Antimicrobial flavonoids from solanum dobium fres

Two flavonoids compounds were isolated from Solanum dobium Fers [Solanaceae]. One major compound was identified as astragalin [kampferol-3-O-glucoside], and a minor compound that was tentatively identified as quercetin-3-glycoside. The antimicrobial activities of the 2 compounds were tested against 12 microorganisms [7 bacteria, 2 fungi and 3 C and ida of different strains]. The major compound was found to possess a pronounced antibacterial activity as presented by the minimum inhibitory concentration showing activity 4 times as that of streptomycin and double that of tobramycin against Pseudomonas aeruginosa UM 60690. It displayed double activity of streptomycin against both Salmonella typhi UM 26049 and Flavobacterium meningosepticum UM 260494. In addition, the isolated astragalin showed a significant 2-4 times antic and idal activity as compared with nystatin against C and ida intermedia ATCC 5159, C and ida albicans Um 050494, and C and ida lipolytica ATCC 8661. However, this compound did not show any significant antifungal activity. The isolated minor flavonoid showed significant antic and idal, antifungal as well as moderate antibacterial activity

Preliminary screening of malaysian plants for antimicrobial activity

The alcoholic extract of 85 Malaysian higher plants belonging to 31 different families was assayed for antimicrobial activity against 12 bacteria, 3 fungi, 6 Candida/yeast and one flagellate. The evaluation tests for the antimicrobial activities were performed using the filter paper disc diffusion and tube dilution assays. Solanum nigrum [Solanaceae], Lawsonia inermis [Lecythidaceae], Phyllanthus niruri [Euphorbiaceae], and Spondias dulcis [Anacardiaceae] extracts exhibited strong antimicrobial activities against the tested microorganisms. However, L. inermis extract displayed strong antifungal activity against Aspergillus niger and Cunninghamella elegans. 6 other extracts showed moderate antimicrobial activities as compared to streptomycin and nystatin standard antibiotics

Microbial oxidation of oleic acid

Resting cells of Saccharomyces cerevisiae converted oleic acid [I] into 10-hydroxyoctadecanoic acid [II] in 45% yield. Nocardia aurantia [ATCC 12674], Nocardia sp. [NRRL 5646] and Mycobacterium fortuitum [UI 53378] have also converted oleic acid into 10-oxo-octadecanoic acid [III] in 65%, 55% and 80% yield, respectively. N. aurantia resting cells transformed III into the corresponding methyl ester [IV] in 37% yield. Structures of all metabolities were suggested by PMR and 13C- NMR, IR and mass spectrometry. The chemical Bayer-Villiger oxidation technique with 10-oxo-octadecanoic acid, followed by mass spectral analysis of neutral extracts, has been used to confirm the position of the oxo-functional group in the structures of keto-fatty acid. The PMR analysis of diastereometric S[+].O-acetylm and elate esters of hydroxystearate proved to be efficient in ascertaining stereochemical purities of hydroxy fatty acids

Metabolism of t-2 toxin by mucor and aspergillus sp

Biotransformation of the trichothecene [T-2 toxin] was attempted using non-trichothecene producing-strains of fungi in order to isolate and identify new T-2 metabolites. Incubation of the mycotoxin [T-2] with the growing culture of Mucor mucedo [MC 4605] and Aspergillus niger [NRRL 2295] produced a series of partially hydrolyzed and selectively acetylated derivatives. The purified cultural extracts of M. mucedo were analyzed by gas chromatography/mass spectroscopy and thin layer chromatography to reveal 3-acetoxy-T-2 [Ac-T-2, 69.40%], 4-deacetyl- T-2 [HT-2, 5.50%], 3-acetoxy HT-2 [Iso-T-2, 3.68%], 3-acetoxy- 3'-hydroxy-HT-2 [Iso TC-1, 1.42%]. The maximum percentage of metabolite formation was obtained after 11, 8, 9, 13, and 14 days, respectively. Similar metabolites were isolated from A. niger including HT-2 [10.0%], Iso-T-2 [4.48%], Iso-TC-1 [3.39%], and 3'-hydroxy-HT-2 [TC-3, 4.45%], which were maximally produced at about 4, 3, 5, 8 days, respectively