*2.12.8. Plectranthus hereroensis*

*2.12.3. Plectranthus caninus*

22 Terpenes and Terpenoids

*2.12.4. Plectranthus ecklonii*

*2.12.5. Plectranthus ernstii*

*2.12.6. Plectranthus fruticosus*

(**112**) and barbatusin (**113**) [52, 53].

potent apoptotic inducer in leukemia cells [56].

*Plectranthus caninus* afforded coleons M (**106**), N (**107**), P (**108**), Q(**109**), R (**110**), S (**111**), and T

*Plectranthus ecklonii* is traditionally used in South Africa for treating stomach aches, nausea, vomiting, and meningitis. Ecklonoquinone A (**114**) and B (**115**) and parviflorons D (**116**) and F (**117**) were isolated [54, 55]. Compound **117** showed potent activity against *Listeria monocytogenes* and *M. tuberculosis* and both **116** and **117** were found to be very toxic against vero cell lines. The potency of parvifloron D (**116**) was further confirmed and showed fast and

Two pimaranes rel-15(ζ),16-epoxy-7*α*-hydroxypimar-8,14-ene (**118**): rel-15(ζ),16-epoxy-7-oxopimar-8,14-ene (**119**) and a labdane 1*R*,11*S*-dihydroxy-8*R*,13*R*-epoxylabd-14-ene (**120**) were isolated. The three compounds showed activity against *M. tuberculosis* and different strains of *S. aureus* [57].

*Plectranthus fruticosus* cultivated in Porugal afforded 4 labdanes, *ent*-labda-8(17),12Z,14-trien-2*β*-ol (**121**),*ent*-2*α*-acetoxylabda-8(17),12*Z*,14-trien-3*β*-ol (**122**), ent-3*β*-acetoxylabda-8(17), Horminone (**150**), 16-acetoxy-7*α*,12-dihydroxy-8,12-abietadiene-11,14-dione (**153**) and 7*α*-12 dihydroxy-17(15→16)-abieta-8,12,16-triene-11,14-dione (**157**);3*β*-acetoxy-6*β*,7*α*-12-trihydroxy-17(15→16)18(4→3)bisabeo-abieta-4(19)8,12,16-triene-11,14-dione (**158**) were isolated [13, 66, 71], on the other hand, the structure of an aristolane sesquiterpene aldehyde (**159**) have been revised [72], all compounds showed moderate antimicrobialactivity [13, 66, 71, 72], while **158** showed antiviral activity [73].
