Extraction And Isolation Of Saponins From The Stem And Leaf Of Monordica Chararntia And Its In Vitro Activity

Monordica charantia, which has been researched extensively by scholars as a medicinal and edible plant in recent years. Monordica charantia is rich in many chemical active components, including saponins, steroids, proteins and polypeptides, alkaloids, carbohydrates, flavones, organic acids, trace elements, amino acids, vitamins and so on. It also have various pharmacological effects such as antidiabetic, antivirus, antitumor, antioxidant, antibacterium, antifertility, anti-inflammatory, immunoregulation, antihypertensive. Monordica charantia has become popular and in high demand because of its medical benefits, drawing great attention of scholars at home and abroad. However, the chemical active components and pharmacological effects of stem and leaf of Monordica charantia study is less, which have plenty of saponins and pharmacological activity significantly, with a high development and utilization value.A method was established to isolate saponin from the stem and leaf of momordica charantia. The objectives of this study are to investigate the antioxidant, anti-cancer and hypoglycemic activity of saponin in DPPH and ABTS+ radical, HepG2 cell, a-glycosidase. The dissertation is constituted by following parts:(1) Separation and extract saponin from the stem and leaf of momordica charantia: To obtain different components, the stem and leaf of momordica charantia extract with petroleum ether, ethyl acetate, n-butanol were prepared by 70% ethanol. By AB-8 Macroporous resins system separating saponins, get a good results. Macroporous resins fraction which was rich in saponins and the content is about 84.38 mg/g. The purified saponin was subjected to a series of chromatography on silica gel column and semi-prepartive HPLC to yield Momordicoside L and Momordicine IV, which were identified by 1H-NMR and 13C-NMR.(2) To evaluate the anti-oxidant and cytotoxicity activity of saponins in vitro: DPPH and ABTS+ radical scavenging capacity were carried out to evaluate the anti-oxidant capacity of saponins. The results show that the DPPH radical scavenging capacity arrangement is Vc> n-butanol> ethyl acetate> petroleum ether> ethanol extract> Macroporous resins> Momordicoside L> Momordicine Ⅳ. ABTS+ radical scavenging capacity arrangement is Vc> n-butanol> ethyl acetate> Macroporous resins> petroleum ether> Momordicine Ⅳ> ethanol extract> Momordicoside L. In general, n-butanol component has higher anti-oxidant activity, but Momordicoside L and Momordicine Ⅳ almost no inhibitory effect, indicating that the anti-oxidant capacity is very weak. Using HepG2 cancer cell as the model cells to study the effect of saponins on anti-HepG2 by the MTT method. N-butanol and macroporous resins fractions, IC50s are 386.63 and 303.22 μg/mL, respectively. Momordicoside L and Momordicine Ⅳ, IC50s are 6.60 and 10.26 μg/mL. Separation of monomer inhibition of HepG2 cells was significantly greater than the total saponins.(3) α-glycosidase inhibitory activity of saponins:we studied the inhibitive effects of saponins on α-glycosidase by using enzyme-inhibitor model and investigated the inhibitiory kinetic characteristics by using Lineweaver-Burk method. In 0～800 μ,g/mL concentration range, Momordicoside L and Momordicine IV have higher inhibition effect. When the inhibitor concentration in 800 μg/mL, Momordicoside L has a stronger inhibition effect than the acarbose and Momordicine Ⅳ same as acarbose. Inhibitory kinetic results indicated that Momordicoside L and Momordicine Ⅳ were competitive inhibitors. According to Michaelis-Menten equation, get the Michaelis constant Km increases, Vmax unchanged, also accord with the characteristics of competitive inhibition.