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The pentacyclic triterpenes of ursane and oleanane skeletons found to accumulate in a number of terrestrial plants in free or glycosidic form.1) Some of these metabolites such as amyrins and ursolic acid have been reported as the bioactive constituents from a number of plants used in traditional and folk medicine.2,3) Amyrins were found to exhibit interesting pharmacological activities such as anti-inflammatory, 4,5) antiproteolytic, 6) antifungal 7) etc. whereas, ursolic acid was found to exhibit significant activities such as hepatoprotective, anti-inflammatory, antiviral and anti-tumor etc.8) Ursolic acid was identified as one of the active components in rosemary (Rosmarinus officinalis) to inhibit the growth of some of the food associated bacteria and yeast. 9) Ursolic acid and its 3-keto and 11-keto derivatives have been shown to inhibit the growth of Staphylococcus aureus.10) It was also reported that ursolic acid decreases the cytopatholic effects in vitro cells exposed to Herpes simplex virus.11) Interestingly a-amyrin palmitate isolated from Santalum album found to exhibit insect (Atteva fabriciella, Eligama norcissu, Eupterote geminata) growth inhibiting and chemosterilant activities.12) The low acute toxicity and structure activity studies of these skeletons suggest that defined substituents on the lipophilic 5-ring backbone can increase selectivity and potency of a desired action 13) and are identified as the potent natural lead compounds for drug development.In connection with our chemical screening on Diospyros melanoxylon leaves, we have isolated large quantities of amyrins (0.94%) as an inseparable mixture of a-and b-and ursolic acid (0.56%), which prompted us to screen for antimicrobial activity along with their synthesized lipophilic fatty acid ester chains. The common functionality in these compounds is the hydroxyl at C 3 . In case of ursolic acid it has got an additional carboxylic acid functionality at C 17 . It was reported in literature that the acid moiety at C 17 and ester functionality at C 3 are highly essential for enhanced pharmacological activities of pentacyclic triterpenes. 14,15) In view of these observations, the C 3 -OH can be exploited to synthesize highly lipophilic ester chains. Interestingly some of the higher fatty acid esters (C 16 , C 18 ) of pentacyclic triterpenes have been reported from natural sources. 12) Lipophilicity is an important parameter in the development of antimicrobial agents. It increases with increase of the carbon chain. Molecules with carbon chains above C-10 are fairly lipophilic and good candidates for pharmacological evaluation. Further the partition coefficient (log P), which is well known as an index of lipophilicity, is an important physicochemical parameter in the development of antibacterial agent because it is known to be closely related to the permeation through a lipid coat of bacteria.16) In view of the above, we have now prepared the highly lipophilic 3-O-fatty acid ester chains (C 12 -C 18 ) of amyrins and ursolic acid and screened for ...

The synthesis of two types of imidazole-based surfactants, [(ROCOCH 2 MIm)Br] and [(RNHCOCH 2-MIm)Br], of varying chain lengths (C 10 , C 12 and C 16 ), was conducted in the present work. The synthesis involves an initial reaction of bromoacetic acid with fatty alcohols or fatty amines, followed by quaternization with N-methyl imidazole. The micellar properties of all the synthesized compounds were determined using surface tensiometry and compared with [(RMIm)Br], a well-studied alkyl-substituted imidazole-based surfactant. Within the same homologous series, a decrease in critical micelle concentration (cmc) was observed with increasing alkyl chain length in all three types of cationic surfactants. Introduction of an ester [(ROCOCH 2 MIm)Br] or an amide group [(RNHCOCH 2 MIm)Br] in the alkyl chain lowers the cmc when compared to a cationic surfactant without functional group, [(RMIm)Br]. The synthesized surfactants were also assayed for antimicrobial activities and found to possess good activities against selected strains.

The voltage-dependent anion channel (VDAC) and mitochondrially located hexokinase have been implicated both in pathways leading to cell death on the one hand, and immortalization in tumor formation on the other. While both proteins have also been implicated in death processes in plants, their interaction has not been explored. We have examined cell death following heterologous expression of a rice VDAC in the tobacco cell line BY2 and in leaves of tobacco plants and show that it is ameliorated by co-expression of hexokinase. Hexokinase also abrogates death induced by H2O2. We conclude that the ratio of expression of the two proteins and their interaction play a major role in modulating death pathways in plants.

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Ionic liquids, 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIm][PF(6)]) and 1-ethyl-3-methyl imidazolium hexafluorophosphate ([EMIm][PF(6)]), were used for the methanolysis of sunflower oil using Candida antarctica lipase (Novozyme 435) and gave yields of fatty acid methyl esters at 98-99% within 10 h. The optimum conditions of methanolysis in hydrophobic ionic liquids are 2% (w/w) lipase, 1:1 (w/w) oil/ionic liquid and 1:8 (mol/mol) oil/methanol at 58-60 degrees C. Methanolysis using hydrophilic ionic liquids, 3-methyl imidazolium tetrafluoroborate ([HMIm][BF(4)]) and 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIm][BF(4)]), gave very poor yields. A hydrophobic ionic liquid thus protects the lipase from methanol. Recovered ionic liquids and lipase were used for four successive reaction cycles without any significant loss of activity.