The activity of commercial antimicrobials, and essential oils and ethanolic extracts of Olea europaea on Streptococcus agalactiae isolated from pregnant women.

BACKGROUND: Streptococcus agalactiae also known as Group B Streptococcus (GBS) is a major cause of disease in pregnant women and new born babies where it causes early and late onset disease characterised by sepsis, pneumonia and meningitis. Ten to 37 % of pregnant women in the world are colonised with GBS while intrapartum antibiotic prophylaxis has led to significant reduction in early onset disease. The increase in drug resistant microorganisms has become a major threat. Development of vaccines is still in progress so there is need for new and safer alternatives to treatment. METHODS: Benzyl penicillin, Ampicillin, Cefotaxime, Ceftriaxone, Levofloxacin, Erythromycin, Clindamycin, Linezolid, Vancomycin, Tetracycline and Cotrimoxazole, Olea europaea leaf extracts and essential oil were tested against GBS isolates from South Africa and Namibia. RESULTS: The isolates showed 100% sensitivity to benzyl penicillin, ampicillin, ceftriaxone, levofloxacin, linezolid, vancomycin, O. europaea leaf extracts and essential oils. Only one isolate (0.6%) was resistant to cefotaxime and 23.4 and 10.4% were resistant to clindamycin and erythromycin respectively. CONCLUSION: GBS isolates showed sensitivity to O. europaea extracts at low minimum inhibitory concentrations. Β lactams are still the drugs of choice for treatment of GBS disease but O. europaea extracts potent as an alternative source of antimicrobials.

Bioactive Constituents, Radical Scavenging, and Antibacterial Properties of the Leaves and Stem Essential Oils from Peperomia pellucida (L.) Kunth.

BACKGROUND: Peperomia pellucida is an annual herbaceous ethnomedicinal plant used in the treatment of a variety of communicable and noncommunicable diseases in the Amazon region. OBJECTIVE: The study aimed at profiling the bioactive constituents of the leaves and stem essential oils (LEO and SEO) of P. pellucida, their in vitro antibacterial and radical scavenging properties as probable lead constituents in the management of oxidative stress and infectious diseases. Materials and. METHODS: The EOs were obtained from the leaves and stem P. pellucida using modified Clevenger apparatus and characterized by a high-resolution gas chromatography-mass spectrometry, while the radicals scavenging and antibacterial effects on four oxidants and six reference bacteria strains were examined by spectrophotometric and agar diffusion techniques, respectively. RESULTS: The EOs exhibited strong antibacterial activities against six bacteria (Escherichia coli [180], Enterobacter cloacae, Mycobacterium smegmatis, Listeria ivanovii, Staphylococcus aureus, Streptococcus uberis, and Vibrio paraheamolyticus) strains. The SEO antibacterial activities were not significantly different (P < 0.05) from the LEO against most of the test bacteria with minimum inhibitory concentration ranging between 0.15 and 0.20 mg/mL for both EOs. The two oils were bactericidal at 0.20 mg/mL against S. aureus while the minimum bactericidal concentration (0.15 mg/mL) of LEO against L. ivanovii was lower than of SEO (0.20 mg/mL) after 24 h. The LEO IC50 value (1.67 mg/mL) revealed more radical scavenging activity than the SEO (2.83 mg/mL) and reference compounds against 2,2-diphenyl-1-picrylhydrazyl radical. The EOs also scavenged three other different radicals (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical, lipid peroxyl radical, and nitric oxide radical) in concentration-dependent manner. CONCLUSION: Our results suggest that apart from the indigenous uses of the plant extracts, the EO contains strong bioactive compounds with antibacterial and radicals scavenging properties and may be good alternative candidates in the search for novel potent antibiotics in this present era of increasing multidrug-resistant bacterial strains as well as effective antioxidants agents. SUMMARY: Established gas chromatography-mass spectrometry technique was applied to quantitatively and qualitatively analyze the volatile constituents in Peperomia pellucida essential oil (EO)The Clinical and Laboratory Standards Institute (2014) guidelines were employed to evaluate the antibacterial effects of the EOsAmong the known prominent bioactive terpenoids, linalool 17.09%, limonene 14.25%, ß-caryophyllene 12.52%, and linalyl acetate 10.15% were the main constituents of the EOs in this current studyThe leaf and stem EOs were bactericidal at a concentration below 0.23 mg/mL against three multidrug-resistant bacteria and significantly scavenged known free radicals reported to be associated with contagious and oxidative stress-related disorders. Abbreviations used: GC-MS: Gas chromatography-mass spectrometry, DPPH: 2,2-diphenyl-1-picrylhydrazyl, ABTS: 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, DMSO: Dimethyl sulfoxide, LP•: Lipid peroxide radical, NO•: Nitric oxide radical, LEO: Leaf essential oil, SEO: Stem essential oil, RC: Reference compound, TBARS: Thiobarbituric acid.

Antibacterial and Antioxidant Properties of the Leaves and Stem Essential Oils of Jatropha gossypifolia L.

Antibacterial and antioxidant properties of the leaves and stem essential oils (EOs) of Jatropha gossypifolia and their efficacies against infectious and oxidative stress diseases were studied in vitro. The EOs obtained using Clevenger modified apparatus were characterized by high resolution GC-MS, while their antioxidant and antibacterial properties were examined by spectrophotometric and agar diffusion techniques, respectively. The EOs exhibited strong antibacterial activity against Escherichia coli, Enterococcus faecium, and Staphylococcus aureus. The stem essential oil (SEO) was more active than the leaf essential oil (LEO) against test bacteria with minimum inhibition concentration (MIC) ranging from 0.025 to 0.05 mg/mL and the LEO from 0.05 to 0.10 mg/mL. The SEO was bactericidal at 0.025 and 0.05 mg/mL against S. aureus and E. faecium, respectively, and the LEO was bacteriostatic against the three bacteria at 0.05 and 0.10 mg/mL. The SEO IC50 (0.07 mg/mL) showed that the antiradical strength was superior to LEO (0.32 mg/mL) and ß-carotene (1.62 mg/mL) in scavenging 2, 2-diphenyl-1-picrylhydrazyl radicals (DPPH•). The oils effectively reduced three other oxidants to neutral molecules in concentration dependent manner. Findings from this study suggest that, apart from the traditional uses of the plant extracts, the EOs have strong bioactive compounds with noteworthy antibacterial and antiradical properties and may be good candidates in the search for lead compounds for the synthesis of novel potent antibiotics.