Anti-vibrio potentials of acetone and aqueous leaf extracts of Ocimum gratissimum (Linn)

Purpose: To evaluate the anti-vibrio potentials of acetone and aqueous leaf extracts of Ocimum gratissimum and determine its relevance in the treatment of vibrios infection. Methods: The agar-well diffusion method was used for screening the extracts for their anti-vibrio activity. Broth micro-dilution assay was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts. Time-kill assay was used to assess bactericidal and/or bacteriostatic activity. Results: The acetone extract showed activity against 47.5 % (19/40) of the test bacteria, while the aqueous extract had activity against 30 % (12/40). MIC and MBC values range for the acetone extract were 0.625 – 5.0 mg/mL and 2.5 – 10 mg/mL respectively. The range of MIC exhibited by the antibiotic (gentamicin) against the vibrios is 0.002 mg/mL and >0.256 mg/mL. Significant reduction in the bacterial density was at 2 × MIC after a 4 h interaction period, while bacterial density after 6 and 8 h interactions with extract was highly bactericidal. Growth inhibition and efficacy of the crude acetone extract were observed to be both concentration- and time-dependent. Conclusion: The bacteriostatic and bactericidal activities observed for Ocimum gratissimum leaf suggest that the plant is a potential source of bioactive components that may be effective in the treatment of vibrios infections.

Development of docetaxel and alendronate-loaded chitosan-conjugated polylactide-co-glycolide nanoparticles: In vitro characterization in osteosarcoma cells

Purpose: To develop docetaxel (DTX)- and alendronate (ALN)-loaded, chitosan (CS)-conjugated polylactide- co-glycolide (PLGA) nanoparticles (NPs) to increase therapeutic efficacy in osteosarcoma cells. Methods: Drug-loaded PLGA NPs were prepared by nanoprecipitation and chemically conjugated by the carboxylic group of PLGA to the amine-bearing CS polymer. The nanocarrier was characterized by dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and differential scanning calorimetry as well as by in vitro drug release and cell culture studies. Results: NP size was within the tumour targeting range (~200 nm) with an effective positive charge (20 mV), thus increasing cellular uptake efficiency. Morphological analysis revealed clear spherical particles with uniform dispersion. The NPs exhibited identical sustained release kinetics for both DTX and ALN. CS-conjugated PLGA with dual-drug-loaded (DTX and AL) NPs showed typical time-dependent cellular uptake and also displayed superior cytotoxicity in MG-63 cells compared with blank NPs, which were safe and biocompatible. Conclusion: Combined loading of DTX and ALN in NPs increased the therapeutic efficacy of the formulation for osteosarcoma treatment, thus indicating the potential benefit of a combinatorial drug regimen using nanocarriers for effective treatment of osteosarcoma.

Triptolide induces cell apoptosis in human stomach cancer cell via caspase 3-dependent cascade pathway

Purpose: To evaluate the effect of triptolide on the induction of cell apoptosis in human gastric cancer BGC-823 cells. Methods: The cytotoxicity of triptolide was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay. The effect of triptolide on cell proliferation was measured using lactate dehydrogenase (LDH) assay. Cell apoptosis was determined by Annexin V/propidium iodide (PI) double-staining assay. Results: MTT results indicate that triptolide significantly decreased cancer cell numbers in dose- and time-dependent manners in MTT assay. Data from LDH assay showed that triptolide markedly induced cytotoxicity in gastric cancer cells. Triptolide also remarkably induced both early and late apoptotic process in BGC-823 cells. In addition, the compound down-regulated the expression of anti-apoptotic Bcell lymphoma-2 (bcl-2) and up-regulated the expression of pro-apoptotic BCL-2-associated X (bax) in a dose-dependent manner. Furthermore, the pro-apoptotic activity of triptolide was involved in the activation of caspase-3 pathway in BGC-823 cells. Conclusion: Taken together, the findings strongly indicates that the pro-apoptotic activity of triptolide is regulated by caspase 3-dependent cascade pathway, and thus needs to be further developed for cancer therapy.