Elsevier

Industrial Crops and Products

Volume 74, 15 November 2015, Pages 803-809
Industrial Crops and Products

Polyphenols, antioxidant and antimicrobial activities of leaf and bark extracts of Solidago canadensis L.

https://doi.org/10.1016/j.indcrop.2015.06.014Get rights and content

Highlights

  • Phenols, antioxidant and antimicrobial activity of S. canadensis L. were examined.

  • Efficacy of ultrasound- and high pressure-assisted extractions was compared.

  • Leaf has higher phenols, tannis and flavonoids, and antioxidactivity than bark.

  • Ultrasonic extracts at full bloom stage had the highest DPPH, ORAC and phenols.

  • Leaf extracts had antimicrobial activity against L. monocytogenes and S. aereus.

Abstract

The leaf and bark of Solidago canadensis L. (SCL) contain a wide range of bioactive compounds that may be responsible for their biological activities. However, little information is available about their specific active compounds, as well as their contributions to the antioxidant and antimicrobial properties. This study investigated the total phenolics, tannins and flavonoid contents and antioxidant and antimicrobial activities of high pressure (HPE) or ultrasound (UE) assisted ethanolic extracts from leaf and bark of SCL at three ripening stages (vegetative growth (VG), full bloom (FB) and maturity after flowering (MF)). The antioxidant activities and contents of total phenolic (TPC), tannins (TTC) and flavonoids (TFC) varied with ripeness stage, tissue type and extraction method. Overall, the UE leaf extracts at the FB stage exhibited the highest TPC (3.8 mg GAE/g DM), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity (0.547 mg AAE/g DM) and oxygen radical absorbing capacity (ORAC) value (57.86 mmol TE/g DM). The HPE extracts of MF samples had the greatest TFC (2.45 mg RE/g DM) and reducing power (3.38). The greatest TTC (4.17 g/100 g DM) was observed in the ethanolic extracts at the MF stage. All leaf extracts exhibited antimicrobial activity against Listeria monocytogenes and Staphylococcus aureus, but only the HPE extracts of the VG samples showed activity against Salmonella spp. The UE leaf extracts at the MF stage demonstrated the maximum inhibitory potency against Escherichia coli, L. monocytogenes and S. aureus. These results highlighted the potential of using S. canadensis extracts as natural antimicrobial and antioxidant substances for food applications.

Introduction

Solidago canadensis L. (SCL) is an herbaceous perennial plant of the family plant of Asteraceae that is widely distribute in South America, Europe and Asia (Skrzypczak and Budzianowski, 2001). SCL is generally considered a harmful invasive plant that poses a serious threat to the ecosystems and the biodiversity, and causes great economic loss to the regions they invade (Wang et al., 2011). Burning SCL is harmful to people and also increases environmental pollution (Dai, 2009). Several recent studies have revealed that the leaves of SCL contain a wide range of active ingredients that are responsible for its antioxidant, antimicrobial, anti-inflammatory and spasmolytic and diuretic properties (Dai, 2009, Wang et al., 2011). The accumulation of certain polyphenols (such as flavonoids, tannins, phenolic acids and others) and their derivatives are mainly responsible for these potential health benefits (Akharaiyi, 2011, Cowan, 1999, Dai, 2009, Deng et al., 2014b, Skotti et al., 2014).

The bioactive component content, and the antioxidant and antimicrobial activities of plants are often closely related to the ripening stage of plants and their contents differ in different parts of plants, such as bark, leaf, seed, root, flower and stem (Fernández-Agulló et al., 2013, Gurjar et al., 2012, Moulehi et al., 2012, Piccirillo et al., 2013, Shabir et al., 2011, Wei et al., 2010). For example, the content of phenolic compounds in SCL at the same ripening stage decreased following the sequence: yellow flowers > leaves > roots (Wang et al., 2011). The levels of methanol soluble polyphenolic compounds in the cherry laurel leaf were higher than in the fruit (Karabegović et al., 2014a). The amount of phenolic acids in blueberry leaves varied depending on ripeness stage and the extraction solvent used, and only semi-mature and commercial-mature samples showed activity against Listeria monocytogenes and Staphylococcus aureus (Deng et al., 2014b). Akharaiyi (2011) found that antioxidant activities were higher in the Datura metel leaf than in the bark. The root extracts showed no antibacterial activity, while the leaf extracts exhibited more therapeutic effect on the tested isolates. However, no detailed information is available about main active compounds, and the antioxidant and antimicrobial properties of bark of SCL. Furthermore, there is no data on the impact of ripening stage on the phenolic composition, and the antimicrobial and antioxidant activities of SCL. Therefore, it is important to investigate the impact of harvesting maturity of the leaves and barks on their bioactive compounds, and the resultant antioxidant and antimicrobial activities.

Extraction is crucial first step for the isolation and purification of these bioactive components of plant materials. Generally, the conventional extraction techniques (such as solvent extraction, steam distillation, etc.) are often limited by the long extraction time, environmental pollution, low yield and mass transfer resistances caused by the involvement of more than one phase in the system (Deng et al., 2014b; Karabegović et al., 2014 Xi et al., 2011). To provide an effective alternative to the traditional extraction methods, new physical techniques such as high pressure processes (Prasad et al., 2010, Xi et al., 2011) and ultrasound (Esclapez et al., 2011, Ramamoorthy and Bono, 2007) have been applied to disrupt the cell wall and release active components during product extraction. Ultrasound traveling through a solid medium can generate minute vapor-filled bubbles that collapse rapidly or generate voids in liquids, a phenomenon termed acoustic cavitation, which is a result of pressure fluctuation (Deng and Zhao, 2008). This acoustic cavitation can accelerate the disruption of cell walls, reduce particle size and enhance the penetration of solvents into cellular materials and facilitate the release of extractable compounds (Esclapez et al., 2011). The yields of anthocyanins and total phenolics obtained by ultrasound from mangosteen hulls were 45.6% and 8.8% higher, respectively, compared with those without ultrasonic treatment (Cheok et al., 2013). Sonication-assisted extraction (UE) gave the highest extraction yield of total flavonoids compared with other extraction methods (Ramamoorthy and Bono, 2007). High hydrostatic-pressure (HHP) processing uses water as a medium to transmit pressures from 200 to 600 MPa to plant materials, leading to enhanced mass transfer rate, solvent permeability in cells and secondary metabolite diffusion (Ahmed and Ramaswamy, 2006). HHP can also destroy microstructural changes in vegetal materials, such as cellular formation and cellular membrane damage, as well as the secondary and tertiary structures of macromolecules (Deng et al., 2014a, Xi et al., 2011). High hydrostatic-pressure-assisted extraction (HPE) was reported as a simpler and more effective alternative to conventional extraction methods and was used for the extraction of bioactive compounds from green tea leaves (Xi et al., 2011). Prasad et al. (2010) stated that HPE samples showed higher extraction yields with high phenolic contents and higher antioxidant and antityrosinase activities from longan fruit pericarp. However, there are no comparative studies on major bioactive components, and the antioxidant and antimicrobial properties of SCL bark and leaf extracts obtained by HHP and ultrasound assisted extraction.

Hence, the objectives of the present study were: (1) to determine the antioxidant and antimicrobial properties, and total phenolics, tannins and flavonoid contents of the extracts from SCL bark and leaves at different maturity stages; (2) to evaluate the effects of extraction methods (HPE, UE and ethanol extraction) on the active composition, and antimicrobial and antioxidant activities; and (3) to understand the relationships among bioactive properties, and antioxidant and antimicrobial activities.

Section snippets

Materials

S. canadensis L. samples were harvested at three different ripening stages: vegetative growth (VG, early July), full bloom (FB, early September) and maturity after flowering (MF, late October) (Huang and Guo, 2005). The leaves and barks were collected by hand. All samples were immediately freeze-dried, pulverized, passed through a 40 mesh standard sieve, and then stored at −80 °C until use. All chemical agents and standards were obtained from Sigma–Aldrich (St. Louis, USA).

Ethanolic extraction (EE)

Leaf and bark powders

Total phenol, tannins and flavonoids contents

The TPC, TTC and TFC determined in leaf and bark extracts of SCL are shown in Table 1. The TPC, TTC and TFC of the leaf and bark extracts varied from 0.601 to 3.808 mg GAE/100 g DM, 2.527–4.169 g/100 g DM and 0.113–2.452 g RE/100 g DM, respectively. Our results are comparable to previous reports on the SCL species from in vitro culture (Skrzypczak and Budzianowski, 2001). Compared with the bark, the leaf extracts had more TPC (except for the HPE extracts at the VG stage), TTC (except for the UE and

Conclusions

This study was the first attempt to evaluate the effects of different extraction techniques (HPE, UE and EE) on the extraction of polyphenols from the leaf and bark of S. canadensis at different maturities and their antioxidant and antimicrobial activities. The results showed that the extraction techniques and the nature of the plant material affect the contents of phenolic compounds and their antioxidant and antimicrobial properties in various degrees. The UE extracts at the FB stage had the

Acknowledgments

This research was supported by the National Natural Science Foundation of China (No. 31271955), the Agri + X Foundation of Shanghai Jiao Tong University and the Shanghai Minhang District Commission of Science and Technology.

References (37)

  • I. Moulehi et al.

    Variety and ripening impact on phenolic composition and antioxidant activity of mandarin (Citrus reticulate Blanco) and bitter orange (Citrus aurantium L.) seeds extracts

    Ind. Crops Prod.

    (2012)
  • C. Piccirillo et al.

    Chemical composition and antibacterial properties of stem and leaf extracts from Ginja cherry plant

    Ind. Crops Prod.

    (2013)
  • K.N. Prasad et al.

    Enhanced antioxidant and antityrosinase activities of longan fruit pericarp by ultra-high-pressure-assisted extraction

    J. Pharm. Biomed. Anal.

    (2010)
  • E. Skotti et al.

    Total phenolic content, antioxidant activity and toxicity of aqueous extracts from selected Greek medicinal and aromatic plants

    Ind. Crops Prod.

    (2014)
  • J. Ahmed et al.

    High pressure processing of fruits and vegetables

    Stewart Postharvest Rev.

    (2006)
  • F. Akharaiyi

    Antibacterial, phytochemical and antioxidant activities of Datura metel

    Int. J. PharmTech. Res.

    (2011)
  • E.M. Altuner et al.

    High hydrostatic pressure extraction of phenolic compounds from Maclura pomifera fruits

    Afr. J. Biotechnol.

    (2014)
  • D. Banerjee et al.

    Antioxidant activity and total phenolics of some mangroves in Sundarbans

    Afr. J. Biotechnol.

    (2008)
  • Cited by (88)

    • Enhancement of anthocyanins extraction from haskap by cold plasma pretreatment

      2023, Innovative Food Science and Emerging Technologies
    View all citing articles on Scopus
    View full text