Pharmacognostical studies of the plant drug Mimosae tenuiflorae cortex.

The bark of the Mimosa tenuiflora (Willd.) Poiret (Leguminoseae) tree, known as tepescohuite in Mexico, is commonly used in this country and in Central America to elaborate different products for the treatment of skin burns and lesions. The cicatrizing properties of extracts obtained from this bark have been scientifically studied, attributing the main biological activity to its tannin and saponin content. Studies include clinical trials of phytodrugs based on Mimosae tenuiflora bark extracts for treatment of venous leg ulcerations. Recent commercialization of the plant drug Mimosae tenuiflorae cortex requires pharmacognostical information to develop quality-control methods for raw materials and extracts produced with this plant drug. The present paper reports a group of ethnobotanical, morphological, chemical, and molecular studies performed with Mimosae tenuiflora materials obtained by collection in the southeastern Mexican state of Chiapas. Macro- and micro-morphological parameters were established to authenticate the genuine drug that allowed detection of adulterants usually found in commercial samples of this plant material. These morphological characteristics can be used for rapid identification of the drug and are particularly useful in the case of powdered materials. The chemical studies performed demonstrated that tannins represent the major component group in the bark. Its content in genuine tepescohuite is 16% and is mainly composed of proanthocyanidins, a condition permitting a tannin-based chemical-control method for fingerprinting the plant drug. Contrariwise, the saponin concentration in Mimosae tenuiflora bark is extremely low, and its isolation and content evaluation represent a complex procedure that is unsuitable for routine control purposes. Finally, random amplified DNA (RAPD) analysis results a useful tool for obtaining DNA specific markers of Mimosae tenuiflora species which should be useful in future studies involving raw material authentication by molecular methods.

Morphoanatomical studies of Uncaria tomentosa and Uncaria guianensis bark and leaves.

The genus Uncaria Schreber (Rubiaceae) includes species that are widely distributed in tropical areas. The inner bark of the stems and leaves of two native species of South America, Uncaria tomentosa (Willd. ex Roemer & Schultes) DC., and Uncaria guianensis (Aublet) J. F. Gmelin, "cat's claw" are used in either folk medicine or in procuring phytotherapeutic drugs. These species contain about sixty active substances which are being tested widely for possible medicinal value. The following applications are considered: peptic ulcer, rheumatism, tumours, antiinflammatory effect, inflammation, diabetes and as general tonic. Currently, Uncaria tomentosa is in demand as tea, tablets or capsules in more than 30 countries outside Perú, as well as inside the country. Pharmacognosy studies are required to determine the comparative morphoanatomical and micrographic features for identification and quality control purposes. Several microscopic parameters, including phloem fibers, calcium oxalate crystals, starch granules, trichomes, and foliar architecture should be considered. The aim of our work is to analyse comparative morphoanatomical and micrographic features which might provide assistance in the identification, analysis and standardization of Uncaria tomentosa (Willd. ex Roemer & Schultes) DC. and Uncaria guianensis (Aublet) J. F. Gmelin stem bark and leaves in order to obtain phytotherapeutic drugs, and of the crude drug as well.

Inhibitory activity of xanthine-oxidase and superoxide scavenger properties of Inga verna subsp. affinis. Its morphological and micrographic characteristics.

Hexane, dichloromethane and ethanolic extracts of Inga verna subsp. affinis were evaluated as inhibitors of xanthine-oxidase and as scavengers of the superoxide produced by the action of the enzyme. Ethanolic but not hexane and dichloromethane extracts showed inhibitory properties of xanthine-oxidase (IC50=27.3 microg/ml) with an additional superoxide scavenging capacity (IC50=12.7 microg/ml). The antioxidant potential was confirmed with the free radical 1,1-diphenyl-2-picryl hydrazyl (DPPH) assay, which showed that the ethanolic extract scavenges 50% DPPH free radicals at 11.6 microg/ml. HPLC study of the phenol content of the active extract, revealed the presence of ellagic and gallic acids as its main constituents. The main morphological and micrographic characteristics of Inga verna subsp. affinis are described in this paper too, in order to aid in its inequivocal identification since Inga spp. are noted for their morphological variation, which makes taxonomic classification very difficult.