Structural analysis of Centrolobium tomentosum seed lectin with inflammatory activity.

A glycosylated lectin (CTL) with specificity for mannose and glucose has been detected and purified from seeds of Centrolobium tomentosum, a legume plant from Dalbergieae tribe. It was isolated by mannose-sepharose affinity chromatography. The primary structure was determined by tandem mass spectrometry and consists of 245 amino acids, similar to other Dalbergieae lectins. CTL structures were solved from two crystal forms, a monoclinic and a tetragonal, diffracted at 2.25 and 1.9 Å, respectively. The carbohydrate recognition domain (CRD), metal-binding site and glycosylation site were characterized, and the structural basis for mannose/glucose-binding was elucidated. The lectin adopts the canonical dimeric organization of legume lectins. CTL showed acute inflammatory effect in paw edema model. The protein was subjected to ligand screening (dimannosides and trimannoside) by molecular docking, and interactions were compared with similar lectins possessing the same ligand specificity. This is the first crystal structure of mannose/glucose native seed lectin with proinflammatory activity isolated from the Centrolobium genus.

Centrolobium tomentosum: macro-and microscopic diagnosis of the leaf and stem

Centrolobium tomentosum Guillemin ex Benth., Fabaceae, known as "araribá-rosa", is a large tree that is widespread throughout Brazil. The bark of its stem is used in folk medicine as an astringent and the leaves are employed as a poultice for wounds and bruises. The aim of this study was to contribute to the pharmacognostic quality control of this medicinal species through a macro- and microscopic diagnosis of its leaves and stems. Mature leaves and young stems were collected at Embrapa (Colombo, PR) and analyzed using standard microtechniques. The leaves are opposite or alternate, compound, imparipinnate, oblong-lanceolate and hypostomatic with paracytic stomata. The mesophyll is dorsiventral and the midrib is biconvex with a collateral vascular bundle in a circular arrangement. The petiolule is circular and its vascular system is composed of two major vascular bundles in the middle, with smaller bundles between them. The rachis has a structure similar to the petiole, and these parts have a sclerenchymatic sheath shaped in multiple arcs, which surrounds a collateral vascular bundle that is centrally located. The stem has a uniseriate epidermis with peripheral phellogen and a sclerenchymatic sheath composed of many arcs, which surrounds the phloem. The stems and leaves also have non-glandular and glandular trichomes, phenolic compounds and idioblasts made of calcium oxalate crystals. This manuscript has an important role in the morpho-anatomical diagnosis of the Brazilian flora.