Preparation Of Antihypertensive Effective Fractions Of Eucommia Ulmoides Oliv. And Its Hypotensive Effect Study

Aim: To prepare lignans fraction and iridoids fraction from Eucommiaulmoides Oliv., and to evaluate their hypotensive effect single and together, tofind out the main fractions for antihypertension.Method: Using ethanol extracting, macroporous resin sticking, water orethanol eluotropic method to enrich lignans and iridoids components inEucommia ulmoides Oliv. To isolate pinoresinol glucoside (PDG) monomer bySephadex LH-20, RPC-C18. To determine the content of effective fractionand monomer using UV and HPLC method. To investigate their hypotensiveeffect on norrnotensive SD rats and SHRs after they were administrated byintravenous injection or intragastfic gavage. Blood pressure was measureddirectly in carotid artery or by the tail-cuff method.Results: The purity of PDG monomer we isolated was 98.8％. Thecontent of the lignans and the iridoids prepared from Eucomrnia ulmoides Oliv.were 70％and 60％respectively, reach the standard of Chinese traditionalnew medicine type 5. Our pharmacodynamic experiment show thatintravenous administration of 30, 60 mg·kg^-1Eucommia ulrnoides Oliv. lignansdecreased SD rats blood pressure dose-dependently (P＜0.05), the maximaleffects produced by 30, 60 mg/kg were 37±9, 57±4 mmHg respectively andthere were significant difference between them (P＜0.05) ; but there is noeffect with 15～60 mg·kg^-1Eucommia ulmoides Oliv. iridoids. The hypotensiveeffect produced by the lignans and the iridoids together have no significantdifference with the single lignans (P＞0.05). Oral administration of 150, 300mg·kg^-1·d^-1Eucommia ulmoides Oliv. lignans also decreased SHRs bloodpressure dose-dependently (P＜0.05). The regimen of twice a day has agood hypotensive effect and a steady effect was reached at d 4 afteradministration. The maximal effects produced by 150, 300 mg·kg^-1·d^-1were 15±6,36±9 mmHg respectively and there were significant difference betweenthem (P＜0.05); and there is no effect with 125 mg·kg^-1·d^-1 Eucommiaulmoides Oliv. iridoids; and the hypotensive effect produced by the lignansand the iridoids together have no significant difference with the single lignans(P＞0.05) Conclusion: The content of the lignans and the iridoids prepared fromEucommia ulmoides Oliv. were 70％and 60％respectively, reach the standardof Chinese traditional new medicine type 5. Eucommia ulmoides Oliv. lignanshave dose-dependently hypotensive effect. Eucommia ulmoides Oliv. iridoidshave no hypotensive effect. The combination of them produces no synergisticeffect. Eucommia ulmoides Oliv. lignans is the main effective fractions forantihypertension.