Determination of Flavan‑3‑ols by High‑Performance Liquid Chromatography‑Photodiode Array, Antioxidant Potential, Antimicrobial Activity and Pharmacognostic Evaluation of Maytenus obtusifolia (Mart.) Leaves

Background: Maytenus obtusifolia Mart. (Syn. Monteverdia obtusifolia Mart. Biral), Celastraceae, is a species located on the coast of Brazil, which is commonly used as anti‑inflammatory and on the treatment of gastric ulcers. Objectives: The aim of this study consists of the determination of quality control parameters of the plant material, as well as to develop, validate high‑performance liquid chromatography‑photodiode array methodology for the quantification of its analytical markers and evaluate the antioxidant potential and antimicrobial activity of the extract. Materials and Methods: The plant material and ethanolic crude extract (ECE) were evaluated through pharmacopoeial and nonpharmacopoeial methods. Anti‑oxidant assay was assessed using the 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) method. Minimum inhibitory concentration was used to evaluate antimicrobial activity assay. Results: The assays have provided the following results: granulometry (d50 0.82 mm), moisture content (6.41%–9.03%), pH of aqueous solution (5.41), apparent bulk density (0.41 mg/mL), heavy metals (<10 ppm), total ash (5.20%), and sulfated ash content (6.36%). Total flavonoid (2.14%; 6.24%), tannin (6.51%; 17.85%), and phenolic content (41.95; 134.76 mg AG/g) regarding leaves powder and its ECE, respectively. The validated method was specific, linear, precise, accurate, and robust. The content of (‑)‑Epigallocatechin, (+)‑Catechin and (‑)‑Epicatechin on the ECE was 1.00%, 0.40%, and 0.33%, respectively. The anti‑oxidant activity was evaluated by DPPH assay and have presented an IC50 at 18.01 μg/mL. In addition, the most important antimicrobial activity of the ECE was against Aspergillus flavus (MIC at 128 μg/mL). Conclusion: These data have demonstrated to be very useful toward the analysis and pharmacognostic quality control of M. obtusifolia Mart.