ABSTRACT
Aims@#This study was aimed to screen indigenous medicinal plants for their antibacterial potential against methicillin-resistant Staphylococcus aureus (MRSA).@*Methodology and results@#Three indigenous plants (Nigella sativa, Zingiber officinale and Calotropis procera) and thymoquinone were screened for antibacterial activity against MRSA, isolated from septic wounds of patients admitted to Mayo Hospital Lahore, Pakistan. Isolated bacteria were screened for methicillin and cefoxitin resistance by the Kirby-Bauer method, followed by mecA gene-specific polymerase chain reaction (PCR). Confirmed MRSA was processed for antibacterial activity of plant extracts and thymoquinone followed by cytotoxicity assay of plant extract having least minimum inhibitory concentration (MIC) value. Out of total samples (n=100), S. aureus (29%), MRSA (26%) and vancomycin-resistant S. aureus (VRSA) (21.7%) isolates were recovered based on morphology, biochemical profile and antibiotic susceptibility testing. Nigella sativa showed the highest antibacterial activity (10.06 ± 6.53 mm) against MRSA followed by Z. officinale (4.06 ± 3.72 mm) and C. procera (3.65 ± 3.33 mm) in comparison to standard thymoquinone (17.93 ± 10.14 mm). The least MIC value recorded was for Z. officinale at 36.89 ± 3.75 μg/mL. Zingiber officinale was the most effective antibacterial agent, followed by N. sativa and C. procera and non-toxic for eukaryotic cells at all tested concentrations (1500 μg/mL to 2.92 μg/mL).@*Conclusion, significance and impact of study@#It was concluded that Z. officinale may be used as an effective alternative for treating septic wound infection in local or topical preparations. As pathogenic S. aureus is becoming life-threatening among antibiotic-resistant bacteria and traditional plants are in used for centuries to treat septic wound infections.
Subject(s)
Plants, MedicinalABSTRACT
Aims@#This paper presents the report on biodiesel and biogas production at a laboratory scale from Scenedesmus strain.@*Methodology and results@#Previously isolated and identified Scenedesmus were grown in 10 Liter flask using BG-11 media at 16 h light and 8 h dark cycle. Oven-dried biomass (20 g) from 16-day-old culture of Scenedesmus was finely grounded and subjected to lipids extraction by chloroform-methanol-NaCl mixture. Microalgal lipids (6 mL) were subjected to transesterification by using NaOH leading to the production of 5 mL biodiesel and 4 mL of glycerin. Biodiesel was rich in methyl esters of linoleic acid, phosphorothioc acid and dodecanoic acid, as shown by gas chromatography-mass spectrometry (GC-MS) analysis. Oven-dried microalgae (2 g) without lipid extraction and leftover biomass (2 g) after lipid extraction were subject to biogas production through anaerobic digestion. Biogas (34, 27 and 19 mL) were recorded respectively in oven-dried whole biomass; lipid extracted biomass and control over a period of 15 days of anaerobic digestion.@*Conclusion, significance and impact of study@#It was concluded that water bodies are rich in diverse algae, especially Scenedesmus sp., and this algae can be cultured to produce biodiesel and biogas. But the lipid accumulation potential of microalgae requires special treatment and lipid extraction methods are not up to the mark, which is a major bottleneck in biofuel production from microalgae.