Facile Synthesis of Kwakhurin, a Marker Compound of <i>Pueraria mirifica</i> and Its Quantitative NMR Analysis for Standardization as a Reagent

Abstract

The side effects of kwao keur dietary supplements (obtained from the tuberous root of Pueraria mirifica) have recently been reported by the Ministry of Health, Labour and Welfare, Japan. To control the quality of kwao keur products, its ingredients need to be maintained by characteristic marker compounds, such as miroestrol, deoxymiroestrol, and kwakhurin (KWA). In this study, we described the facile synthesis of KWA, a marker compound of P. mirifica. Our revised synthetic method produced KWA with shorter steps and higher yield than the reported method. Furthermore, the absolute purity of KWA was determined by quantitative NMR analysis for standardization as a reagent, and its purity was 92.62 0.12%.

AI-Driven Synthetic Route Design Incorporated with Retrosynthesis Knowledge

“…Finally, the introduction of a nitrile group into the benzyl group of 18 would provide the target molecule 1 . Additional demonstrations for two other drug-like molecules, kwakhurin 47 and α7 nicotinic acetylcholine receptor silent agonist, 48 are shown in Figure 5 c,d and Figure 5 e,f, respectively. To confirm the difference in each step’s score between ReTReK with and without retrosynthesis knowledge, four retrosynthesis knowledge scores were added to each step in the synthetic routes ( Figure S5 ).…”

“… Comparison of the synthetic route for three target compounds (a,b) hepatitis B virus capsid inhibitor, 45 (c,d) kwakhurin, 47 and (e,f) α7 nicotinic acetylcholine receptor silent agonist 48 ) found by ReTReK with retrosynthesis knowledge (a, c, and e) and the corresponding route found without retrosynthesis knowledge (b, d, and f). …”

“…The Reaxys reaction database was used to construct the ReTReK model. We evaluated the performance of ReTReK using drug-like molecules − for demonstrations and molecules from the ChEMBL database for quantitative evaluations. We successfully demonstrated that synthetic routes designed using ReTReK with retrosynthesis knowledge were preferable to those designed without retrosynthesis knowledge.…”

Miroestrol Quantification in <i>Pueraria mirifica</i> Crude Drugs and Products by Single-Reference UPLC/PDA/MS Using Relative Molar Sensitivities to Kwakhurin

“…For reliable quantitative determination of an analyte using the single-reference method with RMS, it has been reported to be ideal to select the reference that has the same absorption maximum as the analyte for reducing the influence of differences in the absorption spectral resolution on the intensity of response from the detectors. 18) Because the absorption curve of KWA was relatively shallow from 280 to 300 nm, the detection wavelength for the RMS method was set at 285 nm, the absorption maximum of MIR. The peaks of MIR and KWA were confirmed in the negative mass with the selected ion monitoring (SIM) mode as deprotonated molecules [M − H] − at m/z 357 and 367 (Figs.…”

“…Atom numbering was determined according to references. 4,19) Quantitative signals are enlarged. To validate the RMS method for MIR quantification, MIR content in PM crude drugs and commercial products was calculated by a single-reference LC/PDA method with RMS using KWA as a reference standard, and the value was then compared with that obtained by the conventional absolute calibration method (Table 2).…”