Abstract
A phytochemical investigation of
Terminalia bellerica,
Terminalia chebula and
Terminalia horrida afforded 34 compounds including two ellagic acid glycosides namely 4-
O-(4″-
O-galloyl-α-
l-rhamnopyranosyl)ellagic acid and 4-
O-(3″,4″-di-
O-galloyl-α-
l-rhamnopyranosyl)ellagic acid as determined by NMR. Chebulic ellagitannins display potent antioxidant capacities.
Thirty-four polyphenolic substances in methanol extracts of the fruits of
Terminalia bellerica,
Terminalia chebula and
Terminalia horrida, three plants used in Egyptian folk medicine, were initially identified by HPLC–ESI-MS and quantitated by analytical HPLC after column chromatography on Sephadex LH-20. After purification by semi-preparative HPLC the compounds were identified by their mass and fragmentation patterns using ESI-MS–MS. For several compounds detailed
1H/
13C NMR analysis at 600
MHz was performed. Two polyphenolics, namely 4-
O-(4″-
O-galloyl-α-
l-rhamnopyranosyl)ellagic acid and 4-
O-(3″,4″-di-
O-galloyl-α-
l-rhamnopyranosyl)ellagic acid were identified by NMR. Antioxidant capacities of the raw fruit extracts and the major isolated substances were determined using the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), oxygen radical absorbance capacity (ORAC) and ferric reducing ability of plasma (FRAP)
in vitro assays and indicated that chebulic ellagitannins have high activity which may correlate with high potential as cancer chemopreventive agents. Therefore, further studies (metabolism, bioavailability and toxicity) of the polyphenolics in
Terminalia species using preclinical models and
in vivo human intervention trials are warranted.