Tricyclic compounds having cytostatic and/or cytotoxic activity and methods of use thereof

1. A compound of formula I:

wherein both B and C rings may be completely or partially saturated or unsaturated with respect to bond 4b-8a, 5-6 and 7-8; the C ring may have an N or substituted N depending on the saturation level of the C ring, and the substitution may be all of R 1 , R 2 and R 3 ;

X and Y=NH; P=NH;

R 1 =H; and R 2 =H;

Z=S;

wherein Z may be attached to the C ring at positions 5, 6, 7 or 8 and may be attached to more than one of said positions 5, 6, 7, or 8 on the ring;

wherein when the C-ring is saturated or partially saturated the Z or R 3 creates chirality, then all stereoisomers thereof both separately and as racemic and/or diastereoisomeric mixtures are included;

R 3 =aryl, alkylaryl, and substituted saturated or unsaturated alkylaryl wherein said substitution may be at either the alkyl or the aryl portion of the alkylaryl group and may be one or more substituents independently selected from (i) an alkoxy group, (ii) halogen atoms including chlorine, bromine, iodine, and fluorine, (iii) alkyl groups including straight or branched chains having from one to six carbon atoms, (iv) an aryl group, (v) a heteroaryl group having at least one atom in the aryl ring that is not carbon selected from oxygen, nitrogen or sulfur, and (vi) a carboxylic acid having up to seven carbon atoms.

2. The compound according to claim 1 , wherein Y=NH; R 2 =H; P=NR 4 ; R 4 =H; X=NH; R 1 =H; Z=S and R 3 ≡a phenyl.

3. The compound according to claim 1 , wherein Y=NH; R 2 =H; P=NR 4 ; R 4 =H; X=NH; R 1 =H; Z=S; and R 3 =a phenyl having a methyl substitution.

4. The compound according to claim 3 , wherein the substitution on the phenyl is at the 4 position of the phenyl ring.