From the natural product 4-(4'-O-acetyl-α-L-rhamnosyloxy)benzylisothiocyanate (1), isolated from the flowers of Moringa oleifera Lam (Moringaceae), four new semisynthetic derivatives, N-[4-(4'-O-acetyl-α-L-rhamnosyloxy)benzyl]-2-(pyridinil-4-carbonil)hydrazine-1-carbothioamide (3), 4-(4'-O-acetyl-2',3'-dimesyloxy-α-L-rhamnosyloxy)benzylisothiocyanate (4), N-[(4'-O-acetyl-α-L-rhamnosyloxy)benzyl]hydrazinecarbothioamide (5), 4-[4'-O-acetyl-2',3'-O-bis(decanoiloxy)-α-L-rhamnosyloxy]benzylisothiocianate (6), and the known compound 4-(2',3',4'-O-triacetyl-α-L-rhamnosyloxy)benzylisothiocyanate (2), were obtained. All compounds were tested for their cytotoxicity against the tumor cell lines SF-295, HL-60, HCT-116 e PC-3. The natural product 1 and the semisynthetic derivatives 2 and 4 were the most active compounds (IC50 from16.0 to 3.7 µmol L-1) against all tumor cell lines.

The chemical investigation of the ethanol extracts of stems, roots and leaves of Lippia sidoides led to the isolation of: steroid β-sitosterol, naphthoquinone tecomaquinone, monoterpene carvacrol, flavonoid 4',5,7-trihydroxyflavanone (naringenin), 3',4',5,7-tetrahydroxyflavanone and 4',5,7-trihydroxy-6-methoxyflavone flavonoids mixture, and 3,4,4',6'-tetrahydroxydihydrochalcone-2'-O-β-D-glucopyranoside and 4,4',6'-trihydroxydihydrochalcone-2'-O- β-D-glucopyranoside dihydrochalcones mixture. Their structures were characterized on the basis of spectral data, mainly ¹H and 13C NMR (1D and 2D) and mass spectra. The ethanol extract and isolated compounds were evaluated for their antioxidative properties using the method of inhibition of free radical DPPH (2,2-diphenyl-1-picrylhydrazyl).

Six known alkaloids iboga type and the triterpen α- and β-amyrin acetate were isolated from the roots and stems of Peschiera affinis. Their structures were characterized on the basis of spectral data mainly NMR and mass spectra. 1D and 2D NMR spectra were also used to unequivocal ¹H and 13C chemical shift assignments of alkaloids. The ethanolic extract of roots, alkaloidic and no-alkaloidic fractions and iso-voacristine hydroxyindolenine and voacangine were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and also spectrophotometric detection by reduction of the stable DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical.