Increasing world population has markedly increased the demand for vegetable oils for domestic and industrial purposes. Plant-based vegetable oils have been identified as one of the oils with high nutritive value. Castor plant is one of the oilseed with rich oil content owing to its high monounsaturated fatty acid and bioactive compounds. Its fatty acid profile constitutes mainly of ricinoleic acid and other minor acids such as stearic, palmitic, and oleic acid. Ricinoleic acid of castor oil is unique among all other vegetable oils, making it attractive for a wide spectrum of applications. The predominant triglyceride component in the oil is triricinolein. Minor biological compounds including carotenoid, tocopherol, tocotrienol, phytosterol, phospholipid, phytochemical, and phenolic compounds are present in castor oil. These compounds offer oxidation stability, anti-inflammatory, and antioxidant properties to the oil. The acid, anisidine, iodine, viscosity, and saponification values indicate that castor has good oil quality compared to other vegetable oils. Castor oil composition is influenced by the area of production and method of extraction adopted. The chemical structure of castor oil is centered on the ricinoleic acid and three major functional groups linked by glycerol moiety. More research on the oil’s component is being investigated nevertheless efficient and eco-friendly extraction methods are required. This review, therefore, summarizes the castor oil composition namely the triglyceride, various fatty acids and bioactive compounds, extraction methods, as well as its physicochemical properties.

Soil contamination with toxic metals is a major global concern due to their effects on plants and the ecosystem. In contaminated soils, some plant species have the ability to remediate heavy metals. Ricinus communis L., is an industrial crop plant gaining popularity in the remediation of heavy metal contaminated soils owing to its strong and deep penetrating roots aiding high metal accumulation and large biomass level. Ricinus communis can tolerate high amounts of metals by adopting different strategies, which include the production of antioxidant enzymes, subcellular localization, and exudation of organic acid. At the molecular level, R. communis can tolerate metal stress by activating stress-responsive genes. Proper selection of metal-tolerant R. communis cultivars is effective in the remediation of metal-contaminated soils, owing to their high capacity for metal tolerance. Exogenous application of mineral fertilization and the use of microbes and chelating agents increase metal solubility and availability for plant uptake in soil. Also, good agronomic practices such as co-planting of R. communis with other leguminous crops enhance R. communis growth and metal tolerance, thereby improving remediation of metal-contaminated soils. This review, therefore, critically discusses the recent approaches in using R. communis to remediate metal-contaminated soils.

The present study was conducted to assess the effect of toxicity of cadmium (Cd) on growth, tolerance index (TI), antioxidant activities, and malondialdehyde (MDA) content in two contrasting wild castor accessions (16-024 and S2-4) via hydroponic experiment (0 and 100 mg/L Cd). The results showed that Cd significantly reduced the growth rate, seedling height, root length, and shoot length of the castor accessions compared to the control, with the Cd effect being more severe in S2-4 than in 16-024. In addition, biomass response including the root and shoot fresh weight and root dry weight decreased in both accessions compared to the control. Compared to the control group, the shoot dry weight of accession S2-4 declined by 21.7%, whereas there was no change in 16-024, suggesting a level of tolerance in 16-024. Analysis of TI on all the growth parameters and biomass content revealed that accession 16-024 was highly tolerant to Cd stress than S2-4. The results further revealed that the expression of the antioxidant enzymes, viz., superoxide dismutase (SOD), catalase (CAT), non-enzymatic antioxidant, glutathione, and MDA content, was influenced by genotype. S2-4 exhibited a higher antioxidant activity (SOD, CAT) and lipid peroxidation activity than 16-024, indicative of oxidative damage from Cd stress.

Sweet potato is a multifunctional root crop and a source of food with many essential nutrients and bioactive compounds. Variations in the flesh color of the diverse sweet potato varieties are attributed to the different phytochemicals and natural pigments they produce. Among them, carotenoids and anthocyanins are the main pigments known for their antioxidant properties which provide a host of health benefits, hence, regarded as a major component of the human diet. In this review, we provide an overview of the major pigments in sweet potato with much emphasis on their biosynthesis, functions, and regulatory control. Moreover, current findings on the molecular mechanisms underlying the biosynthesis and accumulation of carotenoids and anthocyanins in sweet potato are discussed. Insights into the composition, biosynthesis, and regulatory control of these major pigments will further advance the biofortification of sweet potato and provide a reference for breeding carotenoid- and anthocyanin-rich varieties.

Increased urbanization and industrialization have greatly contributed to the emission of higher amount of heavy metals such as cadmium, nickel, and lead into the environment. These metals are non-biodegradable and toxic, causing much effects on plants and by extension to animals and humans, which have become a major global concern. The inherent ability of plants to resist heavy metal toxicity seems to be the most sustainable and cost-effective strategy. Castor plant is widely studied due to its tolerance to the effects of heavy metal contaminated soils, owing to its large biomass content and high accumulating capacity. Castor plants to some extent can tolerate elevated levels of heavy metals through several developed mechanisms, such as activation of antioxidant enzymes, exclusion, accumulation of proline, compartmentalization, organic acid exudation, and phytochelatins. Molecular studies have identified some stress-responsive to aid the tolerance of heavy metals in castor. Stress caused by heavy metal toxicity affects seedling growth, biomass, photosynthetic pigments, protein level, and nutrient uptake of castor plant. The response of castor, however, to these stresses differs among cultivars, metal type and concentration, and time of metal applied. This review aims to summarize the physiological responses and various defense mechanisms of castor to tolerate and eradicate heavy metal toxicity and some stress-responsive genes identified at transcriptional and posttranscriptional levels that confer metal tolerance in this plant.