Recovery and Seasonal Variation of Cinnamtannin B‐1 from Laurel (Laurus nobilis L.) Pruning Wood Wastes

Abstract

Cinnamtannin B‐1 (C‐B1) is a commercially‐available trimeric A‐type procyanidin with remarkable cellular actions mainly derived from its high radical scavenging activity. C‐B1 is the main phenolic compound of laurel wood, which has previously been isolated by a combination of conventional chromatographic techniques. The first aim of this work was to find laurel trees containing as much C‐B1 as possible, and learn about the influence of variables, such as gender and harvest time, on the production of C‐B1 by the tree. It was found that all studied trees tend to give higher C‐B1 percentages in the May‐July period, from 6 % to 18 %, and lower ones around March (spring) and November (fall), from 1 % to 8 %. In a general way, it also seems that the female trees tend to produce a bit more C‐B1 (from 2.8 % to 17.3 %) than male ones (from 1.7 % to 13.4 %). In addition, eight minor phenolic compounds [(−)‐ent‐catechin (1), (−)‐ent‐epicatechin‐(4α→8)‐ent‐epicatechin (2), (epi)catechin‐(4→8)‐(epi)afzelechin‐(4→8)‐(epi)catechin (3), (+)‐epiafzelechin‐(4β→8)‐epicatechin (4), (−)‐epicatechin (5), (−)‐afzelechin‐(4α→8)‐epicatechin (6), (epi)afzelechin‐(4→8)‐(epi)afzelechin‐(4→8)‐(epi)catechin (7) and (+)‐epicatechin‐(4β→8,2β→O‐7)‐epicatechin‐(4β→8)‐catechin (C‐D1)] were found and quantified in the ethyl acetate extract of the wood samples. The second aim of this work was to improve the recovery of C‐B1 from laurel wood. The use of the fast centrifugal partition chromatography (FCPC) technique has allowed for a recovery of 96 % of a technical‐grade C‐B1 (64 % in a previous protocol using conventional column chromatography on silica gel and size‐exclusion chromatography).

Proanthocyanidins in Pruning Wood Extracts of Four European Plum (Prunus domestica L.) Cultivars and Their hLDHA Inhibitory Activity

“…Regarding AcOEt extracts, cultivar ‘De la Rosa’ (3.3 %) showed the higher yield followed by the two samples of ‘Reina Claudia Verde’ (2.4 % and 1.8 %). These extraction yields are higher than those of other woods from agricultural wastes processed by us in the past, such as olive wood (1.6 % yield), [29] sweet cherry wood (0.9 % yield) [32] or laurel wood (0.3–0.8 % yield), [31] and of the same order of magnitude than other useful woods like, for example, Phoebe zhennan wood residues (3.8 % yield) [42] …”

“…Pieces of wood (with a diameter of 0.8–1.4 cm), without leaves, were dried and processed as reported before, [32] and extracted sequentially with dichloromethane (DCM) and AcOEt for 2 h at reflux ( Figure 10). [31] Starting from 20 g of wood shavings, 240–660 mg of AcOEt extracts were obtained, of which around 10 mg are used for the total phenolic content and DPPH radical‐scavenging activity assays and around 5 mg for the HPLC analyses and component quantification and the h LDHA inhibitory activity assay.…”

“…Agricultural works on fruit crops generate every year big amounts of pruning wood, which is an interesting (renewable, cheap and abundant) waste to get bioactive compounds like flavonoids, among many other compounds [24] . The valorization of agro‐industrial residues has been reported in numerous occasions, [25–28] and our group has made some contributions on the recovery of natural products from plant materials obtained from certain crops and wild plants [23,29–32] . In these works, we have focused our attention on the antioxidant and antimicrobial activities of isolated phenolic compounds, but more recently, we have started to explore the applicability of small organic molecules in the treatment of primary hyperoxalurias (PHs).…”

A‐type proanthocyanidins: Sources, structure, bioactivity, processing, nutrition, and potential applications

“…In addition to its anticancer activity, CTB‐1 exhibits minimal cytotoxicity on normal colon epithelial cells, suggesting that CTB‐1 has a low potential for adverse effects. CTB‐1 could also significantly enhance the efficacy of anticancer drugs and their clinical significance through synergistic drug interactions (Alejo‐Armijo et al., 2022; Carriere et al., 2018).…”