2179 J. Indian Chem. Soc., Vol. 91, December 2014, pp. 2179-2187 Physico-chemical characterization of spineless safflower petals and HPLC-based process optimization for extracting quercetin-3-O-rutinoside S. Mahibalan a , A. Sajeli Begum* a , Ravi Sojitra a , S. Ameer Basha b , Sameer K. Chandavenkata c and C. Sudhakar d a Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad-500 078, Telangana, India E-mail : sajeli@hyderabad.bits-pilani.ac.in b Palem Regional Agricultural Research Station, Professor Jayashankar Telangana State Agricultural University, Mahaboob Nagar District, Telangana, India c International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad, Telangana, India d Agricultural Research Station, Professor Jayashankar Telangana State Agricultural University, Tandur, Telangana, India Manuscript received online 18 June 2014, accepted 03 July 2014 Abstract : The study was aimed to assure the safety of consumption of spineless safflower petals as decoction through physico-chemical characterization and to add value to it by optimizing an eco-friendly extraction process validated by HPLC for quercetin-3-O-rutinoside. Results of determination of tannins, swelling index, hemolytic activity, arsenic, heavy metals (Hg, Pb, Cr, Cd), etc., complied with standard acceptable limits. Different extraction techniques of modern and conventional usage substantiated by reverse phase-HPLC assay were endeavored to evaluate the extraction capacity. Techniques like Soxhlet extraction, heat reflux and maceration with stirring yielded 88.72 ± 5.27 ppm, 74.32 ± 0.67 ppm and 34.30 ± 4.06 ppm of quercetin-3-O-rutinoside, respectively. The ultrasonic assisted extraction yielded 40.64 ± 0.11 ppm under optimum irradiation time. Comparative analysis of yield of quercetin-3- O-rutinoside expounded the higher efficiency of microwave assisted extraction (MAE) method (104.18 ± 4.05 ppm). The high yielding MAE process was improved by modifying various physical and chemical phenomena. A rapid, reproducible, thermally safe, and cost effective MAE process adoptable for maximum recovery of quercetin-3- O-rutinoside from safflower petals was optimized. Keywords : Microwave, safety, quercetin-3- O-rutinoside, safflower petals, Soxhlet extraction, ultrasonic. Introduction Herbal tea rich in flavonoids is being ingested world- wide mainly for natural antioxidants to relieve day-to-day stress related disorders. In this context, safflower petals consumed broadly have huge commercial scope amongst beverage and pharmaceutical industries, provided its non- toxicity and flavonoid level are well established. Analyz- ing the physico-chemical parameters of a plant material can ascertain the safety required for internal administra- tion. In this facet, characterization of certain important properties of safflower petals was carried out following World Health Organization (WHO) guidelines 1 . Another key part of the study was process optimization for ex- tracting quercetin-3-O-rutinoside, from characterized saf- flower petals. Despite its presence and certainly proved medicinal value against various diseases, no attempt has so far been made to optimize an extraction process for this flavonoid glycoside from safflower pet- als. An incomplete extraction process producing a poorly prepared extract may be therapeutically inefficient and produce erroneous results as well. Thus, the present work included a reproducible, high pressure liquid chromato- graphy (HPLC) based study of effect of various modern and conventional extraction techniques in order to de- velop an effective procedure producing more quercetin- 3-O-rutinoside. Safflower (Carthamus tinctorius; Family : Asteraceae) is extensively cultivated as oil seed crop and red dye source 2 . The worldwide research and development on different aspects of safflower has been revitalized in the