Chemical composition and antioxidant activity of the endemic Crataegus microphylla Koch subsp. malyana K. I. Chr. & Janjić from Bosnia

Highlights

• Endemic species Crataegus microphylla Koch subsp. malyana K. I. Chr. & Janjić.

• Soxhlet and ultrasound ethanolic extraction of leaves with flowers and berries.

• Determination of total phenolic and flavonoids content.

• Determination of antioxidant activity.

• High-performance liquid chromatography with electrochemical detection.

Abstract

Crataegus is a genus of well-known medicinal plants that comprises numerous species with various biological activities. Determination of chemical composition and antioxidant activity of some endemic species of this genus could lead to the finding potentially active compounds.

This work presents the first phytochemical investigation of endemic species Crataegus microphylla Koch subsp. malyana K. I. Chr. & Janjić from Bosnia. Etanolic extracts of leaves with flowers and berries were prepared by ultrasound and Soxhlet extractions. The results of HPLC-ED analysis of plant extracts revealed the highest content of gallic acid, caffeic acid, and hyperoside in leaves with flowers prepared by Soxhlet extraction 0.04 mg GAE/g DW, 0.60 mg CA/g DW and 2.61 mg HYP/g DW, respectively. The content of total phenolic compounds, determined by Folin-Ciocalteu method, varied from 2.47 to 13.35 mg GAE/g DW. Total flavonoid content was determined using AlCl₃ method. The content of flavonoids ranged 0.01-1.09 mg QE/g DW. The ABTS and DPPH assays were used for the evaluation of antioxidant activity of plant extract. The extract that showed the best antioxidant activity for DPPH antioxidant assay was extract of leaves with flowers prepared by Soxhlet extraction (IC₅₀ 0.78 mg/mL). For ABTS method extract of berries prepared by Soxhlet extraction showed the best antioxidant activity (IC₅₀ 0.39 mg/mL).

Introduction

The species Crataegus (Hawthorn) belongs to the family Rosaceae and includes between 150 and 1200 species. It is widespread in the Northern hemisphere (Asia, Europe and North America). On the territory of Bosnia and Herzegovina, there are several Crataegus species such as C. monogyna, C. rhypidophylla, C. oxantia, C. leavigata.

Endemic Crataegus microphylla (C. microphylla) growing wild, forms isolated enclaves in Bosnia and Herzegovina (Christensen, 1992; Christensen and Janjić, 2004).

The high contents of phenolic compounds such as phenols, phenolic acids, procyanidins, flavonoids, triterpenes, polysaccharides, catecholamines were found in the flowers, leaves, flowers with leaves, and berries of the genus Crataegus L. (Meda et al., 2005; Melikoglu et al., 2004; Gazdik et al., 2008; Froehlicher et al., 2009; Dinesh et al., 2012; Nabavi et al., 2015; Edwards et al., 2012). These compounds have a wide range of pharmacological activities such as anti-inflammatory, anti-allergic, anti-cancerogenic and anti-arthritic (Le Marchand et al., 2000; Rotelli et al., 2003; Mamani-Matsuda et al., 2006; Kumar et al., 2012)

Studies have shown that several species of the genus Crataegus L. have a wide spectrum of pharmacological action on the cardiovascular system (Ammon and Handel 1981; Nabavi et al., 2015; Rastogi et al., 2016). For hundreds of years, it has been used for medical purposes and as food in Europe and China. Research suggests that extracts of fruits and hawthorn leaves have a multiple health effect, which includes hypolipidemic, anti-arterosclerotic, hypotensive and cardioprotective effects. Fruit extracts also have an antioxidant activity (Kostić et al., 2012; Tahirovic and Basic, 2014; Konyaliglu et al., 2017).

Literature data are rather poor concerning chemical composition (Melikoglu et al., 2004; Amanzadeh et al., 2007), and antioxidant activity of C. microphylla (Sharifi et al., 2013). Phytochemical studies have shown that C. microphylla possesses a high content of phenolic components. Some of these components, such as chlorogenic acid and catechin, are probably responsible for their radioprotective potential (Hosseinimehr et al., 2007; Aksoy-Sagirli et al., 2017). It has also been proven that flavonoids and proanthocyanidins are the main constituents responsible for its biological activities (Bahorun et al., 1994; Dinesh et al., 2012; Edwards et al., 2012). Many of these components have an effect on the reduction of oxidative stress (Zhang et al., 2001). Topal et al. (2013) reported that the methanol extract of C. microphylla preserved endothelium-dependent vascular relaxation and contractions in diabetes induced by streptozotocin. It has been reported that dried parts of plants such as flowering tops, flowers, leaves and fruits are used as a crude drug (WHO, 2002; CE, 2004). Hawthorn is also used in food industry for production of different products such as jams, beverages, juices, and herbal teas (Chang et al., 2006). The main active compounds are flavone, and flavonol derivates, procyanidins, and (−) − epicatechin (ESCOP, 1992; Nabavi et al., 2015).

The aim of this work was to determine total phenolic and flavonoid content, as well as content of hyperoside, vitexin, galic, and caffeic acid by HPLC-ED method and antioxidant activity of ethanolic extracts of endemic C. microphylla. To the best of our knowledge, these are the first data on the chemical composition and antioxidant activity of the endemic plant species C. microphylla, from Bosnia and Herzegovina.