Gomphrenin-Based Decarboxylated and Acylated Pigments from Basella alba L. Fruit Extracts Impair Survival of Colorectal Cancer Cells but Not Normal Cells – In Vitro Study

Abstract

The fast-growing, soft-stemmed vine, Basella alba L., yields high quantities of gomphrenin pigments in its dark-violet fruits which can be converted to their decarboxylated derivatives while still possessing coloring properties. These pigments are much less investigated in terms of the health-promoting properties than their source counterparts. Hence, decarboxylated derivatives with potential health-promoting properties were generated by controlled thermal modifications of gomphrenin structure. Bioactivity experiments were performed on gomphrenin acylated (malabarin and globosin) and decarboxylated derivatives (17-decarboxy-gomphrenin, 2-decarboxy-gomphrenin, and 2,17-bidecarboxy-gomphrenin) derived from the fruit extracts using preparative HPLC. High-resolution mass spectrometric analyses of decarboxylated gomphrenins brought deep fragmentation patterns in the positive ionization mode. The combination of elimination pathways specific to 17-decarboxy-gomphrenin and 2-decarboxy-gomphrenin contributed to the generation of pyridinium, dihydroindolic, as well as indolic and dehydrated indolic derivative ions characteristic of the fragmentation spectra of 2,17-bidecarboxy-gomphrenin. First studies on two Duke’s type C colorectal adenocarcinoma cell lines were performed on the isolated pigments. HT-29 cell line was obtained from a primary (“in situ”) colon tumor, SW620 cancer cells was derived from a metastatic site, whereas non-cancerous CHO-K1 cell line served for comparative purposes. Gomphrenin, 2-decarboxy-gomphrenin and malabarin revealed the highest cytotoxic properties towards cancer cells, affecting cell proliferation and aggravating cancer cell survival due to programmed cell death. The obtained results show specific, beneficial health properties of decarboxylated and acylated gomphrenins.