Anti-inflammatory tirucallane triterpenoids from Anopyxis klaineana Pierre (Engl.), (Rhizophoraceae).

Phytochemical investigation of the stem bark extract of Anopyxis klaineana was carried out by various chromatographic techniques resulting in the isolation and characterization of three new tirucallane triterpenoids, namely 3,23-dioxotirucalla-7,24-dien-21-oic acid (1), 3,4-secotirucalla-23-oxo-4(28)7,24-trien-3,21-dioic acid (2) and 3,4-secotirucalla-4-hydroxy-23-oxo-7,24-diene-3,21-dioic acid-21-methyl ester (3), along with nine known compounds (4-12). The structural elucidation of the compounds was performed by means of high-resolution mass spectrometry (HRMS(n)), nuclear magnetic resonance (NMR), and by comparison to literature data. Although none of the isolated compounds showed antibacterial efficacy against selected environmental and clinically important pathogenic Gram-positive and -negative bacteria, they demonstrated moderate DPPH free radical scavenging properties. Furthermore, compounds 1 and 7 exhibited remarkable anti-inflammatory potential in a prostaglandin E2 (PGE2) competitive enzyme immunoassay with IC50 values of 3.63 µM and 10.23 µM, respectively.

Tramadol--a true natural product?

We have independently investigated the source of tramadol, a synthetic analgesic largely used for treating moderate to severe pain in humans, recently found in the roots of the Cameroonian medicinal plant, Nauclea latifolia. We found tramadol and its three major mammalian metabolites (O-desmethyltramadol, N-desmethyltramadol, and 4-hydroxycyclohexyltramadol) in the roots of N. latifolia and five other plant species, and also in soil and local water bodies only in the Far North region of Cameroon. The off-label administration of tramadol to cattle in this region leads to cross-contamination of the soil and water through feces and urine containing parent tramadol as well as tramadol metabolites produced in the animals. These compounds can then be absorbed by the plant roots and also leached into the local water supplies. The presence of tramadol in roots is, thus, due to an anthropogenic contamination with the synthetic compound.

Sonhafouonic acid, a new cytotoxic and antifungal hopene-triterpenoid from Zehneria scabra camerunensis.

A new hopene-type triterpenoid, namely sonhafouonic acid 1a was isolated from Zehneria scabra camerunensis, together with eight known compounds. The structure of 1a was established by extensive NMR and high resolution MS techniques and confirmed by single-crystal X-ray crystallographic analysis. Compound 1a exhibited inhibitory activity against mycelial growth of two peronosporomycete phytopathogens Pythium ultimum and Aphanomyces cochliodes and cytotoxicity towards brine shrimp larvae (Artemia salina) at 10 µg/mL.