Anticancer and Antioxidant Activities of Rhizospheric Soil Bacteria of Lophocereus marginatus.

Identification of new sources of compounds with anticancer and antioxidant potential is essential for cancer treatment. Rhizospheric bacteria have emerged as a promising source of these agents. This study is aimed at investigating the anticancer and antioxidant properties of bacteria isolated from the rhizosphere of Lophocereus marginatus. Six rhizobacteria of L. marginatus were isolated and molecularly identified by sequencing the 16S rRNA gene and MALDI-TOF. We evaluated the inhibitory activity of methanol (MeOH) and ethyl acetate (EtOAc) extracts obtained from rhizobacteria against the murine lymphoma cell line L5178Y-R, as well as normal Vero monkey kidney cells and peripheral blood mononuclear cells (PBMCs). Compared with those of normal cells, the MeOH extract of Paenibacillus sp. PMS-B023 showed selective anticancer activity against lymphoma, with 50% inhibitory concentration (IC50) values of 117.5 μg/mL and a selectivity index (SI) > 2.1, as compared with those of normal cells. L-Pro-L-Val cycle, gageostatin B, cinnamic acid, parvifloracin, daidzein, genistein, actinomycin D, actinomycin Y4, and surfactin C were detected in the MeOH extract, which may be responsible for its antilymphoma activity. We did not find significant antioxidant activity in any of the extracts evaluated using the 2,2-diphenyl-1-picrylhydrazyl technique (IC50 > 250  μg/mL). The results showed that Paenibacillus sp. PMS-B023 has antitumor potential and selective activity against L5178Y-R lymphoma cells. The presence of anticancer compounds was also demonstrated, as previously described in the literature.