Maryam Gholami

Computer-aided design of novel antibacterial 3-hydroxypyridine-4-ones: application of QSAR methods based on the MOLMAP approach

Abstract3-Hydroxypyridine-4-one derivatives have shown good inhibitory activity against bacterial strains. In this work we report the application of MOLMAP descriptors based on empirical physicochemical properties with genetic algorithm partial least squares (GA-PLS) and counter propagation artificial neural networks (CP-ANN) methods to propose some novel 3-hydroxypyridine-4-one derivatives with improved antibacterial activity against Staphylococcus aureus. A large collection of 302 novel derivatives of this chemical scaffold was selected for this purpose. The activity classes of these compounds were determined using the two quantitative structure activity relationships models. To evaluate the predictability and accuracy of the obtained models, nineteen compounds belonging to all three activity classes were prepared and the activity of them was determined against S. aureus. Comparing the experimental results and the predicted activity classes revealed the accuracy of the obtained models. Seventeen of the nineteen synthesized molecules were correctly predicted by GA-PLS model according to the antimicrobial evaluation method. Molecules 5f and 5h proved to be moderately active and active experimentally, but were predicted as inactive and moderately active compounds, respectively by this model. The CP-ANN based prediction was correct for sixteen out of the nineteen synthesized molecules. 5a, 5h and 5q were moderately active and active based on the antimicrobial assays, but they were introduced as members of inactive, moderately active and inactive classes of compounds, respectively according to CP-ANN model.

Antimicrobial and antioxidant activity and chemical composition of the essential oil of Tanacetum macrophyllum (Waldst. et Kit.) Schultz. Bip.

Abstract The essential oil of Tanacetum macrophyllum growing wild in Turkey was obtained by hydrodistillation, and antimicrobial activity of the essential oil was tested against six bacteria and two yeasts including Candida albicans and Aspergillus niger by disc diffusion method. Further the oil of this plant was analyzed by GC and GC/MS technique. Best effect of the oil was against pseudomonas earuginosa. Twenty-eight components, representing 95.6% of the total oil, were identified. The main component of the oil was β-eudesmol (89.5%). The antioxidant activity of the essential oil was measured by the ferric reducing antioxidant power (FRAP) assay.

Essential oil composition of four Hypericum species from Iran

L., is used as a valuable medicinal plant for nervous exhaustion, depression, and seasonal affective disorders [3]. This genus contains a wide range of different natural product classes, including naphthodianthrones (e.g., hypericin), prenylated phloroglucinols (e.g., hyperforin), xanthones, flavonoids, biflavonoids, tannins, proanthocyanidins, and phenolic acids [4]. Hypericum helianthemoides (Spach) Boiss., H. hirtellum (Spach) Boiss., H. scabrum L., and H. dogonbadanicum Assadi. are four Hypericum species whose oils have been subjected to analysis in this article. H. dogonbadanicum, the only member of the section Campylusporus in Iran, is a narrow endemic plant confined to mountainous regions NE of Gachsaran city, SW of Iran; the other three species belong to the Hirtella section and are distributed W and NW of Iran [2]. Here we report on the chemical composition of these four species, two of which, Hypericum helianthemoides and H. hirtellum, have not been subjected to any previous phytochemical analysis. Data on the constituents of the four Hypericum oils are shown in Table 1. According to Table 1, monoterpenes are the major constituents of H. scabrum (Fars, Doshman Ziari, 2005; 73.7%) and H. dogonbadanicum (Kohkilooyeh, Gachsaran, 2006; 59.4%), while the major compounds in H. helianthemoides (Fars, Hesami, Roshan Kuh, 2005) and H. hirtellum (Fars, Neyriz, 2006) are sesquiterpenes with 74.1% and 53.0% of the total oils, respectively. The first major compound of H. scabrum and H. dogonbadanicum is α-pinene, which is a major and characteristic constituent of many Hypericum species like H. perforatum [5], H. forrestii [6], H. perfoliatum [7], H. triquetrifolium [8], H. hircinum [9], H. hyssopifolium, and H. heterophyllum [10]. In three previous works on H. scabrum oil, α-pinene was also shown to be the first major compound and in two of them, like ours, α-pinene constituted more than 40% of the total oil [11, 12]. However, in the other report α-pinene only comprised 11.2% of the total oil [13]. Comparison of the other constituents of these reports and ours show that the other major compounds are completely different from each other, which could be attributed to different localities where the plant materials were collected. The major constituents of H. dogonbadanicum oils of our work and previous work [14] were the same but differ in order and percentage. α-Pinene (34.7%), β-pinene (32.1%), limonene (12.1%), and camphene (6.6%) were the first four major compounds of previous work that were the first (12.8%), third (4.7%), second (8.2%), and sixth (3.9%) majors of ours. Major compound percentages in our work were totally less than the previous work. Because of the very limited distribution range of this species, locality could not be an important factor in this difference. Our plant material was collected before bud blooming; different stages of flowering may resulted in different chemical compositions of these two oils. Two first major compounds of H. helianthemoides and H. hirtellum are the same; β-caryophyllene (23.3%, 14.1%) and spathulenol (17.4%, 12.3%) with respective percentage. β-Caryophyllene was also among the major constituents of H. perforatum [5], H. triquetrifolium [8], H. bupleuroides [15], H. carinatum [16], H. maculatum [17], H. foliosum [18], and H. brasiliense [19]; and spathulenol was one of the main compounds of H. perforatum [5], H. hissopifolium [20] and H. linarioides [21]. α-Pinene is also the fourth and third major compounds of H. helianthemoides (6.7%) and H. hirtellum (9.8%), respectively. The third major constituent of H. helianthemoides is 14-hydroxy-9-epi-(E)-carophyllene, with the caryophyllene skeleton. Compounds with this skeleton comprise 47.9% of H. helianthemoides total oil. Nonane was a characteristic constituent of H. perfoliatum [7], H. triquetrifolium [8], H. hircium [9], H. scabrum [11], H. caprifoliatum [16], H. foiosum [18], and H. richeri [22] oils, the amount of which was not considerable in the four Hypericum oils of our work.

Microbial biotransformation of some monoterpene hydrocarbons

High commercial value compounds can be obtained through the microbial biotransformation of monoterpenes. Some of these monoterpenic substances are not expensive and produced in a variety of plant species. Biotransformation of some monoterpene hydrocarbons such as α-pinene, β-pinene, myrcene and p-cymene by 7 strain bacteria and 2 strain fungi was investigated. It was observed that some of microorganisms transformed monoterpenes to oxygenated monoterpenes in a good yield which among themStaphylococcus epidermidis showed higher yields.