The Glucosinolates: A Sulphur Glucoside Family of Mustard Anti-Tumour and Antimicrobial Phytochemicals of Potential Therapeutic Application

Abstract

This study reviewed aspects of the biology of two members of the glucosinolate family, namely sinigrin and glucoraphanin and their anti-tumour and antimicrobial properties. Sinigrin and glucoraphanin are converted by the β-sulphoglucosidase myrosinase or the gut microbiota into their bioactive forms, allyl isothiocyanate (AITC) and sulphoraphanin (SFN) which constitute part of a sophisticated defence system plants developed over several hundred million years of evolution to protect them from parasitic attack from aphids, ticks, bacteria or nematodes. Delivery of these components from consumption of cruciferous vegetables rich in the glucosinolates also delivers many other members of the glucosinolate family so the dietary AITCs and SFN do not act in isolation. In vitro experiments with purified AITC and SFN have demonstrated their therapeutic utility as antimicrobials against a range of clinically important bacteria and fungi. AITC and SFN are as potent as Vancomycin in the treatment of bacteria listed by the World Health Organisation as antibiotic-resistant “priority pathogens” and also act as anti-cancer agents through the induction of phase II antioxidant enzymes which inactivate potential carcinogens. Glucosinolates may be useful in the treatment of biofilms formed on medical implants and catheters by problematic pathogenic bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus and are potent antimicrobials against a range of clinically important bacteria and fungi. The glucosinolates have also been applied in the prevention of bacterial and fungal spoilage of food products in advanced atmospheric packaging technology which improves the shelf-life of these products.

The value of bioactive compounds of cruciferous vegetables (Brassica) as antimicrobials and antioxidants: A review

“…The henzyl‐isothiocyanate shows a 60 mm inhibition diameter against S. aureus and S. saprophyticus , while the control barely exceeds 10 mm in both (3 μmol). In other reports, the presence of glucosinolates (2 ppm) in Brassica juncea oil (85% allyl isothiocyanate, 10% butenyl isothiocyanate), shows antifungal activity, inhibiting the growth of Penicillium roqueforti, P. corylophilum, Eurotium repens, A. flavus, and Endomyces fibuliger in rye bread (Melrose, 2019; Suhr & Nielsen, 2003).…”

“…The structure of the side chain determines its classification, based on the precursor amino acid, (1) aliphatic (e.g., glucoraphanin; Ala, Leu, Ileu, Val, Met), (2) aromatic (e.g., gluconasturtiin; Phe, Tyr), and (3) indole (e.g., glucobrassicin; Trp). Now, about 130 types of glucosinolates have been identified, from 11 plant families, however, only five of them are the most commonly found in foods for human consumption, glucobrassicin, sinigrin, glucoraphasatin (dehydroerucin), glucoraphanin, and glucoiberin (Melrose, 2019; Wang et al., 2019). According to studies carried out by Wang et al., (2019), the content and types of glucosinolates present in plants such as rocket, are affected by germination.…”

“…The bioactive potential of glucosinolates produced by vegetables of the Brassicaceae family is evident, making them excellent candidates in the biocontrol of pathogens that cause serious infections in humans. However, most of the glucosinolates tested act synergistically with conventional antibiotics, improving their effect (Melrose, 2019). Over time, it has been reported that breakdown products such as isothiocyanate exhibit inhibitory activity against a large number of microorganisms including fungi and pathogenic bacteria, being Escherichia, Klebsiella, Salmonella, Bacillus, Serratia, Staphylococcus, and Listeria the most representative species (Alvarez, del Moreira, Roura, Ayala‐Zavala, & González‐Aguilar, 2015).…”

Selenium biofortification in the 21st century: status and challenges for healthy human nutrition

“…GLS and their hydrolysis products (isothiocyanates, ITC) in particular, are recognized key molecules in cancer prevention, and have received great attention in biofortification studies of Brassicaceae spp . (Melrose 2019 ; Prieto et al 2019 ). Increased accumulation of ITC has been recently observed in kale ( Brassica oleracea L.) roots in response to selenite and NaCl joint application, thus making this food crop superior for chemopreventive effects (Kim et al 2018 ).…”

Sulforaphane displays the growth inhibition, cytotoxicity and enhancement of retinoic acid-induced superoxide-generating activity in human monoblastic U937 cells

“…broccoli and its sprouts and is synthesized by hydrolysis of sulforaphane glucosinolate (Posner et al, 1994). In higher plants, sulforaphane protects them from infections by various bio-invaders such as aphids, ticks, bacteria or nematodes (Melrose, 2019). In recent times, sulforaphane attracted as an effective carcinogenesis prophylactic drug (Zhang et al, 1992;Tortorella et al, 2015).…”