food and bioproducts processing 9 0 ( 2 0 1 2 ) 793–798 Contents lists available at SciVerse ScienceDirect Food and Bioproducts Processing j our nal ho mepage: www.elsevier.com/locate/fbp Extraction of ursolic acid from Ocimum sanctum leaves: Kinetics and modeling Mangesh D. Vetal, Vikesh G. Lade, Virendra K. Rathod * Department of Chemical Engineering, Institute of Chemical Technology, Mumbai 400019, India a b s t r a c t Ursolic acid (UA) is a triterpene compound which shows significant biological potential. This study deals with the optimization and kinetics of UA extraction from Ocimum sanctum (OS) leaves in a stirred batch extraction. The influ- ence of various extraction parameters on the extraction yield has been studied. The optimum extraction conditions were extraction time 40 min, speed of agitation 1000 rpm, temperature 323 K, solute to solvent ratio of 1:120. This resulted in 11.21 mg of UA/g of dried leaf powder of OS. The extraction kinetics behavior of UA from OS revealed that the extraction of UA followed a first order kinetics. The kinetic expression developed by Spiro and Siddique was used and the model is in good agreement with the experimental results. The diffusion coefficient determined ranged from 2 × 10 -11 to 6.10 × 10 -11 m 2 /s for the all set of experiments. The activation energy for the extraction of UA was found to be E a = 10.45 kJ/mol. © 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Keywords: Ursolic acid; Ocimum sanctum; Batch extraction; Kinetic model; Activation energy 1. Introduction In recent years, extraction and purification of bioactive com- pounds from natural sources has become very important for the use of phytochemicals in the preparation of food supplements or nutraceuticals, functional food ingredients, food additives, pharmaceutical and cosmetic products. This diversified use of bioactives has gained scientific and indus- trial importance for their production and also led to the identification of new bio-resources. Holy basil (OS Linn.) or ‘Tulsi’ possesses valuable antioxidant properties for culinary and wide spectrum of medicinal uses viz. anti-carcinogenic, anthelmintic, antirheumatic, antibacterial, antidepressant, antiepileptic, hepatoprotective, radioprotective (Dharmani et al., 2004; Pemminati et al., 2007). OS Linn. leaves con- tain 0.7% volatile oil comprising about 71% eugenol and 20% methyl eugenol. UA, carvacrol, caryophyllene, apigenin, lute- olin, apigenin-7-O-glucuronide, orientin and molludistin are Abbreviations: UA, ursolic acid; OA, oleanolic acid; OS, Ocimum sanctum; C l,exp,i , experimental concentration of the component in the liquid phase at time t; C l,pre,i , predicted concentration of the component in the liquid phase at time t; N, number of observations; PE(%), relative percent error; R, the universal gas constant (kJ/mol K); RMSE, root mean square error; D, diffusion coefficient; r, the radius of the particle; V s , volume of solids in the system; V l , volume of the liquid phase;  , partition coefficient; C l , concentration of the component in the liquid phase at time t; C l∞ , concentration in the liquid phase at equilibrium; k obs , observed first order rate constant; t, extraction time. ∗ Corresponding author. Tel.: +91 22 33612020; fax: +91 22 33611020. E-mail addresses: vk.rathod@ictmumbai.edu.in, virendrakrathod@gmail.com (V.K. Rathod). Received 20 January 2012; Received in revised form 11 July 2012; Accepted 17 July 2012 other additional phytoconstituents found in the OS (Gupta et al., 2002). UA is a triterpene compound found in many plants like apple, basil, bilberries, elder flower, and pep- permint. UA have shown diverse pharmacological activities such as anti-inflammatory, antitumor, hypoglycemic, antiul- cer, antilipidemic (Safayhi and Sailer, 1997; Li et al., 2003; Prakash and Gupta, 2005; Perez et al., 1995; Nishino et al., 1988; Suanarunsawat et al., 2009). UA and its derivatives have antiviral potential and also inhibit the development of several viruses including HIV (Kashiwada et al., 2000). Usually, the separation of medicinally active components from plant parts (seeds, flowers, roots, leaves) is carried out by solid–liquid extraction process with selective solvents (Pin et al., 2011). There are several novel extraction methods such as supercritical fluid extraction (Danielsk et al., 2007), Ultrasound assisted extraction (Charpe and Rathod, 2012) and microwave assisted extraction (Liazid et al., 2011) have been reported in the literature for the extraction of natural 0960-3085/$ – see front matter © 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fbp.2012.07.003