Abstract

Abstract

Recently, there has been increased interest in the discovery of new natural herbal remedies for treating diabetes and inflammatory diseases. In this context, this work analyzed the antidiabetic and anti-inflammatory potential of Artemisia absinthium, Artemisia vulgaris and Trigonella foenum-graecum herbs, which have been studied less from this point of view. Therefore, extracts were prepared and processed using membrane technologies, micro- and ultrafiltration, to concentrate the biologically active principles. The polyphenol and flavone contents in the extracts were analyzed. The qualitative analysis of the polyphenolic compounds was performed via HPLC, identifying chlorogenic acid, rosmarinic acid and rutin in A. absinthium; chlorogenic acid, luteolin and rutin in A. vulgaris; and genistin in T. foenum-graecum. The antidiabetic activity of the extracts was analyzed by testing their ability to inhibit alpha-amylase and alpha-glucosidase, and the anti-inflammatory activity was analyzed by testing their ability to inhibit hyaluronidase and lipoxygenase. Thus, the concentrated extracts of T. foenum-graecum showed high inhibitory activity on a-amylase-IC50 = 3.22 +/- 0.3 mu g/mL-(compared with acarbose-IC50 = 3.5 +/- 0.18 mu g/mL) and high inhibitory activity on LOX-IC50 = 19.69 +/- 0.52 mu g/mL (compared with all standards used). The concentrated extract of A. vulgaris showed increased alpha-amylase inhibition activity-IC50 = 8.57 +/- 2.31 mu g/mL-compared to acarbose IC50 = 3.5 +/- 0.18 mu g/mL. The concentrated extract of A. absinthium showed pronounced LOX inhibition activity-IC50 = 19.71 +/- 0.79 mu g/mL-compared to ibuprofen-IC50 = 20.19 +/- 1.25 mu g/mL.

Abstract

Background: Differences in regulatory policies between countries as well as a lack of appropriate standardized methods for the authentication and quality control of herbal products directly impact their quality and safety. Echinacea products are among the top-selling herbal products in Europe and the United States with indications for a broad range of ailments. The increased use of Echinacea species has led to concerns about adulterated products resulting from challenges in morphology-based identification, due to overlapping morphological variation, frequent hybridization between species, and deliberate adulteration. Purpose: This study addressed the need for a novel analytical strategy in the authentication of herbal products. Methods: A combination of high performance thin layer chromatography (HPTLC) and DNA metabarcoding was employed. Fifty-three Echinacea herbal products marketed across Europe were tested to evaluate the accuracy of these methods in plant identification and their potential for detecting substitutes, adulterants and other unreported plant constituents. Results: HPTLC provides high resolution in the detection of Echinacea phytochemical target compounds, but does not offer information on the other species within the product. Alternatively, we showed that the limitation of HPTLC in detecting non-targeted species can be overcome by the complementary use of DNA metabarcoding. Using DNA metabarcoding, Echinacea species were detected in 34 out of the 38 retained products (89%), but with a lack of discriminatory resolution at the species level due to the low level of molecular divergence within the Echinacea genus. All of the tested herbal products showed considerable discrepancies between ingredients listed on the label and the ones detected using DNA metabarcoding, registering an overall ingredient fidelity of only 43%. Conclusion: The results confirm that DNA metabarcoding can be used to test for the presence of Echinacea species and simultaneously to detect other species present in even highly processed and multi-ingredient herbal products.

Abstract