@article { ISI:000308099200029, title = {Preparative separation of alpha- and beta-santalenes and (Z)-alpha- and (Z)-beta-santalols using silver nitrate-impregnated silica gel medium pressure liquid chromatography and analysis of sandalwood oil}, journal = {Analyst}, volume = {137}, number = {19}, year = {2012}, month = {MAY}, pages = {4564-4570}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The major sesquiterpene constituents of East-Indian sandalwood oil (Z)-alpha- and (Z)-beta-santalols have shown to be responsible for most of the biological activities and organoleptic properties of sandalwood oil. The work reported here describes the strategic use of medium pressure liquid chromatography (MPLC) for the separation of both alpha- and beta-santalenes and (Z)-alpha- and (Z)-beta-santalols. Silver nitrate impregnated silica gel was used as the stationary phase in MPLC for quantitative separation of alpha- and beta-santalenes and (Z)-alpha- and (Z)-beta-santalols with mobile phases hexane and dichloromethane, respectively. The purities of alpha-santalene and (Z)-alpha-santalol obtained were \>96\%; however, beta-santalene and (Z)-beta-santalol were obtained with their respective inseparable epi-isomers. Limits of quantification (LoQ) relative to the FID detector were measured for important sesquiterpene alcohols of heartwood oil of S. album using serial dilutions of the standard stock solutions and demonstrated that the quality of the commercial sandalwood oil can be assessed for the content of individual sesquiterpene alcohols regulated by Australian Standard (AS2112-2003), International Organization for Standardization ISO 3518: 2002 (E) and European Union (E. U.).

}, issn = {0003-2654}, doi = {10.1039/c2an35575b}, author = {Daramwar, Pankaj P. and Srivastava, Prabhakar Lal and Priyadarshini, Balaraman and Thulasiram, Hirekodathakallu V.} } @article {43289, title = {Self-assembly to function: design, synthesis and broad spectrum antimicrobial properties of short hybrid E-vinylogous lipopeptides}, journal = {Journal of Medicinal Chemistry}, volume = {56}, year = {2013}, month = {NOV}, pages = {8468-8474}, abstract = {Nonribosomal E-vinylogous gamma-amino acids are widely present in many peptide natural products and have been exploited as inhibitors for serine and cysteine proteases. Here, we are reporting the broad spectrum antimicrobial properties and self-assembled nanostructures of various hybrid lipopeptides composed of 1:1 alternating alpha-and E-vinylogous residues. Analysis of the results revealed that self-assembled nanostructures also play a significant role in the antimicrobial and hemolytic activities. In contrast to the alpha-peptide counterparts, vinylogous hybrid peptides displayed excellent antimicrobial properties against various bacterial and fungal strains. Peptides that adopted nanofiber structures displayed less hemolytic activity, while peptides that adopted nanoneedle structures displayed the highest hemolytic activity.}, doi = {10.1021/jm400884w}, author = {Shankar, S. Shiva and Benke, Sushil N. and Nagendra, Narem and Srivastava, Prabhakar Lal and Thulasiram, Hirekodathakallu V. and Gopi, Hosahudya N.} } @article { ISI:000330790100004, title = {Biocatalyst mediated regio- and stereo-selective hydroxylation and epoxidation of (Z)-alpha-santalol}, journal = {Organic \& Biomolecular Chemistry}, volume = {12}, number = {7}, year = {2014}, month = {JAN}, pages = {1048-1051}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Biocatalyst mediated regio- and stereo-selective hydroxylation and epoxidation on (Z)-alpha-santalol were achieved for the first time, using a fungal strain Mucor piriformis. Four novel metabolites were characterized as 10,11-cis-beta-epoxy-alpha-santalol, 5 alpha-hydroxy-(Z)-alpha-santalol, 10,11-dihydroxy-alpha-santalol and 5 alpha-hydroxy-10,11-cis-beta-epoxy-alpha-santalol. Using Amano PS lipase from Burkholderia cepacia, alpha- and beta-isomers of 10,11-cis-epoxy-alpha-santalol were resolved efficiently.

}, issn = {1477-0520}, doi = {10.1039/c3ob42174k}, author = {Daramwar, Pankaj P. and Srivastava, Prabhakar Lal and Kolet, Swati P. and Thulasiram, Hirekodathakallu V.} } @article { ISI:000348833400001, title = {Characterization of 10-hydroxygeraniol dehydrogenase from catharanthus roseus reveals cascaded enzymatic activity in iridoid biosynthesis}, journal = {Scientific Reports}, volume = {5}, year = {2015}, month = {FEB}, pages = {Article Number: 8258}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

Catharanthus roseus [L.] is a major source of the monoterpene indole alkaloids (MIAs), which are of significant interest due to their therapeutic value. These molecules are formed through an intermediate, cis-trans-nepetalactol, a cyclized product of 10-oxogeranial. One of the key enzymes involved in the biosynthesis of MIAs is an NAD(P)(+) dependent oxidoreductase system, 10-hydroxygeraniol dehydrogenase (Cr10HGO), which catalyses the formation of 10-oxogeranial from 10-hydroxygeraniol via 10-oxogeraniol or 10-hydroxygeranial. This work describes the cloning and functional characterization of Cr10HGO from C. roseus and its role in the iridoid biosynthesis. Substrate specificity studies indicated that, Cr10HGO has good activity on substrates such as 10-hydroxygeraniol, 10-oxogeraniol or 10-hydroxygeranial over monohydroxy linear terpene derivatives. Further it was observed that incubation of 10-hydroxygeraniol with Cr10HGO and iridoid synthase (CrIDS) in the presence of NADP(+) yielded a major metabolite, which was characterized as (1R, 4aS, 7S, 7aR)-nepetalactol by comparing its retention time, mass fragmentation pattern, and co-injection studies with that of the synthesized compound. These results indicate that there is concerted activity of Cr10HGO with iridoid synthase in the formation of (1R, 4aS, 7S, 7aR)-nepetalactol, an important intermediate in iridoid biosynthesis.

}, issn = {2045-2322}, doi = {10.1038/srep08258}, author = {Krithika, Ramakrishnan and Srivastava, Prabhakar Lal and Rani, Bajaj and Kolet, Swati P. and Chopade, Manojkumar and Soniya, Mantri and Thulasiram, Hirekodathakallu V.} } @article { ISI:000355247900001, title = {Functional characterization of novel sesquiterpene synthases from Indian sandalwood, santalum album}, journal = {Scientific Reports}, volume = {5}, year = {2015}, month = {MAY}, pages = {Article Number: 10095}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

Indian Sandalwood, Santalum album L. is highly valued for its fragrant heartwood oil and is dominated by a blend of sesquiterpenes. Sesquiterpenes are formed through cyclization of farnesyl diphosphate (FPP), catalyzed by metal dependent terpene cyclases. This report describes the cloning and functional characterization of five genes, which encode two sesquisabinene synthases (SaSQS1, SaSQS2), bisabolene synthase (SaBS), santalene synthase (SaSS) and farnesyl diphosphate synthase (SaFDS) using the transcriptome sequencing of S. album. Using Illumina next generation sequencing, 33.32 million high quality raw reads were generated, which were assembled into 84,094 unigenes with an average length of 494.17 bp. Based on the transcriptome sequencing, five sesquiterpene synthases SaFDS, SaSQS1, SaSQS2, SaBS and SaSS involved in the biosynthesis of FPP, sesquisabinene, beta-bisabolene and santalenes, respectively, were cloned and functionally characterized. Novel sesquiterpene synthases (SaSQS1 and SaSQS2) were characterized as isoforms of sesquisabinene synthase with varying kinetic parameters and expression levels. Furthermore, the feasibility of microbial production of sesquisabinene from both the unigenes, SaSQS1 and SaSQS2 in non-optimized bacterial cell for the preparative scale production of sesquisabinene has been demonstrated. These results may pave the way for in vivo production of sandalwood sesquiterpenes in genetically tractable heterologous systems.

}, issn = {2045-2322}, doi = {10.1038/srep10095}, author = {Srivastava, Prabhakar Lal and Daramwar, Pankaj P. and Krithika, Ramakrishnan and Pandreka, Avinash and Shankar, S. Shiva and Thulasiram, Hirekodathakallu V.} } @article {44437, title = {Comprehensive metabolic and transcriptomic profiling of various tissues provide insights for saponin biosynthesis in the medicinally important Asparagus racemosus}, journal = {Scientific Reports}, volume = {8}, year = {2018}, month = {JUN}, pages = {Article Number: 9098}, abstract = {Asparagus racemosus (Shatavari), belongs to the family Asparagaceae and is known as a "curer of hundred diseases" since ancient time. This plant has been exploited as a food supplement to enhance immune system and regarded as a highly valued medicinal plant in Ayurvedic medicine system for the treatment of various ailments such as gastric ulcers, dyspepsia, cardiovascular diseases, neurodegenerative diseases, cancer, as a galactogogue and against several other diseases. In depth metabolic fingerprinting of various parts of the plant led to the identification of 13 monoterpenoids exclusively present in roots. LC-MS profiling led to the identification of a significant number of steroidal saponins (33). However, we have also identified 16 triterpene saponins for the first time in A. racemosus. In order to understand the molecular basis of biosynthesis of major components, transcriptome sequencing from three different tissues (root, leaf and fruit) was carried out. Functional annotation of A. racemosus transcriptome resulted in the identification of 153 transcripts involved in steroidal saponin biosynthesis, 45 transcripts in triterpene saponin biosynthesis, 44 transcripts in monoterpenoid biosynthesis and 79 transcripts in flavonoid biosynthesis. These findings will pave the way for better understanding of the molecular basis of steroidal saponin, triterpene saponin, monoterpenoids and flavonoid biosynthesis in A. racemosus.}, doi = {10.1038/s41598-018-27440-y}, author = {Srivastava, Prabhakar Lal and Shukla, Anurag and Kalunke, Raviraj M.} }