Spider plant (Cleome gynandra L.) is an important leafy vegetable that grows naturally in many parts of the world. The leaves are highly nutritious and are used mainly for human consumption. The mineral content and phenolic compounds of 17 genotypes (local and exotic) of spider plant and four standards (swiss chard, jute mallow, cowpea, and pumpkin) were investigated. Leaf samples were harvested from plants raised at Thohoyandou, South Africa. Exotic genotypes were superior to local genotypes for most of the minerals. Swiss chard possessed significantly high levels of some minerals such as iron and manganese in comparison with exotic spider plant genotypes. The calcium content in the local (‘MP-B-3-CG’) and exotic (‘GPS’) genotypes was >30.0% and >60.0% higher than in swiss chard, respectively. Total phenolics among spider plant genotypes ranged from 9.86 to 12.21 mg GAE/g DW and were superior to pumpkin. In addition, the spider plant genotypes varied significantly in the antioxidant capacity as estimated by the 2,2 diphenyl-1-picrylhydrazyl method and ferric-reducing antioxidant power. The main flavonoid in the leaves of spider plant genotypes was quercetin-3-rutinoside. Crotonoside (glycoside) was detected in all the spider plant genotypes and swiss chard. A positive correlation was observed between total phenolic content and each of the three flavonoids. The PCA biplot associated exotic genotypes (‘ML-SF-29′, ‘PS’, ‘TZ-1’, and ‘GPS’) and local genotypes (‘ML-3-KK’, ‘ML-13-SDM’, and ‘ML-12-TMP’) with high Al, Fe, Zn, N, and TPC. Cluster analysis indicated high “distant groups” between exotic and local genotypes of spider plant. These results indicated that some of the local germplasm of spider plant was largely inferior to the exotic germplasm in terms of their mineral composition but contained considerable quantities of quercetin-3-rutinoside, particularly in the local genotypes ‘MP-B-2-CG’ and ‘MP-B-1-CG’. There is a need for genetic improvement of the local germplasm in some of the minerals particularly to benefit the end-users.

Indigenous leafy vegetables are used mainly for human consumption since they provide health promoting phytonutrients and bioactive compounds such as antioxidants, flavonoids, minerals and vitamins. However, the phytonutrients and bioactive compounds in the leaves of these vegetables vary widely both quantitatively and qualitatively due to genetic and environmental factors. This study determined the diversity, molecular size variation and the relationships between the minerals and nutrients. Four common leafy vegetables and one standard were used in the study. The mean iron and manganese leaf content was 279.44 mg/kg DW and 247.86 mg/kg DW, respectively. The total phenolic content ranged between 0.37 and 0.50 mg GAE/g. Nineteen different bioactive compounds, varying widely in molecular size, were detected in the four common leafy vegetables. Jute mallow leaves contained only two bioactive molecules which included quercetin-3′-glucoside. None of the eight quercetin-related derivatives that were present among the leafy vegetables were detected in Swiss chard. In cowpea, 2,2 diphenyl-1-picrylhydrazyl free radical scavenging activity was four-fold higher than in pumpkin and Swiss chard leaves. These results demonstrated that the common leafy vegetables varied widely in mineral composition and bioactive compounds, suggesting that a combination of these vegetables in the human diet can provide a wider range of nutrients.

Spider plant (Cleome gynandra L.) is an indigenous leafy vegetable that is a rich source of minerals, proteins, vitamins, flavonoids, antioxidants and many other compounds. Morphological characterization of the germplasm for optimal genetic exploitation is limited by environmental factors. The objective of this study was to determine the degree of genetic diversity between exotic and local spider plant accessions using molecular markers. The spider plant germplasm consisted of 18 local and exotic accessions. Seven polymorphic simple sequence repeat (SSR) markers were used in the study. The SSR marker combinations revealed a total of 46 alleles at 7 loci, with an average of 6.57 alleles per locus. An average polymorphic information index of 0.69 was recorded. According to Nei’s genetic distance analysis, low population differentiation was observed between the local and exotic spider plant accessions, which was indicated by a low fixation index value of 0.024 and a high Nm (10.20). Analysis of molecular variance showed no significant (p < 0.327) variation among and within the local and exotic accessions. Furthermore, low population differentiation was recorded when accessions were grouped based on their stem colour, with an Fst value of 0.007. In both the hierarchical clustering using an unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCoA), the local accession ‘ML-3-KK’ was grouped alone, suggesting that this accession was different from the rest of the accessions and could be useful in selection programmes for spider plant genetic improvement. Both the UPGMA and PCoA were similar in clustering the eighteen spider plant accessions into four groups. The local spider plant accessions were more genetically diverse (with sixteen rare alleles) when compared to the exotic accessions (with only three rare alleles). The rare alleles provided useful information on the genetic variability in certain loci and identification of accessions that could be used as parental lines in spider plant breeding programmes.