Anthocyanin Content in Seeds, Leaves and Flowers of Lablab purpureus.

Lablab purpureus contain bioactive phytochemicals with potential to be utilized in the pharmaceutical and nutraceutical markets. Ninety four Lablab purpureus accessions are conserved at the USDA, ARS, Plant Genetic Resources Conservation Unit, Griffin, GA. Anthocyanins are not only responsible for leaf, stem, flower, and seed color but can inhibit colon cancer cells.

The objectives of this study are to determine the amount of anthocyanin from leaves, flowers, whole seeds, and seed coats of Lablab purpureus using a modified CCM-200 meter. An Opti Sciences CCM-200 chlorophyll content meter was converted to an experimental hand-held anthocyanin meter. The 655 nm light emitting diode (LED) of the CCM was replaced with a 520 nm LED in order to measure absorbance near the wavelength at which free anthocyanin aglycones, cyanidin and pelargonidin monoglucosides absorb. Anthocyanin indexes will be recorded from each of three leaves, flowers, and seed coats, using this anthocyanin meter. HPLC will be used to analyze anthocyanin derivatives from leaves and seeds as well. Preliminary analysis revealed that leaf anthocyanin indexes ranged from 4.7 – 11. However, seed coat anthocyanin indexes ranged from 1.4 – 42.3 for these L. purpureus accessions. The extremely low anthocyanin indexes (near 1) were recorded from the buff colored seed coats while the very high anthocyanin indexes (42.3) were recorded from the black seed coats. Lablab pupureus seeds should produce specific anthocyanin compounds. This indicates that leaf and seed anthocyanins produced in L. purpureus may include cyanidin glucosides.

A useful, quantitative method employed in the quantification of anthocyanin indexes from different L. purpureus accessions will be demonstrated. The Lablab purpureus accessions identified in this study can serve as potential new sources of high anthocyanins and possibly cyanidin-3-glusoside to be introduced into breeding lines or cultivars and/or used as a pharmaceutical or nutraceutical crop in the southeastern U.S.