In vitro and in vivo antimalarial activity of green synthesized silver nanoparticles using Sargassum tenerrimum - a marine seaweed.

Green nanotechnology has recently attracted a lot of attention as a potential technique for drug development. In the present study, silver nanoparticles were synthesised by using Sargassum tenerrimum, a marine seaweed crude extract (Ag-ST), and evaluated for antimalarial activity in both in vitro and in vivo models. The results showed that Ag-ST nanoparticles exhibited good antiplasmodial activity with IC50 values 7.71±0.39 µg/ml and 23.93±2.27 µg/ml against P. falciparum and P. berghei respectively. These nanoparticles also showed less haemolysis activity suggesting their possible use in therapeutics. Further, P. berghei infected C57BL/6 mice were used for the four-day suppressive, curative and prophylactic assays where it was noticed that the Ag-ST nanoparticles significantly reduced the parasitaemia and there were no toxic effects observed in the biochemical and haematological parameters. Further to understand its possible toxic effects, both in vitro and in vivo genotoxicological studies were performed which revealed that these nanoparticles are non-genotoxic in nature. The possible antimalarial activity of Ag-ST may be due to the presence of bioactive phytochemicals and silver ions. Moreover, the phytochemicals prevent the nonspecific release of ions responsible for low genotoxicity. Together, the bio-efficacy and toxicology outcomes demonstrated that the green synthesized silver nanoparticles (Ag-ST) could be a cutting-edge alternative for therapeutic applications.

UPLC-MSE Guided Isolation of New Antifeedant Limonoids from Fruits of Trichilia connaroides.

UPLC-MSE guided isolation of CHCl3 extract from the fruits of Trichilia connaroides yielded two new mexicanolide-type limonoids trichanolide F (1) and trichanolide G (2) along with a known compound carapanolide U (3). The structures of the limonoids were characterized by extensive spectroscopic analysis (MS, IR, 2D NMR). These limonoids (1-3) were evaluated for their antifeedancy against Spodoptera litura F. To further explore and draw the meaningful structure activity relationship studies, secophragmalin-type limonoids, namely, secotrichagmalin B, C (4, 5) and semisynthetic derivatives (5a-5l) were also screened for antifeedancy. The results revealed that trichanolide F (1) displayed highest antifeedant index (AFI) and caused larval mortality at 24 h. Derivative 5b caused larval toxicity, whereas 3, 5a, 5d, and 5g lead to pupal mortality and 2, 5f, 5k, and 5l caused adult deformities. Overall, the study provided new insights into the antifeedant potential of isolated and chemically modified limonoids from T. connaroides for the control of spodopteran pests.