Antitumor activity of bacterial exopolysaccharides from the endophyte Bacillus amyloliquefaciens sp. isolated from Ophiopogon japonicus

Abstract

The endophytic bacterium, MD-b1, was isolated from the medicinal plant Ophiopogon japonicas and identified as the Bacillus amyloliquefaciens sp. with 99% similarity based on the partial sequence analysis of 16S rDNA. Exopolysaccharides were extracted from the endophyte for the evaluation of its antitumor activity against gastric carcinoma cell lines (MC-4 and SGC-7901). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and microscopy were performed to estimate the cell viability and morphological changes of the MC-4 and SGC-7901 cells following treatment with the exopolysaccharides at 14, 22 and 30 μg/μl. The results revealed that the exopolysaccharides displayed concentration-dependent inhibitory effects against the MC-4 and SGC-7901 cells, with an IC50 of 19.7 and 26.8 μg/μl, respectively. The exopolysaccharides also induced morphological abnormalities in the cells. These effects indicated the the exopolysaccharides had an antitumoral mechanism of action associated with the mitochondrial dysfunction of the treated cells. This is the first study to investigate the endophytic microorganism isolated from O. japonicas and also the first discovery of such antitumoral exopolysaccharides derived from the genus Bacillus. This provides a promising and reproducible natural product source with high therapeutic value for anticancer treatment, thereby facilitating the development of new anticancer agents.

Endophytic bacterium,Bacillus amyloliquefaciens, enhances ornamental hosta resistance to diseases and insect pests

“…Previous studies have demonstrated that some isolates of B. amyloliquefaciens can improve plant disease resistance (Sun et al 2006;Chen et al 2013). Consistent with this, we found that all B. amyloliquefaciens isolates from hosta showed antifungal activity (Table 1).…”

“…It was isolated from five hosta cultivars, but not from cultivar 'Sum and Substance'. Similarly, B. amyloliquefaciens has been reported to be an endophyte of numerous plants (Sun et al 2006;Choudhary & Johri 2009;Chen et al 2013;White et al 2014).…”

“…Bacillus amyloliquefaciens is one of the most common bacterial endophytes infecting many plants, and due to its beneficial effect of improving plant disease resistance, it has gained considerable attention (Sun et al 2006;Chen et al 2009a;Li et al 2012b;Chen et al 2013). Previous studies have demonstrated that various lipopeptides are among the main metabolites responsible for anti-pathogen activity of B. amyloliquefaciens (Sun et al 2006;Ongena & Jacques 2008;Alfonzo et al 2012).…”

In silico identification and characterization of antineoplastic asparaginase enzyme from endophytic bacteria

“…42 Ophiopogon japonicas is a medicinal plant common in South-East Asia with anticancer activity 43 and isolation of B. amyloliquefaciens from this herb has been reported. 44 It is assumed that some of the anticancerous attributes of medicinal plants are derived from endosymbiont bacteria in the plant. 45 Paenibacillus spp.…”

Antitumor activity of aRhodococcussp.Lut0910isolated from polluted soil

“…Antitumor activity of extract was conducted using MTT assay. 11,12 The human hepatocellular carcinoma HepG2 and cervical carcinoma Hela cells were collected at the stage of logarithmic growth using 0.25% trypsin. More than 98% of cells were alive according to Trypan blue staining.…”