Components from flower of Hylocereus polyrhizus (Weber) Britt. & Rose

Autor: Liang, Chih-Chiang, 梁志強
Rok vydání: 2018
Druh dokumentu: 學位論文 ; thesis
Popis: 106
The Pitaya (Hylocerus spp.), belongs to Cactaceae, is originally from the tropical rain forests in Mexico, Central and South America. H. undatus Britt.& Rose, H. polyrhizus (Weber) Britt.& Rose, H. costaricensis (Weber) Britt.＆Rose are three most common climbing cacti in Taiwan. The flower shape of pitaya fruit is huge, with the size ranging from 20-30 cm in length. It was first indicated as a herbal medicine in “Lingnan Herbal Medicine Record”, which indicated that the pitaya flower was used for the treatment of chest pain, managed cough and sputum. Therefore, these therapeutic effects were used to treat lung and respiratory diseases. In Taiwan, stem cropping and reducing the number of flowers are the common steps in order to improve the healthy and fruit quality. Therefore, these cropped stems and flowers have become agricultural by-produces and are usually discarded. Given that the pitaya fruit have been proved to be an effective herbal medicine in Chinese medicine, we speculate that we can extract and analyze the main effective ingredients of these agricultural by-products as novel therapeutic drugs in the future. In this study, we established a protocol of extraction and purification. We dried flowers of H. polyrhizus and pulverized and performed reflux extraction with methanol. After concentration, the partition extract was dissolved in water and partition with EtOAc to obtain EtOAc layer and water layer. The water layer was separated Diaion HP-20, LiChroprep RP-18e and Sephadex LH-20 column chromatography, Pre⁃HPLC. Five compounds, denoted as kaempferol 3-O-β-D- rutinoside (1), isorhamnetin 3-O-β-D-rutinoside (2), kaempferol 3-O-β-D-robinobioside (3), isorhamnetin 3-O-β-D-robinobioside (4), kaempferol 3-O-β-D-glucopyranoside (5), were isolated from the dried flower of H. polyrhizus. The chemical structures of these compounds were identified by nuclear magnetic resonance (NMR) spectra.The anti-oxidative activities were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2，2’-azino-bis -(3-ethylbenthiazoline-6-sulfonic acid (ABTS．＋) radical scavenging. The Torlox and Acarbose were used as positive controls. The results showed that partition’s DPPH scavenging activity were SC50: DMeOH layer 385.6±9.8 µg/ml. ABTS．＋ scavenging activity were SC50: DMeOH layer 98.7±0.8 µg/ml, EtOAc layer 428.9±24.3 µg/ml, methanol extract layer 550.4 ± 9.9 µg/ml, DH2O layer 628.4±9.3 µg/ml, Water layer 717.4±13.9 µg/ml. The compound 2 possessed potent ABTS．＋ scavenging activity (SC50 at 72.7 ± 3.22 µM) but not the other compounds. The antiglycation activities were also determined by α-glucosidase inhibitory assay. The partition extracts and all of 5 compounds did not showed α-glucosidase inhibitory effect. In addition, high-performance liquid chromatography (HPLC) method was developed to analyze the five major flavonoids in flower of H. polyrhizus. The analysis was performed using Purospher® STAR RP-18 endcapped HPLC columns (4 mm i.d. × 250 mn, 5 µm) with an isocratic mobile phase of 0.05 % trifluoroacetic acid-acetonitrile (86:14) at flow rate of 1.0 ml/min. The detection wavelength was set at 350 nm. The column temperature was maintained at 40℃, we made a calibration curve for five compounds. Other than that, we have also established an extraction method to extract flavonoid glycosides from H. polyrhizus flower by applying 20x (v/w of sample) of 75 % EtOH, and treated with ultrasound for 60 min to get the best yields. The yield of total content of five compounds flavone glycoside was 4.18 mg/g. By applying the above methods, we were able to detect the changes of flavonoid glycosides from flower buds to fully blossomed flowers (from day 3, 5, 7, 10, 12, 14). The results indicated that the contents of these five compounds increased from buds to fully blossomed flowers. The highest total content in the 14th day was 10.46 mg/g. We also compared the contents of these flavonoid glycosides from calyx, petal, stamen, pistil and receptacle (about 8-10 day). The result showed that the total content of five flavonoids in petal was 16.63 mg/g, with compounds 1 and 3 as the main components. Compared with other parts, Calyx was 4.07 mg/g, with compounds 2 and 5 as the main components. Stamen was 3.97 mg/g, with compounds 4 as the main components. Pistil’s was 3.97 mg/g. However, these five compounds were not found in the receptacle. The method can be used for the quality of the commercially pitaya flower.
Databáze: Networked Digital Library of Theses & Dissertations
Externí odkaz: