γ-Sitosterol from Acacia nilotica L. induces G2/M cell cycle arrest and apoptosis through c-Myc suppression in MCF-7 and A549 cells

Ethnopharmacological relevance

Acacia nilotica is widely distributed in Asia. In India, it occupies an important place in the indigenous system of medicine against anti-inflammatory, antioxidant, cancers, and/or tumors.

Aim of the study

The purpose of this study is to investigate the inhibitory effect of Acacia nilotica leaves extract and γ-Sitosterol on cell proliferation, the apoptotic effect and cell cycle arrest in breast and lung cancer cells.

Materials and methods

GC–MS and HPLC were used to determine the chemical constituents of this extract and γ-Sitosterol respectively. Human MCF-7 and A549 cell lines were treated with Acacia nilotica extract and γ-Sitosterol. Cell viability was determined by MTT assay. Cell proliferation was determined by BrdU incorporation assay. Apoptosis was detected by cell morphologic observation through AO/EtBr staining, cell cycle analysis, and immunoblot analysis on the expression of protein associated with cell cycle arrest.

Results

Experimental results of bioactive compound analysis indicate that γ-Sitosterol, bioactive ingredients of Acacia nilotica extract. The IC₅₀ value of extract on MCF-7 and A549 cancer cells was 493.3 ± 15.2 and 696.6 ± 11.5 μg/ml, respectively. Acacia nilotica extract and γ-Sitosterol were inhibited the cell proliferation by 54.34 ± 1.8 and 42.18 ± 3.9% for MCF-7 and 58.26 ± 1.5 and 44.36 ± 3.05% for A549 cells. The percentage of apoptotic cells observed in the MCF-7 and A549 cell lines were increased to 42.46 and 36.8% of extract; 46.68 and 43.24% for γ-Sitosterol respectively. Flow cytometric analysis results demonstrate that cells were arrested at the G2/M phase and decrease the c-Myc expression.

Conclusions

This study demonstrates in vitro results, which support the ethnomedical use of γ-Sitosterol against cancer. Experimental results of this study suggest that γ-Sitosterol exerts potential anticancer activity through the growth inhibition, cell cycle arrest and the apoptosis on cancer cells.     

Effect of root canal debridement on inflammatory cytokine levels

In endodontic infections, inflammatory mediators such as cytokines are released, recruited and retained until the infection is eradicated. Root canal therapy is performed to prevent the spread of infection. The aim of this study was to investigate the effects of root canal debridement (cleaning and shaping) on periapical inflammation by measuring the levels of inflammatory cytokines, Interleukin‐8 (IL‐8) and Interleukin‐10 (IL‐10). The study includes twenty patients with pulp necrosis and asymptomatic apical periodontitis. Periradicular sample was collected using paper points before and after root canal debridement. Cytokine levels were determined by Sandwich Enzyme‐Linked Immunosorbent Assay (ELISA). Data were analysed using paired t‐test (PASW Statistics 18) (P = 0.05). All samples showed the presence of IL‐8 and IL‐10 prior to root canal debridement. Significantly reduced levels (P < 0.05) of IL‐8 and IL‐10 were detected after root canal debridement. In conclusion, root canal debridement significantly decreased the levels of the tested pro‐ and anti‐inflammatory cytokine in the periradicular interstitial fluid.     

Occurrence of group C Streptococci in children in a South Indian village

Throat swabs were collected from 310 children aged 5-14 years attending a rural health camp at Orathur near Chennai. Group C Streptococci were isolated from 13/310 (4.19%) cases. Seven out of 13 patients had symptoms of respiratory tract infection. Biochemical characterization of the isolates was done by hemolytic characteristics, Voges-Proskauer test, fermentation of trehalose and sorbitol and hydrolysis of 4-methylumbelliferyl-D-a-glucuronide. Four out of 13 strains were identified as S. equisimilis.     

Pharmacokinetics of dolasetron with coadministration of cimetidine or rifampin in healthy subjects

Purpose: Dolasetron is a selective 5-HT₃ receptor antagonist. The purpose of this study was to determine the effect of cimetidine and rifampin on the steady-state pharmacokinetics of orally administered dolasetron and its active reduced metabolite, hydrodolasetron. Methods: A group of 18 healthy men (22 to 44 years old) were randomized to receive each of the following three treatments in a three-period crossover design: 200 mg dolasetron daily (treatment A); 200 mg dolasetron daily plus 300 mg cimetidine four times daily (treatment B); or 200 mg dolasetron daily plus 600 mg rifampin daily (treatment C). Each study period was separated by a 14-day washout period. Serial blood samples were collected before the first dose (baseline) on day 1 and at frequent intervals up to 48 h after the morning dose on day 7 for quantification of dolasetron and its metabolites, hydrodolasetron (both isomers), 5′OH hydrodolasetron, and 6′OH hydrodolasetron. Serial urine samples were also collected at baseline and during the periods 0–24 and 24–48 h following the morning dose on day 7, and analyzed for dolasetron and its metabolites. Results: Plasma and urine dolasetron concentrations were below quantifiable concentrations for all three treatments. Mean steady-state area under the plasma concentration-time curve (AUC_ss(0–24)) of hydrodolasetron increased by 24%, mean apparent clearance (CL_app,po) decreased by 19%, and maximum plasma hydrodolasetron concentration (C_max,ss) increased by 15% when dolasetron was coadministered with cimetidine. When dolasetron was given with rifampin, mean hydrodolasetron AUC_ss(0–24) decreased by 28%, CL_app,po increased by 39%, and hydrodolasetron C_max,ss decreased by 17%. Small differences were found in mean t_max (0.7 to 0.8 h), CL_r (2.0 to 2.6 ml/min per kg), and t_1/2 (7.4 to 8.8 h) for hydrodolasetron between treatment periods. Approximately 20% and 2% of the dolasetron dose were excreted in urine as the R(+) isomer and S(−) isomer of hydrodolasetron, respectively, across all three treatments. Dolasetron mesylate was well tolerated in this study during all three treatment periods, with the highest incidence of adverse events reported during the control period when dolasetron mesylate was given alone. Conclusion: Based on the small changes in the pharmacokinetic parameters of dolasetron and its active metabolites, as well as the favorable safety results, no dosage adjustments for dolasetron mesylate are recommended with concomitant administration of cimetidine or rifampin. Received: 10 February 1998 / Accepted: 1 June 1998     

Distinct regulation of C3a-induced MCP-1/CCL2 and RANTES/CCL5 production in human mast cells by extracellular signal regulated kinase and PI3 kinase

Complement component C3a causes a robust degranulation in human mast cells. Whether C3a also stimulates chemokine production in human mast cells and what signaling pathway it activates is not known. In the present study, we demonstrate that CD34+ cell-derived primary mast cells and a human mast cell line LAD 2 express surface C3a receptors at similar levels. Furthermore, C3a caused approximately 50% internalization of cell surface C3a receptors in both cell types. We therefore used LAD 2 cells as a model to study C3a-induced biological responses and signaling in human mast cells. We found that C3a stimulated substantial degranulation and induced chemokine monocyte chemoattractant protein 1 (MCP-1/CCL2) and regulated upon activation, normal T-cell expressed and secreted (RANTES/CCL5) production in LAD 2 mast cells. C3a caused a rapid and sustained extracellular-signal-regulated kinase (ERK) phosphorylation and Akt phosphorylation in LAD 2 mast cells. Furthermore, U0126 and LY294002, which respectively inhibit MEK-induced ERK phosphorylation and PI3 kinase-mediated Akt phosphorylation had distinct effects on C3a-induced responses. Thus, U0126, which blocked C3a-induced RANTES/CCL5 production by 50.6+/-2.3%, inhibited MCP-1/CCL2 generation by 85.2+/-0.6%. In contrast, LY294002 had no effect on C3a-induced RANTES/CCL5 production but blocked MCP-1/CCL2 generation by 83.7+/-1.5%. These data demonstrate that C3a activates divergent signaling pathways to induce chemokine production in human mast cells.     

Effect of aqueous extract of Tragia involucrata Linn. on acute and subacute inflammation

Antiinflammatory activity of aqueous extract of Tragia involucrata was tested on carrageenan-induced hind paw oedema and cotton pellet granuloma models in albino rats. In the subacute model, cotton pellet granuloma was produced by implantation of 10 mg sterile cotton in the axilla under ether anaesthesia. The animals were administered an aqueous extract at various concentrations of 50, 100, 200, 300 and 400 mg/kg. Phenyl butazone (80 mg/kg) was used as a standard drug. The paw diameter was measured at different time intervals and the dry granuloma weight was taken after the treatment. The aqueous leaf extract (400 mg/kg) showed the maximum inhibition (84.23%) of oedema at the end of 3 h following carrageenin-induced rat paw oedema. In subacute inflammation, the extract showed 76.25% reduction in granuloma weight. The results prove that the aqueous leaf extract showed highest antiinflammatory activity in acute and subacute inflammation and also support the usage of traditional claims.