SC-CO2 extract of a polyherbal mix of 1:1:2 tulsi leaves, bay leaves and cardamom seeds having appreciable antioxidant potency was encapsulated using spray drying technology. Maltodextrin and gum arabic (60:40) were used as wall materials at an inlet temperature of 140 degrees C to obtain an encapsulated powder with appreciable encapsulation efficiency. The powder had smooth rounded morphology as observed by scanning electron microscope and had antioxidant activity, phenolic content, reducing power and anti-inflammatory potency. The encapsulated SC-CO2 extract of the polyherbal mix was evaluated for its possible usage as a natural antioxidant in soybean oil. 30-day storage and frying stability studies of soybean oil samples, administered individually with the encapsulated and non-encapsulated extracts and commercial antioxidants TBHQ and BHT, established that the encapsulated polyherbal SC-CO2 extract had the best antioxidant efficacy. This encapsulate allows controlled release of the antioxidant and is therefore advocated as a promising 'green' antioxidant for soybean oil. (C) 2015 Elsevier Ltd. All rights reserved.