Studies On Isolation, Structure Modification And Pharmacological Activities Of Saponins From The Leaves And Stems Of Panax Quiquefolium L. Cultivated In China

The investigation on the saponin composition of leaves and stems of Panax quiquefolium L. cultivated in Fusong county of Jilin province has resulted in the isolation and structure elucidation of three new dammarane saponins named quinquenoside A (4) , quinquenoside B (9) , quinquenoside C (22) , along with twenty-three known compounds :ginsenoside Rb₁ (2) ,-Rb₂ (17) ,-Rb₃ (7) ,-Rc (1) ,-Rd (3) ,-F₂ (11) ,20 (S) -Rg₃ (23) ,20 (R) -Rg₃ (26) ,20 (S) -Rh₂ (13) ,20 (R) -Rh₂ (14) ,-Rg₁ (19) ,20 (S) -Rg₂ (15) ,20 (R) -Rg₂ (16) , -Re (8), -F₁(20), 20(S)-Rh₁(5), 20(R)-Rh₁(6), -Rg₆(21), gypenoside IX(10), psuedo-ginsenoside F₁₁ (24) ,-RT₅ (12) , notoginseoside Fe(25), majoroside F₄(18) .Their structures were established on the basis of chemical and spectral (IR, MS,¹³C-NMR, ¹H-NMR, HMBC, HMQC, DEPT, ¹H- ¹H COSY) evidences.With comlinatorial chemistry, we prepared not only 20 (S)-ginsenoside Rg₃, 20 (R)-ginsenoside Rg₃,20 (S)-ginsenoside Rh₂,20 (R)-ginsenoside Rh₂ and 20 (S)-protopanaxadiol by hydrolysis of panaxadiol saponins, but also 20 (S)-ginsenoside Rg₂,20 (S)-ginsenoside Rh₁ and 20 (S)-protopanaxatriol by hydrolysis of panaxatriol saponins. In the same time, three new ocotillol-type sapnonis named PGQ(27), PHQ(28), PDQ(29) were successfully transformed from ginsenoside Rg₃, Rh₂ and protopanaxadiol respectively, and their structures were elucidated by means of spectral data analysis. The mechanism of the oxidation and cyclization of the side chain was firstly discussed in this dissertation.The pharmaceutical activities of anti-hemorrhagic shock and anti-acute myocardial injury of PGQ, one of the new ocotillol-type saponins, were studied respectively as follows:Firstly, the dogs were exsanguinate from the femoral artery until the mean blood pressure (MBP) fell less than 5.33Kpa, resuscitation with i.v. 4.0 mg·kg^-1,2.0mg·kg^-1 of PGQ ,the result showed that PGQ had the statistical effects of anti- hemorrhagic shock compared with control group (p<0.05, p<0.01).Secondly,the Wistar rats were intravenous injected with PGQ 6.0mg·kg^-1,12.0mg·kg^-1 before injected with ISO (2.0mg·kg^-1) which induce myocardial ischemia injury, the ST-segment elevation could be decreased by PGQ significantly(p<0.05,p<0.01).The results showed that PGQ had ameliorative effects on acute myocardial injury electrocardiogram induced by isoproterenol(ISO).