Antimicrobial and Cytotoxic Effects of Mexican Medicinal Plants

Abstract

The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC 50 ≤30 µg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents.

Antitumor and immunomodulatory effects of Justicia spicigera Schltdl (Acanthaceae)

“…Spleen is involved in fighting the systemic infections, whereas NK cells play a critical role in immune surveillance by the secretion of cytokines such as IFN-␥ (Randy and Venkataraman, 2002). Previously, we showed that Justicia spicigera ethanol extracts tested at 100 g/ml stimulated the proliferation of human peripheral blood mononuclear cells with similar potency as compared to phytohemagglutinin 1 g/ml (Jacobo-Salcedo et al, 2011). In this study, we showed that Justicia spicigera stimulates the phagocytosis, NO production and H 2 O 2 release with higher potency than LPS in human differentiated macrophages.…”

“…Previously, we showed that Justicia spicigera showed strong cytotoxic effects against HeLa cells (Jacobo-Salcedo et al, 2011). In this study, we showed that JSE exerted cytotoxic effects and induced 35% apoptosis in HeLa cells, compared to untreated cells.…”

“…Recently, we showed that ethanolic extracts of Justicia spicigera leaves had high cytotoxic effects against HeLa cells (IC 50 = 17 g/ml), and stimulated the proliferation of human peripheral blood mononuclear cells in a concentration dependent manner, and tested at 100 g/ml showed a similar potency as compared to phytohemagglutinin 1 g/ml (Jacobo-Salcedo et al, 2011).…”

“…Previously, we showed that Justicia spicigera had the highest cytotoxic activity on HeLa cells (IC 50 = 17 g/ml) (Jacobo-Salcedo et al, 2011). To analyze whether JSE has the potential effect to induce apoptosis in cancer cell lines, HeLa cells were treated with JSE and analyzed by flow cytometry.…”

“…Positive controls received lipopolysaccharides (LPS) 1 g/ml. After 48 h of treatment, the MTT assay was performed and the relative viability was calculated as described (Jacobo-Salcedo et al, 2011).…”