Chemical relationships of Polypremum procumbens/, Tetrachondra hamiltonii and Peltanthera yoribunda

Polypremum procumbens (Buddlejaceae) was found to contain sorbitol, cornoside, salidroside and conandroside. One collection of Peltanthera floribunda (Buddlejaceae) contained verbascoside, two others the cornoside-derived rengyolone (=halleridone). From Tetrachondra hamiltonii (Tetrachondraceae) was isolated sorbitol, cornoside and verbascoside. Iridoids were not found in any of the taxa. The taxonomic significance of the different chemical constituents is discussed, and the data demonstrate a close relationship between Polypremum and Tetrachondra. They may also suggest an inclusion of Peltanthera in Gesneriaceae. These findings are in concert with recently published chloroplast DNA sequence data.