Plants of the Cerrado with antimicrobial effects against Staphylococcus spp. and Escherichia coli from cattle.

BACKGROUND: Both diarrhea in calves and mastitis in cows limit cattle production. The bacteria involved in these diseases have shown multi-resistance to antimicrobials, however plant metabolites therefore can provide an alternative method of control. This study selected and characterized Cerrado plant extracts showing inhibitory effects against Escherichia coli and Staphylococcus spp. from cattle. Thirteen leaf extracts were initially screened and diameters of inhibition zones produced against the pathogens were recorded using an agar disk diffusion method. Total condensed tannin contents were determined and antibacterial activities were analyzed after tannin removal from the five selected extracts. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were evaluated by macro-dilution antimicrobial susceptibility tests, and the extracts were characterized by high performance liquid chromatography. RESULTS: Inter- and intra-specific bacterial variations in the susceptibility to the extracts were detected. The aqueous extract (AE) from Caryocar brasiliense Cambess. leaves produced larger inhibition zones against E. coli strains than did other selected extracts. However, the AE from Schinopsis brasiliensis was the most effective against Staphylococcus spp. strains (P < 0.001). The MIC of ethanolic extracts (EE) from C. brasiliense (0.27 mg/mL) and S. brasiliensis (0.17 mg/mL) were lower than those of other extracts. The MIC and MBC of the Annona crassiflora EE were 6.24 mg/mL for all bacteria. Flavonoids were the main metabolites detected in the A. crassiflora EE as well as in the AE and EE from C. brasiliense, while tannins were the main metabolites in the S. brasiliensis leaf extracts. CONCLUSION: The AE from C. brasiliense was more effective against Gram-negative bacteria, while the AE from S. brasiliensis was more effective against Gram-positive bacteria. A. crassiflora EE and S. brasiliensis extracts are potent bactericide. After removal of the tannins, no antimicrobial effects were observed, indicating that these metabolites are the main active antibacterial components.

Plants of the Cerrado naturally selected by grazing sheep may have potential for inhibiting development of Haemonchus contortus larva.

Plant species naturally selected by sheep grazing in the Cerrado region of Brazil were assessed in vitro for activity against Haemonchus contortus. One year of observations showed the plant families in the region exhibiting greatest richness to be Fabaceae, Rubiaceae, Malpighiaceae, Bignoniaceae, Myrtaceae, and Annonaceae. Nine species commonly selected by grazing sheep showed variation in the selectivity index with respect to the dry and rainy seasons. Coproculture was conducted in five replicates of 11 treatments: ivermectin, distilled water, or dehydrated leaves of nine selected plant species administered at 333.3 mg g(-1) fecal culture. The dried powder of Piptadenia viridiflora and Ximenia americana leaves significantly reduced the number of infective larvae compared to the distilled water control. These species showed efficacy of over 85 % despite low concentrations of proanthocyanidin. High-performance liquid chromatography analyses of extracts of these plants showed major peaks of UV spectra characteristic of flavonoids. Those naturally selected plant species with high antihelminthic efficacy show promise for use in diet as an alternative control of H. contortus in sheep.

Extract of Mangifera indica L. leaves may reduce biofilms of Staphylococcus spp. in stainless steel and teatcup rubbers.

Human ingestion of antimicrobial residues in dairy products is a problem of public health. In this study we evaluated antibacterial effectiveness of aqueous and ethanolic leaf extracts of Mangifera indica L. as a natural alternative for reduction of Staphylococcus spp. biofilms. Eight Staphylococcus spp. strains from cows with mastitis and the Staphylococcus aureus strain (ATCC 25923) were evaluated. High performance liquid chromatography indicated the presence of phenolic compounds in the aqueous extract. Agilent Technologies gas chromatography revealed the presence of phenolic compounds, carbohydrates, and gallic acid in ethanolic extract. The tannin contents were 2.27 ± 0.01 and 2.67 ± 0.01% for ethanolic extract and aqueous extract, respectively. Extracts were evaluated in agar diffusion test and the size of inhibition zones were compared. The ethanolic extract was the most effective, showing minimum inhibitory concentrations and minimum bactericidal concentrations between 1.8-7.5 and 15.1-45.3 mg/ml, respectively. After tannin removal, the extracts were less effective, indicating these secondary metabolites as one of the main antibacterial compounds. The ethanolic extract at 45.3 mg/ml reduced mature biofilms in teat rubber (average: 3.91 log reduction) and stainless steel (average: 3.87 log reduction) after 5 min of contact. The extracts of M. indica leaves represent natural alternatives against Staphylococcus spp. strains and the ethanolic extract shows potential as a natural sanitizer.

Control of Haemonchus contortus in sheep using basidiocarps of Agaricus blazei Murril.

OBJECTIVE: This study evaluated the effects in vitro and in vivo of Agaricus blazei against Haemonchus contortus in sheep. METHODS: The in vitro efficacy of aqueous extract on egg hatching inhibition (EHI) was investigated and after 72 h incubation with varying concentrations the effects on, blastomeres, embryonated eggs, and first stage larvae (L1) were evaluated. Larval development inhibition (LDI) for dry powder and the aqueous extract were evaluated in fecal cultures of sheep infected with H. contortus. In vivo efficacy was determined by reduction in fecal egg count (FEC). Lambs were treated with powder A. blazei (11.4 g/kg pc) or trichlorfon, or were untreated and the possible toxicity of this fungus was monitored by plasmatic enzyme analysis. RESULTS: Concentrations equal to and higher than 3.62 mg/mL and of aqueous extract were 100% effective in the EHI test. In the LDI test, LC90 was estimated for 5.66 and 106.0 mg/g fecal culture for aqueous extract and powder, respectively. The mean FEC in lambs 14 days post-treatment with A. blazei powder was significantly lower than observed for the negative control, and the serum levels of aspartate transaminase and alanine transaminase were normal. CONCLUSION: The fungi supplementation promotes, respectively, high and moderate anthelmintic efficacy with in vitro and in vivo tests, respectively, suggesting it as an alternative or complementary treatment for haemonchosis in sheep.