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The present study reports the biosynthesis of silver nanoparticles (IH-AgNPs) using aqueous leaf extract of Indigofera hisruta L. The biosynthesized IH-AgNPs were found to be FCC crystals, 5-10 nm in size, spherical in shape and stable. The biosynthesized IH-AgNPs showed dose-dependant cytotoxicity against prostate cancer (PC3) (IC = 68.5 μg/mL), colon cancer (COLO205) (IC = 85.2 μg/mL), and mouse melanoma (B16F10) (IC = 80.9 μg/mL). IH-AgNPs were found to be nontoxic towards normal CHO (Chinese hamster ovary) cells. The biosynthesized IH-AgNPs showed effective in vitro antioxidant activity against DPPH (IC = 63.43 μg/mL) and HO (IC = 89.93 μg/mL) radicals. IH-AgNPs exhibited effective antibacterial activity against both Gram+ve and Gram-ve bacteria. MIC values of IH-AgNPs against S. aureus, B. subtilis, P. aeruginosa and E. coli were found to be 7.8 μg/mL, 3.9 μg/mL, 15.6 μg/mL and 15.6 μg/mL respectively. IH-AgNPs also showed inhibitory activity against fungal pathogens including C. albicans, C. nonalbicans and C. tropicalis. Considering the results together, we demonstrate that IH-AgNPs exhibits three different bioactivities (3-in-1 system) and they could be employed as future antimicrobial, antioxidant and anticancer agents/drug delivery vehicles in the field of biomedicine.

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Multiple shoots of Spilanthes acmella Murr. were induced from nodal buds of in vivo and in vitro seedlings on Murashige and Skoog (MS) medium containing 1.0 mg dm -3 6-benzyladenine (BA) and 0.1 mg dm -3 α-naphthaleneacetic acid (NAA). Adventitious shoots were successfully regenerated from the leaf explants derived from the above mentioned multiple shoots. The efficiency of shoot regeneration was tested in the MS medium containing BA, kinetin, or 2-isopentenyl adenine in combination with NAA, indole-3-acetic acid (IAA), or indole-3-butyric acid (IBA) and gibberellic acid. Maximum number of shoots per explant (20 ± 0.47) was recorded with 3.0 mg dm -3 BA and 1.0 mg dm -3 IAA. An anatomical study confirmed shoot regeneration via direct organogenesis. About 95 % of the in vitro shoots developed roots after transfer to half strength MS medium containing 1.0 mg dm -3 IBA. 95 % of the plantlets were successfully acclimatized and established in soil. The transplanted plantlets showed normal flowering without any morphological variation.Additional key words: growth regulators, medicinal plant, tissue culture. ⎯⎯⎯⎯Spilanthes acmella is an acutely threatened plant species (Narayana Rao and Raja Reddy 1983). S. acmella (marati mogga) is one of the important medicinal plants belonging to the family Asteraceae. The active compound was found to be spilanthol (Ramsewak et al. 1999). It is a perennial herb grown in the tropics and subtropics. Direct regeneration from leaf, as another alternative step for clonal propagation and germplasm conservation, is a well established factor. Successful plant regeneration has been reported from leaf explants, e.g., in Indian spinach (Mitra and Mukherjee 2001), Plumbago species (Das and Rout 2002), safflower (Radhika et al. 2006) and Carthamus species (Sujatha and Dinesh Kumar 2007). In view of the medicinal properties of S. acmella, its threatened nature and the increased demand for it in the pharmaceutical industry, there is a need for a large scale multiplication. In the present study, the direct shoot regeneration and histological studies from leaf explants of S. acmella have been studied. Direct regeneration of this plant species has not been reported so far.Spilanthes acmella Murr. shoots 22 cm long with 5 nodes were collected from 15-week-old field grown plants raised from seeds. They were divided into shoot tips and nodes, each measuring about 1 -4 cm in length.These served as explants for multiple shoot production. Explants were initially washed in running tap water for 15 min, and then rinsed in 10 % Teepol for 5 min followed by 0.1 % Bavistin for 5 min. The explants were thoroughly washed with sterile distilled water four times. Surface sterilization was carried out in 70 % ethanol for 45 s. Then the explants were treated with 0.05 % HgCl 2 for 4 min and 5 -6 times rinses in sterile distilled water. The nodal and shoot tip explants were inoculated in the Murashige and Skoog (1962; MS) medium fortified with 1.0 mg dm -3 6-benzyladenine (BA) and 0.1 mg dm -3 α-naphthalene acetic acid...