1. a Phytochemistry and Phytopharmacology Division , Tropical Botanic Garden and Research Institute , Pacha-Palode, Thiruvananthapuram, 695 562, Kerala, India
2. b Microbiology Division , Tropical Botanic Garden and Research Institute , Pacha-Palode, Thiruvananthapuram, 695 562, Kerala, India
3. c Department of Chemistry , Gandhigram Rural University , Gandhigram, 624 302, Tamil Nadu, India