Which of the following is the principal alkaloid obtained from seeds of nux vomica?

Strychnine (kuchila) is a powerful alkaloid obtained from the seeds of strychnos nux vomica. The seeds contain two principal alkaloids; strychnine and brucine. The seeds also contain a glucoside, loganin. Strychnine is 10 to 20 times more poisonous than brucine. Ref: The Essentials of Forensic Medicine and Toxicology by KS Narayan Reddy, 27th edition, Page 545.