Comprehensive Phenolic Profiling of Cyclopia genistoides (L.) Vent. by LC-DAD-MS and -MS/MS Reveals Novel Xanthone and Benzophenone Constituents

In the present study, the effect of mangiferin (a xanthone glucoside, isolated from the leaves of Mangifera indica) on the atherogenic potential of streptozotocin (STZ)-diabetes was investigated. In addition, the effect of mangiferin on oral glucose tolerance in glucose-loaded normal rats was also determined. The chronic intraperitoneal (i.p.) administration of mangiferin (10 and 20 mg/kg) once daily (o.d.) for 28 days exhibited antidiabetic activity by significantly lowering fasting plasma glucose level at different time intervals in STZ-diabetic rats. Further, mangiferin (10 and 20 mg/kg, i.p.) showed significant antihyperlipidemic and antiatherogenic activities as evidenced by significant decrease in plasma total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C) levels coupled together with elevation of high-density lipoprotein cholesterol (HDL-C) level and diminution of atherogenic index in diabetic rats. In addition, the chronic administration of mangiferin (10 and 20 mg/kg, i.p.) for 14 days significantly as well as markedly improved oral glucose tolerance in glucose-loaded normal rats suggesting its potent antihyperglycemic activity. The accumulating evidences suggest that both pancreatic and extrapancreatic mechanisms might be involved in its antidiabetic or antihyperglycemic action. In conclusion, the present study demonstrates that mangiferin possesses significant antidiabetic, antihyperlipidemic and antiatherogenic properties thus suggesting its beneficial effect in the treatment of diabetes mellitus associated with hyperlipidemia and related cardiovascular complications.

In the present study, a methodology based on liquid chromatography with diode array detection (HPLC/DAD) coupled to an electrospray ionization (ESI) interface and a triple quadrupole mass spectrometer for the simultaneous identification of phenolic compounds in fruit juices has been developed. 72 available phenolic compound standards from diverse families present in fruits have been studied in order to analyze their fragmentation pattern. As a result, a general strategy for the characterization of unknown phenolic compounds in fruit juices was designed: (i) taking into account its UV-visible spectrum and elution order, assign the unknown polyphenol to a polyphenol class, (ii) identify the quasi-molecular ion using positive and negative MS spectra, being supported by adducts generated with solvent or sodium and molecular complexes, (iii) determinate the pattern of glycosylation in positive mode using ESI(+)-CID MS/MS product ion scan experiments, selecting the quasi-molecular ion as precursor ion, and finally, (iv) study the identity of the aglycone through ESI(+)-CID MS/MS product ion spectra from the protonated aglycone, [Y(0)](+). This strategy was successfully employed for the characterization of known and unknown phenolic compounds in juices from 17 different fruits.

Two novel phenolic glycosides cis-p-coumaric acid 4-O-(2'-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside and trans-p-coumaric acid 4-O-(2'-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside were isolated and identified from Salvia officinalis together with 4-hydroxyacetophenone 4-O-(6'-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside, luteolin 7-O-beta-D-glucoside, 7- and 3'-O-beta-D-glucuronide, 6-hydroxyluteolin 7-O-beta-D-glucoside and 7-O-glucuronide, and 6,8-di-C-beta-D-glucosylapigenin (vicenin-2). The luteolin glucuronides and vicenin-2 were identified as new sage constituents.