14.

Antibacterial and Cytotoxic Activities of Diterpenoids Isolated from Indian Plectranthus coesta

Shobha Waldia, Nagendra Kaushik, Akhilesh K. Verma, Bipin C. Joshi, Uma Pathak 1 and Mukesh C. Joshi

Department of Chemistry, L.S.M. Govt. PG College Pithoragarh, Kumaun University, Nainital, Uttarakhand, 262501, India.

Department of Chemistry, University of Delhi, Delhi-110007, India.

Department of Chemistry, Kwangwoon University , Seoul-139701, South Korea.

Department of Chemistry, Motilal Nehru College, Benito Juarez Marg, Delhi University , South Campus, New Delhi-110021, India.

Abstract: Plectranthus is known for its medicinal value . The paper describes the antibacterial and cytotoxic activity of diterpenoids ent -7-hydroxykaur-15,16-en-19-oic acid (1), 17-oxokaur-15,16-en-19-oic acid (2) and ent-7-hydroxy-15,16-epoxykauran-19-oic acid (3), isolated from the shade-dried and powdered leaves of Indian Plactranthus coesta. Diterpenoid 3 was isolated for the first time from Indian P. coesta . Diterpenoid 1, shows potent activity against E. coli (15.6 µg/mL), P. aureginosa (17 µg/mL) and K. planticola (32.5 µg/mL), while diterpenoid 2, also showed good activity against E. coli (61 µg/mL), P. aureginosa (61 µg/mL), K. planticola (61 µg/mL) and S. epidermidis (125 µg/mL). Diterpenoids 1-3 were found to be more efficacious on U87 cancer cells and less toxic on normal human HEK and HeLa cells.

Keywords: Antibacterial activity; Cytotoxicity; Diterpenoid; Plectranthus coesta .