Synthesis of new bis-pyrazole linked hydrazides and their in vitro evaluation as antimicrobial and anti-biofilm agents: A mechanistic role on ergosterol biosynthesis inhibition in Candida albicans.

Literature reports suggest that pyrazoles and hydrazides are potential antimicrobial pharmocophores. Considering this fact, a series of nineteen conjugates containing hybrids of bis-pyrazole scaffolds joined through a hydrazide linker were synthesized and further evaluated for their antimicrobial activity against a panel of Gram-positive and Gram-negative bacteria along with Candida albicansMTCC 3017 strain. Although the derivatives exhibited good antibacterial activity, some of the derivatives (13d, 13j, 13l, 13p, and 13r) showed excellent anti-Candida activity with MICs values of 3.9 µg/ml, which was equipotent to that of the standard Miconazole (3.9 µg/ml), which has inspired us to further explore their anti-Candida activity. The same compounds were also tested for anti-biofilm studies against various Candida strains and among them, compounds 13l and 13r efficiently inhibited the formation of fungal biofilms. Field emission scanning electron micrographs revealed that one of the promising compound 13r showed cell damage and in turn cell death of the Candida strain. These potential conjugates (13l and 13r) also demonstrated promising ergosterol biosynthesis inhibition against some of the strains C. albicans, which were further validated through molecular docking studies. In silico computational studies were carried out to predict the binding modes and pharmacokinetic parameters of these conjugates.

Synthesis of Novel Fatty Substituted 4-methyl-2HChromen-2-one via Cross Metathesis: Potential Antioxidants and Chemotherapeutic Agents.

A series of novel fatty substituted 4-methyl-2H-chromen-2-one (coumarins) were synthesized by employing cross metathesis, a key step in the synthesis. The antioxidant activities of the title compounds were compared with the commercial antioxidants, namely butylated hydroxy toluene (BHT) and α-tocopherol, glycosidic and other substituted 4-methyl-2H-chromen-2-ones. Among the different 4-methyl-2H-chromen-2-ones, the glycosidic substituted 4-methyl-2H-chromen-2-ones was excellent, while those with aliphatic fatty acid chain and hydroxyl substitutents were good. Among the substituted 4-methyl-2H-chromen-2-ones, glycosidic, hydroxyl and cyano containing 4-methyl-2H-chromen-2-ones exhibited good, while fatty substituted exhibited moderate anticancer activities against the four different cancer cell lines tested, namely DU145 (Prostate carcinoma cancer cell), HepG2 (Hepato cellular carcinoma cancer cell), SKOV3 (Ovarian cancer cell) and MDA-MB 231 (Human breast cancer cell). The study reveals that these substituted coumarins can be potential candidates in a number of food and pharmaceutical formulations.

Synthesis, Surface Active Properties and Cytotoxicity of Sodium N-Acyl Prolines.

Sodium N-acyl prolines (NaNAPro) were synthesized using mixture of fatty acids obtained from coconut, palm, karanja, Sterculia foetida and high oleic sunflower oils via Schotten-Baumann reaction in 58-75% yields to study the synergetic effect of mixture of hydrophobic fatty acyl functionalities like saturation, unsaturation and cyclopropene fatty acids with different chain lengths and aliphatic hetero cyclic proline head group on their surface and cytotoxicity activities. The products were characterized by chromatographic and spectral techniques. The synthesized products were evaluated for their surface active properties such as surface tension, wetting power, foaming characteristics, emulsion stability, calcium tolerance, critical micelle concentration (CMC) and thermodynamic properties. The results revealed that all the products exhibited superior surface active properties like CMC, calcium tolerance and emulsion stability as compared to the standard surfactant, sodium lauryl sulphate (SLS). In addition, palm, Sterculia foetida and high oleic sunflower fatty N-acyl prolines exhibited promising cytotoxicity against different tumor cell lines.

Synthesis of novel lipoamino acid conjugates of sapienic acid and evaluation of their cytotoxicity activities.

Novel lipoamino acids were prepared with the coupling of sapienic acid [(Z)-6-hexadecenoic acid] with α - amino group of amino acids and the resulting N-sapienoyl amino acids were tested for their cytotoxicity activities against four cancer based cell lines. Initially, sapienic acid was synthesized by the Wittig coupling of triphenylphosphonium bromide salt of 6-bromohexanoic acid and decanal with a Z specific reagent. The prepared sapienic acid was subsequently converted to its acid chloride which was further coupled with amino acids by the Schotten-Baumann reaction to form N-sapienoyl amino acid conjugates. Structural characterization of the prepared N-sapienoyl amino acid derivatives was done by spectral data (IR, mass spectra and NMR). These lipoamino acid derivatives were screened for in vitro cytotoxicity evaluation. Cytotoxicity evaluation against four cancer cell lines showed that N-sapienoyl isoleucine was active against three cell lines whereas other derivatives either showed activity against only one or two cell lines with very moderate activity and two derivatives were observed to be inactive against the tested cell lines.

A marine sponge associated strain of Bacillus subtilis and other marine bacteria can produce anticholinesterase compounds.

BACKGROUND: Acetylcholinesterase (AChE) inhibitors or anticholinesterases reduce the activity of enzyme acetylcholinesterase that degrades the neurotransmitter acetylcholine in the brain. The inhibitors have a significant pharmacological role in neurodegenerative diseases like Alzheimer's and Parkinson's etc. Although plants have been a significant source of these compounds, there are very few sporadic reports of microorganisms producing such inhibitors. Anticholinesterase activity in bacterial associates of marine soft corals and sponges were not previously reported. RESULTS: We screened 887 marine bacteria for the presence of acetylcholinesterase inhibitors, in a microplate based assay, and found that 140 (15.8%) of them inhibit the electric eel enzyme, acetylcholinesterase. Majority of the active isolates were bacterial associates of soft corals followed by sediment isolates while most of the potent inhibitors belonged to the bacterial associates of marine sponges. Maximum inhibition (54%) was exhibited by a bacterial strain M18SP4P (ii), isolated from the marine sponge Fasciospongia cavernosa. Based on phenotypic characterization and 16S rDNA sequencing, the strain was identified as Bacillus subtilis - revealing yet another activity in a strain of the model organism that is considered to be a cell factory. TLC bioautography of the methanol extract of this culture, showed the presence of two major components having this activity, when compared to Galanthamine, the positive control. CONCLUSION: From the results of our study, we conclude that acetylcholinesterase inhibitors are quite prevalent in marine bacteria, particularly the bacterial associates of marine invertebrates. Several potential AChE inhibitors in marine bacteria are waiting to be discovered to provide easily manipulable natural sources for the mass production of these therapeutic compounds.

Evaluation of critical nutritional parameters and their significance in the production of rhamnolipid biosurfactants from Pseudomonas aeruginosa BS-161R.

Eleven biosurfactant producing bacteria were isolated from different petroleum-contaminated soil and sludge samples. Among these 11 isolates, two were identified as promising, as they reduced the surface tension of culture medium to values below 27 mN m(-1) . Besides biosurfactant production property, they exhibited good flocculating activity. Microbacterium sp. was identified as a new addition to the list of biosurfactant and bioflocculant-producers. Optimization of various conditions for rhamnolipid production was carried out for one of the promising isolate, Pseudomonas aeruginosa BS-161R. Bioglycerol (2.5%), as a cheap renewable carbon source, attained better rhamnolipid yield, while sodium nitrate appeared to be the preferable nitrogen source. The optimum carbon to nitrogen (C/N) and carbon to iron (C/Fe) ratios achieved were 15 and 28,350, respectively, which favored rhamnolipid production. Physical parameters like pH, temperature, and agitation speed also affected the production of rhamnolipids. Results from shake flask optimization indicated that the concentration of bioglycerol, sodium nitrate, and iron were the most significant factors affecting rhamnolipid production, which was supported by the results of central composite rotatable design. After optimization of the culture conditions, the production of rhamnolipids increased by ninefold from 0.369 to 3.312 g L(-1) .

New bioactive macrocyclic diterpenoids from Jatropha multifida.

Two new macrocyclic diterpenoids, multifidanol (1) and multifidenol (2) along with several known compounds have been isolated from the stem of Jatropha multifida. The structures of the new compounds were established from the extensive studies of their 1D and 2D NMR spectra. The cytotoxic and antimicrobial activities of these two constituents were examined.