Separation, Identification, and Antidiabetic Activity of Catechin Isolated from Arbutus unedo L. Plant Roots

Abstract

Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used widely in the traditional medicine as an antidiabetic agent. The current study aimed to isolate the pharmacologically active compound from A. unedo roots using accelerated solvent extraction technology, to determine its chemical structure using different instrumental analytical methods, and also to evaluate the α-glucosidase inhibitory activity. The roots of A. unedo were exhaustively extracted by high-pressure static extraction using the Zippertex® technology (Dionex-ASE, Paris, France), and the extract was mixed with XAD-16 resin to reach quantifiable amounts of active compounds which were identified by high-pressure liquid chromatography (HPLC), 1H NMR (300 MHz), and 13C NMR. The antidiabetic activity of the isolated compound was evaluated using the α-glucosidase inhibitory assay. The active compound was isolated, and its structure was identified as catechin using instrumental analysis.The results revealed that the isolated compound has potential α-glucosidase inhibitory activity with an IC50 value of 87.55 ± 2.23 μg/mL greater than acarbose. This was used as a positive control, which has an IC50 value of 199.53 ± 1.12 μg/mL. According to the results achieved, the roots of A. unedo were considered the best source of catechin and the Zippertex® technology method of extraction is the best method for isolation of this therapeutic active compound. In addition, the α-glucosidase inhibitory activity results confirmed the traditional use of A. unedo roots as an antidiabetic agent. Future clinical trials and investigations of antidiabetic and other pharmacological effects such as anticancer are required.

Ethnobotanical Survey of Medicinal Plants Used by Traditional Healers to Treat Diabetes in the Taza Region of Morocco

“…This remarkable result led Naceiri Mrabti and collaborators to fractionate the root aqueous extract of A. unedo and to isolate the major compounds. The results revealed the presence of catechin as the main compound, which was isolated and tested for its inhibitory effect against α -glucosidase [ 92 ]. Indeed, the inhibitory activity of α -glucosidase was increased (IC 50 = 87.55 ± 2.23 mg/mL), compared with the inhibitory activity of aqueous extract [ 92 ].…”

Antidiabetic Effects of Flavan-3-ols and Their Microbial Metabolites

“…Their IC 50 values were 14.7, 8.1, 13.3, and 61.1 µM respectively [ 21 ]. C was also shown to inhibit α-glucosidase stronger than acarbose (IC 50 = 87.55 µg/mL vs. 199.53 ± 1.12 μg/mL, respectively) [ 22 ].…”

“…[40] [21]. C was also shown to inhibit α-glucosidase stronger than acarbose (IC 50 = 87.55 µg/mL vs. 199.53 ± 1.12 µg/mL, respectively) [22]. Interestingly, isolated procyanidins B2, B5 (dimeric), and C1 (trimeric) also had stronger α-glucosidase inhibitory activities than acarbose (IC 50 = 4.7 ± 0.2, 5.5 ± 0.1, and 3.8 ± 0.2 µg/mL, versus IC 50 = 130.0 ± 20.0 µg/mL, respectively), suggesting that the inhibitory activity could be correlated to the molecular weight of the compound [23].…”

Development and Applications of Water‐based Extraction Methods in Natural Products Isolation Chemistry

“…ASE with water was used to extract the roots of the shrub Arbutus unedo using a Zippertex solid/liquid extractor (100°C; static nitrogen pressure of 100 bar), to afford catechin (4; 2.25% w/w) ( Figure 3). [29] Aerial parts of the herb Mutellina purpurea (extracted with ASE, 40% v/v MeOH/H 2 O) afforded chlorogenic acid (5), which was isolated via high-performance countercurrent chromatography. [30] The extraction procedure enabled the rapid isolation of natural product 5 in high purity (96% via HPLC).…”