Since ancient times Caesalpinia sappan heartwood dye has been well-known for its medicinal and dyeing properties. Isolation of the red dye using both conventional and newly developed microwave method was carried out. The conventional heating of 2 h provided 0.656 ± 0.049 g of the dye and by microwave heating at 540 W for 20 min, the yield obtained was 0.747 ± 0.047 g. Both the dyes were found to be the same as evidenced by UV, TLC and HPTLC studies. Antioxidant activity of the dyes was also carried out using DPPH and nitric oxide methods to confirm the similarity in their biological activity. The procedure developed can be used for the fast extraction of the red dye of C. sappan without affecting the nature of the product.

Pharmaceutics present in the environment are of growing concern for their potential consequences on human and ecosystem health. In long-term monitoring investigations of sewage and surface water samples, diclofenac was identified as one of the most important pharmaceutically active compounds. Pangasius sp. were exposed to determine the lethal concentration (LC50) of diclofenac. The histopathological studies in a fish hepatopancreas sample showed significant changes like nucleation, differentiation, and hepatocytes. The large lesions and infiltration in hepatocytes were distinctly seen due to the toxic effect of diclofenac. In HPLC analysis, the control fish liver tissue showed no significant changes, whereas the diclofenac-exposed fish liver tissue showed a significant peak with a quicker run time. The studies confirmed that the diclofenac compound affects hepatocytes to a noteworthy extent. Therefore, this calls for reduction of diclofenac usage and also to have a checkpoint especially for diclofenac in the pharmaceutical effluent released into the water bodies.

Gracilaria canaliculata was used as a novel source to extract agar, and for the green synthesis of silver nanoparticles. Silver nanoparticles (0.1 - 0.3%) were incorporated into the agar matrix to develop an environment-friendly food packaging material using the solution casting method. The concentration of nanoparticles affected the physical, thermal, and mechanical properties of the films. Films containing higher concentrations of silver nanoparticles exhibited promising properties, and demonstrated strong antimicrobial activity against both Gram-negative and Gram-positive foodborne pathogens. The film formulation exhibited no cytotoxic effect on HepG2 cells, with cell viability exceeding 94%. These findings suggested that the film possessed favourable characteristics for use as a food packaging material, presenting a potential alternative to plastics.

The relation between the intensity of Siberian High, defined as the mean sea level pressure over the Siberian region bounded by 87.5 & 102.5° E longitudes and 47.5 & 52.5° N latitudes (PSH) and Indian northeast monsoon rainfall has been studied in antecedent and concurrent modes based on monthly/seasonal mean PSH and monthly/seasonal rainfall data of Tamil Nadu (NMR) for the 34 year period, 1971 to 2004. It has been found that a positive relationship exists between the PSH and NMR of October-November (ON) which is significant in the antecedent mode [PSH(AS/Sep)] and modest in concurrent mode. The relationship turns negative for NMR (Dec) with both PSH(Sep) (antecedent) and PSH(Dec) (concurrent). By and large, negative anomaly profile of PSH during September-November (SON) followed by a positive PSH (Dec) anomaly is associated with a deficient NMR, but, a normal to positive PSH anomaly profile in SON becoming negative in December is associated with an excess NMR. The manifestation of PSH on NMR has been shown to be by way of modulating the strength of low level easterlies over the Bay of Bengal off the southeast coast of peninsular India as well as the latitudinal positions of Sub Tropical Ridge at 200 hPa (STR) and Equatorial Trough at 850 hPa (ET) over India. An intense PSH (Sep) is associated with strengthening of easterlies over the Bay of Bengal as well as southward location of STR/ET thereby favouring a good NMR (ON). During December, a weaker than normal PSH (Dec) is associated with northward location of ET from its normal latitudinal position near the equator which becomes conducive for good NMR(Dec). That a weaker than normal PSH in December is associated with good NMR(Dec) is comprehended from an analysis of time series of PSH. It has been found that the PSH itself undergoes a phase change in December on most occasions, i.e., an intense PSH (Nov) is by and large, followed by a weaker than normal PSH (Dec) and vice versa.