Effect of novel therapeutic medicine swertiamarin from Enicostema axillare in zebrafish infected with Salmonella typhi.

Herbal treatments have been practiced by humans over centuries and therefore possess time-proven safety. However, it is crucial to evaluate the toxic effects of herbal medicine to confirm their safety, particularly when developing therapeutic drugs. Use of laboratory animals such as mice, rat, and rabbits was considered as gold standard in herbal toxicity assessments. However, in the last few decades, the ethical consideration of using higher vertebrates for toxicity testing has become more controversial. As a possible alternative model involving lower vertebrates such as zebra fish were introduced. Hence in the present study, swertiamain compound isolated from E. axillare was assessed for it antimicrobial activity in zebra fish larvae againt S. typhi. The cumulative mortality rate and bacterial localization in zebra fish larvae were studied. Biochemical markers assays were performed to find the preventive role of the compound during the typhoid infection. The results showed that zebra fish can be successfully used as a model to study typhoid infection and the anti-bacterial compound swertiamarin used in this study clears the bacterial load and pathogenic symptoms to a great extent.

Developmental toxicity, antioxidant, and marker enzyme assessment of swertiamarin in zebrafish (Danio rerio).

A secoiridoid glycoside called swertiamarin has been widely used as a herbal medicine for many decades. In particular, swertiamarin from the Enicostema axillare herb has been used as a multipurpose drug to treat innumerable health problems. As this medicine is consumed orally, its toxicity level should be determined. To examine the safety of this compound, toxicology work was done in zebrafish, and this is the first report to describe swertiamarin toxicity in zebrafish. Zebrafish embryos were used in this swertiamarin toxicity study, and morphological changes were observed. Further, the compound was also studied in adult zebrafish to determine the impact of the compound on the fish liver. Enzyme profiling with superoxide dismutase, glutathione peroxidase, catalase, reduced glutathione levels, glutathione S-transferase, lactate dehydrogenase, glutamic oxaloacetic transaminases, lipid peroxidation, Na+ /K+ -ATPase, and glutamic pyruvic transaminases) was evaluated (p ≤ 0.05). Results suggest that swertiamarin is a safe drug only at a low concentration (40 µM). This study also shows that even herbal medicinal compounds may be toxic to humans at higher dosages. Hence, irrespective of whether a drug is synthetic or natural, it needs to be tested for its toxicity before use in humans.

Selenium nanoparticle synthesis from endangered medicinal herb (Enicostema axillare).

Green synthesis of selenium nanoparticles (SeNPs) was achieved by a simple biological procedure using the reducing power of E. axillare leaf extract. This method is capable of producing SeNPs in a size range of around 56.23-98.18 nm, under ambient lab condition. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy-dispersive X-Ray (EDX). To check the potential hazards of nanotoxicity median lethal concentration (LC50) and Na + /K + -ATPase activity was assessed on zebra fish which showed the LC50 of 258.72 ppm for 96 h and Na + /K + -ATPase seems to significantly decrease with increase in SeNPs concentration. Antibactericidal activity explored the use of SeNPs against wide range of pathogens. Cytotoxicity of SeNPs was assayed against human lung cancer cells (A549) confirmed that SeNPs are able to inhibit the cell growth by dose-dependent manner. In conclusion, green synthesized selenium nanoparticles are less toxic and harmless. This is the first report on green synthesized selenium nanoparticles using E. axillare possessing anti-bacterial and anti-cancer activity.

Dietary effect of Rubus coreanus ethanolic extract on immune gene expression in white leg shrimp, Penaeus vannamei.

The objective of this study was to evaluate the effect of dietary supplementation of a Rubus coreanus ethanolic extract on immunostimulatory response in white leg shrimp Penaeus vannamei. Shrimps with an average initial weight of 0.5 ± 0.04 g were collected and acclimatized for 10 days. Four experimental diets including a control diet, a probiotic diet and 0.25 and 0.5% of R. coreanus ethanolic extract (RcEE) diets were used to feed the shrimps. After 8 weeks of culture, shrimp fed with probiotic and 0.25% RcEE diet had showed significant enhancement in the growth while shrimp fed with 0.5% RcEE diet showed significantly increased expression of immune genes and antioxidant enzymes activities. One week of challenge experiments for all the four diets fed shrimps showed decreased cumulative mortality in the 0.5% RcEE diets fed shrimps, when compared with the probiotic and 0.25% RcEE diet fed shrimp groups. The results indicates that R. coreanus ethanolic extract could be used as a herbal immunostimulant for shrimps to increase its immunity and disease resistance against the bacterial pathogen, Vibrio alginolyticus.