The protective effect of the Vacha rhizome extract on chronic stress-induced immunodeficiency in rat

Context: Chronic stress is an inevitable factor in the modern day society which affects cell mediated as well as humoral immunity. There is a need to prevent stress effects with traditionally used herbs. Objective: The present study was undertaken to investigate the immunoprotective effect of Vacha (Acorus calamus L. Acoraceae) rhizome under stressful condition. Materials and methods: Soxlet extraction of Vacha rhizome was performed with increasing polarity of solvents, i.e., petroleum ether to ethanol. The extract was concentrated by distilling off the solvent in flash evaporator and dried in desiccators. The benzene extract was found to have anti-stress property in our earlier studies and hence it was used in the present experiment. Extract was administered every day for 4 weeks orally to adult female rats prior to exposure to stress, restraint (1 h) and forced swimming exercise (15 min). Results: Vacha rhizome extract significantly prevented the stress induced reduction in total and differential leukocytes count, immunoglobulin content, bone marrow cellularity and viability, lymphocytes counts in lymphoid organs, islands of white pulp of spleen (ED(50) = 10 mg, p < 0.001) and a significant increase in circulating immune complexes and apoptotic index of lymphoid organs (ED(50) = 10 mg, p < 0.001) compared to controls. Discussion and conclusion: The present study clearly indicates that Vacha extract not only prevents stress-induced suppression of immunity and structural involution of lymphoid organs, but also boosts immunity in normal rats. Therefore, it is suggested that Vacha extract administration maintains normal immunity despite the body experiencing stress.