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Abstract: Metallic nanoparticles (MNPs) have been widely used for diagnostic and therapeutic purposes in clinical practice. A number of MNP formulations are being investigated in clinical trials for various applications. This increase in the use of NPs results in higher exposure to humans, leading to toxicity issues. Hence, it is necessary to determine the possible undesirable effects of the MNPs after in-vivo application and exposure. One of the main reasons for the toxicity of MNPs is the release of their respective metallic ions throughout the body. Many research studies are in progress investigating the various strategies to reduce the toxicity of MNPs. These research studies aim to change the size, dose, agglomeration, release, and excretion rates of MNPs. In this perspective review, we discussed the possible strategies to improve the therapeutic effects of MNPs through various processes, with lessons learned from the studies involving silver nanoparticles (AgNPs). We also discussed the ways to manage the toxicity of MNPs by purification, surface functionalization, synergistic effect, and targeted therapy approach. All these strategies could reduce the dose of the MNPs without compromising their therapeutic benefits, which could decrease the toxicity of MNPs. Additionally, we briefly discussed the market and toxicology testing for FDA-regulated MNPs.

Polyhydroxyalkanoates (PHAs) are a group of biopolymers produced from various microorganisms that attracted many researchers for their use as a substitute for conventional petrochemical plastics. PHA possesses similar material properties to petrochemical plastics with the added benefits of biocompatibility, biodegradability, hydrophobicity, thermoplasticity, piezoelectricity, and stereospecificity. The first discovery of PHA production in cyanobacteria was in 1969, and the commercialization of PHA produced from cyanobacteria is not feasible to date. The difficulty with the commercial production of cyanobacterial PHA is due to the low biomass production and lower PHA accumulation than the heterotrophic bacteria. The biosynthesis of PHA, production of cyanobacterial PHA, and strategies to improve the production of PHA and commercialization are discussed in this chapter.

Elaeocarpus venustus is an endemic as well as endangered tree species habitated in the wet evergreen forests of Southern Western Ghats (SWG), India. Due to insufficient natural regeneration, low seedling tendency, and prevailing anthropogenic disturbances, their distribution has been shrinking in their native environment. Towards conserving this endangered species, we have attempted to propagate E. venustus in its habitat by adopting vegetative propagation techniques of cutting and air layering through growth hormones. Significant growth has been observed by providing 2 mM concentration of indole-3-butyric acid (IBA) for both cutting and air layering. Higher rooting response has been observed through cutting and air layering techniques during monsoon periods. Based on the results of the study, we suggest that the cutting and air layering techniques can be employed as promising strategies towards the in situ conservation and promotion of Elaeocarpus venustus tree species as well as other endangered species in Western Ghats.

The xylitol production was performed with acidophilic Meyerozyma caribbica. The particle size of 0.02 ± 0.01 to 0.1 ± 0.05 mm was rich in glucose (12.0 ± 0.5 g/L), whereas 0.5 ± 0.25 to 2.0 ± 0.5 mm had a high content of xylose (8.0 ± 0.5 g/L). The xylitol production in the synthetic, non-detoxified and detoxified hydrolysate media was studied (50 ± 0.5 g/L) using 10% v/v non - induced cells of M. caribbica for 120 h. At the end of fermentation with the specific growth rate of 0.056 ± 0.01 (μ), xylitol yields of 45.00 ± 1.00%, 10.00 ± 1.00% and 54.00 ± 1.00% were obtained. The detoxification of the hydrolysate prepared using an identified corncob particle size of 0.5 ± 0.25 to 2.0 ± 0.5 mm could be used as the prospective pretreatment process for ecofriendly and industrial scale production of xylitol with M. caribbica.

Boobalan T, Mohan Rasu K, Arumugam N, Saravanan S, Jothi Basu M, Jeyakanthan J, Arun A. 2018. Studies on the diversity of macrofungus in Kodaikanal region of Western Ghats, Tamil Nadu, India. Biodiversitas 19: 2283-2293. We have demonstrated the distribution of macro fungal communities in the selected forest territory of Kodaikanal (Poondi) region, which houses about 100 mushrooms species diverse forms of mushrooms including both the soil-inhabiting (n = 45) and wood-inhabiting (n = 55) species. Kodaikanal is situated on a plateau between the Parappar and Gundar valleys; this area experiences peculiar lower temperature between 8.2°C and 19.7°C, higher humidity between 92% and 95%, which in turn enhances the growth of different types of mushrooms throughout the year. However, the peak production and macro fungal flushes were observed during the winter season followed by the northeast monsoon (Oct-Dec 2015). A total of 100 species belonging to 51 families were documented from this study sites. Moreover, some species (e.g., Ganoderma sp and Phellinus sp) persists all around the year in this region. However, some incidents of logging and burning of host trees have resulted in the decline of the macro fungal populations in this region. Hence the present study highlights the diversity of macro fungal population and also suggests their importance as part of biodiversity conservation.

Elaeocarpus venustus is an endemic as well as endangered tree species habitated in the wet evergreen forests of Southern Western Ghats (SWG), India. Due to insufficient natural regeneration, low seedling tendency, and prevailing anthropogenic disturbances, their distribution has been shrinking in their native environment. Towards conserving this endangered species, we have attempted to propagate E. venustus in its habitat by adopting vegetative propagation techniques of cutting and air layering through growth hormones. Significant growth has been observed by providing 2 mM concentration of indole-3-butyric acid (IBA) for both cutting and air layering. Higher rooting response has been observed through cutting and air layering techniques during monsoon periods. Based on the results of the study, we suggest that the cutting and air layering techniques can be employed as promising strategies towards the in situ conservation and promotion of Elaeocarpus venustus tree species as well as other endangered species in Western Ghats.

The floristic diversity of plants and their abundance were analyzed in 2.5 km campus to explore their medical importance by random sampling. The results for plant diversity in IIT-M campus showed nearly 100 species of flowering plants, with genera belonging to nearly 40 families. The most dominant family in the present study is Fabaceae with 15 species (25%) of the medicinal trees. In addition, the dominant medicinal herbs belong to the families of Acanthaceae, Apocynaceae, Fabaceae and Rubiaceae containing 4 species (12%) each. The identified medicinal tree and herb are verified with Red data book to explore their conservation status of every identified medicinal trees and herbs. On comparison with the existing IUCN red data list, the conservation status of 73% of trees and herbs identified in the present study were not assessed. Also, the biodiversity of plants focused on ethano-botanical aspects to reveal their medicinal uses.

Drug delivery through biogenically synthesized silver nanoparticles (AgNPs) in cancer treatment is exerted by smaller size entailing high surface area and synergistic effects of embedded biomolecules. In this study, prepared ternary conjugates of silver with plant active compound and anticancer drug towards reducing the dose through synergy, rendered by Electrostatic Attraction (EA) of functionalized drug on to the surface of biogenically synthesized AgNPs. The biogenic synthesis resulted in particles of nanometer range as well as serving reducing and capping agents. The cytotoxicity and synergistic effect of ternary therapeutic nano conjugates evaluated using MDA-MB-453 breast cancer cells were found to be superior than Doxorubicin (Dox). Quantitative HPTLC analysis showed 57.22 % inhibition by Dox-AP-AgNPs at a concentration of 2.5 µg/mL of Andrographolide and 0.95 µg/mL of Dox validating synergistic effect of the ternary conjugate.

cis- and trans-2-Substituted-3,6-dihydro-2H-pyran-3-ols have been prepared via an aldol condensation/ring-closing metathesis/enzymatic resolution sequence. The process can be scaled up to yield gram quantities of enantiomerically pure material.

meso-Dialkylporphyrinogen-like mixed cyclic oligomers containing furans, pyrroles and thiophenes have been synthesized by ‘3+1’, ‘3+2’ and ‘3+ketone’ approaches. Condensation of 2,5-bis[1-methyl-1(1H-pyrrol-2-yl)-ethyl]furan with 2,5-bis[(α-hydroxy-α,α-dimethyl)furan or 2,5-bis[(α-hydroxy-α,α-dimethyl)thiophene resulted in the formation of the mixture of cyclic tetramer, cyclic octamer and cyclic hexamer possessing different numbers of furans (thiophenes) and pyrroles. The major product was found to be the cyclic tetramer in ‘3+1’ condensation while cyclic pentamer was the major product in ‘3+2’ condensation. Appreciable amounts of cyclic decamer was isolated in ‘3+2’ condensation. The formation of furan–pyrrole alternating cyclic hexamer in ‘3+1’ condensation indicates acid-catalyzed, reversible cleavage of the starting material during the reaction. In the same analogy, cyclic dodecamer was synthesized by ‘4+2’ approach. Synthesis of cyclic dodecamer and cyclic pentadecamer was also achieved by condensing 2,5-bis[1-methyl-1(1H-pyrrol-2-yl)-ethyl]furan with ketones. The effect of catalysts, temperature, templates, solvent and concentration was examined and no appreciable changes in the product distribution were found.

Regioselective 1,3-dipolar cycloadditions of captodative 1-acetylvinyl p-nitrobenzoyloxy (1a) with propionitrile oxide, diphenylnitrile imine and diazoalkanes provided the corresponding 5-acetyl- isoxazoles and pyrazoles. Evidence to support the formation of the initial cycloadducts was obtained. The addition of nitrones also proved to be highly regio- and stereoselective.

Cynodon dactylon is a potential source of metabolites such as flavanoids, alkaloids, glycosides and β-sitosterol and has been traditionally employed to treat urinary tract and other microbial infections and dysentery. The present work attempts to evaluate the activity of C. dactylon extracts for glycemic control. Aqueous extracts of C. dactylon analyzed by HPLC-ESI MS have identified the presence of apigenin, luteolin, 6-C-pentosyl-8-C-hexosyl apigenin and 6-C-hexosyl-8-C-pentosyl luteolin. Evaluation of hypoglycemic activity through an extensive in silico docking approach with PPARγ (Peroxisome Proliferator-Activated Receptor), GLUT-4 (glucose transporter-4) and SGLT2 (sodium glucose co-transporter-2) revealed that luteolin, apigenin, 6-C-pentosyl-8-C-hexosyl apigenin, 6-C-hexosyl-8-C-pentosyl luteolin interact with SGLT2. Interactions of these molecules with Gln 295 and Asp 294 residues of SGLT2 have been shown to compare well with that of the phase III drug, dapagliflozin. These residues have been proven to be responsible for sugar sensing and transport. This work establishes C. dactylon extract as a potential SGLT2 inhibitor for diabetic neuropathy thus enabling a possibility of this plant extract as a new alternative to existing diabetic approaches.

Regioselective 1,3-dipolar cycloadditions of captodative 1-acetylvinyl p-nitrobenzoyloxy (1a) with propionitrile oxide, diphenylnitrile imine and diazoalkanes provided the corresponding 5-acetyl- isoxazoles and pyrazoles. Evidence to support the formation of the initial cycloadducts was obtained. The addition of nitrones also proved to be highly regio- and stereoselective.

Both cis - and trans -2-substituted-1,2,3,6-tetrahydro-pyridin-3-ols have been prepared via an aldol condensation–ring-closing metathesis sequence. A stereodivergent synthesis of optionally functionalized deoxyimino sugars was achieved via asymmetric dihydroxylation or epoxidation/nucleophilic substitution of these tetrahydropyridines.

Captodative olefins 1-acetylvinyl carboxylates proved to be highly regioselective dipolarophiles in 1,3-dipolar cycloadditon to propionitrile oxide, arylphenylnitrile imines, diazoalkanes, and nitrones to yield the corresponding 5-substituted heterocycles. The addition of the latter was also stereoselective, being slightly susceptible to steric demand of the carboxylate substituent in the olefin. All atempts to cleave the isoxazolidine N−O bond under reductive conditions failed, providing diverse products with side-group reduction. FMO theory was unsuccessful to explain the regioselectivity observed with nitrones, since the opposite orientation was predicted. The recently formulated DFT/HSAB theoretical model was able to rationalize this regioselectivity, identifying the nucleophilic and electrophilic atoms involved in the process via calculation of interaction energies, suggesting the specific direction of the electronic process at each of the reaction sites.

The palladium-catalyzed reaction of the captodative olefin 3-(p-nitrobenzoyloxy)-3-buten-2-one (1a) with aryl and vinyl halides gave coupled products 4-aryl- and 4-vinyl-3-(p-nitrobenzoyloxy)-3-buten-2-ones, 4 and 6 respectively, with high Z stereoselection. (Ph3P)2PdCl2 also catalyzed cross-coupling alkylation, phenylation and vinylation with trialkylorganostannanes and bromo olefin (Z)-4-bromo-3-(p-nitrobenzoyloxy)-3-buten-2-one (2), providing the corresponding trisubstituted alkenes. For the preparation of n-butyl substituted derivative (Z)-3-(p-nitrobenzoyloxy)-3-octen-2-one (8b), the transmetallation with n-BuZnCl was a more efficient method. Retention of the Z configuration of 2 was in all cases maintained.

Department of Chemistry, Bharathidasan University, Tiruchirapalli-62 0 024 Manuscript received 10 July 1992, accepted 12 November 1992 Carbon-13 Nmr Substituent Shifts for the Substitution of 2 -lsoxazoline in Butane

Department of Chemistry, Bharathidasan University, Tiruchirapalli-620 024 Manuscript received 10 July 1992, accepted 12 November 1992 Carbon-13 Nmr Substituent Shifts for the Substitution of 2 -lsoxazoline in Butane