Cleistanthin B causes G1 arrest and induces apoptosis in mammalian cells

Sumatranins A-J: Lignans with Immunosuppressive Activity from Cleistanthus sumatranus

Chemical investigation of the twigs of Cleistanthus sumatranus (Phyllanthaceae) led to the isolation of 10 undescribed lignans, sumatranins A-J (1-10). Compounds 1-4 are unprecedented furopyran lignans characterized by a unique 2,3,3a,9a-tetrahydro-4H-furo[2,3-b]chromene heterotricyclic framework. Compounds 9 and 10 are rare 9'-nor-dibenzylbutane lignans. Structures were established based on analyses of spectroscopic data, X-ray crystallographic data, and experimental ECD spectra. Immunosuppressive assays revealed compounds 3 and 9 displayed moderate inhibitory effects with good selectivity indexes against LPS-induced B lymphocyte proliferation.

Phytochemical analysis and bioactivity reports of ethnomedicinal plants from West Bengal, India

The biodiversity-rich forests of the Jhargram subdivision of West Bengal, India houses many lesser-known prospective plants. Four ethnomedicinal plants from this locality-Cleistanthus collinus, Tiliacora racemosa, Eupatorium odoratum, and Sida acuta reported for traditional medical uses by local forest tribes have been analyzed for phytochemical constituents and bioactivity potential, viz., antioxidant, antibacterial and antitumor activity. Cleistanthus and Tiliacora plants were rich in alkaloids while Eupatorium and Sida showed tannin abundance. Tiliacora showed maximum alkaloid content, that is, 711 mg strychnine equivalent/gm dry weight. Consequently, these plant extracts showed decent antioxidant activity which is reflected in their antibacterial and antitumor potencies. Cleistanthus showed strong bactericidal activity against Gram-negative bacteria, particularly against Klebsiella pneumoniae and Pseudomonas aeruginosa, while Tiliacora showed robust antitumor activity against cervical cancer cells SiHa at a 50% inhibitory concentration (IC₅₀) of 86 µg/ml. Hence, the biodiversity-rich Jhargram forest should be conserved to protect the potential repertoire for ethnomedicinal plants.

Reveals of candidate active ingredients in Justicia and its anti-thrombotic action of mechanism based on network pharmacology approach and experimental validation

Thrombotic diseases seriously threaten human life. Justicia, as a common Chinese medicine, is usually used for anti-inflammatory treatment, and further studies have found that it has an inhibitory effect on platelet aggregation. Therefore, it can be inferred that Justicia can be used as a therapeutic drug for thrombosis. This work aims to reveal the pharmacological mechanism of the anti-thrombotic effect of Justicia through network pharmacology combined with wet experimental verification. During the analysis, 461 compound targets were predicted from various databases and 881 thrombus-related targets were collected. Then, herb-compound-target network and protein-protein interaction network of disease and prediction targets were constructed and cluster analysis was applied to further explore the connection between the targets. In addition, Gene Ontology (GO) and pathway (KEGG) enrichment were used to further determine the association between target proteins and diseases. Finally, the expression of hub target proteins of the core component and the anti-thrombotic effect of Justicia's core compounds were verified by experiments. In conclusion, the core bioactive components, especially justicidin D, can reduce thrombosis by regulating F2, MMP9, CXCL12, MET, RAC1, PDE5A, and ABCB1. The combination of network pharmacology and the experimental research strategies proposed in this paper provides a comprehensive method for systematically exploring the therapeutic mechanism of multi-component medicine.

Two new bioactive lignans from leaves and twigs of Cleistanthus concinnus Croizat

Two new lignans (1-2), along with five known compounds (3-7) with different structures were isolated from leaves and twigs of Cleistanthus concinnus Croizat. The new lignans were elucidated as (7'R,8'S)-3,3',5'-trimethoxy-4,4'-dihydroxy-7-en-7',9- epoxy-8,8'-lignan (1) and (7'R,8'S)-3,3'-dimethoxy-4,4'-dihydroxy-7-en-7',9-epoxy-8, 8'-lignan (2) by comprehensive spectroscopic analysis including 1D and 2D NMR as well as HREIMS and comparing their NMR data with known compounds in the literature. Among these isolated compounds, compound 1, 2, 3, and 6 were tested for anti- inflammatory effects by inhibiting NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Compound 1, 2, and 6 exhibit NO inhibitory activity.[Formula: see text].

Anti-Inflammatory and Antinociceptive Studies of Hydroalcoholic Extract from the Leaves of Phyllanthus brasiliensis (Aubl.) Poir. and Isolation of 5-O-β-d-Glucopyranosyljusticidin B and Six Other Lignans

The aim of this study was to investigate the chemical composition and the antiinflammatory/antinociceptive properties of the hydroalcoholic extract derived from the leaves of Phyllanthus brasiliensis (HEPB) in rodents. A new arylnaphthalene lignan glycoside, 5-O-β-d-glucopyranosyljusticidin B, together with six known lignans, were isolated from HEPB. 1D and 2D NMR experiments and HRMS were used to elucidate the structure of the new compound. HEPB toxicity and antinociceptive activity were evaluated through acute oral toxicity and formalin models in mice, respectively. The anti-inflammatory effects of HEPB were assessed using carrageenan- and dextran-induced paw edema models in rats. HEPB showed low toxicity. Oral administration of HEPB reduced paw edema induced by carrageenan, but not by dextran. HEPB and its fractions from FR6 to FR10 (FR6-10) inhibited the neurogenic and inflammatory phases of formalin-induced linking, demonstrating its antinociceptive activity. These results indicated that lignans from Phyllanthus brasiliensis exerted antinociceptive/anti-inflammatory effects not related to the histaminergic pathway.

Synthesis and antiproliferative activity of derivatives of the phyllanthusmin class of arylnaphthalene lignan lactones

A series of arylnaphthalene lignan lactones based on the structure of the phyllanthusmins, a class of potent natural products possessing diphyllin as the aglycone, has been synthesized and screened for activity against multiple cancer cell lines. SAR exploration was performed on both the carbohydrate and lactone moieties of this structural class. These studies have revealed the importance of functionalization of the carbohydrate hydroxy groups with both acetylated and methylated analogues showing increased potency relative to those with unsubstituted sugar moieties. In addition, the requirement for the presence and position of the C-ring lactone has been demonstrated through reduction and selective re-oxidation of the lactone ring. The most potent compound in this study displayed an IC₅₀ value of 18 nM in an HT-29 assay with several others ranging from 50 to 200 nM. In an effort to elucidate their potential mechanism(s) of action, the DNA topoisomerase IIa inhibitory activity of the most potent compounds was examined based on previous reports of structurally similar compounds, but does not appear to contribute significantly to their antiproliferative effects.

Evaluation of in vivo antitumor activity of cleistanthin B in Swiss albino mice

To evaluate the in vivo antitumor activity of cleistanthin B in Ehrlich's ascites carcinoma (EAC) and Dalton's ascites lymphoma (DAL) cell lines induced malignant ascites mouse models and DAL cell line induced solid tumor mouse model. All animals were injected with 2 × 10⁶ EAC/DAL cells i.p./s.c. to induce malignant ascites and solid tumor and treated with 5-fluorouracil (5-FU) 20 mg/kg or cleistanthin B for 10 days. Cleistanthin B was given at three doses viz. 25, 50 and 100 mg/kg. The percentage increase in life span and the overall survival in malignant ascites animals and the tumor volume in solid tumor animals were measured. The haematological parameters were assessed in all animals before and 2 weeks after the treatment. Cleistanthin B 50 mg/kg and 5-FU significantly prolonged the life span (>25%) of malignant ascites tumor bearing animals. The overall survival was significantly improved by both. Only cleistanthin B 50 mg/kg significantly reduced the elevated WBC counts in EAC tumor bearing animals. Both 5-FU and cleistanthin B 50 mg/kg reversed the malignancy induced increase in neutrophils and platelet counts and decrease in lymphocyte counts but not to the normal range. Only 5-FU significantly reduced the solid tumor volume. None of the three doses of cleistanthin B was effective against the solid tumor. Cleistanthin B has antitumor activity against EAC and DAL tumor mice but it is not as effective as 5-FU. At 50 mg/kg dose cleistanthin B exerts significant antitumor activity compared to 25 and 100 mg/kg dose. Its effect on WBC count is higher and advantageous when compared to 5-FU. But cleistanthin B in the doses used is not effective against solid tumor.

Cleistanthus collinus poisoning

Cleistanthus collinus, a toxic shrub, is used for deliberate self-harm in rural South India. MEDLINE (PUBMED) and Google were searched for published papers using the search/ MeSH terms “Cleistanthus collinus,” “Euphorbiaceae,” “Diphyllin,” “Cleistanthin A,” Cleistanthin B” and “Oduvanthalai.” Non-indexed journals and abstracts were searched by tracing citations in published papers. The toxic principles in the leaf include arylnaphthalene lignan lactones — Diphyllin and its glycoside derivatives Cleistanthin A and B. Toxin effect in animal models demonstrate neuromuscular blockade with muscle weakness, distal renal tubular acidosis (dRTA) and type 2 respiratory failure with conflicting evidence of cardiac involvement. Studies suggest a likely inhibition of thiol/thiol enzymes by the lignan-lactones, depletion of glutathione and ATPases in tissues. V-type H+ ATPase inhibition in the renal tubule has been demonstrated. Mortality occurs in up to 40% of C. collinus poisonings. Human toxicity results in renal tubular dysfunction, commonly dRTA, with resultant hypokalemia and normal anion gap metabolic acidosis. Aggressive management of these metabolic derangements is crucial. Acute respiratory distress syndrome (ARDS) is seen in severe cases. Cardiac rhythm abnormalities have been demonstrated in a number of clinical studies, though the role of temporary cardiac pacemakers in reducing mortality is uncertain. Consumption of decoctions of C. collinus leaves, hypokalemia, renal failure, severe metabolic acidosis, ARDS and cardiac arrhythmias occur in severe poisonings and predict mortality. Further study is essential to delineate mechanisms of organ injury and interventions, including antidotes, which will reduce mortality.

Mechanisms of toxicity of Cleistanthus collinus: vacuolar ATPases are a putative target

Ingestion of Cleistanthus collinus, a shrub native to South India, either intentionally or accidentally, is a common cause of death in the area. Consumption of a boiled decoction of leaves is highly toxic, but medical management of patients is mainly supportive because the molecular mechanisms of toxin action are unknown. Distal renal tubular acidosis is one of the symptoms of poisoning in patients and adenosine triphosphate (ATP) requiring proton pumps is important for acid secretion in the kidney. Hence, we hypothesized that these may be putative targets for C. collinus action and we tested this by exposing rat renal brush border membrane (BBM) as well as cultured kidney cells to a boiled decoction of C. collinus. Exposure to the C. collinus decoction resulted in significant inhibition of vacuolar type H(+)-ATPase (V-ATPase) activity in renal BBM as well as blocking of the proton pump in renal BBM vesicles. C. collinus decoction was also found to inhibit acidification of intracellular organelles in cells in culture, similar to the effect seen with either bafilomycin or concanamycin - specific inhibitors of the V-ATPase. This was accompanied by a decrease in V-ATPase activity, but an increase in protein levels. These results demonstrate that the V-ATPase in renal cells is a putative target for the toxins in C. collinus and the inhibition of this important proton pump probably plays a role in the development of distal renal tubular acidosis and subsequent renal failure seen in poisoned patients.

Cleistanthin A causes DNA strand breaks and induces apoptosis in cultured cells

Cleistanthin A is a novel anticancer agent isolated from Cleistanthus collinus (Rox B). It caused chromatid aberrations in a dose dependent manner. However, the concentrations that induced the aberrations, neither affected viability nor induced DNA strand breaks. Only at higher concentrations and after long exposure, DNA strand breaks were observed. Cleistanthin A induced apoptosis in Chinese hamster ovary (CHO) cells, in cervical carcinoma (Si Ha) cells and in a p53 deficient cell line K562. Cleistanthin A-induced cell death was low in bcl-2 transfected cells. Cleistanthin A inhibited the incorporation of [3H]thymidine into DNA; however, it did not affect the transport of [3H]thymidine into these cells. These studies indicate that the cytotoxic effects of cleistanthin A are mediated by the inhibition of DNA synthesis, induction of DNA damage and apoptosis.