Original Contribution Enhanced antilipopolysaccharide (LPS) induced changes in macrophage functions by Rubia cordifolia (RC) embedded with Au nanoparticles $ Ashwani Kumar Singh a,n , Yamini B. Tripathi b , Nidhi Pandey b , D.P. Singh c , Deepshikha Tripathi d , O.N Srivastava a,n a Department of Physics, Banaras Hindu University, Varanasi, India 2210055 b Department of Medicinal Chemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India c Department of Physics, University of Santiago, Chile d R and D Centre, Prof SN Tripathi Memorial Foundation, Gandhi Nagar, Naria, Varanasi 221005, India article info Article history: Received 10 January 2013 Accepted 4 June 2013 Available online 14 June 2013 Keywords: Gold nanoparticles Herbs Anti-inflammatory Nitric oxide LPS abstract In this paper, we have shown that gold nanoparticles (Au (NPs)) embedded in Rubia cordifolia (RC) matrix (RC-Au (NPs)) exhibit a high therapeutic value relating to its anti-inflammatory characteristics. It was prepared by utilizing the reducing properties of RC to convert HAuCl 4 into Au (NPs). In order to compare its effectiveness, with respect to Au (NPs), the latter was synthesized separately by reducing HAuCl 4 with lemon extract. These Au (NPs) along with RC-Au (NPs) were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and UV-visible spectroscopy. The enhancement in anti- inflammatory characteristics was assessed as its inhibitory potential for lipopolysaccharide (LPS)-induced nitric oxide (NO) release, by rat peritoneal macrophages. The RC-Au (NPs) significantly enhanced its potential to inhibit NO release, which was reported in terms of inhibitory concentration for 50% inhibition (IC 50 ¼11.98ng/ml), as compared to either RC extract (IC 50 ¼47 Â 10 3 ng/ml) or to Au (NPs) (IC 50 ¼587.50 ng/ml). & 2013 Elsevier Inc. All rights reserved. Introduction Nanoparticles are used medically for enhancing the therapeutic potential of drugs by altered pharmacokinetics, biodistribution, or cellular uptake. RC has been in clinical use as an antioxidant and anti- inflammatory agent for a long time [1]. Gold has its own importance because of its relatively nonreactive and comparatively safe nature. In Ayurveda, the traditional system of Indian medicine, gold has been in clinical use for centuries and is termed as “Swarna Bhasma” for various ailments [2]. In the allopathic system also, gold salts are used to treat inflammation/arthritis [3,4]. Recently gold nanoparticles are being used for diagnostics and also as a drug carrier [5]. Nanos- tructures are defined as materials with overall dimension under 100 nm and can be synthesized in a variety of ways. One of them, which corresponds to “green synthesis,” is through the reduction of the respective metal salts by plant extracts. This was first reported in 2004 [6], followed by other reports related to flavonoids as the reducing agent [7], and also as a stabilizer such as azacryptand [8]. Recently, Au (NPs) have been employed to boost the antioxidant characteristics of Trolox [9] and melatonin [10] and for enhancing the bioefficacy of antibodies. Studies also suggest their noncytotoxic, nonimmunogenic, and biocompatible properties on RAW 264.7 macrophages [9], along with a reduced rate of release in reactive oxygen and nitrite species. Antioxidants are of prime importance in preventing the progress of age-related chronic and degenerative diseases. Therefore, there is a demand for an efficient antioxidant. Many herbal products are being used. However, these are effective only when given in higher doses. Therefore, enhancement in their anti-inflammatory characteristic would be of great interest. Gold nanoparticles generally have enhanced bioactivity, and thus it is quite likely that their use, in conjunction with RC, may enhance anti- inflammatory characteristics. However, in this process, it is logical to study the toxicity of the nanoparticles, because while enhancing the efficacy, the associated toxicity also increases. Besides, some of the nanostructures, such as carbon nanotubes, by themselves, have also been associated with induction of inflammation [11]. In this paper, the HPLC-standardized-alcoholic extract of the roots of Rubia cordifolia Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/freeradbiomed Free Radical Biology and Medicine 0891-5849/$ - see front matter & 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.freeradbiomed.2013.06.006 Abbreviations: Au (NPs), gold nanoparticles; EDAX, energy dispersive X-ray analysis; LPS, lipopolysaccharide; NO, nitric oxide; RC, Rubia cordifolia; RC-Au (NPs), Rubia cordifolia-embedded gold nanoparticles; SAED, selected area electron diffraction pattern ☆ This work was supported by DST-UNANST and UGC. n Corresponding authors. E-mail addresses: ashwanikumarsingh143@gmail.com (A.K. Singh), hepons@yahoo.com (O.N. Srivastava). Free Radical Biology and Medicine 65 (2013) 217–223