Synthesis, antimicrobial evaluation and QSAR studies of N'-benzylidene/(1-phenylethylidene)undec-10-enehydrazides.

A series of N'-benzylidene/(1-phenylethylidene)undec-10-enehydrazide was synthesized starting from undec-2-enoic acid through multi-step reactions. Synthesized derivatives were evaluated for their in vitro antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Candida albicans by tube dilution method. The preliminary results showed the significance of o-NO2, m-NO2 and m-OCH3 groups at phenyl ring in describing antimicrobial activity of synthesized compounds. QSAR studies revealed that second order molecular connectivity index (2χ) and Balaban topological index (J) are the key parameters for antimicrobial activity of synthesized hydrazide derivatives and can be cosidered as important factors for interaction with target site of different microorganisms. It is pertinent to note that multi-target QSAR models were more significant in demonstrating the antimicrobial activity than one-target QSAR models.

Metabolic engineering of chloroplasts for artemisinic acid biosynthesis and impact on plant growth.

Chloroplasts offer high-level transgene expression and transgene containment due to maternal inheritance, and are ideal hosts for biopharmaceutical biosynthesis via multigene engineering. To exploit these advantages, we have expressed 12 enzymes in chloroplasts for the biosynthesis of artemisinic acid (precursor of artemisinin, antimalarial drug) in an alternative plant system. Integration of transgenes into the tobacco chloroplast genome via homologous recombination was confirmed by molecular analysis, and biosynthesis of artemisinic acid in plant leaf tissues was detected with the help of 13C NMR and ESI-mass spectrometry. The excess metabolic flux of isopentenyl pyrophosphate generated by an engineered mevalonate pathway was diverted for the biosynthesis of artemisinic acid. However, expression of megatransgenes impacted the growth of the transplastomic plantlets. By combining two exogenous pathways, artemisinic acid was produced in transplastomic plants, which can be improved further using better metabolic engineering strategies for commercially viable yield of desirable isoprenoid products.