Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs

Abstract

The study was designed to evaluate the phenolic, flavonoid contents and antioxidant and antimicrobial activities of onion (Allium cepa), garlic (Allium sativum), mint (Mentha spicata), thyme (Thymus vulgaris), oak (Quercus), aloe vera (Aloe barbadensis Miller), and ginger (Zingiber officinale). All extracts showed a wide range of total phenolic contents, that is, 4.96 to 98.37 mg/100 g gallic acid equivalents, and total flavonoid contents, that is, 0.41 to 17.64 mg/100 g catechin equivalents. Antioxidant activity (AA) was determined by measuring reducing power, inhibition of peroxidation using linoleic acid system, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. Different extracts inhibited oxidation of linoleic acid by 16.6–84.2% while DPPH radical scavenging activity (IC50 values) ranged from 17.8% to 79.1 μg/mL. Reducing power at 10 mg/mL extract concentration ranged from 0.11 to 0.84 nm. Furthermore the extracts of these medicinal herbs in 80% methanol, 80% ethanol, 80% acetone, and 100% water were screened for antimicrobial activity by disc diffusion method against selected bacterial strains, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pasteurella multocida, and fungal strains, Aspergillus niger, Aspergillus flavus, Rhizopus solani, and Alternaria alternata. The extracts show better antimicrobial activity against bacterial strains as compared to fungal strains. Results of various assays were analyzed statistically by applying appropriate statistical methods.

How extraction method affects yield, fatty acids composition and bioactive properties of cardoon seed oil?

“…According to Kollia et al (2016), who applied different extraction techniques (ultrasound assisted and classic extraction) for the evaluation of antioxidant properties of cardoon and artichoke plant parts, the implement extraction protocol may also affect the efficiency of bioactive compounds retrieval and consequently the recorded antioxidant activity. Similar results have been reported by Qadir et al (2017) where herb extracts from different extraction solvents (methanol, ethanol, acetone, and water) exhibited great differences in antioxidant properties determined via reducing power, and radical scavenging activity assays (DPPH and lipid peroxidation inhibition via linoleic acid). Chen et al (2013) who correlated total phenolic and flavonoid contents of 43 garlic genotypes with five antioxidant activity assays suggested that the selection of the proper assay is essential for obtaining consistent and reliable results regarding antioxidant properties of natural matrices.…”

Changes in the Content of Phenolic Compounds and Biological Activity in Traditional Mexican Herbal Infusions with Different Drying Methods

“…The different types of drying that are carried out in the spices have an influence on the content of bioactive compounds. Some may favor the detection of biologically active constituents that were not present in the raw material [5]. The results showed that antioxidant activity is favored by microwave drying and freeze-drying.…”

“…The benefits derived from the use of natural products, that are rich in bioactive substances, have promoted a growing interest in the pharmaceutical industries. Plants contain a wide variety of phytochemicals, antioxidants or bioactive molecules, which can counteract free radicals, and thus, retard the progress of many chronic diseases associated with oxidative stress and reactive oxygen species [5,6]. The consumption of infusions, or foods high in antioxidants, has been associated with beneficial effects against cancer, cardiovascular diseases, diabetes and other diseases associated with aging [7].…”

Efficacy of Allium sativum oil to alleviate tebuconazol-induced oxidative stress in the liver of adult rats

“…The antioxidant activities of Allium sativum were determined by ABTS and DPPH radical scavenging assays. Therefore, the protective effects of Allium sativum are due to their antioxidant and radical scavenging capacities (39)(40)(41).…”