Rauvolfia grandiflora (Apocynaceae) extract interferes with staphylococcal density, enterotoxin production and antimicrobial activity

Abstract

Staphylococci bacteria are involved in many human and animal infections and development of alternative antimicrobial drugs against pathogenic bacteria is of great interest to the pharmaceutical industry. This study investigated the in vitro effect of Rauvolfia grandiflora methanol extract (root bark fraction) (RGE) on the density of ATCC strains of Staphylococcus aureus and Staphylococcus epidermidis, and a clinical enterotoxin-producer, S. aureus bovine strain. The alkaloid, isoreserpiline, obtained from dichloromethane extract of R. grandiflora was ineffective against the strains tested. After incubation of staphylococci strains in the presence of 1.2 µg.mL -1 RGE, a significant inhibition of cell growth was observed using both spectrophotometry and ELISA assays. Twelve drugs were evaluated for their antimicrobial effects on culture RGE-treated cells using the disk diffusion method. Penicillin resistant strains became sensitive to the drug after RGE treatment. Furthermore, enterotoxin production by RGE-treated S. aureus was evaluated using a standardized ELISA method. Although staphylococcal LSA 88 bovine strain cells remained viable after exposure to the extract, enterotoxin production was precluded in 20% after RGE treatment. Significant interference in staphylococci cell density, drug sensitivity and enterotoxin secretion was observed after treatment. The study highlights the necessity to find new methods of disease prevention and new antibiotic therapies against staphylococcal infections.

The Olive Compound 4‐Hydroxytyrosol Inactivates Staphylococcus aureus Bacteria and Staphylococcal Enterotoxin A (SEA)

“…Because the toxin is present in contaminated foods and exerts adverse effects on the gastrointestinal tract, there is a need to find food‐compatible safe conditions to inactivate it. Efforts to inhibit the toxin or its release from S. aureus include the use of electrolyzed water (Suzuki and others 2002), high pressure and heat (Margosch and others 2005), radiation and pulsed electric fields (Walkling‐Ribeiro and others 2008), condensed tannins (Choi and others 2007) and other plant extracts (Ifesan and Voravuthlkunchai 2009; Carlos and others 2010), peptides (Wang and others 2008), phenolic compounds (Rúa and others 2010), licochalcone A (Qiu and others 2010), essential oils (Friedman and others 2004; Nuñez and others 2007; de Souza and others 2010; Parsaeimehr and others 2010; Qiu and others 2011), and toxin‐specific antibodies (Larkin and others 2010). …”

In Vitro Anti-Toxoplasma gondii and Antimicrobial Activity of Amides Derived from Cinnamic Acid

“…On the contrary, the same compound 5 had an antagonistic effect toward AMO, reducing its inhibition halo ( p < 0.05). Carlos et al [ 20 ] also described the antagonistic effect between the control and the Rauvolfia grandiflora extracts with the antibiotics ampicillin, oxacillin, and cephalosporin.…”

“…[ 2 ]. The development of alternative antimicrobials against pathogenic bacteria is of great interest to the pharmaceutical industry [ 20 ].…”

Plants as Sources of Anti-Inflammatory Agents

“…Another group of compounds known for their anti-inflammatory activity is alkaloids. They usually contain nitrogen in a heterocyclic ring, in a state of negative oxidation, with an amine group that gives them a basic character [ 103 ]. The alkaloids are classified according to the nature of the nitrogen atom present in their structure.…”