Preprint / Version 1

Chromatographic Separation of Breynia retusa (Dennst.) Alston Bark, Fruit and Leaf Constituents from Bioactive Extracts

Authors

  • Stefano Dall’Acqua Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy; [email protected]
  • Kouadio Sinan Department of Biology, Science Faculty, Selcuk University, 42130 Konya, Turkey; [email protected] (K.I.S.); [email protected] (G.A.)
  • Irene Ferrarese Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy; [email protected]
  • Stefania Sut DAFNAE, Department of Agronomy, Food, Natural Resources, Animals and Environment, Agripolis Campus, University of Padova, 35020 Legnaro, Italy; [email protected]
  • Kouadio Bene Laboratoire de Botanique et Phytothérapie, Unité de Formation et de Recherche Sciences de la Nature, 02 BP 801 Abidjan 02, Université Nangui Abrogoua, CI-YM. IV98 Abidjan, Ivory Cost; [email protected]
  • Mohamad Mahomoodally Department of Health Sciences, Faculty of Medicine and Health Sciences, University of Mauritius, 80832 Réduit, Mauritius; [email protected]
  • Nabeelah Sadeer Department of Health Sciences, Faculty of Medicine and Health Sciences, University of Mauritius, 80832 Réduit, Mauritius; [email protected]
  • Gunes Ak Department of Biology, Science Faculty, Selcuk University, 42130 Konya, Turkey; [email protected] (K.I.S.); [email protected] (G.A.)
  • Gokhan Zengin Department of Biology, Science Faculty, Selcuk University, 42130 Konya, Turkey; [email protected] (K.I.S.); [email protected] (G.A.)

Keywords:

antioxidant, bioactive compounds, Cup Saucer plant, enzyme inhibitors, traditional medicine

Abstract

Breynia retusa (Dennst.) Alston (also known as Cup Saucer plant) is a food plant with wide applications in traditional medicine, particularly in Ayurveda. Extracts obtained with four solvents (dichloromethane, methanol, ethyl acetate and water), from three plant parts, (fruit, leaf and bark) were obtained. Extracts were tested for total phenolic, flavonoid content and antioxidant activities using a battery of assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), total antioxidant capacity (TAC) (phosphomolybdenum) and metal chelating. Enzyme inhibitory effects were investigated using acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase as target enzymes. Results showed that the methanolic bark extract exhibited significant radical scavenging activity (DPPH: 202.09 ± 0.15; ABTS: 490.12 ± 0.18 mg Trolox equivalent (TE)/g), reducing potential (FRAP: 325.86 ± 4.36: CUPRAC: 661.82 ± 0.40 mg TE/g) and possessed the highest TAC (3.33 ± 0.13 mmol TE/g). The methanolic extracts were subjected to LC-DAD-MSn and NMR analysis. A two-column LC method was developed to separate constituents, allowing to identify and quantify forty-four and fifteen constituents in bark and fruits, respectively. Main compound in bark was epicatechin-3-O-sulphate and isolation of compound was performed to confirm its identity. Bark extract contained catechins, procyanidins, gallic acid derivatives and the sulfur containing spiroketal named breynins. Aerial parts mostly contained flavonoid glycosides. Considering the bioassays, the methanolic bark extract resulted a potent tyrosinase (152.79 ± 0.27 mg kojic acid equivalent/g), α-amylase (0.99 ± 0.01 mmol acarbose equivalent ACAE/g) and α-glucosidase (2.16 ± 0.01 mmol ACAE/g) inhibitor. In conclusion, methanol is able to extract the efficiently the phytoconstituents of B. retusa and the bark is the most valuable source of compounds. Keywords: antioxidant, bioactive compounds, Cup Saucer plant, enzyme inhibitors, traditional medicine

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