Antibacterial Action

Lebanstin from Ilex paraguariensis (Yerba Mate)

The content on this page comes from ScienceDirect, and has been translated into Polish.

Link to source –https://www.sciencedirect.com/science/article/abs/pii/S0367326X21001374

Abstract

Reportedly, infectious diseases are among the leading causes of death worldwide. The World Health Organization (WHO) warns of an increase in deaths due to antibacterial resistance. Recently, there has been a growing trend towards seeking new active antibacterial compounds in plants. Ilex paraguariensis , known as Yerba Mate, is a plant known for being rich in numerous bioactive compounds that play an important role in human health. In this study, Yerba Mate was extracted with a mixture of acetone : water (1:1), and then fractionated with hexane , chloroform and ethyl acetate . The resulting fractions were tested for antibacterial activity against Staphylococcus aureus and Salmonella species. The minimum inhibitory concentration (MIC) values for S. aureus S. aureus and from 1.56 mg/mL to 3.12 mg/mL for Salmonella species. The water fraction was further treated with various enzymes to mimic in vivo digestion active metabolite ranged from 1.56 to 3.12 mg/mL for both the chloroform and ethyl acetate fractions. Whereas for the water fraction, the MIC values ranged from 0.78 to 3.12 mg/mL on digestion and the fractions obtained were then tested for antibacterial activity. Furthermore, the Yerba Mate aqueous fraction was run on High Performance Liquid Chromatography (HPLC) and collected fractions were tested for antibacterial activity, to identify the active compound. Fraction 3 was tested on various S. aureus strains, and the MIC values ranged from 0.19 to 1.56 μg/mL. Using NMR spectroscopy, a new pyrazinone, Libanstin, was identified from Ilex paraguariensis .

Graphical abstract

Introduction

Staphylococcus aureus is a Gram-positive bacterium. It is a human pathogen that causes minor and major illnesses. This bacterium shows resistance to many antibiotics due to mutations leading to changes in antibiotic binding sites and to high expression of efflux pumps [10]. Salmonella species are Gram-negative bacteria. They cause infections leading to numerous clinical syndromes. The risk of infection with multidrug-resistant Salmonella arises when antibacterial agents are used against these bacteria [7].

Herbal medicines are widely used as therapeutic agents due to their availability, growing demand for natural and organic products, and confirmed synergistic effects [26]. Ilex paraguariensis is a herb commonly used in Latin American countries. The leaves of this plant contain a high concentration of many bioactive molecules: phenolic compounds, mainly tannins, flavonoids and phenolic acids [2]. It is also rich in theobromine, caffeine, caffeoylquinic acid and dicaffeoylquinic acid derivatives [18].

Polyphenols present in Yerba Mate contribute to its antioxidant activity [5] and provide protection of body tissues against oxidative stress [20]. Saponins are glycosidic compounds that have both a hydrophobic and a hydrophilic part. Metasaponins from Ilex paraguariensis show anticancer [19], antiparasitic [23,24] and anti-inflammatory [18] activity. A synergistic anti-inflammatory effect is also observed between Yerba Mate saponins and quercetin [18].

Xanthines are purine alkaloids found in various plant extracts. Caffeine, theobromine and theophylline are three xanthines present in Yerba Mate [27]. These alkaloids serve as a source of “energetic dietary supplements” for the plant [21].

In this study, the antibacterial activity of Ilex paraguariensis after liquid-liquid partitioning against S. aureus and Salmonella species was investigated. In addition, the bioactive compound(s) responsible for this antibacterial activity were examined.

Section excerpts

General experimental

All 1D ( ^1H and ^13C ) and 2D (COSY, HSQC-DEPT and HMBC) NMR spectra were recorded on a Bruker 500 MHz Avance HD spectrometer with a 5-mm BBFO Smart probe with Z gradient ( ^1H at 500 MHz, ¹³ °C at 125.7 MHz). 2D experiments were recorded using standard pulse programs. Samples were dissolved in CDCI3 _and solvent signal chemical shifts at 7.24 ppm (δH ) and _77.0 ppm (δC ₎ were used as the internal standard (reference signal). Observed chemical shift values (δ) are given in ppm and

MIC values of Yerba Mate fractions against S. aureus and Salmonella strains

Yerba Mate leaves were first extracted with various solvents to test for the strongest antibacterial activity against several bacterial strains. It was extracted with ethanol and further subfractionated with hexane, chloroform, ethyl acetate and water. MIC values were not detected in these extracts at the highest concentration tested (4.375 mg/ml). Yerba Mate was then extracted with pure acetone and subsequently subfractionated. Comparison of the MIC values (2.5 mg/ml) of the fraction with their fractions

Discussion

Plant extracts or their bioactive compounds have been widely studied for their antimicrobial activity, especially against the growth of multidrug-resistant bacteria [16]. Ilex paraguariensis (Yerba Mate) has recently gained popularity due to increased consumption and biological activity. Marcin et al. [15] studied methanolic and ethanolic extracts of Yerba Mate against S. aureus , S. enteritidis , L. monocytogenes and E. coli [15]. The ethanolic extract had a lower MIC value than

Conclusion

Plants have been used to treat many infectious diseases since ancient times. Numerous studies show antiproliferative, antioxidant, anti-inflammatory, antifungal and antibacterial effects of various plant extracts. In this study, the aqueous fraction, after liquid-liquid separation of the acetone:water (1:1) extract from the stems and leaves of Ilex paraguariensis , showed the highest antibacterial activity. Furthermore, the bioactive compound responsible for this effect was identified

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contributions

SE-S and EF carried out the experimental procedures and helped prepare the manuscript. GP and AAF helped with compound identification, NMR analysis and manuscript revision. RAM conceived the study design, was involved in the interpretation of results and manuscript revision. All authors read and approved the final version of the manuscript.

The content on this page comes from National Library of Medicine, and has been translated into Polish.

Link to source – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9516501/