Asarone and Shyobunone Content in Indian Acorus calamus Fresh Plants and Dried Rhizome Samples

Background: Acorus calamus, traditionally used as a neuroprotective, anti-inflammatory, immunomodulatory and analgesic agent, has α-asarone, β-asarone, and shyobunone as its major phytoconstituents. β-asarone is associated with dose-dependent cytotoxicity, mutagenicity and carcinogenicity. Ascertaining content of these phytoconstituents becomes essential for developing safe and efficacious medicines from this plant. Objectives: The study aimed to estimate the content of α-asarone, β-asarone and shyobunone in Acorus calamus fresh plants and dried rhizome samples collected from different regions of India. Materials and Methods: Dried rhizomes and fresh rhizomes and leaves of Acorus calamus were collected from various locations in India. Novel, simple, rapid and accurate reverse phase high performance liquid chromatography methods for estimation of α-asarone, β-asarone and shyobunone were developed and validated. 0.05% Ortho Phosphoric Acid (OPA) in water: acetonitrile (55:45) for simultaneous estimation of α-asarone and β-asarone and 0.05% Ortho Phosphoric Acid (OPA) in water, acetonitrile and methanol (15:40:45) was the mobile phase used for analysis of shyobunone. Results: The content of α-asarone, β-asarone, and shyobunone in various calamus samples ranged from 0.004-0.10% w/w, 2.30-4.40% w/w and 0.018-0.10%w/w respectively. All rhizome samples were found to contain higher amounts of these phytoconstituents, followed by leaves. Within the dried rhizomes, these phytoconstituents were found to be localized in greater amounts within the wood, as compared to the bark. Conclusion: The content of β-asarone in the calamus samples is found to be lower than what has been reported earlier in the Indian varieties, possibly due to spontaneous mutations with alteration in ‘ploidy’ status.