608 Research Article Received: 7 February 2009 Revised: 7 August 2009 Accepted: 11 November 2009 Published online in Wiley Interscience: 12 January 2010 (www.interscience.wiley.com) DOI 10.1002/jsfa.3857 Antiaflatoxigenic and antioxidant activity of an essential oil from Ageratum conyzoides L. Rajaram P Patil, a* Mansingraj S Nimbalkar, b Umesh U Jadhav, c Vishal V Dawkar c and Sanjay P Govindwar c Abstract BACKGROUND: Aflatoxin contamination of various commodities can occur as a result of infection, mainly by Aspergillus flavus and Aspergillus parasiticus. Every year, almost 25% of the world’s food supply is contaminated by mycotoxins. Aflatoxins B 1 , B 2 ,G 1 and G 2 , which occur naturally, are significant contaminants of a wide variety of commodities. A number of biological activities have been associated with Ageratum conyzoides. We have therefore investigated the antiaflatoxigenic, antioxidant and antimicrobial activity of essential oils of A. conyzoides. This could help to turn A. conyzoides, a nuisance weed, into a resource. RESULTS: The essential oil of Ageratum conyzoides L. shows the presence of 12 compounds when analyzed by gas chromatography–mass spectrometry. The growth and aflatoxin production of the toxigenic strain Aspergillus parasiticus was completely inhibited by essential oil. All the studied concentrations of the oil demonstrate a reduction in mycelia growth and decreased production of different aflatoxins in fungi, as revealed by liquid chomatographic– tandem mass spectrometric analysis. Volatiles from macerated green leaf tissue of A. conyzoides were also effective against A. parasiticus. The strongest antibacterial activity was observed against the bacteria Staphylococcus aureus and Bacillus subtilis in a disk diffusion bioassay. Essential oil and methanol extract of A. conyzoides L. were assayed for their antioxidant activity. Methanol extract showed the highest antioxidant activity in FRAP and DPPH assay, whereas essential oil showed greater lipid peroxidation inhibition than methanol extract. CONCLUSION: The plant’s ethno-medicinal importance, antioxidant potential, inhibitory activity against the Aspergillus group of fungi and production of aflatoxins may add a new dimension to its usefulness in the protection of stored product. c  2010 Society of Chemical Industry Keywords: A. conyzoides; aflatoxin; essential oil; LC-MS/MS; antioxidant INTRODUCTION Aflatoxin contamination of various commodities can occur as a result of infection mainly by Aspergillus flavus and Aspergillus parasiticus. Approximately 25% of the world’s food supply is contaminated by mycotoxins annually. Aflatoxin B 1 ,B 2 ,G 1 , and G 2 , which occur naturally, are significant contaminants of a wide variety of commodities. 1 Minimizing the aflatoxin content is a high priority as the year 2004 evidenced an outbreak of lethal aflatoxicosis in Kenya. 2 There were many examples of mycotoxicosis in the context of animal husbandry. 3 The constituents of essential oils and their antimicrobial properties have been the subject of investigations during the past decades. Many authors have observed their antifungal and antiaflatoxigenic action. 4 Fungicidal constituents from essential oils have been identified against various fungi. 5 Different plant extracts have been previously reported to inhibit mycotoxin formation even without inhibiting mycelium growth. 6 It has been well documented that many natural and synthetic antioxidants inhibit aflatoxin formation; for example, eugenol exerts its action through its antioxidant properties, which includes the inhibition of lipid peroxidation and superoxide dismutase. 7 Selected food additives, viz. butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), are used for the preservation of foods, but because of the possible toxicities of these synthetic antioxidants 8 increased attention has been directed towards natural antioxidants. Many essential oils and extracts have been qualified as natural antioxidants. 9 They have been proposed as potential substitutes for synthetic antioxidants in specific sectors of food preservation, where their use does not conflict with their aroma. Essential oils are quite complex mixtures constituted by several components, and this complexity often makes it difficult to explain the component responsible for these activities. 10 Generally, the action of essential oils is a result of the combined effects of both their active and inactive compounds. ∗ Correspondence to: Rajaram P Patil, Department of Agrochemicals and Pest Management, Shivaji University, Kolhapur-416 004, (MS), India. E-mail: rajarampatil@gmail.com a Department of Agrochemicals and Pest Management, Shivaji University, Kolhapur-416 004, Maharashtra, India b Department of Botany, Shivaji University, Kolhapur-416 004, Maharashtra, India c Department of Biochemistry, Shivaji University, Kolhapur-416 004, Maharash- tra, India J Sci Food Agric 2010; 90: 608–614 www.soci.org c  2010 Society of Chemical Industry