Medicinal use of serrulatane diterpenes

A compound of Formula (I),

• or a geometric isomer, stereoisomer, pharmaceutically acceptable salt or solvate thereof, or a combination thereof, wherein:
• X is CH2, CHOH or C(O);
• R1 is independently H, OH, OC1-5alkyl, OCH2Ph, OC2-5alkenyl, OC4-5alkadienyl, OC(O)C1-5alkyl, OC(O)Ph, OC(O)C2-5alkenyl, OC(O)C4-5alkadienyl or ═O;
• R2 is independently H, OH, OC1-5alkyl, OCH2Ph, OC2-5alkenyl, OC4-5alkadienyl, OC(O)C1-5alkyl, OC(O)Ph, OC(O)C2-5alkenyl, OC(O)C4-5alkadienyl or ═O;
• R3 is independently H, OH, OC1-5alkyl, OC(O)C1-5alkyl or ═O;
• and no more than one of R1, R2 and R3 is H;
• where R4 is OH, OC1-5alkyl, OCH2Ph, OC2-5alkenyl, OC4-5alkadienyl, OC(O)C1-5alkyl, OC(O)Ph, OC(O)C2-5alkenyl or OC(O)C4-5alkadienyl;
• and
• A---B is CH═C or CH2—CH,
• provided that where R2 is H, X is not CH2.