Raju K. Chalannavar

Synthesis and antimosquito properties of 2,6-substituted benzo[d]thiazole and 2,4-substituted benzo[d]thiazole analogues against Anopheles arabiensis.

A novel and efficient one pot synthesis was developed for 2,6-substituted-benzo[d]thiazole analogues 4a-k and 2,4-substituted-benzo[d]thiazole analogues 4l-pvia three component condensation reaction of substituted arylaldehyde, 2-amino-6-halo/4-methyl-benzo[d]thiazole and 2-naphthol or 6-hydroxyquinoline in presence of 10% w/v NaCl in water by microwave method. This method enabled for short reaction times, easy work-up and significant high yields. The title compound 4b was used for single crystal X-ray studies in order to understand its conformation and packing features. The title compounds 4a-p were screened for antimosquito properties such as repellency, insecticidal and larvicidal activity against Anopheles arabiensis by mosquito feeding-probing assay, cone bio-assay and standard WHO larvicidal assay, respectively. Among these analogous 4b, 4d and 4p exhibit the highest repellent activity comparable to the positive control DEET, and 4a and 4k knockdown most mosquitoes on repellent assays.

Community prevalence of methicillin and vancomycin resistant Staphylococcus aureus in and around Bangalore, southern India

INTRODUCTION Staphylococcus aureus is a known colonizer in humans and has been implicated in community acquired soft tissue infections. However emergence of methicillin resistant S. aureus(MRSA) has aroused great concern worldwide. This study aimed to determine the prevalence of MRSA in the community of Bangalore, southern India. METHODS Swabs were collected from anterior nares, forearm, dorsum and palm of the hands of 1,000 healthy individuals residing in and around Bangalore, belonging to different socioeconomic strata and age groups. RESULTS Analysis verified that 22.5% and 16.6% of the individuals presented Staphylococcus aureus and MRSA, respectively, at any of the three sites. Vancomycin resistance was observed in 1.4% of the S. aureus isolates, which was confirmed by detection of the vanA gene. It was interesting to note that 58.8% of the children in the age group 1-5 years-old presented MRSA, the highest percentage compared to other age groups of < 1 (44.4%) year-old, 5-20 (21.7%) years-old, > 40(11%) years-old and 20-40 (9.9%) years-old. Among the population of various socioeconomic strata, maximum MRSA colonization was observed among doctors (22.2%), followed by upper economic class (18.8%), lower economic class (17.7%), apparently healthy hospital in-patients (16.5%), nurses (16%) and middle economic class (12.5%). Most of the MRSA isolates were capsular polysaccharide antigen type 8 (57.1%). CONCLUSIONS There is a need for continuous surveillance and monitoring of the presence of MRSA in the community and a clearer understanding of the dynamics of the spread of MRSA will assist in controlling its dissemination.

Antimosquito properties of 2-substituted phenyl/benzylamino-6-(4-chlorophenyl)-5-methoxycarbonyl-4-methyl-3,6-dihydropyrimidin-1-ium chlorides against anopheles arabiensis

Eight novel dihydropyrimidine analogs named DHPM1-DHPM8 was synthesized in their hydrochloride salt form using one pot synthesis between methyl 2-chloro-4-(4-chlorophenyl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate and substituted arylamines in isopropanol. The antimosquito effect of the test compounds were assessed against the adult mosquito Anopheles arabiensis. For adulticidal properties the test compounds were sprayed onto ceramic tiles and screened using the cone bio-assay method. The larvicidal activity was tested by monitoring larval mortality daily and up to 3 days of exposure. Repellency properties were tested in a feeding-probe assay using unfed female Anopheles arabiensis. Compounds DHPM1, DHPM4, DHPM5 and DHPM6 exerted larval mortality equivalent to temephos (trade name Abate, a commercial larvicidal compound). Compounds DHPM1 to DHPM5 repelled or knocked down 92 to 98% of mosquitoes exposed to rodent skin treated with the compounds. None of the compounds showed any significant activity against the adult mosquito Anopheles arabiensis.

Chemical composition of essential oil of Psidium cattleianum var. lucidum (Myrtaceae)

accounting for 61% of the essential oil. The major component was caryophyllene oxide (12.43%), while other predominant constituents were identified as bicyclo(4.4.0)dec-l-ene (6.61%), 2,3-butanediol diacetate (4.84%) and patchoulene (4.73%). The presence of many terpenic and ester compounds is thought to contribute to the unique flavor of the P. cattleianum var. lucidum leaves.

The chemical composition of leaf essential oils of Psidium guajava L. (white and pink fruit forms) from South Africa

Abstract: The leaf oils of Psidium guajava (white fruit) and Psidium guajava (pink fruit) collected in KwaZulu-Natal province of South Africa has been examined by Gas chromatography-Mass spectrometry (GC-MS), and the apparent concentrations were determined by gas chromatography with a flame ionization detector. A total of twenty compounds of 88.9 % from white fruit and forty eight compounds representing 97.5 % from pink fruit of the oils were identified. P. guajava (white fruit) produced oil that was much richer in hydrocarbons (38.8 %), sesquiterpenes hydrocarbons (24.0 %), oxygenated sesquiterpenes (19.1 %) and alcohol (6.8 %). The major constituents of the essential oil were caryophyllene oxide (14.0 %), caryophyllene (13.9 %), 1H-cycloprop[e]azulene (11.6 %), adamantane (9.4 %), 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol (6.8 %), α-cubebene (6.7 %), 1,2,3,4-tetrahydronaphthalene (3.9 %), β-humulene (3.5 %), 1,2,4a,5,6,8a- hexahydronaphthalene (3.2 %) and α-caryophyllene (3.0 %). The leaf oil of P. guajava (pink fruit) contained a mixture of hydrocarbons (30.5 %), sesquiterpene hydrocarbons (25.4 %), alcohol (24.4 %) and oxygenated sesquiterpenes (15.0 %). The major constituents of the essential oil were caryophyllene oxide (13.0 %), tetracyclo[6.3.2.0(2,5).0(1,8)]tridecan-9-ol (12.9 %), caryophyllene (9.5 %), 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol (9.5 %), 1H-cycloprop[e]azulene (8.1 %), Z-3-hexadecen-7-yne (4.6 %) and eudesma-4(14),11-diene (4.1 %). High concentration of caryophyllene oxide and caryophyllene in both the oils suggests its usefulness as natural preservatives in the food industry. The terpenic and ester compounds could contribute to the unique flavor of P. guajava leaves.

Chemical composition of essential oil from the seed Arils of Strelitzia nicolai Regel & Koern from South Africa

Abstract: The essential oil components of arils from seeds of Strelitzia nicolai were investigated by GC and GC-MS. The oil yields of dried arils obtained by hydrodistillation were 0.86 %. Twenty-five compounds representing 94.2 % of the S. nicolai aril oil were identified. The main chemical constituents belongs to alcohols (1.24 %), amides (3.14 %), amine (31.75 %), aromatic compounds (4.86 %), esters (0.65 %), ethers (28.18 %), hydrocarbons (5.13 %) and ketones (19.30 %).

Preparation of poly(vinyl alcohol)/chitosan/starch blends and studies on thermal and surface properties

Biopolymers are abundantly available from its natural sources of extraction. Chitosan(CH) is one of the widely used natural polymer which is perspective natural polysaccharide. Natural polymer blend with synthetic polymer enhances property of the material such as polyvinyl alcohol (PVA). PVA is nontoxic degradable synthetic polymer and very good film forming polymer. In this study prepared hybrid based film by adding starch into Chitosan/PVA which slighlty increased the surface and thermal property of ternary blend film.Biopolymers are abundantly available from its natural sources of extraction. Chitosan(CH) is one of the widely used natural polymer which is perspective natural polysaccharide. Natural polymer blend with synthetic polymer enhances property of the material such as polyvinyl alcohol (PVA). PVA is nontoxic degradable synthetic polymer and very good film forming polymer. In this study prepared hybrid based film by adding starch into Chitosan/PVA which slighlty increased the surface and thermal property of ternary blend film.