Oligomerization of esculin improves its antibacterial activity and modulates antibiotic resistance.

In this particular study, the antibacterial activity of esculin and oligomer fractions was assessed. MIC values of esculin and its oligomer fractions as well as of some antibiotics against Gram-positive and Gram-negative strains and against Escherichia coli multiresistant variants were determined by the standard broth microdilution method. Both esculin and oligoesculin fractions exhibited antibacterial effect against reference strains; Staphylococcus aureus, Enterococcus faecalis, Salmonella enteritidis and Salmonella typhimurium. It appears that E3 oligomer fraction had the greatest antibacterial activity against these reference strains. Besides, as E2 and E3 revealed the best antibacterial effect against multiresistant variants of E. coli, we decided to test the effect of each, combined to the antibiotic against which the variants were resistant. In the interaction study, E2 and E3 oligoesculin fractions were found to be effective in reducing the resistance of E. coli 6574 to ofloxacin and the resistance of E. coli 6228 to amoxicillin. Only E3 oligoesculin fraction showed a synergetic interaction with amoxicillin and tetracyclin against E. coli 6708, but no interaction was found either with E2 or E3 fractions against E. coli 6234. Our study allowed us to conclude that oligomerization of esculin increases its antibacterial potential, according to the degree of polymerization.

Limoniastrum guyonianum methanol extract induces immunomodulatory and anti-inflammatory effects by activating cellular anti-oxidant activity.

Evaluation of the immunomodulatory activity of plant extracts is an interesting and growing area of research. In this study, effects of a methanolic extract of Limoniastrum guyonianum stems (M extract) on mice immune cell function in vitro were investigated. These studies showed that mitogen-induced lymphocyte proliferation was dose-dependently inhibited by the extract. Further, the lectin-induced response appeared to be more sensitive to the suppressive effects of the extract than were LPS-stimulated responses. In studies to assess any potential effects of extract on innate immunity, the results showed that the extract significantly enhanced the killing activity of isolated NK cells. In addition, studies here demonstrated that the extract could enhance lysosomal enzyme activity and inhibit nitrite oxide (NO) production by murine peritoneal macrophages ex vivo, suggesting a potential anti-inflammatory effect in situ. The anti-inflammatory activity was concomitant with the cellular anti-oxidant effect in macrophages and splenocytes.

An aqueous extract of Limoniastrum guyonianum gall induces anti-tumor effects in melanoma-injected mice via modulation of the immune response.

The objectives of this study were to evaluate the in vitro and in vivo anti-tumor potential of the aqueous gall extract (G extract) from Limoniastrum guyonianum and to elucidate its immunological mechanisms, in part, by assessing its effects on the growth of transplanted tumors and the immune response in these tumor-bearing mice. Here, mice were inoculated with B16F10 mouse tumor cells and then treated intraperitoneally with G extract at 25 or 50 mg extract/kg BW for 7, 14, or 21 days. At each timepoint, effects of the extract on the tumor growth, splenocytes proliferation, NK cell activity, and CTL activity among splenocytes isolated from the mice were measured. G extract-induced tumor growth inhibition was associated with characteristic apoptotic changes in the tumor cells, like nuclear condensation. In addition, the extract inhibited melanin synthesis and tyrosinase activity among melanoma cells in a concentration-related manner. G extract did not only significantly inhibit the growth of the transplantable tumor, but also remarkably increased splenocytes proliferation and both NK and CTL activities in tumor-bearing mice. The extract was also seen to have promoted lysosomal activity of host macrophages and gave rise to enhanced cellular anti-oxidant activity in several cell types in mice.

Evaluation of in vitro antioxidant and apoptotic activities of Cyperus rotundus

OBJECTIVE@#To evaluate in vitro antioxidant and apoptotic activities of Cyperus rotundus (C. rotundus).@*METHODS@#The phytochemical study and the antioxidant activities of both methanol and aqueous extracts from C. rotundus aerial part were determined. In addition, these extracts were also investigated for their cytotoxic and apoptotic activities. The major compound of the methanol extract was isolated. Both methanol and aqueous extracts (300, 150, and 50 μg/mL) were evaluated for their antioxidant activity by the xanthine/xanthine oxidase assay system. However, 16, 8, and 4 mg/mL of each extract were tested to investigate their OH. formation scavenging potential. Aqueous extract (800, 400, and 200 μg/mL) and methanol extract (350, 175, and 88 μg/mL) were tested against lipid peroxidation, induced by 75 μM H2O2. The cytotoxicity (by MTT assay) and cell DNA fragmentation of both extracts were evaluated towards K562 and L1210 cell lines. The major compound was obtained from the butanol fraction of methanol extract and its structure was determined by RMN spectroscopic analysis.@*RESULTS@#The methanol and aqueous extracts showed respectively, 88% and 19% inhibition of xanthine oxidase activity. Yet, the same extracts inhibited lipid peroxidation by 61.5% and 42.0%, respectively. Both extracts inhibited OH. formation by 27.1% and 25.3%, respectively. Only methanol extract induced DNA degradation. Orientin was determined as the major compound isolated from the butanol fraction of methanol extract.@*CONCLUSIONS@#It appears that C. rotundus extracts exhibit a potential use as a natural antioxidant and an apoptosis inducer.