[1] Res Ctr Univ Kerala, Univ Coll, Dept Bot, Thiruvananthapuram 695034, Kerala, India
[2] Govt Coll, Dept Bot, Kasaragod 671123, Kerala, India
[3] Reg Canc Ctr, Lab Immunopharmacol & Expt Therapeut, Thiruvananthapuram 695011, Kerala, India
[4] Univ Rome Sapienza, Dept PDTA, Sect Environm & Landscape, Lab Phytogeog & Appl Geobot, I-00196 Rome, Italy