ABSTRACT
Cordyceps sinensis(C.sinensis)is a widely used and highly valuable traditional Chinese medicine.Several dipeptides have been detected in C.sinensis,but current scientific knowledge of its chemical makeup remains limited.In this study,an improved approach that integrates offline two-dimensional liquid chromatography(2D LC)separation,precursor ion list,library screening,and diagnostic ion filtering was established to systematically screen and characterize dipeptides in C.sinensis.Offline 2D LC integrating hydrophilic interaction LC and reverse phase separations was established to eliminate interference and identify the target dipeptides.A library containing the potential 400 dipeptides was created,and a precursor ion list with all theoretical precursor ions was adopted to trigger the MS/MS scan with high sensitivity.To identify dipeptides,the type and connection sequence of amino acids were determined according to the product ions.Ile and Leu residues were differentiated for the first time according to the characteristic ion at m/z 69.07.Ultimately,170 dipeptides were identified or tentatively characterized from C.sinensis,and most are reported for the first time in this species herein.In addition,the identified dipeptides were also applied for discrimination among the three Cordyceps species,and 11 markers were identified.The obtained results provide a deeper understanding of the chemical basis of C.sinensis.
ABSTRACT
Object To investigate the chemical constituents of Buddlejae officinalis Maxim. , the relationship between their bioactivities, and the medicinal application of the herb. Methods Various chro-matographic techniques were employed for the isolation and purification of the constituents, including silica gel, Sephadex LH-20, and pre-HPLC. The structures of 11 isolated chemical compounds were elucidated by chemical and spectral analysis (NMR, IR, UV, and MS). The aldose reductase inhibiting test and test on DNA topoisomerase Ⅳ inhibitory effect were applied to evaluate the bioactivity of both the purified compounds and the crude fraction. Results Eleven compounds were isolated from the extracts of B. offic-inalis. They are four flavones and their glycosides; apigenin (Ⅰ), linarin (Ⅱ), apigenin-7-O-?-L-rhamnopyranosyl (1-6)-?-D-glucopyranoside (Ⅲ), and luteolin-7-O-?-D-glucoside (Ⅶ); four phenylen-thanoid glycosides: verbascoside (Ⅴ), isoacteoside (Ⅵ), cistanoside F, a and b (Ⅶ-1 and 2), campneo-side Ⅱ , a and b (Ⅷ-1 and 2); three triferpenoid saponins: mimengoside A (Ⅸ), mimengoside B (Ⅹ), songaroside A (Ⅺ). Some of the them (such as Ⅱ ,Ⅲ , and Ⅵ) showed the aldose reductase inhibitory activities with a higher inhibitory rate than that of quercetin (the positive control), others (such as Ⅰ,Ⅱ , Ⅴ, Ⅵ, and Ⅺ) displayed the inhibititory activities against the DNA topoisomerase Ⅳ . Conclusion Among all the isolated compounds, Ⅲ , Ⅶ-1 and 2, Ⅷ-1 and 2, and Ⅺ are separated for the first time both from the plant and the genus. Their bioactivities of bacteriostatic and against aldose reductase with DNA topoisomerase Ⅳ as target are tested for the first time and are related to the medicinal application of B. officinalis.