Anticancer Effects of High Glucosinolate Synthesis Lines of Brassica rapa on Colorectal Cancer Cells

Glucosinolates and Their Hydrolytic Products-A Love Story of Environmental, Biological, and Chemical Conditions

BACKGROUND

Glucosinolates (GSL) play an important role in providing defense to plants and helping them to cope with various biotic, as well as abiotic, stresses. Many living beings including humans and animals, including some herbivores, have adapted themselves to use this defense mechanism for their own use. More than 120 glucosinolates are distributed within a large number of plants. Many factors are known to influence the GSL composition in a plant. Among these, cofactors, myrosinase isozymes, heavy metals and the environmental conditions such as light, CO2 and temperature are important in regulation. These factors ensure that different glucosinolate compositions can be produced by the plants, thus impacting the defense mechanism.

OBJECTIVE

The objective of the current review is to highlight the importance of the factors responsible for affecting glucosinolate composition and concentration.

METHODS

The review has been compiled using accessible literature from Pubmed, Scopus, and Google scholar. Efforts have been made to restrict the literature to the last 5 years (2018-2023), with some exceptions.

RESULTS

The current critical review acts as a resource for all the researchers working on these essential compounds. It provides information on the factors that may influence glucosinolate production. It also gives them an opportunity to modify the glucosinolate composition of a plant using the given information.

CONCLUSIONS

Glucosinolates have long been an ignored class of biomolecule. The plethora of biological activities of the compounds can be useful. Though there are some harmful components such as goitrin and progoitrin, these can be easily removed by modulating some of the factors highlighted in the review.

HIGHLIGHTS

The current review has covered most of the factors that have the ability to modify glucosinolate composition and concentration. The mechanistic action of these factors has also been discussed using the current available literature.

Brassicaceae Mustards: Phytochemical Constituents, Pharmacological Effects, and Mechanisms of Action against Human Disease

The Brassicaceae genus consists of many economically important mustards of value for food and medicinal purposes, namely Asian mustard (Brassica juncea), ball mustard (Neslia paniculata), black mustard (B. nigra), garlic mustard (Alliaria petiolata), hedge mustard (Sisymbrium officinale), Asian hedge mustard (S. orientale), oilseed rape (B. napus), rapeseed (B. rapa), treacle mustard (Erysimum repandum), smooth mustard (S. erysimoides), white ball mustard (Calepina irregularis), white mustard (Sinapis alba), and Canola. Some of these are commercially cultivated as oilseeds to meet the global demand for a healthy plant-derived oil, high in polyunsaturated fats, i.e., B. napus and B. juncea. Other species are foraged from the wild where they grow on roadsides and as a weed of arable land, i.e., E. repandum and S. erysimoides, and harvested for medicinal uses. These plants contain a diverse range of bioactive natural products including sulfur-containing glucosinolates and other potentially valuable compounds, namely omega-3-fatty acids, terpenoids, phenylpropanoids, flavonoids, tannins, S-methyl cysteine sulfoxide, and trace-elements. Various parts of these plants and many of the molecules that are produced throughout the plant have been used in traditional medicines and more recently in the mainstream pharmaceutical and food industries. This study relates the uses of mustards in traditional medicines with their bioactive molecules and possible mechanisms of action and provides an overview of the current knowledge of Brassicaceae oilseeds and mustards, their phytochemicals, and their biological activities.

High-Altitude Medicinal Plants as Promising Source of Phytochemical Antioxidants to Combat Lifestyle-Associated Oxidative Stress-Induced Disorders

Oxidative stress, driven by reactive oxygen, nitrogen, and sulphur species (ROS, RNS, RSS), poses a significant threat to cellular integrity and human health. Generated during mitochondrial respiration, inflammation, UV exposure and pollution, these species damage cells and contribute to pathologies like cardiovascular issues, neurodegeneration, cancer, and metabolic syndromes. Lifestyle factors exert a substantial influence on oxidative stress levels, with mitochondria emerging as pivotal players in ROS generation and cellular equilibrium. Phytochemicals, abundant in plants, such as carotenoids, ascorbic acid, tocopherols and polyphenols, offer diverse antioxidant mechanisms. They scavenge free radicals, chelate metal ions, and modulate cellular signalling pathways to mitigate oxidative damage. Furthermore, plants thriving in high-altitude regions are adapted to extreme conditions, and synthesize secondary metabolites, like flavonoids and phenolic compounds in bulk quantities, which act to form a robust antioxidant defence against oxidative stress, including UV radiation and temperature fluctuations. These plants are promising sources for drug development, offering innovative strategies by which to manage oxidative stress-related ailments and enhance human health. Understanding and harnessing the antioxidant potential of phytochemicals from high-altitude plants represent crucial steps in combating oxidative stress-induced disorders and promoting overall wellbeing. This study offers a comprehensive summary of the production and physio-pathological aspects of lifestyle-induced oxidative stress disorders and explores the potential of phytochemicals as promising antioxidants. Additionally, it presents an appraisal of high-altitude medicinal plants as significant sources of antioxidants, highlighting their potential for drug development and the creation of innovative antioxidant therapeutic approaches.

Ethyl acetate fraction of Osmanthus fragrans var. aurantiacus and its triterpenoids suppress proliferation and survival of colorectal cancer cells by inhibiting NF-κB and COX2

ETHNOPHARMACOLOGICAL RELEVANCE

Colorectal cancer (CRC) remains a significant global health concern, and targeting inflammation has emerged as a promising approach for its prevention and treatment. Medicinal plants and phytochemicals have garnered attention for their potential efficacy against inflammation with minimal toxicity. Osmanthus fragrans var. aurantiacus Makino (O. fragrans) has a history of traditional use in Korea and China in treating various inflammation-related conditions, but its potential use for CRC has not been uncovered.

AIM OF THE STUDY

This study aims to explore the potential anti-proliferative and pro-apoptotic properties of O. fragrans, focusing on its impact on CRC treatment. By investigating O. fragrans, we aim to uncover its anti-proliferative and apoptotic effects in human CRC cells, potentially paving the way for effective and well-tolerated therapeutic strategies for CRC patients.

MATERIALS AND METHODS

Ethanol (EtOH) extracts of O. fragrans leaf and flower, along with specific fractions (n-hexane, ethyl acetate (EtOAc), n-butanol, and the aqueous residue) were evaluated for their anti-proliferative effects in human CRC cells using MTT assays, and compared to normal colon cells. Mechanistic insights and chemical profiling were obtained through flow cytometry, colorimetric assays, western blotting, and molecular docking, and high-performance liquid chromatography (HPLC) system.

RESULTS

Both flower and leaf EtOH extracts of O. fragrans exhibited significant anti-proliferative effects in human CRC cells, with the leaf extract demonstrating higher potency. The EtOAc fraction from the leaf extract displayed the strongest anti-CRC cell proliferative effects while no cytotoxic effects in normal colon cells. Chemical profiling of these fractions identified triterpenoids as significant components in the EtOAc fractions. The leaf EtOAc fraction caused cell cycle arrest and apoptosis, accompanied by elevating intracellular reactive oxygen species and mitochondrial dysfunction in CRC cells. Additionally, it inhibited NF-κB and ERK1/2 signaling, leading to reduced COX2 expression. Notably, two triterpenoids isolated from the leaf EtOAc fraction, maslinic acid and corosolic acid, displayed potent anti-cancer activity in CRC cells without affecting normal colon cells. Corosolic acid exhibited a strong binding affinity to COX2 and reduced its expression, supporting its role in the anti-inflammatory and anti-cancer effects.

CONCLUSIONS

Our findings suggest that O. fragrans, particularly its triterpenoid-rich EtOAc fraction, holds promise as a novel therapeutic agent for CRC prevention and therapy. These results provide valuable insights into the potential application of O. fragrans and its bioactive compounds in combating CRC.

Antioxidant and Anti-Inflammatory Activities of High-Glucosinolate-Synthesis Lines of Brassica rapa

Excessive oxidative stress and inflammatory responses are associated with the development of various diseases, including cancer. Glucosinolates (GSLs) are phytochemicals known for their antioxidant properties, and doubled haploid lines (DHLs) of Brassica rapa with high GSL contents (HGSL) were intentionally developed from two edible subspecies of Brassica rapa: B. rapa subsp. trilocularis and B. rapa subsp. chinensis. The purpose of the present study is to assess the capacity of HGSL DHLs to mitigate oxidative stress and inflammation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, compared to pak choi as a parental control. Our findings demonstrate that HGSL DH lines effectively suppressed the expression of inducible nitric oxide synthase, leading to the reduced levels of nitric oxide at non-toxic concentrations. Additionally, these lines exhibited scavenging activity against reactive oxygen species and free radicals. The enhanced antioxidant capacity of HGSL DHLs was mechanistically attributed to the upregulation of antioxidant enzymes, such as NADPH quinone oxidoreductase 1 (NQO1), the glutamate-cysteine ligase catalytic subunit (GCLC), and heme oxygenase-1 (HMOX1). Furthermore, we confirmed that these effects were mediated through the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway via p38 phosphorylation. Moreover, HGSL DHLs demonstrated inhibitory effects on pro-inflammatory cytokines and signal transducers and activators of transcription 3 (STAT3) phosphorylation. Collectively, our results indicate that HGSL DHLs possess better antioxidant and anti-inflammatory properties compared to the parental control pak choi in LPS-stimulated RAW264.7 cells, suggesting that HGSL DHLs of Brassica rapa could be considered as a beneficial daily vegetable for reducing the risk of inflammation-associated diseases.