1. Drug and Herbal Research Centre; Faculty of Pharmacy; Universiti Kebangsaan Malaysia; Jalan Raja Muda Abdul Aziz 50300 Kuala Lumpur Malaysia
2. Institute of Functional Biomolecules; State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University; Nanjing 210093 China
3. Department of Chemistry; Vidya Bharati Mahavidyalaya; Amravati Maharashtra 444 602 India