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The essential oil extracted from the leaves of Pogostemon paniculatus (Willd.) Benth. (Lamiaceae), was analysed by gas chromatography-mass spectrometry (GC-MS). Nineteen compounds constituting 85.36% of the total oil were identified in the oil. Patchouli alcohol (30.65%), α-guaiene (10.67%), β-guaiene (9.09%), caryophyllene (8.64%), eicosene (5.27%) were the major constituents present. The essential oil was analysed for antimicrobial activity by disc diffusion assay and minimum inhibition concentration against six bacteria and three fungi. Results showed inhibitory activity against some of the tested microorganisms. The essential oil was also tested for the DPPH free-radical scavenging activity and had an inhibitory concentration (IC(50)) value of 18.5 µg mL(-1).

Abstract:Bacopa monnieri (L.) Wettst. (Plantaginaceae), commonly known as Brahmi, is used in Ayurveda as a medicinal herb, found throughout the Indian subcontinent in wet, damp and marshy areas. The herb yields pharmaceutically active compounds called bacosides. The current investigation was carried out to assess the potential for increasing biomass and the concentration of bacoside A from the in vitro regenerated shoots in different media (MS, B5, NN and N6), the strength of the MS medium (0.25, 0.50, 0.75, 1.0, 1.50 and 2.0X) and carbon source [sucrose, glucose, fructose, maltose, sucrose + glucose (1:1), sucrose + maltose (1:1), glucose + fructose (1:1), glucose + maltose (1:1), fructose + sucrose (1:1) and fructose + maltose (1:1)]. All the culture media were supplemented with 2 mg/L Kinetin (Kin) at pH 5.8. High performance liquid chromatography (HPLC) was used to determine the bacoside A content from the regenerated shoots. Optimum number of adventitious shoots (70.75 shoots per explant), fresh weight (2.344 g), dry weight (0.166 g) and bacoside A content (13.052 mg/g DW) were obtained from the cultures grown in the MS medium. Bacoside A production was highest in the shoots grown in the glucose + fructose combination (15.588 mg/g DW) among the different carbon sources tested. These findings suggest that B. monnieri culture requires full strength MS medium and a moderate level of sucrose. The present study is useful to obtain optimum production of biomass and bacoside A from the in vitro regenerated shoots of B. monnieri.

Plant regeneration potential from node & leaf explants of Pogostemon paniculatus through direct shoot proliferation was studied on Murashige and Skoog medium supplemented with various concentrations of cytokinins & auxins. As the seed germinability of the plant is low in vitro, we have tried these explants for micropropagation. Among different concentrations of individual hormones tested for nodal explants, benzylaminopurine (BAP) at 5µM & kinetin (Kn) at 0.5µM showed 4 & 2 mean number of shoots/explant respectively & combination of Kn (0.5 µM)  + BAP (1.5 µM) showed 15 mean number of shoots/explant. For leaf explant combination of Kn (0.5 µM) + BAP (1.5 µM) showed 20 mean number of shoots/explant. Other hormones tested at all concentrations showed callus formation without the shoot development. Roots were established on the isolated shoots on naphthaleneacetic acid (NAA) at 0.25µM. Rooted plants were acclimatized. This is the first report of Pogostemon paniculatus micropropagation.

Copper based compounds are used to control pests worldwide but they can be toxic to fish and other non-target organisms. So, it is essential to identify effective formulations with the lowest non-target toxicities. In this study the toxic effects of Bordeaux mixture on fingerlings of common carp (Cyprinus carpio L.) was studied. In the common carp fingerlings behavioural, histological alteration and biochemical variations were evaluated. The LC50 of Bordeaux on common carp was 0.04, 0.05, 0.06 and 0.07 mg/L. Fish mortality increased significantly with increasing concentration and time of exposure. Behavioural responses of fish samples exposed to Bordeaux mixture included uncontrolled swimming, erratic movements, loss of balance and swimming near the water surface with sudden jerk movements. The treated fingerlings showed histopathological alterations in their muscles and gill lamellae. Splitting of muscle fibre and muscle band degeneration of studied fish samples was observed in muscle tissue. The major changes observed in gills included ruptured gill epithelium, lamellar fusion, epithelial lifting and vacuolization at the tip of lamellae. The fungicide decreased the concentration of glycogen and protein in muscle and gill tissue compared to control samples. In conclusion, this study suggests that judicious use of fungicides should be practiced by farmers. Use of Bio pesticides and natural products should be encouraged to reduce the toxic effects of the fungicides.