.  doi: 10.1002/fsn3.1990

. Published online 2020 Nov 9

Maryam Aziz, ¹ Farhan Saeed, ¹ Nazir Ahmad, ¹ Aftab Ahmad, ¹ Muhammad Afzaal, ¹ Shahzad Hussain, ² Abdellatif A. Mohamed, ² Mohamed S. Alamri, ² and Faqir Muhammad Anjum ³

Abstract

The main objective of current study was to evaluate the antioxidant potential and nutritional composition of milk thistle with special reference to silymarin. For the purpose, different varieties of milk thistle were procured from three different cities of Pakistan. The study was comprised of three different phases. In 1st phase, nutritional composition, that is, moisture, fat, protein, fiber, and nitrogen free extract, was determined according to their respective methods. Moreover, antioxidant potential and quantification of silymarin content were explored in 2nd phase. Furthermore, in last phase, milk thistle seeds tea was developed and evaluated for nutritional and sensorial characteristics. At last, data obtained from each parameter was subjected to appropriate statistical design to determine the level of significance. Results showed significant difference in the nutritional and chemical composition of different milk thistle varieties as well as locations. Moreover, moisture content, ash content, fat content, fiber content, protein content, and NFE varied from 6.27% to 5.01%, 2.37 to 1.25%, 23.19 to 19.74%, 7.4 to 4.39%, 30.09 to 20.74%, and 45.42 to 34.13%, respectively. Furthermore, silymarin content quantified though HPLC ranged from 1669.5 mg/g to 1607.6 mg/g for soxhlet extract whereas, 1,840.6 mg/g to 1765.9 mg/g for microwave‐assisted extraction extract. Conclusively, it was depicted from the results that in case of variety, Blue was the best than White whereas, Islamabad was best in case of location.

Keywords: Chemical, Milk Thistle, Nutrition, Silymarin

1. INTRODUCTION

Herbs fundamentally, plants or part of plants used for the treatment of many physiological disorders due to the presence of many phytochemicals and medicinal properties. Among these, milk thistle is an important herb playing a role as an antioxidant. This herb botanically known as silybum marianum, belongs to family, Asteraceae (Li et al., ²⁰¹²). Milky white veins present on the leaves when broken their leaves these veins produce milky fluid due to this reason this herb named as milk thistle. Milk thistle have two types White and Blue (Evans, ²⁰⁰²; Rainone, ²⁰⁰⁵). Silybum marianum seeds comprises of oil content 26.05%, moisture content 4.48%, ash content 1.93%, crude fiber 5.48%, carbohydrates content 87.2% and total proteins 23% (Khan et al., ²⁰⁰⁷). The active constituents present in the seeds of the milk thistle are apigenin, silybonol, proteins, betaine, fixed oil, and free fatty acids (Marderosian, ²⁰⁰¹).

The main bioactive component of medicinal plant (milk thistle) is silymarin. Silymarin is the mixture of different flavonolignans such as, silybinin A and B (SBN A&B), isosilybinin A and B (ISBN A&B), silychristin (SCN), and silydianin (SDN) (Anthony & Saleh, ²⁰¹³; Li et al., ²⁰⁰⁸). It is a well‐known Chinese herb (Radek et al., ²⁰⁰⁷). Silymarin present in the seeds, fruit as well as in the leaves of the milk thistle but the seed part has the maximum concentration of silymarin (Hobbs, ²⁰⁰⁸). Silymarin content in the fruit of the milk thistle varies depend on the milk thistle varieties, geographic and climate changes in which it grows (Ghahreman, ¹⁹⁹⁹). Milk thistle is used as medicine for the management of different diseases due to the presence of phytoconstituents such as antioxidants and total phenolics presence.

Milk thistle comprises high amount of oil due to this reason silymarin extraction is impossible in one step. Oil should be removed from the seeds before extraction of silymarin as it is the by‐product of silymarin industrial production. For recovery and purification of silymarin from silybum marianum plant seeds, extraction is first and important step. Studies described many different extraction methods for the extraction of silymarin from milk thistle plant seeds (Alvarez et al., ²⁰⁰³; Benthin et al., ¹⁹⁹⁹; Wallace et al., ²⁰⁰³). Microwave‐assisted method, sample pretreatment, soxhlet extraction and reflux mercerization (With or without shaking) are the locally applied extraction methods (Mani et al., ²⁰⁰⁷). Now days, Microwave‐assisted extraction (MAE) has been usually documented as a useful, simple, and effective extraction method. When extraction is done through microwave than high extraction yield obtained in less time by using less solvent at same temperature (Hoang et al., ²⁰⁰⁷; Rohner et al., ²⁰⁰⁴; Teo et al., ²⁰⁰⁸; Zygmunt & Namiesnik, ²⁰⁰³; Huie, ²⁰⁰²).

Different preparations of milk thistle are safe and well tolerated with no any serious side effects. Commercially standardized extract of the milk thistle seeds are accessible in the form of tablets, tincture, extract, and capsule (Barceloux, ²⁰⁰⁸). Milk thistle seeds can be used in raw form or made into a tea (Bhattacharya, ²⁰¹¹). Milk thistle tea has antioxidant power due to the presence of flavonoid (silymarin) that treats liver issues and promote healthier liver functions. Moreover, reduces the bad LDL cholesterol level and total cholesterol level in the body.Tea decreases the nucleic acid, lipid membranes and proteins damage by trapping reactive oxygen species (ROS), for example, singlet oxygen, superoxide, proxy radicals, and hydroxyl. Furthermore, antioxidant level improves in humans by using milk thistle tea. The free radicals quenching ability of milk thistle tea is better than black tea.

Reference:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7802570/