Myristica lowiana Phytochemicals as Inhibitor of Plasmid Conjugation in Escherichia coli.

Hexane extract and methanol fraction from the stem bark of Myristica lowiana specifically and significantly inhibited the conjugal transfer of the IncW plasmid R7K, a plasmid which harbors ampicillin-, streptomycin-, and spectinomycin-resistant genes. The transfer of this plasmid via the conjugative pilli of Escherichia coli was reduced by 76.5 ± 2.0% and 79.0 ± 1.2% by hexane extract and methanol fraction of M. lowiana, respectively. The hexane extract exhibited significant anti-conjugant activity at a non-cytotoxic concentration of 100 mg/L as assessed against adult human dermal fibroblast cells. The hexane extract and methanol fraction were screened using phytochemical tests, NMR spectroscopy, IR spectroscopy, and high-resolution electrospray ionization mass spectrometry (HRESIMS) and were found to contain terpenoids, sterols, and fatty acids.

Inhibiting plasmid mobility: The effect of isothiocyanates on bacterial conjugation.

Bacterial conjugation is the main mechanism for the transfer of multiple antimicrobial resistance genes among pathogenic micro-organisms. This process may be controlled by compounds that inhibit bacterial conjugation. In this study, the effects of allyl isothiocyanate, l-sulforaphane, benzyl isothiocyanate, phenylethyl isothiocyanate and 4-methoxyphenyl isothiocyanate on the conjugation of broad-host-range plasmids harbouring various antimicrobial resistance genes in Escherichia coli were investigated, namely plasmids pKM101 (IncN), TP114 (IncI2), pUB307 (IncP) and the low-copy-number plasmid R7K (IncW). Benzyl isothiocyanate (32 mg/L) significantly reduced conjugal transfer of pKM101, TP114 and pUB307 to 0.3 ± 0.6%, 10.7 ± 3.3% and 6.5 ± 1.0%, respectively. l-sulforaphane (16 mg/L; transfer frequency 21.5 ± 5.1%) and 4-methoxyphenyl isothiocyanate (100 mg/L; transfer frequency 5.2 ± 2.8%) were the only compounds showing anti-conjugal specificity by actively reducing the transfer of R7K and pUB307, respectively.

Wound healing potential of methanol extract of Spathodea campanulata stem bark formulated into a topical preparation.

This study evaluated the wound healing potential of Spathodea campanulata stem bark in Sprague Dawley rats using the excision wound model. The methanol extract contained glycosides, flavonoids and tannins, and was relatively stable when stored at the room temperature for six (6) months. Solvent-free, semi-solid extract of S. campanulata was incorporated into an aqueous cream and applied (10 % w/w and 20 % w/w) on excision wounds of thirty two (32) rats. Cicatrin(®) cream was used as a standard wound healing agent. Prior to the remedial cream application, done later on twice daily, sixteen (16) rats had their wounds infected with Staphylococcus aureus, while in the remaining sixteen the wounds were kept clean. The surface area of the excision wounds was monitored planimetrically every four (4) days until a complete wound closure or healing took place. Excision wounds treated with 20 % w/w Spathodea cream and Cicatrin(®) cream showed a rapid and comparable decrease (p > 0.05) in wound size. In uninfected wounds, both 20 % w/w Spathodea cream and Cicatrin(®) cream application resulted in ∼ 95 %-wound closure seen on Day 20, and a complete closure seen on Day 24. In infected wounds, both 20 % w/w Spathodea cream and Cicatrin(®) cream administration led to ∼ 91 %-wound closure on Day 24 and a complete wound contraction on Day 28. The results of this study justify the folkloric use of S. campanulata stem bark to the effect of wound treatment.