Protection of immunocompromised mice from fungal infection with a thymus growth-stimulatory component from Selaginella involvens, a fern

Abstract

Context: Recent studies have shown that the water extract of Selaginella involvens (Sw.) Spring, a wild fern, exhibits thymus growth-stimulatory activity in adult mice (reversal of involution of thymus) and remarkable anti-lipid peroxidation activity. Follow-up studies were carried out in the present study.

Materials and Methods: Activity-guided isolation of the active component (AC) was carried out. The effect of AC on immune function was studied using fungal (Aspergillus fumigatus) challenge in cortisone-treated mice. The in vitro antifungal activity of AC was assayed using disc diffusion assay. In vitro and in vivo effect of AC on DNA synthesis in thymus was studied using ³H-thymidine incorporation. In in vitro anti-lipid peroxidation, hydroxyl radical scavenging and inhibition of superoxide production were assayed.

Results: The active principle/component (AC) was isolated in a chromatographically pure form from the water extract of S. involvens. AC showed positive reaction to glycosides. AC possessed both thymus growth-stimulatory and antioxidant properties. It protected cortisone-treated mice from A. fumigatus challenge. It did not exhibit in vitro antifungal activity. Increased ³H-thymidine incorporation was observed in the reticuloepithelium of thymus obtained from AC-treated mice. However, in vitro AC treatment to thymus for 5 h did not result in an increase in ³H-thymidine incorporation.

Discussion and conclusion: AC (named as Selagin), from S. involvens, could reverse involution of thymus to a large extent, exhibit remarkable antioxidant activity, and protect immunocompromised mice from fungal infection. Therefore, it is very promising for the development of a drug to ameliorate old age-related health problems and prolong lifespan.

Keywords::

• Aspergillus fumigatus
• anti-lipid peroxidation
• aging
• involution of thymus
• glycoside

Acknowledgements

We thank Mr. Raju Antony, Peridophyte Taxonomist, TBGRI, for his help in the correct identification of the species. Dr. Ajikumaran Nair, Dr. (Mrs.) Subhisha, and Mrs. Ambili (Research Scholars, TBGRI) are acknowledged for their help in the course of this work. We also thank Mr. Santhosh Kumar, G. for technical assistance in animal experiments.

Declaration of interest

Indian Council of Medical Research (ICMR), Senior Research Fellowship was awarded to Mrs. V. Gayathri to carry out this work. Apart from this, there is no potential conflict of interest.