Phytochemical composition and potential biological activities assessment of raspberry leaf extracts from nine different raspberry species and raspberry leaf tea

Article type: Research Article

Authors: Luo, Ting^{a; b; 1} | Chen, Sirui^{a; 1} | Zhang, Haihua^c | Jia, Shijie^a | Wang, Jinling^{a; d; *}

Affiliations: [a] School of Forestry, Northeast Forestry University, Harbin, Heilongjiang, China | [b] University of Texas Southwestern Medical Center, Dallas, TX, USA | [c] Heilongjiang Province Standards and Testing Co. Ltd, Harbin, Heilongjiang, China | [d] Key Laboratory of Forest Food Resources Utilization of Heilongjiang Province, Harbin, Heilongjiang, China

Correspondence: [*] Corresponding author: Jinling Wang, No. 26 Hexing St., Harbin, Heilongjiang, P. R. China, 150040. Tel.: +86 139 3652 3028; Fax: +86 451 8219 0222; E-mail: [email protected].

Note: [1] Co-first author.

Abstract: BACKGROUND:The scientific interest regarding raspberry leaf composition and potential benefits grow. Still, little is known about raspberry leaves. OBJECTIVE:Extracts from nine raspberry leaf species and Autumn Bliss raspberry leaf tea (LT) were evaluated for their phenolic characteristics along with potential biological activities. METHODS:Phenolic constituents in leaf extracts from LT and nine raspberry species, including European red raspberry (ERR), Australian red raspberry (ARR), U.S. Raspberry (USR), Autumn Bliss (AB), Heritage (H), Tulameen (T), Longyuan Qiufeng (LQ), Qiuping (Q), and Fengman Hong (FH) were evaluated by UPLC-MS. Regarding to the bioactive activities, antioxidant activities (DPPH and ABTS assays), antidiabetic properties (α-amylase inhibition and α-glucosidase inhibition assays), antibacterial activities (growth inhibition zone measurement and a minimum inhibitory concentration (MIC)), and anti-inflammatory properties (inhibition of hyaluronidase activity and inhibition of albumin denaturation), were investigated. RESULTS:The results showed that ERR extract exhibited the highest levels of total phenolic (5.56±0.058 mg/g), the highest chlorogenic acid (597.03±10.90 mg/kg) and rutin level (2771.9±41.52 mg/kg). Autumn Bliss LT possessed the lowest total phenolics, and lowest DPPH scavenging activity. A high correlation between phenolic content and antioxidant activity was found in these extracts. CONCLUSIONS:High phytochemical contents and biological activities of these raspberry leaves, including antioxidant, antidiabetic, antibacterial, and anti-inflammatory effect were shown, which indicated their consumption would be beneficial to health.

Keywords: Raspberry leaf, phytochemicals, antioxidant, antibacterial, antidiabetic, anti-inflammatory

DOI: 10.3233/JBR-190474

Journal: Journal of Berry Research, vol. 10, no. 2, pp. 295-309, 2020