiting CDC20 and CDC25 enzymes.

Sesquiterpenoids from Meliaceae Family and Their Biological Activities

Sesquiterpenoids, an important class of natural products possessing three isoprene-derived units, are widely distributed across plants and have a variety of biological activities. All sesquiterpenoids are derived from farnesyl pyrophosphate (FPP), a biosynthesis precursor that can form various carbon skeletons. In order to provide a reference for further research and development of these compounds, this review focused on the increasing number of isolated and volatile sesquiterpenoids found to be produced by plants of the Meliaceae family between 1968 and 2023. The related articles were collected from SciFinder, Google Scholar, and PubMed. According to a literature review, several studies were started for more than 55 years on the plant's stem barks, twigs, leaves, flowers, seeds, and pericarps, where approximately 413 sesquiterpenoid compounds from several groups such as eudesmane, aromadendrane, cadinane, guaiane, bisabolane, furanoeremophilane, humulene, germacrane, and oppositane-type were isolated and identified with some minor products. Additionally, the hypothetical route of sesquiterpenoids biosynthesis from this family was identified, and eudesmane-type was reported to be 27% of the total compounds. The antimicrobial, antidiabetic, antioxidant, antiplasmodial, antiviral, and cytotoxic activities of the isolated compounds and major volatile sesquiterpenoids constituent on essential oil were also evaluated. The result showed the fundamental of using the sesquiterpenoid compounds from the Meliaceae family in traditional medicine and the discovery of new drugs.

Orally bioavailable styryl derivative of rohitukine-N-oxide inhibits CDK9/T1 and the growth of pancreatic cancer cells

The chromone alkaloid is one of the classical pharmacophores for cyclin-dependent kinases (CDKs) and represents the first CDK inhibitor to reach clinical trials. Rohitukine (1), a chromone alkaloid isolated from Dysoxylum binectariferum inspired the discovery of several clinical candidates. The N-oxide derivative of rohitukine occurs naturally, with no reports on its biological activity. Herein, we report isolation, biological evaluation, and synthetic modification of rohitukine N-oxide for CDK9/T1 inhibition and antiproliferative activity in cancer cells. Rohitukine N-oxide (2) inhibits CDK9/T1 (IC₅₀ 7.6 μM) and shows antiproliferative activity in the colon and pancreatic cancer cells. The chloro-substituted styryl derivatives, 2b, and 2l, inhibit CDK9/T1 with IC₅₀ values of 0.17 and 0.15 μM, respectively. These derivatives display cellular antiproliferative activity in HCT 116 (colon) and MIA PaCa-2 (pancreatic) cancer cells with GI₅₀ values of 2.5-9.7 μM with excellent selectivity over HEK293 (embryonic kidney) cells. Both analogs induce cell death in MIA PaCa-2 cells via inducing intracellular ROS production, reducing mitochondrial membrane potential, and inducing apoptosis. These analogs are metabolically stable in liver microsomes and have a decent oral pharmacokinetics in BALB/c mice. The molecular modeling studies indicated their strong binding at the ATP-binding site of CDK7/H and CDK9/T1.

Rohitukine content across the geographical distribution of Dysoxylum binectariferum Hook F. and its natural derivatives as potential sources of CDK inhibitors

Dysoxylum binectariferum is an important medicinal plant distributed in the Western Ghats of India. The species has gained international importance for its anticancer component, rohitukine, a chromone alkaloid. Flavopiridol, P-276-00 and IIIM-290 are the derivatives of rohitukine in clinical trials against a wide range of cancers. Flavopiridol was recently approved as an orphan drug for chronic lymphocytic leukemia treatment. In this study, we report the isolation and characterization of rohitukine from the bark of D. binectariferum. Further, rohitukine was estimated across the Western-Ghats and the North-East regions of India. Additionally, D. binectariferum is also reported (∼45 compounds) to produce many natural derivatives of rohitukine and terpenoids, which were investigated in-silico to reveal promising CDK inhibitors. The metabolite fingerprinting of tissues of D. binectariferum was studied using HPTLC and FTIR. The distribution of major chromone alkaloid rohitukine was estimated by HPLC. Further, the pharmacological potential of D. binectariferum compounds was evaluated in-silico by discovering the potential protein targets, molecular docking, ADMET analysis and MD simulation. The isolation of rohitukine has yielded 0.6% from the bark of D. binectariferum. A higher percent of rohitukine was found in the Jog populations (0.58% & 1.28%: leaf & bark), whereas least was observed in the Phasighat population (∼0.06%: both leaf & bark). Across the geographic regions, a higher percent of rohitukine was found in the Central-southern Western Ghats, whereas lower in the northern parts of the Western Ghats and Northeast regions. The leaves produce a considerably higher percent of rohitukine and could be used as a sustainable source of rohitukine. The rohitukine analogues, along with other chromone alkaloids of D. binecatariferum were found to be more interactive with the "kinases" family of proteins, majorly "Serine/threonine-protein kinase PFTAIRE-2" (CDK15) with high confidence level (0.94-0.98). The molecular docking of these chromone alkaloids found a strong binding energy with six CDKs (-3.1 to -10.6 kcal/mol) along with a promising ADMET profile. In addition, molecular dynamic simulation found that the rohitukine complexes are virtually constant with CDK-1, 2, 9 and 15, which is substantiated with MM-PBSA free energy calculations. The chromone alkaloids, majorly rohitukine and its analogues were closely clustered with flavopiridol, P-276-00 and IIIM-290 along with other chrotacumines in the chemical phylogeny. In conclusion, D. binectariferum is a rich source of chromone alkaloids, which could lead to the discovery of more potential scaffolding for CDK inhibitors as anticancer drugs.

Two new cycloartane type triterpenes from Dysoxyllum binectariferum

Dysoxyllum binectariferum is an important medicinal plant known for various biological activities like anti-inflammatory, CNS depressants, contraceptive, analgesic, immunomodulatory, antimalarial, antifeedant, leishmanicidal and antiviral. It is a rich source of rohitukine, a basic skeleton of flavopiridol. Phytochemical investigation of chloroform extracts of Dysoxyllum binectariferum leaves, lead to the isolation of beddomeilactone (1) and two new cycloartane type triterpenoids beddomeilactol (2) and binectarilactone-A (3) with modified A ring. Compounds were assessed for their in-vitro α-glucosidase inhibitory activity. Compound 1 was found to be most potent, showing IC50 of 17.99 ± 0.26 µg/ml which is comparable to the positive control acarbose.

New Chromones from Bouvardia ternifolia (Cav.) Schltdl with Anti-Inflammatory and Immunomodulatory Activity

The extract, fractions, and compounds of the Bouvardia ternifolia root were evaluated as an antiarthritic using a complete Freund's adjuvant (CFA) model in mice and NF-κB inhibition in RAW 264.7 macrophages. Four active compounds, including two new compounds, ternifoliol and ternifolial, were isolated by open column chromatography and identified by spectroscopic and spectrometric techniques, resulting in benzochromone-like structures with aromatic rings and hydroxyl groups, which could be responsible for the anti-inflammatory activity and inhibitory NF-κB. Changes in the joint cytokine profile monitored the antiarthritic effect. A decrement was observed in the local concentration of the following cytokines with different treatments: IL-17 by 64% and 70.3% with the aqueous extract (BtAq), ethyl acetate extract (BtAcOEt), and M3 fraction; interleukin-1 beta (IL-1β) by 10.2% and 15.7% with BtAq and the M4 fraction, respectively; IL-6 with M1, M2, M3, and M4 between 42% and 64%; necrosis factor-alpha (TNF-α) by 60.9% with M4. Conversely, the anti-inflammatory cytokine interleukin-10 (IL-10) increased between 94% and 99% with M1, M2, M3, and M4. Kidney IL-6 decreased with BtAq, M1, M2, M3, and M4 between 68.9% and 85.8%. TNF-α decreased with BtAcOEt, BtAq, M1, M2, and M4 between 34% and 80.2%. The NF-κB pathway was inhibited with BtAcOEt (90.1%), M1 (85%), M2 (93.5%), M3 (84.5%), M4 (90.3%), ternifoliol (75.6%), bouvardin (20.4%), and scopoletin (89%). We conclude that B. ternifolia modulated the inflammatory response at the joint and kidney levels and the NF-κB pathway.

Aqueous extract of bay leaf (Laurus nobilis) ameliorates testicular toxicity induced by aluminum chloride in rats

Background and Aim

Human exposure to aluminum is inevitable, and one of the most adverse health effects of aluminum is a decrease in male fertility rates. Therefore, this study investigated the ameliorative effects of an aqueous extract from Laurus nobilis-bay leaf (BL) on aluminum chloride (AlCl₃)-induced testicular toxicity in rats.

Materials and Methods

Twenty-four Wistar rats were divided into four groups (n = 6, each group): The control (group 1) received normal saline; Group 2 animals were intraperitoneally administered with 30 mg/kg body weight (BW) AlCl₃; and Groups 3 and 4 were co-administered AlCl₃ with 125 or 250 mg/kg BW of BL extract, respectively, for 21 days. Testes, epididymis, and blood samples were collected. Testicular plasma enzyme activity was measured using a spectrophotometric assay, while concentrations of inflammatory biomarkers were determined using enzyme-linked immunosorbent assay kits.

Results

There was a significant increase (p < 0.05) in testicular enzyme activity in the group treated with AlCl₃. However, there was no significant (p > 0.05) difference in testicular enzyme activity in groups co-administered AlCl₃ and BL extract as compared with that in control. There was a significant (p < 0.05) increase in testicular nitrite concentration in the AlCl₃-treated group, whereas the administration of BL extract significantly (p < 0.05) decreased nitrite concentration in Groups 3 and 4. Furthermore, the administration of BL extracts increased sperm count and improved the morphology of the testes in AlCl₃-treated rats. Flavonoids, phenolic compounds, alkaloids, tannin, glycosides, saponin, anthraquinones, and steroids were identified in BL extract, with alkaloids and glycosides being the most abundant.

Conclusion

Aqueous extract from BL ameliorated the toxic effect of AlCl₃ and exhibited anti-inflammatory properties by inhibiting nitrite production while improving sperm count and morphology in AlCl₃-treated rats. The bioactivity of the extract may be attributed to the presence of a wide range of phytochemicals. Therefore, BL aqueous extract could be a promising source of novel compounds with male fertility-promoting and anti-inflammatory properties.

Naturally Occurring Chromone Glycosides: Sources, Bioactivities, and Spectroscopic Features

Chromone glycosides comprise an important group of secondary metabolites. They are widely distributed in plants and, to a lesser extent, in fungi and bacteria. Significant biological activities, including antiviral, anti-inflammatory, antitumor, antimicrobial, etc., have been discovered for chromone glycosides, suggesting their potential as drug leads. This review compiles 192 naturally occurring chromone glycosides along with their sources, classification, biological activities, and spectroscopic features. Detailed biosynthetic pathways and chemotaxonomic studies are also described. Extensive spectroscopic features for this class of compounds have been thoroughly discussed, and detailed 13C-NMR data of compounds 1-192, have been added, except for those that have no reported 13C-NMR data.

Chromone a Privileged Scaffold in Drug Discovery: Developments on the Synthesis and Bioactivity

Chromones are the class of secondary metabolites broadly occurred in the plant kingdom in a noticeable quantity. This rigid bicyclic system has been categorized "as privileged scaffolds in compounds" in medicinal chemistry. The wide biological responses made them an important moiety in a drug discovery program. This review provides updates on the various methods of synthesis of chromones and biological applications in medicinal chemistry. Various synthetic strategies for the construction of chromones include readily available phenols, salicylic acid and its derivatives, ynones, chalcones, enaminones, chalcones and 2-hydroxyarylalkylketones as starting materials. Synthesis of chromones by using metal, metal free, nanomaterials and different catalysts are included. Details of diverse biological activities such as anti-cancer agents, antimicrobial agents, anti-viral property, anti-inflammatory agents, antioxidants, Monoamine Oxidase-B (MAO-B) Inhibitors, anti-Alzheimer's agents, anti-diabetic agent, antihistaminic potential, antiplatelet agents of chromone derivatives are diecussed.

Discovery of natural anti-inflammatory alkaloids: Potential leads for the drug discovery for the treatment of inflammation

Inflammation is an adaptive response of the immune system to tissue malfunction or homeostatic imbalance. Corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs) are frequently applied to treat varieties of inflammatory diseases but are associated with gastrointestinal, cardiovascular, and kidney side effects. Developing more effective and less toxic agents remain a challenge for pharmaceutical chemist due to the complexity of the different inflammatory processes. Alkaloids are widely distributed in plants with diverse anti-inflammatory activities, providing various potential lead compounds or candidates for the design and discovery of new anti-inflammatory drug candidates. Therefore, re-examining the anti-inflammatory alkaloid natural products is advisable, bringing more opportunities. In this review, we summarized and described the recent advances of natural alkaloids with anti-inflammatory activities and possible mechanisms in the period from 2009 to 2020. It is hoped that this review of anti-inflammatory alkaloids can provide new ideas for researchers engaged in the related fields and potential lead compounds for the discovery of anti-inflammatory drugs.

Evaluation of rohitukine-enriched fraction of Dysoxylum binectariferum Hook.f. (leaves) as anti-arthritic phytopharmaceutical candidate: Chemical standardization, in-vivo validation, formulation development and oral pharmacokinetics

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis is a chronic inflammatory disease of joints. Dysoxylum binectariferum Hook.f (Family: Meliaceae) is a Indian medicinal plant which is traditionally being used to heal inflammation of joints.

AIM OF THE STUDY

This work was aimed to carry out chemical standardization, in-vitro/in-vivo validation, oral pharmacokinetics and formulation development of anti-arthritic botanical lead, the rohitukine-enriched fraction of D. binectariferum.

MATERIALS AND METHODS

The rohitukine-enriched fraction of D. binectariferum was standardized using four chemical markers and was checked for microbial load, heavy metal content, aflatoxins and pesticides. Its in-vitro inhibitory effect on the lipopolysaccharide (LPS) induced production of pro-inflammatory cytokines TNF-α and IL-6 was studied in THP-1 cells. The in-vivo anti-arthritic activity was investigated in collagen-induced arthritis model in DBA/1J mice. The sustained release capsule formulation was developed and characterized for physicochemical and pharmacokinetic properties.

RESULTS

Rohitukine and schumaniofioside A were found to be major chemical constituents of the botanical lead. The rohitukine-enriched fraction of D. binectariferum significantly reduced the production of both pro-inflammatory cytokines TNF-α and IL-6 (>50% inhibition at 3.12 μg/mL) in THP-1 cells. In LPS-treated wild-type mice model, the rohitukine-enriched fraction at 200 mg/kg (PO, QD) completely reduced serum TNF-α levels. In transgenic mice model (collagen-induced arthritis in DBA/1J mice), rohitukine-enriched fraction at 100 mg/kg (PO, QD) dose has resulted in >75% reduction of TNF-α/IL-6 serum levels, 68% reduction in anti-mouse type II collagen IgG1 antibody levels, decreased joint proteoglycan loss and reduced paw edema in DBA/1J mice. The sustained release capsule formulation of rohitukine-enriched fraction showed sustained-release of rohitukine over the period of 24 h, and resulted in an improved plasma-exposure of rohitukine in SD rats.

CONCLUSIONS

The data presented herein demonstrated anti-arthritic potential of rohitukine-enriched fraction of D. binectariferum and this study will serve as the benchmark for further research on this botanical lead and developed sustained release capsule formulation.

Impurity profiling of anticancer preclinical candidate, IIIM-290

IIIM-290, an orally bioavailable preclinical candidate is effective in human xenograft models of leukemia, colon and pancreatic cancer. The promising preclinical data of this lead candidate has shown its potential for clinical development. As a part of its preclinical development, impurity profiling of pilot scale batches is one of the most important component of the CMC documentation. Herein, we report impurity profiling, its quantification in different scale-up batches and analytical method validation. Three impurities ranging from 0.09 to 1.25% in preclinical anticancer candidate, IIIM-290 were detected by validated HPLC method. The impurities (Imp-A, Imp-B and Imp-F) were isolated from the partially purified batch of IIIM-290 using semi-preparative HPLC. Isolated impurities were characterized by ¹H, ¹³C NMR, FTIR and ESI-MS spectral data. Based on the characterization data, the sources of these impurities were identified as unreacted starting material (Imp-A), impurity from botanical raw material (Imp-B; impurity carried from starting material) and the chemically transformed product (Imp-F) of Imp-B, respectively.