RESUMO
Adenophyllum porophyllum var. cancellatum, known as "árnica del monte" in Mexico, is an aromatic annual plant belonging to the Asteraceae family that grows from southern Arizona to central Mexico. The aerial parts of the plant are used in traditional medicine to treat skin diseases such as irritations, infections, and wounds. In this study, the essential oil of this plant was characterized, and its antimicrobial activity was evaluated. This species has large glands in its leaves; therefore, for quality control purposes, an anatomical study of the leaves was performed. The essential oil was isolated from the aerial parts of the plant through hydro-distillation and analyzed using a gas chromatography/mass spectrometry (GC/MS) system. Its anti-yeast activity was evaluated against three Candida species and ten bacterial strains using the disk diffusion technique. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and minimum bactericidal concentration (MBC) were determined using broth microdilution. Anatomical study was performed on the middle part of the leaf. A yield of 0.5% of the essential oil was obtained from the herb, and Eighteen compounds in the essential oil were identified, within them trans pinocamphone (29.5%), limonene (24.7%), pinocarvone (21.8%), and cis pinocamphone (8.0%) were the main components. The inhibition zones were between 10 mm and 20 mm, and the MIC and MFC against the three Candida species ranged from 60 to 500 µg/ml. The leaf anatomy showed anisocytic stomata, simple and glandular trichomes of different types, and large and elliptical-shaped lysigenous glands, which can be used for taxonomic identification. The A. porophyllum var. cancellatum essential oil can serve as an alternative source of natural antimicrobial agents as an affordable approach to control infectious diseases. This is the first study that reports the chemical composition and antimicrobial activity of the essential oil, as well as the leaf anatomy of this species.
RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Verbesina crocata (Cav.) Less. (Arnica or Capitaneja) is an endemic plant from Mexico restricted to the western part of the country. The aerial parts are used in traditional medicine for the treatment of wounds and burns. The objective of this investigation was to carry out a pharmacognostic study of V. crocata and establish markers that allow for the recognition of the characteristics of the plant and validate its traditional use. The study includes anatomical and chemical characteristics of the plant as well as evaluations of its antioxidant capacity and wound healing ability in a murine model. MATERIALS AND METHODS: An anatomical study of V. crocata was performed on the middle part of the leaf and stem. A methanolic extract of this species (VcME) was obtained by methanolic maceration of the aerial parts. Subsequently, a partition of the VcME was made to obtain a hexanic fraction (VcH). The phytochemical preliminary screening and characterization by high-performance liquid chromatography/mass spectrometry (HPLC-ESI/MS) of the VcME and VcH were performed. The antioxidant activity and total phenolic content were quantified. The wound healing capacity of the methanolic extract was determined in CD-1 mice by the healing rate, the tensiometric method, and histological analysis. RESULTS: The anatomical study of V. crocata showed the presence of two types of secretory structures and their position on the leaves. In addition, the characteristics of the middle vein and trichomes are potentially useful for recognition of the species. Chemical compounds detected by HPLC-ESI/MS reveal the presence of sitosterol glycoside and catechin derivatives as principal constituents of V. crocata. The VcME showed low antioxidant capacity and total phenolic. V. crocata had a similar healing effect to Recoveron® in the tensiometric method, but the rate of healing was higher. According to the histological analysis, the treatment of V. crocata promoted the remodelling phase 15 days after the incisional wound. CONCLUSION: This is the first pharmacognostic study of this species that covers the plant anatomy, chemical content and biological properties related to its traditional use. V. crocata favours wound healing according to physical and histological evaluations. In addition, the characteristics of the middle vein, trichomes and catechin glycosides are potentially useful for the recognition of this species.
