Submitted to: Journal of Dietary Supplements
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2016
Publication Date: 8/2/2016
Citation: Morris, J.B., Wang, M.L. 2016. Functional vegetable guar (Cyamopsis tetragonoloba L. Taub.) accessions for improving flavonoid concentrations in immature pods. Journal of Dietary Supplement. 14(2):146-157. doi: 10.1080/19390211.2016.1207002.
Interpretive Summary: Immature pods of guar consist of some important chemicals that enhance its use as a health vegetable. Information is needed for health promoting flavonoid content in guar samples. Therefore, 22 guar samples were grown in Georgia field plots for 2 years. The immature guar pods were collected before they dried on the plants and tested for flavonoid content. Several guar samples varied in flavonoid content from the control samples. Several of these guar samples could be used in breeding programs to develop high quality guar varieties containing high flavonoid content.
Technical Abstract: Dry guar (Cyamopsis tetragonoloba L. Taub) seed are primarily used to extract galactomannan gum for oil fracking, however the immature pods are used as a vegetable in India and sold in ethnic grocery stores in the Atlanta, GA area. Twenty-two guar genotypes were grown in the field at Griffin, GA, USA for two years (2010-2011). Since the determination of flavonoid concentration would add value to the guar accessions for use as a functional food vegetable, immature guar pods were evaluated for flavonoid concentration. In this study, the immature pods from these 22 guar accessions were analyzed for flavonoid concentration using high performance liquid chromatography (HPLC). Several accessions including PI 253182, PI 262152, PI 263698, PI 288357 showed significantly greater daidzein concentration than all three controls in 2010. However, PI 179926, PI 180434, PI 182969, PI 183400, PI 253182, PI 262152, PI 263882, and PI 263897 exhibited significantly greater genistein concentration than the second and third best controls in 2011. Both PI 180434 and PI 288359 produced significantly higher kaempferol concentration than the third best control. Daidzein concentration was significantly correlated with quercetin, kaempferol, and genistein concentrations (r2 = 0.74**, r2 = 0.657**, and r2 = 0.812***, respectively) in 2010. Quercetin concentration significantly correlated with kaempferol (r2 = 0.661**) and genistein (r2 = 0.669**) concentrations while kaempferol concentration significantly correlated with genistein (r2 = 0.681**) concentration. However, there was a significant negative correlation between myricetin and daidzein (r2 = -0.583**) concentration in 2010. Only quercetin concentration significantly correlated with kaempferol and genistein (r2 = 0.885*** and r2 = 0.481*, respectively) concentrations in 2011. The accession, PI 542608 was observed to contain high concentrations of kaempferol and quercetin in the cluster analyses. These results will help plant breeders develop guar cultivars with superior flavonoid concentrations.