Essential oils of the leaf and root of Eryngium foetidum L. from Port Blair (Andaman and Nicobar) and Nadugani (Tamil Nadu) in India were investigated by GC and GC-MS analyses. The oils of the leaf and root from the two locations were found to contain alkanes, alkanals, alkenals, fatty acids, aromatic aldehydes, mono-, sesqui-and diterpenes, aromatic aldehydes and terpene aldehyde esters. The main components of the oil of the leaf from Port Blair were identified as a trimethyl benzaldehyde (16.5 %), dodecanal (4.7 %), muurola-4,10(14)-dien-1α-ol (10.2 %), neophytadiene isomer (4.5 %), hexahydrofarnesyl acetone (5.5 %), palmitic acid (4.6 %) and phytol (4.9 %). The composition of the root oil from Port Blair was found to be qualitatively similar to that of leaf oil, having the major constituents two isomers of trimethyl benzaldehydes (4.00 % and 57.0 %) and 2-formyl 1,1,5-trimethyl 2,5-cyclohexadien-4-yl-2-methylbutenoate (4.9 %). The leaf and root oils from Nadugani were found to be qualitatively similar but differed widely in their composition from the oils of Port Blair origin. The principal constituents of the oils of the leaf and root from Nadugani were found to be a trimethyl benzaldehyde (14.3 % and 24.1 %), (E)-2-dodecenal (2.8 % and 14.3 %), τ-cadinol (5.1 % and 7.3 %) and α-cadinol (6.9 % and 10.2 %). Many compounds which were hitherto not reported in the essential oils of E. foetidum were identified in the oils from the two locations in India.

Phosphate solubilizing microorganisms (PSMs) were isolated from rhizoplane, rhizosphere and non-rhizosphere of different leguminous plants. To isolate efficient phosphate solubilizers the rhizosphere and non-rhizosphere soil samples were enriched with different phosphate sources like tricalcium and rock phosphate. PSMs were detected in all the regions, but their number gradually decreased from rhizosphere, rhizoplane and non-rhizosphere soil. When compared to fungal population, bacterial population was more in number. Tephrosia purpurea recorded the highest bacterial population of 30.15 × 10 6 cfu/g, 50.51 × 10 6 cfu/g and 21.10 × 10 6 cfu/g in the rhizoplane, rhizosphere and non-rhizosphere regions respectively. In enrichment culture technique, highest phosphate solubilizing bacterial population was recorded in the rhizosphere soil of Clitoria ternatea (23 × 10 3 cfu/g) in tricalcium phosphate containing Pikovskaya's (PVK) medium. In a plate assay method solubilization zone diameter produced by microorganisms was varied from 0.2 cm to 1.0 cm. The phosphate solubilization ability of the isolated microorganisms in a liquid PVK medium varied from 11.85 mg to 61.96 mg P 2 O 5 . The medium turned acidic during the incubation period. The pH varied among the organisms from the initial 6.5 to the final 3.2 during 15 days of incubation. Citric acid, fumaric acid, gluconic acid, glutaric acid, glyoxalic acid, ketobutyric acid, ketoglutaric acid, malic acid, malonic acid, succinic acid and tartaric acid are produced by the isolated PSMs. Seed or soil inoculation with phosphate solubilizing bacteria (PSB) is known to improve solubilization of fixed and applied phosphates in soil bring about higher crop yield. The PSM are effective as biofertilizers in enhancing crop yields in phosphate deficient soils. They are environmentally friendly and supply phosphate to plants in a sustainable manner.

Essential oils of Cymbopogon citratus (DC.) Stapf grown in three different locations in South India were analysed by GC and GC-MS. The main constituents of the oils from Bangalore and Puttur were identified as β-myrcene, neral, geranial and geraniol. The oil from Nadugani was found to contain the major constituents' neral, geranial, geraniol and geranyl acetate. The present study revealed the presence of six oxygenated monoterpenes and sesquiterpenes which were hitherto not reported in the oil of C. citratus.

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INTRODUCTIONThe sea, covering more than 70% of the surface of planet Earth, contains an exceptional biological diversity, accounting for more than 95% of the whole biosphere. 1 Microbial diversity constitutes an infinite pool of novel chemistry, making up a valuable source for innovative biotechnology.2,3 Actinomycetes have a profound role in ABSTRACT Background: Microbial secondary metabolites are important sources of natural compounds when compared to others with potential, beneficial therapeutic applications. There are chances of discovery of new Streptomyces species and new compounds from the respective genus. Due to ever and over increasing resistance of pathogenic bacteria to our current arsenal of antibiotics, a great need exists for the isolation and discovery of new antibiotics and other drug agents. Based on the above concept actinomycetes are mainly targeted for secondary metabolites production and evaluation of compounds therapeutically. Methods: Totally 15 pure isolates were obtained from two different soil samples by spread plate and quadrant streak techniques. Their colony and surface morphology were studied by morphological and biochemical characterization. Secondary metabolites were extracted by solvent extraction and the presence of bioactive compounds was detected by thin layer chromatography. The antioxidant potential was determined by Dot plot, DPPH and Phosphomolybdenum assay. The nature and the number of active compounds were identified by GC-MS analysis. Results: Among the 15 isolates, 10 isolates were found to have characteristic features of actinomycetes and 8 isolates were found to be fast growing actinomycetes. Among these 8 isolates, isolates of terrestrial origin were found to possess more bioactive compounds than those of marine origin and the four terrestrial isolates selected for evaluation of bioactive compounds and determination of antioxidant potential showed that the isolate TS 1010 had better and efficient secondary metabolite activity. Conclusions: Thus, from the above study it is seen that not only actinomycetes of marine origin, but terrestrial origin are also fast growers and possess better antioxidant and radical scavenging activity.