Phytochemical characterization of turnip greens (Brassica rapa ssp. rapa): A systematic review

Abstract

Objective The Turnip (Brassica rapa L. ssp. rapa) is a leaf and root vegetable grown and consumed worldwide. The consumption of Turnip has been associated with beneficial effects on human health due to their phytochemicals that may control a variety of physiological functions, including antioxidant activity, enzyme regulation, and apoptotic control and the cell cycle. The current systematic review of the literature aims to evaluate both the profile and quantity of phytochemicals commonly found in Turnip greens and to provide perspectives for further investigation. Methods This review was conducted following the PRISMA guidelines. Four bibliographic databases (PubMed, Embase, Web-of-Science and Cochrane Central Register of Controlled Trials) were searched to identify published studies until April 8th, 2020 (date last searched) without data and language restriction. Studies were included if they used samples of Turnip greens (the leaves), and evaluated its phytochemical content. Two reviewers independently evaluated the titles and abstracts according to the selection criteria. For each potentially eligible study, two reviewers assessed the full-texts and independently extracted the data using a predesigned data extraction form. Results Based on the search strategy 5,077 potentially relevant citations were identified and full texts of 37 studies were evaluated, among which 18 studies were eligible to be included in the current review. The majority of included studies were focused on identification of glucosinolates and isothiocyanates (n = 14, 82%), four studies focused on organic acids, and five studies reported phenolic component profile in Turnip greens. Among included studies nine studies (50%) provided information on phytochemical’s content. We found 129 phytochemicals (19 glucosinolates, 33 glucosinolate-breakdown products, 10 organic acids and 59 polyphenolic compounds) reported in Turnip greens. Flavonoids were mainly present as quercetin, kaempferol and isorhamnetin derivatives; while aliphatic forms were the predominant glucosinolate (gluconapin was the most common across five studies, followed by glucobrassicanapin). In general, the phytochemical content varied among the leaves, tops and Turnip roots. Conclusions Emerging evidence suggests the Turnip as a substantial source of diverse bioactive compounds. However, detailed investigation on the pure compounds derived from Turnip green, their bioavailability, transport and metabolism after consumption is further needed. Additional studies on their biological activity are crucial to develop dietary recommendations on the effective dosage and dietary recommendation of Turnip greens for nutrition and health.

Antimicrobial Activity of Brassica rapa L. Flowers Extract on Gastrointestinal Tract Infections and Antiulcer Potential Against Indomethacin-Induced Gastric Ulcer in Rats Supported by Metabolomics Profiling

“…In addition, it is used for lung protection and nephroprotection in Unani and Arab traditional medicine. 4–7 …”

Metabolic diversity in a collection of wild and cultivated Brassica rapa subspecies

“…In contrast, hydroxycinnamoyl glycosides were highly abundant in rapid cycling and yellow sarson, as well as in Chinese cabbage and komastuna, but low in caixin, broccoletto, and wild cabbage. According to previous reports (Soengas et al, 2018;Dejanovic et al, 2021), sinapic acid derivatives were the major hydroxycinnamic acid derivatives in B. rapa, including 1,2-disinapoyl gentiobiose (compound 147-149) and 1-sinapoyl-2-feruloyl gentiobiose (compound 124-128). These were reported to exhibit antioxidant and anti-inflammatory effects in human plasma and human peripheral blood mononuclear cells (Olszewska et al, 2020).…”

“…Similarly, quercetin 3-O-triglucoside-7-O-sinapoylglucoside (compound 258) and quercetin 3-O-triglucoside-7-Oferuloylglucoside (compound 257) displayed 5,577-and 3,549fold change among all genotypes, respectively. Previous studies have shown that kaempferol derivatives were the most abundant flavonols in Chinese cabbage, pak choi, turnip, and mizuna (Soengas et al, 2018;Dejanovic et al, 2021;Kyriacou et al, 2021;Wiesner-Reinhold et al, 2021)…”

Eleocharis dulcis individually and in combination with Brassica rapa as a best cure of diabetes with zero side effects

“…By promoting a modest portion of diet in the form of vegetables, oil‐rich seed, silage, and organic fertilizer. B. rapa extract contains a variety of volatiles, including terpenoids, ketonic, aldehydes, and esters compounds (Dejanovic et al, 2021). Indole derivatives, phenylpropanoids, aldehydes, lignan, sulfurous compounds, and carbohydrate derivatives have also been discovered in turnip leaves and roots extracts (Paul et al, 2019; Wang et al, 2016).…”