Studies On The Steroidal Alkaloids From The Fruits Of Solanum Nigrum L.

Solanum nigrum L.,an annual herb of the genus Solanum in the family Solanaceae,distributed throughout China with black and purple berries to be eaten directly or processed when ripe.The fruit is rich in anthocyanin,saponin,alkaloids,flavonoids,amino acids and trace elements.S.nigrum has anti-tumor,anti-inflammatory,antioxidant and antihypertensive effects in latest pharmacological research.The fresh berries of S.nigrum is also commonly used in the treatment of various tumors in clinical application at the same time.Most of the existing literature focuses on the chemical composition of steroidal saponins and steroidal alkaloids in the whole herb and steroidal saponins in the fruits of S.nigrum,as well as their corresponding pharmacological effects.Therefore,in this thesis,we selected the fruits of S.nigrum as the research object,and conducted a preliminary study on the chemical composition of steroidal alkaloids to investigate the in vivo efficacy of total alkaloids and to screen the biological activity of undescribed compounds.The 80%EtOH extract of the fresh ripe berries of S.nigrum was separated and purified by D151 macroporous resin,AB-8 macroporous resin,silica gel,ODS and preparative HPLC,and twenty-six compounds were isolated from the EtOH extract.The structures of nineteen ingredients were analysed and identified by physicochemical property,HR-ESI-MS,OR,IR and NMR spectroscopic techniques as:Solanigrine A(1),Solanigrine B(2),(3β,12β,22α,25R)-3,12-dihydroxy-spirosol-5-en-27-oic acid(3),solanigroside Q(4),12β,27-dihydroxy solasodine β-chacotrioside(5),12β,27-dihydroxy solasodine(6),Solasonine(7),Solamargine(8),Solasodine(9),Solanigrine C(10),Solanigrine D(11),Solanigrine E(12),Solanigrine F(13),Solanigrine G(14),Solanigrine H(15),Solanigrine I(16),Solanigrine J(17),Solanigrine K(18)and Solalyraine A(19),including eleven previously undescribed steroidal alkaloids(compounds 1-2 and 10-18).And compounds 19 was isolated from S.nigrum for the first timeLewis murine-derived lung cancer cells were selected to construct tumor models in the C57 BL/6J murine line to investigate the in vivo anti-tumor efficacy of the total alkaloids of S.nigrum.Cyclophosphamide(CTX)was selected for positive drugs.The total alkaloids of S.nigrum took 50,100 and 200 mg·kg-1 as low,medium and high dose groups,respectively.The tumor tissues were weighed and the tumor suppression rate was calculated after 14 d of continuous gavage administration.The tumor-inhibiting effect of different doses of the total alkaloids of S.nigrum was observed with the tumor-inhibiting rate of 57.44%in the high-dose group and 73.93%in the CTX group,and the results were statistically significant(P<0.01).To further investigate the in vitro antitumor and anti-inflammatory activities of the monomeric compounds isolated from the fresh ripe berries of S.nigrum,compounds 1-2,4-5 and 10-18 were selected and their screening for antitumor activity against human lung adenocarcinoma A549 cell line was evaluated by means of the CCK-8 method.The effect of compounds on LPS-induced NO release capacity of mouse mononuclear macrophage leukemia cells was determined by Griess method.Both of the previously isolated compounds inhibited the proliferation of A549 cells in a dose-dependent manner,but neither reached IC50 at 50 μM.These results revealed that S.nigrum had weak cytotoxicity.The results of the Griess experiments also showed a weak anti-inflammatory activity of the compounds in a dose-dependent manner,except 1,2,4 and 5 which showed obvious anti-inflammatory effects.The present study has preliminarily elucidated the pharmacological basis of the anti-tumour activity of S.nigrum fruits,providing a number of scientific basis for its safe and rational clinical use.