Quantitative Analysis of the Biologically Active Compounds Present in Leaves of Mexican Sweet Potato Accessions: Phenols, Flavonoids, Anthocyanins, 3,4,5-Tri-Caffeoylquinic Acid and 4-Feruloyl-5-Caffeoylquinic Acid.

Sweet potato is one of the oldest crops cultivated in Mexico, and Mesoamerica is considered as a region with the greatest diversity of this species. Therefore, the present study focused on the evaluation of biologically active compounds, such as caffeoylquinic acid derivatives and flavonoid compounds, in sweet potato leaves of 200 accessions of the main producing regions of Mexico. The analysis of total phenol content (TPC) showed a great variability of concentrations among the examined accessions (54.41 to 284.64 mgTPC/g DW). Likewise, total flavonoid content (TFC) was determined and ranged from 10.01 to 40.17 mgTFC /g DW. Finally, total anthocyanin content (TAC) was evaluated and concentrations obtained varied from 0.05 to 0.98 mgTAC/g DW. Additionally, HPLC analysis of all 200 accessions demonstrated the presence of caffeic acid (CA), 5-caffeoylquinic acid (5-CQA), three isomers of di-caffeoylquinic acid (di-CCA) and 4-feruloyl-5-caffeoylquinic acid (4F-5CQA) in all test samples. Only 21 accessions tested showed the quantitative amount of 3,4,5-tri-caffeoylquinic acid (3,4,5-tri-CQA) with concentrations ranging from 44.73 to 193.22 mg/100 g DW and high content of 4F-5CQA (139.46 to 419.99 mg/100 g DW). The gathered data indicate that leaves of Mexican sweet potatoes are a promising source of phenolic compounds with remarkable nutraceutical potential.

ß-catenin-mediated hair growth induction effect of 3,4,5-tri-O-caffeoylquinic acid.

The hair follicle is a complex structure that goes through a cyclic period of growth (anagen), regression (catagen), and rest (telogen) under the regulation of several signaling pathways, including Wnt/ ß-catenin, FGF, Shh, and Notch. The Wnt/ß-catenin signaling is specifically involved in hair follicle morphogenesis, regeneration, and growth. ß-catenin is expressed in the dermal papilla and promotes anagen induction and duration, as well as keratinocyte regulation and differentiation. In this study, we demonstrated the activation of ß-catenin by a polyphenolic compound 3,4,5-tri-O-caffeoylquinic acid (TCQA) in mice model and in human dermal papilla cells to promote hair growth cycle. A complete regrowth of the shaved area of C3H mice was observed upon treatment with TCQA. Global gene expression analysis using microarray showed an upregulation in hair growth-associated genes. Moreover, the expression of ß-catenin was remarkably upregulated in vivo and in vitro. These findings suggest that ß-catenin activation by TCQA promoted the initiation of the anagen phase of the hair cycle.