Variations in chemical fingerprints and major flavonoid contents from the leaves of thirty‐one accessions of Hibiscus sabdariffa L.

The leaves of Hibiscus sabdariffa L. have been used as traditional folk medicines for treating high blood pressure and fever. There are many accessions of H. sabdariffa L. throughout the world. To assess the chemical variations of 31 different accessions of H. sabdariffa L., fingerprinting analysis and quantitation of major flavonoids were performed by high‐performance liquid chromatography (HPLC). The HPLC method was validated for linearity, sensitivity, precision, repeatability and accuracy. A quadrupole‐time‐of‐flight mass spectrometry (Q‐TOF‐MS) was applied for the characterization of major compounds. A total of 9 compounds were identified, including 6 flavonoids and 3 phenolic acids. In the fingerprint analysis, similarity analysis (SA) and principal component analysis (PCA) were used to differentiate the 31 accessions of H. sabdariffa L. Based on the results of PCA and SA, the samples No. 15 and 19 appeared much different from the main group. The total content of five flavonoids varied greatly among different accessions, ranging from 3.35 to 23.30 mg/g. Rutin was found to be the dominant compound and the content of rutin could contribute to chemical variations among different accessions. This study was helpful to understand the chemical variations between different accessions of H. sabdariffa L., which could be used for quality control. © 2015 The Authors Biomedical Chromatography Published by John Wiley & Sons Ltd.     

Triterpenoids from the Mangrove Plant Hibiscus tiliaceus

Three new triterpenoids with the rarely occurring nigrum skeleton, namely (20E)‐22‐hydroxynigrum‐20‐en‐3‐one ( 1 ), 21β‐hydroxynigrum‐22(29)‐en‐3‐one ( 2 ), and 21α‐hydroxynigrum‐22(29)‐en‐3‐one ( 3 ), were isolated from the mangrove plant Hibiscus tiliaceus. Additionally, five known triterpenoids including friedelin ( 4 ), 12‐oleanen‐3β‐ol ( 5 ), 3β‐hydroxy‐12‐oleanen‐28‐oic acid ( 6 ), 20(29)‐lupen‐3β,28‐diol ( 7 ), and cucurbita‐5,23‐dien‐3β,25‐diol ( 8 ) were also isolated and identified. The latter structures were elucidated by a detailed NMR and MS analyses, as well as by comparison with reported literature data.     

紫荆花与玫瑰茄微量元素含量的比较研究

首次报道紫荆花十种微量元素含量，并与玫瑰茄作了含量比较研究．     

扶桑花与玫瑰茄微量元素含量的比较研究

测定了扶桑花十种微量元素含含量，并与玫瑰茄作了含量比较研究。     

Analogues of the Quararibea metabolite chiral enolic-γ-lactone from (2S,3S)- and (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylic acids

Reaction of dialkyl (2S,3S)- or (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylates with POCl₃ in pyridine followed by diazomethane resulted in the isolation of dialkyl 2S-4-methoxy-5-oxo-2,5-dihydro-2,3-furandicarboxylates, which are analogues of the Quararibea metabolite chiral enolic-γ-lactone (3-hydroxy-4,5-(R)-dimethyl-2(5H)-furanone). An unusual α-hydroxylation of γ-butyrolactone takes place involving POCl₃ in pyridine. When the dehydration was facilitated with methanesulfonyl chloride in triethylamine, instead of POCl₃, aromatic dialkyl 5-[(methylsulfonyl)oxy]-2,3-furandicarboxylates were obtained.