Protection of Mice Against Gram-Positive Bacteria with Maytenus laevis and Other RES Stimulants

Abstract

A survey of botanical preparations revealed a number of specimens capable of inducing hyperphagocytic activity in mice ( 1 ) . Judged by effect upon rate of clearance of intravascular carbon( 2,3), the most potent preparation was a suspension of pulverized leaves of a Venezuelan evergreen (Maytenus laevis) .This preparation was interesting because (a) administered intravenously, it accelerated phagocytosis without inducing hepatosplenomegaly, and (b) it showed evidence of activity following oral administration.The present study deals with the ability of Maytenus laevis leaves to protect mice experimentally challenged with pathogenic bacteria. For comparison, 3 other RES stimulants (endotoxin, zymosan and live Mycobacterium phlei Halpern) were investigated with the same test systems.Materials and methods. The mice employed were 18-22 g females, Swiss Ha/ICR strain supplied by K-G Farms, Parsippany, N. J. Desiccated leaves of Maytenus laevis were pulverized to < 80 mesh, and employed as a suspension in physiological saline. Zymosan (Fleischmann Laboratories, Stamford, Conn.) and fresh Mycobacterium phlei Halpern were also suspended in saline for administration to mice. Endotoxin from Salmonella abortus equi (Difco Laboratories, Detroit, Mich.) was administered in saline solution.Three series of protection tests were conducted. Test series 1 and 2 involved experimental infection with Staphylococcus aureus Smith. The challenge microorganism in test series 3 was P-hemolytic Streptococcus pyrogenes type 4. The virulence of these pathogenic bacteria was maintained by a series of 24 hour mouse passages. Then heart blood was collected with sterile technique and used to inoculate sterilized trypticase soy broth (Baltimore Biological Laboratory, Baltimore.to 24 hours a t 37OC. Virulence titrations rather than bacterial counts, were performed. Considering the broth culture to have unit concentration, suspensions were diluted serially for injection. Staphylococci were diluted with trypticase soy broth fortified with 5% hog gastric mucin to enhance pathogenicity. Streptococcal cultures were diluted only with soy broth.In each test series, the virulence titration and the challenge of treated mice were conducted at the same time. In test series 1, the virulence of the Staphylococcus aureus Smith culture was determined by intraperitoneal injection of groups of 6 mice with 0.5 ml of culture diluted to ~O I -~, 1 F 6 , lo-", and At that time, there were available groups of 301 mice which had been injected intravenously with each RES stimulant on the previous day and groups of 30 mice which had been treated similarly 5 days earlier. Appropriate groups of 6 treated mice were challenged with 5 dilutions of the staphylococcal culture. The animals were caged by group (of 6) and observed for the subsequent week. Dead mice were removed as soon as possible after death. From the recorded deaths, the LD50 of the culture and the standard error were calculated by the statistical method of Miller and Tainter (4).The virulence titrations of stap...

Studies on the Mechanism of Action of Riley Virus

“…The blockading effects of cholesterol oleate were described by Stuart (19), and thorotrast has been widely used as a blockading agent (20)(21)(22)(23). Zymosan has generally been used as a stimulating agent (24)(25)(26), but has also been shown to cause an initial period of blockade (27), as described here. The stimulating effect of stilboestrol has been described by Nicol and coworkers (28), and our results are in agreement with their observations.…”

Traditional use, chemical constituents, and pharmacological activity of Maytenus laevis Reissek

“…The antibacterial activity, in species of the Genus Maytenus, is related to flavonoids and triterpenes (Zhang et al 2020). The evaluation of the aqueous (infusion and decoction) and alcoholic extracts of the leaves and bark of M. laevis have shown activity against Staphylococcus aureus, Streptococcus pyrogenes, Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 27853, in vivo and in vitro (Dicarlo et al 1964, Graak & Flemming 2004).…”

“…Research has shown that extracts of M. laevis induce antibacterial activity due to stimulation of the reticuloendothelial system in experimental animals (Dicarlo et al 1964, Graack & Flemming 1966, Rojas et al 2016.…”